WZVJ THE BRYO-GEOGRAPHY OF SOUTHEASTERN ALASKA by IAN ALMER WORLEY B.A., Youngstown University, 1 9 6 U B.S., Youngstown University, 1 9 6 U M.Sc, The University of Canterbury, New Zealand, 1 9 6 6 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in the Department of Botany We accept this thesis as conforming to the required standard. THE UNIVERSITY OF BRITISH COLUMBIA January, 1 9 7 2 THE BRYO-GEOGRAPHY OF SOUTHEASTERN ALASKA by IAN ALMER WORLSY B.A., Youngstown University, 1964 B.S., Youngstown University, 196U M.Se., The University of Canterbury, New Zealand, 1966 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in the Department of Botany We accept this thesis as conforming to the required standard. THE UNIVERSITY OF BRITISH COLUMBIA January, 1972 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make i t freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the Head of my Department or by his representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of The University of British Columbia Vancouver 8, Canada i i ABSTRACT Thi s i n v e s t i g a t i o n presents a bryo-geographical study o f the Alexander Archipelago and the adjacent mainland o f southeastern A l a s k a . A f l o r a c o n t a i n i n g the 572 t a x a o f hryophytes now known from south-e a s t e r n A l a s k a (67.5 percent o f the known Alaskan b r y o f l o r a ) has been compiled from p u b l i s h e d records and 10,901 c o l l e c t i o n s made by the author. These specimens were obtained from 130 s i t e s during an accumulated f i e l d time o f 40 weeks from 1966 through 1969. There are i n c l u d e d 38 t a x a new t o the s t a t e and 94 which are new t o south-e a s t e r n A l a s k a . The l o c a l d i s t r i b u t i o n o f each taxon has been c i t e d f u l l y e i t h e r w i t h i n the t e x t or as a d i s t r i b u t i o n map. H a b i t a t , b i o l o g i c a l , taxonomic, and d i s t r i b u t i o n a l i n f o r m a t i o n are given f o r each e n t r y . The most s i g n i f i c a n t components o f the f l o r a are t r e a t e d w i t h i n 27 geographical elements. There are probably no bryophytes endemic t o southeastern A l a s k a . Of the t o t a l b r y o f l o r a , t a x a w i t h widespread d i s t r i b u t i o n s comprise ca. 74 percent, northern P a c i f i c B a sin t a x a c o n s t i t u t e ca. 16.8 percent (over one h a l f o f these are western North American endemics), ca. 5«4 percent o f the f l o r a belongs t o the western North American - western Eurasian d i s j u n c t i o n , and ca. 3.8 percent o f the t o t a l d i s p l a y s l e s s d i s t i n c t o r i n d i v i d u a l d i s t r i -b u t i o n p a t t e r n s . The r e g i o n a l f l o r a i s not p a r t i c u l a r l y d i s t i n c t i v e , i s com-i i i posed p r i m a r i l y o f broad endemics or p l a n t s o f widespread ranges, and i s a p o r t i o n o f the cool-temperate, oceanic geographical zone th a t extends from the northern G u l f o f A l a s k a t o Vancouver I s l a n d . Southeastern A l a s k a l i e s w i t h i n the northern p o r t i o n s o f the p r i n c i p a l zone o f western North American endemism. The bulk o f the f l o r a i s o f temperate, c o o l temperate .and.. b o r e a l o r i g i n s w i t h exceedingly few t a x a having t r o p i c a l , subtrop-c i a l , o r a r c t i c a f f i n i t i e s . I t has been d e r i v e d p r i m a r i l y from a widespread A r c t o - T e r t i a r y f l o r a which has been d i s s e c t e d and has re-expanded w i t h the f l u c t u a t i n g events o f the P l e i s t o c e n e . Taxa o f the North P a c i f i c Arc represent a d i v e r s i t y o f d i s t r i b u t i o n a l p a t t e r n s which tends t o fa v o r a recent h i s t o r y o f p o s t - P l e i s t o c e n e expansion from l o c a l r a t h e r than from t r a n s - P a c i f i c sources. S e v e r a l t a x a , p r i m a r i l y h e p a t i c s o f hyperbeeanic h a b i t a t s , d i s p l a y d i s j u n c t ranges wherein c e r t a i n l o c a l populations are p o s t -u l a t e d t o be e s s e n t i a l l y r e l i c t . L o c a l r e f u g i a o f undetermined age e x i s t on the e l e v a t e d marine t e r r a c e s northward from I c y P o i n t t o the v i c i n i t y o f Yakutat Bay. Mountain nunataks were not probable as important r e f u g i a during maximum g l a c i a t i o n s , but seaward head-lands o f the outer i s l a n d s , s t r a n d f l a t s , and exposed p o r t i o n s o f the c o n t i n e n t a l s h e l f a l s o may have served as r e f u g i a and supported d i v e r s e communities. A zone o f s i g n i f i c a n t l y wetter c l i m a t e extends along the iv outermost coast and adjacent to the Dixon Entrance. Over three percent of the local flora (mostly hepatics) are restricted to the zone and are diagnostic of that environment. Areas of drier climate occur within rainshadow zones of the archipelago, along the con-tinental Boundary Ranges, and in the upper Lynn Canal complex. The last region may he especially sensitive to climatic change and an immigration route between the oceanic and continental f l o r i s t i c areas. Relict populations of bryophytes (primarily mosses) from Hypsithermal time persist i n specialized habitats in the archipelago within the drier zone. V TABLE OF CONTENTS CHAPTER PAGE I. INTRODUCTION 1 Objectives and Methods 1 The Study Area 10 Geology and Geomorphology 10 Vegetation 24 II. CLIMATE AND CLIMATIC EFFECTS UPON BRYOPHYTE DISTRIBUTIONS 28 III. VEGETATION TYPES OF SOUTHEASTERN ALASKA WITH ESPECIAL REFERENCE TO THE BRYOPHYTES 46 Introduction 46 Maritime Communities 50 Shoreline Sites 50 Raised Beaches 51 Rock Environments 52 Tide-influenced Meadows 52 Wharfs 53 Aquatic and Wetland Communities 53 Lakes and Fluvial Rocks 53 Streambanks 54 Pool, Pond, and. Lake Margins 54 Slope Drainage Sites 55 Marshes 56 vi Peatlands 56 Forest Communities 58 Trunks of Trees 59 Branches and Twigs 60 Forest Floors 6 l Dead and Decomposing Wood 6 l Roots of Windthrows 63 Humid and Wet Cliffs 63 Dry and Mesic Cliffs 6k Calcareous Cliffs 65 Subalpine and Alpine Communities 66 Communities on Exposed Mineral Substrates 67 Exposed, Moist and Wet Rock 68 Exposed, Dry Rock 68 Exposed, Dry, Calcareous Rock 69 Sand, Gravel, T i l l , and Mineral Soil 70 Road Cutbanks 71 Successional Communities 71 IV. BRYO-GEOGRAPHY 76 Introduction 76 New Records 81* New to Alaska 84 New to Southeastern Alaska 89 v i i i B. Distributions within Western North America . . . . 128 Categories: 128 16. Widespread 128 17. Oceanic 129 18. Interior 131 19. Hyperoceanic 134 C. Distributions within Southeastern Alaska 146 Categories; 146 20. Widespread 146 21. Wet Climate Zone 148 22. Dry Climate Zone 150 23. Northern Distribution in Southeastern Alaska 157 24. Southern Distribution in Southeastern Alaska 160 25. Northern Limit of Distribution in Southeastern Alaska 162 26. Southern Limit of Distribution in Southeastern Alaska 164 27. Limited Records in Southeastern Alaska . . 167 V. POSSIBLE LOCAL REPUGIA WITHIN SOUTHEASTERN ALASKA . . . l68 VI. SUMMARY 187 BIBLIOGRAPHY 194 APPENDIX A. The Bryophyte Flora 223 ix Hepaticae 228 Musci 332 APPENDIX B. Geographical Lists, Bryophytes 556 APPENDIX C. Selected Vascular Plant Distributions 600 APPENDIX D. Note on the Nomenclature of Plagiothecium and Related Genera 611 • APPENDIX E. Collections of F. J. Hermann 612 APPENDIX F. Abbreviations used to Designate Geographical Categories 6lU APPENDIX G. Addendum 6l6 APPENDIX H. Map of Southeastern Alaska 6l7 MAPS Selected Southeastern Alaskan Bryophyte Distributions. 6l8 X LIST OF TABLES TABLE PAGE I. R a i n f a l l v a r i a t i o n w i t h a l t i t u d e i n the v i c i n i t y o f Juneau, A l a s k a 36 I I . Numbers o f t a x a and percents o f the southeastern Alaskan hryophyte f l o r a i n each geographical category 85 xi LIST OF FIGURES FIGURE PAGE 1. Sites of bryophyte collections made in this study . . . . 5 2. Previously published sites of bryophyte collections included in this thesis 6 3. A l l sites of bryophyte collections included in this thesis 8 4. Physiographic divisions of southeastern Alaska 12 5. Climatic zones in southeastern Alaska (generalized) . . . 32 6. Rainfall variation with altitude in the vicinity of Juneau, Alaska 38 J. Generalized annual precipitation zones in southeastern Alaska 39 8. Combined distributions of some "Dry Climate" vascular plant species Ul 9. Combined distributions of some "Dry Climate" bryophyte taxa 42 10. Combined distributions of "Wet Climate" bryophyte taxa . 43 11. Combined distributions of "Dry Climate" and "Wet Climate" taxa 44 12. Areas of possible Pleistocene refugia in southeastern Alaska 172 x i i ACKNOWLEDGEMENTS My thanks are extended to Dr. W. B. Schofield for assistance throughout the preparation of this thesis, and for funding through the National Research Council of Canada. Appreciatively recognized are the day by day efforts and companionship extended by my field assistants Stephen Thorpe, Gordon Hamilton, Frank Boas, and Jon Rawson. I am particularly grateful for the contributions of Mr. Boas whose field abilities and observations are outstanding. The important contributions from Glacier Bay National Monument would not have been undertaken without the impetus and assistance of Professor Donald Lawrence whose advice and encouragement have been thankfully received throughout this study. Within southeastern Alaska technical and logistic support has been given by many Individuals. In particular, thanks are to be ex-tended to Robert Howe, superintendent of Glacier Bay and Sitka National Monuments, Charles Janda, Chief Ranger of Glacier Bay National Monument, Richard Hurd, former director of the Institute of Northern Forestry, A. S. Harris, of the United States Forest Service, Mac Hammer of Saginaw Bay, and Tony Gasbarro, of the United States Forest Service. Mr. D. M. Bishop has been especially helpful with the interpretations of the climatic data. Drs. T. Amakawa, H. Crum, R. Grolle, E. Lawton, M. Mizutani, x i i i A. J. Sharp, and especially Drs. S. Hattori and Z. Iwatsuki have given kind assistance with the determination of certain difficult taxa. This thesis is written in the memory of the late F. R. Stephens whose imagination and contributions to the ecology of the Tongass are sorely missed. It i s dedicated to Greg Streveler of the National Park Service whose enthusiasm, devoted involvement, and astute sense of the natural endowment of southeastern Alaska have been a continuing personal inspiration. 1 CHAPTER I INTRODUCTION I. OBJECTIVES AND METHODS The i n i t i a l objective of this study was to prepare a bryo-geographical study of the Alexander Archipelago of southeastern Alaska based upon published records and personal collections. As the i n i t i a l literature, map, and f i e l d work progressed a subsequent enlargement of the study area was necessitated in order to include the adjacent mainland of the southeastern Alaskan "panhandle". Although numerous specimen citations had been published from the region the structure of the bryoflora appeared to be only imper-fectly known, and many additional taxa seemed yet to be discovered and reported. Furthermore, the frequency and extent of local d i s t r i -butions of the majority of taxa were unkown. Consequently, extensive f i e l d work was proposed to provide data and specimens to assist in the following objectives: 1) the compilation of a bryoflora for southeastern Alaska including new f i e l d data and published material, 2) the determination of the geographical a f f i n i t i e s of the southeastern Alaskan bryophyte fl o r a and of individual taxa, 2 3) the determination of distribution patterns within south-eastern Alaska and their possible origins and derivations, h) the outlining of the bryophyte constituents and bryophyte compositions in the major ecosystems, communities and vegetation types of southeastern Alaska, 5) the interpretation of the principal gross ecological influences upon the composition of the bryoflora and upon its local distributions, 6) the interpretation of the historical influences upon the composition of the bryoflora and upon its local distri-butions , 7) the suggestion of possible post-Pleistocene sources for the elements of the bryoflora, 8) the evaluation of the possibility of local, Pleistocene refugia from geological, geomorphological and biological evidence. The field work was initiated during December of 1966 when 286 collections were made from Coronation, Baranof and Volga Islands from the Canadian Navy Auxiliary Research Vessel Laymore during an algal survey being conducted under the direction of Dr. R. F. Scagel of the University of British Columbia. Field work during the summer of 1967 lasted from 5 July to 12 September. The author and assistant (Stephen Thorpe) traveled by car 3 to Prince Rupert, British Columbia and then by Alaskan State Ferrys ' to Ketchikan, Sitka, Juneau and Haines. Collections were made along the road systems of these towns, and charter aircraft were utilized to reach Plotnikof and Diana lakes of Baranof Island, and Fred's Creek region of Kruzof Island. Joint collection trips were made with Drs. Z. Iwatsuki and A. J. Sharp at Sitka and Lake Diana. One thousand seven hundred six collections were made in the research area. The field season of 1968 (3 May to 13 September) included the communities of Ketchikan, Craig, Klawak, Cape Pole, Wrangell, Peters-burg, Sitka, Juneau, Douglas, Gustavus, Bartlett Cove, Haines, Port Chilcoot and Klukwan. Six thousand one hundred seven collections were made, plus an additional 63 gathered along the Haines and Alaskan Highways. Gordon Hamilton and, later, Franklin Boas were the re-searcher's assistants. A brief trip from Wrangell to Telegraph Creek and return was made by river boat. Some two weeks were spent in Glacier Bay on a variety of successional terrain from stagnant ice termini to mature muskeg slopes (Reiners, Worley, and Lawrence, 1971)• The project advisor, Dr. W. B. Schofield joined the party in Peters-burg and assisted at Saginaw Bay on Kuiu Island. The final field season lasted from 20 June to 10 August 19&9 concentrating within Glacier Bay National Monument. Additional collections were made near Juneau and Sitka, but extended foul weather and lack of funds cancelled proposed trips to sites on the southern k outer coast of Baranof Island. The assistant was Jon Rawson, and 976 collections were added. A total of 10,901 collections from approximately 130 sites (see Fig. 1) were made during an accumulated field time of kO weeks. The specimens were dried in the field in a special drier heated "by gasoline fueled space heaters, and the majority were pack-aged and mailed to the University of British Columbia. The material was sorted and put into herbarium packets. Determinations were made by the author under the guidance of Dr. W. B. Schofield with the assistance of the Herbarium of the University of British Columbia. Various difficult taxa were also assessed by Drs. T. Amakawa, H. Crum, M. Fulford, R. Grolle, S. Hattori, Z. Iwatsuki, and M. Mitzutani. Voucher specimens are housed in the University of British Columbia Bryophyte Herbarium with duplicates, as available, distributed to major bryophyte herbaria. A set of voucher specimens from Glacier Bay National Monument are to be housed at its headquaters. The distribution maps were compiled from these collections, from material housed in the University of British Columbia Herbarium, and from published records. Figure 2 maps the collection sites of previous reports and herbarium material included in this thesis. No attempt was made, due to inadequate time available, to examine other herbaria or personal collections. The recent collections of F. J. Hermann (see Appendix E) will soon be published (personal communication). 5 D I X O N E N T R A N C E F i gu re 1 Sites o f bryophyte co l l ec t i on s in th i s s t u d y 6 D I X O N E N T R A N C E Figure 2 Previously published sites of bryophyte collections included in this thesis 7 Figure 3 maps a l l the collection sites included in this thesis. A brief history of bryology for Alaska has been presented by Worley (1970) and Worley and Iwatsuki (1970). Although the first major bryophyte collections from southeastern Alaska did not begin until 1899 with the Harriman Expedition there were several earlier reports; notably the scattered collections of Hazen and Turner (1886) made in the years 1874-81, the expedition of the Krause brothers in 1881-82 in the Lynn Canal district which was reported by Kurtz (1895) and Stephani (1887), Cooley's (1892) collections of 1891 from near Juneau (also reported by Underwood, 1892), and the collections of Funston from Yakutat which were determined by Evans and reported by Coville (I896). Important collections from Canadian sites near Skagway and the White and Chilkoot Passes were reported by R. S. Williams (1901, 1903) (see also Harvill, 1950). Evans (1900) reported the hepatics collected by the Harriman Expedition of 1899 which visited several coastal sites in southeastern Alaska; the mosses were discussed by Cardot and Theriot (1902). The principal bryophyte investigator aboard the Kelp Expedition of 1913 was Frye who collected more than 1000 packets from coastal sites. Evans re-ported some of these in his "Hepaticae of Alaska" (Evans, 1914) along with collections made by Foster, Riggs, and Wylie. Holzinger and Frye (1912) later presented the moss data from the Kelp Expedition. There were then no major bryophyte investigations for several decades a l -8 D I X O N E N T R A N C E Figure 3 All sites of bryophyte collections included in this thesis 9 though incidental collections, primarily from the vicinity of the larger communities, accumulated slovly in various herbaria. Cooper (I923a,b,c, 1931, 1939) included bryophyte data in his several im-portant ecological investigations at Glacier Bay. Bartram (1938) reported some southeastern Alaskan material from his collections and those of Eyerdam (see also Eyerdam, 1952, 1955)* In 1932 Hulten began his intensive Alaskan studies of the vascular flora. Shortly thereafter Herman Persson initiated a pro-l i f i c series of important bryophyte reports (see Bibliography) from throughout the territory, many dealing with the southeastern district in particular. Although never having visited Alaska, Persson has managed to produce a fine picture of the basic bryoflora, making many significant discoveries in the packets of other collectors and from the vascular plant herbarium sheets of Hulten and others. Additional important reports are those by Clark and Frye (1942), Frye and Clark (1937-47), Lawton (1957), Schofield (1956, 1965, 1968a,b, 1969b), Stair (1947) and Shacklette (1961, 1965). In 1948 Harvill completed a doctoral dissertation on the geography of mosses in Alaska based upon published reports, herbarium material, and some personal collections from central Alaska. This compilation included a few new citations from southeastern Alaska, although i t was essen-tia l l y a literature based study. Significant recent collections from the region include those made by Iwatsuki and Sharp (1968) in I967, Hermann (see Appendix E), and Neiland (during ecological studies made in recent years) of the 10 University of Alaska (Neiland, personal communication). II. THE STUDY AREA Geography and Geomorphology Southeastern Alaska forms the northeastern margin of the Gulf of Alaska along the fiordland of cool-temperate North Pacific North America (see Appendix H for a map of the region). The primary study area is roughly rectangular with its long axis SE-NW, and extends from the mouth of the Dixon Entrance (ca., 5U°40' N, 133° W) and Hyder (ca., 55°50' N, 130° W) northward to Cape Fair-weather (ca., 58°50' N, 138° W) and the mountain summits north of Skagway (ca., 59°U0' N, 135°30* W). For certain aspects of this thesis (eg., species distributions) the area is considered to include the narrow strip of mainland Alaska from Cape Fairweather to Yakutat Bay (ca., 59 o l+0' N, 139°40' W). In a l l , i t is over U00 miles long by 100-150 miles wide with an assemblage of islands, channels and fiords bordered by a strip of mountainous mainland to the east and north. Over 95 percent of this area is Federally administered, the largest unit being Tongass National Forest. Most of the Fairweather Range — Glacier Bay region forms Glacier Bay National Monument. Southeastern Alaska is fully mapped in detail by the U. S. Geo-logical Survey in their topographical series 1:250,000 (also available in shaded relief) and 1:63,360w Orth (1967) has presented a dictionary 11 of Alaskan place names. These, plus the map of Tongass National Forest published by the U. S. Forest Service (Appendix H) includes nearly a l l locations cited in this thesis. Wahrhaftig (196"5) has utilized eight physiographic units to describe the essentail geomorphic character of this portion of Alaska (see Fig. U). The coastal Cordillera that dominates the North Pacific coastlands from the Cascades of Washington to the southern Yukon define the eastern boundary of southeastern Alaska. Along the Alaskan -British Columbia border these mountains are known as the Boundary -Ranges. Seaward of this distinctive range is an intermediate zone of coastal foothills, below which is a region of islands of somewhat subdued relief and lowlands (the Kupreanof Lowland of Wahrhaftig, 1965). Beyond this trough (Bostock, 1948) and the Chatham Trough (Wahrhaftig, 1965) rises another rugged, although generally low, range of mountains represented by the Prince of Wales Mountains in the south-ern portion of the archipelago, and by the Chilkat - Baranof Island Mountains in the north. In the northwest portion of southeastern Alaska the Fairweather mountains form a distinct province which con-tinues northward as a part of the St. Elias Ranges. A southern ex-tension of the Gulf of Alaska Coastal Section (Wahrhaftig, 1965) occurs as lowlands seaward of the Fairweather Mountains and on western Chichagof Island. The Boundary Ranges, and their southward extension, the Coast 12 F i g u r e 4 Phys iog raph ic d i v i s i o n s o f s o u t h e a s t e r n A l a s k a ( A f t e r W a h r h a f t i g , 1 965 ) 13 Ranges of British Columbia, are an uplifted batholith that forms an essentially continuous barrier between the coast and the interior plateaus, broken only by occasional river valleys; notably the valleys of the Taku, the Stikine, and tb the south in British Columbia the Nass, theSkeena, and the Fraser. Along the westward edge of the massive intrusion a complex sequence of metamorphics occur (Hutchin-son, 1970). The intense glaciations of the Pleistocene have created the present strong profiles and rugged topography. Numerous horns and aretes rise sharply above icefields and valley glaciers, the highest in Alaska being Kate's Needle (10,002 f t . ) . Extensive neves and large alpine icefields (Henoch and Stanley, 1967a) l i e astride the range throughout its Alaskan segment, especially the area northwest-ward of the Stikine Valley, and the Taku Icefield, the latter covering nearly 700 square miles (Field and Miller, 1950). The southernmost (56°U5' N) tidewater glacier in North America is the Le Conte which calves into Frederick Sound southeast of Peters-burg. Of the numerous fiords penetrating the system, the Portland Canal is particularly outstanding for its length, some 70 miles, while Tracy Arm and Ford's Terror are classic examples with narrow channels, towering walls, and cascading falls from hanging valleys. The bifur-cation of the head of the Lynn Canal leads to important passes in the northernmost corner of southeastern Alaska: a) Chilkoot and White Ik Passes are the extension of the Chatham Strait — Lynn Canal — Chilkoot Inlet — Taiya Inlet — Taiya Valley lineament; and, b) Three Guardsmen and nearby passes extend from the Chilkat Inlet and the valleys of the Klehini and Chilkat Rivers generally parallel to the NW-SE ranges. To the vest of the Coast and Boundary Ranges is a correspond-ing, but intermittent, zone of downwarping, best expressed to the south of Alaska in Hecate Strait, Queen Charlotte Sound, the Strait of Georgia, and Puget Sound. In southeastern Alaska this province is less veil demarked, but is apparent northward through Clarence Strait and eastern Prince of Wales Island to southwestern Admiralty Island. The emergent portions of this complex are islands of gentle relief and low elevation, the greatest single expanse being the westward portion of Kupreanof Island and adjacent Admiralty and Kuiu Islands. The surface topography of this region has been highly modified by Pleistocene ice loads, and streamlined glacial features (eg., drumlins, "lee and stoss" sculpturing, roches mountonees, etc.) are common. The bedrock geology of this zone is intricate and involved, noteworthy for outcrops and cli f f s of massive limestone, and areas of karst topography (Sainsbury, 1961; Swanston, 1969). All of the larger islands (Revillagigedo, Prince of Wales, Dall, Etolin, Kupreanof, Kuiu, Baranof, Chichagof, and Admiralty) have mount-ains surpassing 3000 ft. of "horn" configuration with prominent cirques 15 on their flanks (usually best developed to the northeast). However, among these a particularly rugged range which rises adjacent to the open Pacific constitutes a distinct geomorphic mountain province. This feature occurs again to the south in the Queen Charlotte Islands and Vancouver Island. In southeastern Alaska this range is best represented on Dall, Chichagof, and Baranof Islands, the last of these maintaining numerous small glaciers (Henoch and Stanley, 1967a). On these islands the summits are frequently horns, and cirques often lead directly through sculptured, steep walled, U-shaped valleys into tidewater. The precise glacial history of this range is l i t t l e known. From Cross Sound and Icy Strait northward the physiographic provinces become less clear. There the archipelago abruptly stops, with the complex fiordlands ceasing northwestward of Icy Point. The Lynn Canal and Glacier Bay, two major N-S overdeepened fiord systems, penetrate northward between the Coast Range, the Chilkat Mountains, and the Fairweather Range. The Chilkat Range, which in part forms the eastern boundary of Glacier Bay National Monument, consists of highly dissected rock horns and ridges with summits between 4000 and 7000 ft. above sea level. Their icefields feed primarily into Glacier Bay, although some glaciers (notably the Davidson) descend into the Lynn Canal watershed. This montane complex merges with the Fairweather Range to the west and blends with the St. Elias Mountains to the north. 16 The most striking range in the study area is the Fairweather massif which towers abruptly above the Gulf of Alaska to ice summits of 12,000-15,000 ft. The range is heavily glacierized (Henoch and Stanley, 1967a,b) and is continuous northward with the mountain arc of southern Alaska. These are active mountains, as is evidenced by the frequency of movement along the Fairweather Fault which lies immediately at their seaward base. This high, coastal range inter-cepts considerable precipitation, much of which forms the remarkably low elevation Brady Ice Cap to its east (Bengston, 1962), and the valley glaciers and piedmont lobes on its western flank (Henoch and Stanley, 1967a). North of Icy Point the coastal topography is markedly different from the archipelago to the south. The broad sweeping beaches and low lying forelands which replace the intricately indented fiord-lands, are broken only by the mouths of some streams, Lituya Bay, the distributaries of the Alsek River (Dry Bay), and Yakutat Bay. Lituya Bay is the sole harbour within this span, and is renowned for the treacherous tidal currents at its mouth. Associated with the outer island ranges is a narrow, but distinctive lowland "strandflat" (Wahrhaftig, I965) formation along the seaward slopes of Chichagof, Kruzof, and Baranof Islands. Smith (1939) and Brew, et al. (1966) have summarized the tectonic history of southeastern Alaska, and the following discussion 17 draws heavily upon their work. Areal exposures of bedrock in southeastern Alaska range from Paleozoic clastic, volcanic and carbonate rocks to Recent unconsoli-dated alluvia. Many rock types occur throughout the region in scattered locations, forming a diversity of habitats in most climatic zones. Southeastern Alaska has been tectonically active since at least the early Paleozoic. The present structural pattern is the result of late Mesozoic and Tertiary events, with igneous and higher grade metamorphics occurring in the three main orographic areas: a) the Coast Mountains, b) the belt trending northward from Baranof and Chichagof Islands through the Fairweather Range to the St. Elias Mountains, and c) the area west and south of Ketchikan. Intrusions and associated metamorphics of Tertiary age are not uncommon and are abundant in the Baranof — Kruzof area. Following uplift and erosion in the Late Cretaceous, a thick sequence of sandstones, conglomerates and volcanics was derived and deposited locally, mainly in the Admiralty Trough. These strata are almost undeformed. Later in the Tertiary a thick sequence of Miocene and Pliocene marine and nonmarine sandstones, siltstones, and volcanics was deposited in the northwestwardmost part of south-* eastern Alaska. This is well represented adjacent to Lituya Bay (D. J. Miller, 196l). 18 The most prominent topographical features of the present have been caused in part by joints (eg., the predominant NE trend of Baranof Island fiords — Brew, et a l . , 196"3) and faults (Twenhofel and Sainsbury, 1958). Vertical movements have combined with earlier structures to give the present physiognomic configuration. It would appear, therefore, that the Pliocene topography would not have been unlike that of Recent time, except that the glaciations of the Pleistocene would have probably: a) accentuated and deepened major drainage patterns, especially those along active faults, b) lowered and subdued those elevated areas that received inundating glaciation, c) oversteepened and otherwise sculptured the higher mountains, d) altered depositional facies upon the adjacent continen-tal shelf, and e) repeatedly(?) removed or restructured the supra-bedrock soils and unconsolidated materials. Orogenic uplift was probably most significant during this period in the Fairweather Range, although to some degree erosion and/or uplift cycles no doubt pre-vailed in each mountain group. Consequently, the same general topo-graphical habitats (eg., mountains, lowlands, islands, mainland and maritime environments, etc.) existed prior to, during, and since the glacial activity of the Pleistocene. Quaternary volcanic activity has persisted until very recent times. There are several occurrences of lavas, primarily basalts, scattered along the Coast Range mainland. These include sites along 19 the Nass, Unuk and Iskut Rivers (Kerr, 1948), near Smeaton and Rudyard Bays, and along the Behm Canal (Heusser, 1952). Post-glacial ash and pumice deposits are prominent on the southeastern portions of Revilla-gigedo Island (Wahrhaftig, 1965), and on Kruzof, northern Baranof and southern Chichagof Islands, the latter source being the Mt. Edgecomb eruptions. The last interglacial high stand of sea level occurred about 30,000-35,000 y B.P. (Milliman and Emery, 1968). A maximum world wide depression was reached between 21,000 and 16,000 y B.P. on the order of a maximum of -IU5 m (Curray, 1965). About 14,000 y B.P. Holocene transgression began. A differential of greater than -50 m occurred until about 11,000 y B.P., by which time deglaciation of the Alexander Archipelago was well under way (Curray, 1965). During periods of sea level depression considerable terrain now subtidal, especially portions of the continental shelf along the outer coast, may have been exposed. Mathews, et al. (1970) have detailed the land-sea relationships in southwestern British Columbia and adjacent Washington subsequent to the climax of the most recent (Fraser) Glaciation. Relative sea level was high at the time of ice retreat (13,000 y B.P.), and directly thereafter underwent a major and rapid lowering of several hundred feet during about the next 1000 years. This lowering was reversed by a second inundation which approached and perhaps in places exceeded the extent of the earlier inundation. The upper known limit of inundation 20 in the region is approximately 600 f t . above present sea level (Easter-brook, 1963). The movements immediately following deglaciation were primarily isostatic; but since approximately 8000 y B.P. changes in sea levels appear to be dominantly eustatic (Mathews, ejb al., 1970). In southeastern Alaska elevated marine features are known to occur at elevations in excess of 500 f t . above present sea level (Twenhofel, 1952). Studies are currently underway (R. D. Miller, U.S.G.S., personal communication; I. A. Worley, unpublished data) to discover the post-glacial land-sea relationships in southeastern Alaska. If a similar pattern occurred both in southeastern Alaska and southwestern British Columbia there also would have been signif-icant changes in the amount of land surface exposed in the archipelago during the last 10,000 to 12,000 years. Pewe, et_ al. (1965) have summarized the known glaciological stages for the Quaternary in Alaska. Four periods of glaciations have been recognized for Alaska: Pre-Illinoian, Illinoian, Wisconsin, and Recent. There is evidence of some Pliocene(?) glaciations in the Middle Miocene— Early Pleistocene Yakataga Formation, and associated rocks, which are exposed occasionally along the north coast of the Gulf of Alaska between Cape Spencer and Cape St. Elias. This glaciation was probably essentially alpine in origin, but of sufficient magnitude and activity to produce calving termini (D. J. Miller, 1957", Rossman, 1963; 21 Plafker, 196?). The Wisconsin glaciation was complex, extending in two major advances with several minor oscillations during the latter. Wisconsin age drift coats nearly a l l of southeastern Alaska, but is lacking along the coast of the Gulf of Alaska between Cape St. Elias and Yakutat Bay, and is rare southward to Icy Point. The glaciers in that coastal stretch seem to have been less extensive during Wis-consin time than subsequently. This may be due in part to continued tectonic uplift of the St. Elias and Fairweather Ranges. Recent glaciation has had only minor effects upon the bulk of the Alexander Archipelago, but several significant expansions have occurred in the mainland ranges during the last 10,000 years. Notable increases culminated variously in the Glacier Bay — Fair-weather Range — St. Elias Range complex between lUOO and 700 years ago and/or between 1791 and 190U A.D. (Pewe, et al., 1965; see also Lawrence, 1950, 1965; Lawrence and Elson, 1953; Viereck, 1967; Meier and Post, 1962; and Post, 1965, 1969); The piedmont lobes that fringe the northeastern Gulf of Alaska coast are either near their maximum extent or have reached i t , leaving prominent terminal and marginal moraines, within the last 1000 years (Plafker and Miller, 1958; Goldthwait, et al . , 1963). The Recent history of Glacier Bay has been summarized by Lawrence (1958) and Goldthwait (1963), and its catastrophic ice recessional patterns are well known (Bonn, 1967). 22 Although no co n c l u s i v e evidence o f pre-Wisconsin g l a c i a t i o n s has been reporte d f o r the b u l k o f southeastern A l a s k a i t seems reason-able t o assume t h a t a s i m i l a r sequence occurred there as has p r e v a i l e d i n the remainder o f the s t a t e . At l e a s t two major g l a c i a t i o n s o f un-c e r t a i n ages are i n f e r r e d f o r the Juneau I c e f i e l d area (M. M i l l e r , 196k). Swanston (196°) r e p o r t s evidence o f two l a t e - P l e i s t o c e n e g l a c i a l advances i n Maybeso Creek v a l l e y on P r i n c e o f Wales I s l a n d . However, throughout most o f the Alexander Archipelago and much o f the as s o c i a t e d mainland a l l t r a c e s o f pre-Late Wiconsin age g l a c i a t i o n s have been o b l i t e r a t e d by e r o s i o n during the most recent maximum, or are b u r i e d as marine sediments (and remain t o be i n v e s t i g a t e d ) . T e r r e s t r i a l evidence o f former g l a c i a t i o n s i s probably a v a i l a b l e along the outermost c o a s t , e s p e c i a l l y n o r t h o f I c y P o i n t , but documentation i s l a c k i n g . I t i s g e n e r a l l y agreed ( F l i n t , 1957; Heusser, 1952, i960) t h a t a c o r d i l l e r a n i c e sheet formed during major g l a c i a l stages. I n i t i a l l y , v a l l e y g l a c i e r s i n the Boundary Ranges and the ranges o f the outer i s l a n d s grew and coalesced i n t o broad piedmont g l a c i e r s ; s i m u l t a n e o u s l y , at higher e l e v a t i o n s neves and i c e f i e l d s a l s o j o i n e d , u n t i l an i c e sheet magnitude was reached. There appear t o have been s e v e r a l centres o f g l a c i a t i o n i n southeastern A l a s k a other than the main c o r d i l l e r a n source i n the Boundary Ranges (Heusser, 1952), most no t a b l y P r i n c e o f Wales I s l a n d (Sainsbury, 1961), Baranof I s l a n d , 23 and Chichagof Island (Coulter, et a l . , 1965). Although i t is recog-nized that the ice sheet reached the Pacific Ocean i t is not clear how extensive the coverage was on the outer, mountainous islands (Heusser, 1952, i960, 1965: see also Chapter V). The directions of ice flow have been indicated by Heusser (1952) and Coulter, et al. (1965). Prominent outflow proceeded southward through Clarence Strait to the Dixon Entrance; westward and southward across the central lowlands and along Sumner Strait, Stephens Passage, Frederic Sound, and Chatham Strait; and westward across northern Chichagof Island along Icy Strait out Cross Sound. The largest sounds, for example Cross Sound and Chatham Strait, show evidence of continued over-deepening across the continental shelf into the Pacific. However, there is no recognized evidence of an extensive off-shore ice sheet. Isostatic rebound from the unloading of glacial ice is s t i l l active in the region (Twenhofel, 1952; Hicks and Shofnos, 1965). Marine deposits are reported (Heusser, 1952; Twenhofel, 1952; D. J. Miller, 196l) from numerous sites within southeastern Alaska at various elevations. In the archipelago most valleys and slopes to elevations of about 1500 f t . are veneered by a mantle of compact glacial t i l l s . Most of the associated mineral soils are derived primarily from ablation t i l l , even those over bedrock (F. R. Stephens, et al., 1969). 24 Vegetation By Late Tertiary times, many of the genera that nov compose the coastal coniferous forest were growing in southeastern Alaska (Hopkins, 1963). During the climatic and glacial stresses of the Pleistocene the composition of the flora repeatedly became altered and reduced in diversity. Most forest elements migrated southward in colder periods, and differentially re-entered the area upon de-glaciation depending upon the characteristics of the individual taxa (Heusser, 1965). This has, no doubt, contributed in part to the limited diversity of the forest compared to its counterpart near to and south of the glacial boundary. Some boreal species and other more hardy taxa returned to or arrived in southeastern Alaska from the major unglaciated territories in Alaska and the Yukon (Steere, 1965; Heusser, 1965; Hulten, 1968; Schofield, 1969b). Postglacial vegetation has been reconstructed by Heusser (i960, 1965) showing that contemporary taxa revegetated the area in a sequence that is nearly identical to that occurring in deglaciated terrain at Glacier Bay and nearby (Lawrence, 1953, 1958; Decker, 1966; Reiners, et_ al . , 1971). The warmest and driest period of postglacial times (the Hypsithermal) appears to have occurred between about 9000 B.P. and 4000 B.P. (Goldthwait; 1966; see also Heusser, 1953) during which some southern or interior plants may have invaded the region. 25 Migration of biota from Asia could have occurred during the Pleistocene across the Bering land bridge during times of its exposure. Hopkins (1967) has outlined the history of Beringia. During the early and middle Tertiary, Asia and North America were connected, and shared many taxa. The first major floristic separation began with the open-ing of the Bering Strait during the late Miocene, which subsequently closed in the early Pliocene. Climatic cooling of the Pliocene con-tinued into the Pleistocene, further segregating the more temperate components of the Pacific biota. By two million years ago a severe arctic and subarctic climate prevailed on the southern edge of the land bridge. Illinoian ice later blocked the intercontinental corridor, but the warming trend of the Sangamon Interglacial permitted some ex-change of organisms even though the bridge had again parted. The bridge was restored, along with cooling climates and expanding glaciations during Wisconsin time. Some fluctuation ensued, with the appearance of Eskimos and Aleuts about 13,000 years ago. Since about 12,000 B.P. the straits have remained open. The present-day forest of southeastern Alaska is richly luxuriant from sea level to about 1500 ft. with treeline above 2400 ft . in the southern portion, and about 1800 ft. in the north (Heusser, 1952). Tree species are few, and only Sitka spruce (Picea sitchensis), western hem-lock (Tsuga heterophylla), Alaskan yellow cedar (Chamaecyparis nootka-tensis), lodgepole pine (Pinus contorta), and mountain hemlock (Tsuga 26 mertensiana) grow throughout the region. Sitka spruce is most common in youthful sites and in low elevation terrain near tidewater where i t i s an important timber and pulp source. Western hemlock and Alaskan yellow cedar are the other important commercial trees, the lat t e r common from the subalpine to sea le v e l , especially on poorly drained s o i l s . Lodgepole pine i s generally restricted to peatlands, headlands, and the subalpine. Mountain hemlock is common in the subalpine and sometimes appears at lower elevations in peatlands or highly exposed, poor s o i l sites. Western red cedar (Thuja plicata), si l v e r f i r (Abies amabilis), large leaf maple (Acer macrophyllum), and western yew (Taxus brevi-folia) occur i n areas i n the south, but are nowhere common. A variety of boreal deciduous trees, as well as subalpine f i r (Abies lasiocarpa) and white spruce (Picea glauca), grow in southeastern Alaska in mainland areas, especially where a more continental climate prevails, and populations occur sporadically within the archipelago at sites with highly specialized local climates. Alnus spp. are important shrubs and small trees throughout, along the forest borders in success-ions! zones, i n avalanche tracks, and in the subalpine. A subtle diversity of forest types (Godman, 1952; see also Chapter III) occurs, conspicuously related to the drainage character-i s t i c s of the substrate. The significance of these forest phenomena has been recognized recently, and their description i s presently incomplete (Gass, et a l . , 1967; F. R. Stephens, et a l , 1969). The 27 development of the shrub, herb and "bryophyte strata are highly correlated with the forest structure, varying from paractically non-existent to the well known, lush, rain forest type with deep mantles of bryophytes festooning every available substrate. Open peatlands (muskegs) cover considerable tracts throughout nearly a l l of southeastern Alaska. They appear in depressions and on slopes from sea level to the subalpine where subsurface drainage is poor. Peat accumulates beneath a cover of mosses (mostly Sphagnum spp.), liverworts, sedges, and heaths (notably Vaccinium spp., Kalmia polifolia, Ledum groenlandicum, Empetrum nigrum), and occasionally Juniperus communis. Shrubby or stunted trees frequently are scattered over the bog surface, usually consisting of Pinus contorta and Chamaecyparis nootkatensis, although Tsuga mertensiana, Pice a sitchensis, and Thuja plicata are also sporadic inhabitants. Under certain poorly understood conditions the peatland surface may develop an intricate assemblage of ponds, these often showing slope-controlled orientation or pattern-ing. The most commonly used subdivisions of these peatlands are "slope", "raised", and "flat" (Dachnowski-Stokes, 19Ul), or "soligenous", ombrogenous, and "topogenous" (Heusser, 1965), but this classification needs considerable reinspection and updating. The southeastern Alaskan vegetation is further considered in Chapter III. 28 CHAPTER II CLIMATE AND CLIMATIC EFFECTS UPON BRYOPHYTE DISTRIBUTIONS The climate of southeastern Alaska has not been treated inten-sively i n one report, but a moderately large literature has accumulated, primarily in the form of raw data. Two important compilations are those by Anderson ( 1 9 5 5 ) and Patric and Black ( 1 9 6 8 ) . The climate of Glacier Bay has been considered by Lowe ( 1 9 6 6 ) . Additional information i s con-tained within the records, in t r a - and inter-office reports, and assorted publications of regional agencies including: the Alaska Fish and Game Department, the United States Geological Survey, the United States Coast Guard, the Federal Aviation Agency, the United States Forest Service, the United States Air Force, the National Park Service, and the United States Coast and Geodetic Survey. The many institute and university research programmes that have been completed or are underway in southeastern Alaska often contain climatically valuable data. Some of these have not been published. The climatic summaries in this thesis have not drawn upon a l l sources of information as the availability of data i s often restricted, and their importance is frequently not proportional to the effort expended to obtain them. However, the conclusions presented here have been reviewed by D. Bishop, hydrologist with the United States Forest Service, Juneau, who has ammassed and compiled a large amount of climatic 29 data and unpublished r e s u l t s f o r southeastern A l a s k a . The c l i m a t e o f southeastern A l a s k a i s not u n l i k e t h a t o f the western p o r t i o n s o f the B r i t i s h I s l e s and the western and southwestern d i s t r i c t s o f the Scandinavian p e n i n s u l a ( F a e g r i , 1968). The o v e r a l l c l i m a t e i s determined c h i e f l y "by the A l e u t i a n Low which c i r c u l a t e s above the waters o f the northern arm of the warm Japanese c u r r e n t . This c a r r i e s the r e l a t i v e l y temperate and moist a i r eastward and south-eastward across the d i s t r i c t i n a succession o f storms. The oro-graphic b a r r i e r s cause a l i f t i n g and c o o l i n g o f the a i r mass and heavy p r e c i p i t a t i o n occurs throughout the y e a r , e s p e c i a l l y during the w i n t e r months. The ocean current has a moderating e f f e c t upon the temper-a t u r e s , g i v i n g c o o l summers and r e l a t i v e l y warm wi n t e r s (Sverdrup, 1940). Those p o r t i o n s o f southeastern A l a s k a t h a t extend w e l l i n t o the Boundary Ranges, e s p e c i a l l y the northernmost extension o f the "panhandle", are s t r o n g l y i n f l u e n c e d by the c o n t i n e n t a l high which l i e s n o r t h and east o f the a r c h i p e l a g o . Annual p r e c i p i t a t i o n i s l e s s i n these areas, and the temperature ranges are s i g n i f i c a n t l y g r e a t e r . The maximum recorded highs and lows at Haines are 99° and -36° F, whereas at Wrangell they are 84° and 0° F, and at Cape D e c i s i o n 80° and 0° F; these g i v i n g ranges o f 135°, 84°, and 80° r e s p e c t i v e l y (Anderson, 1955; P a t r i c and B l a c k , 1968). During the w i n t e r months i n t e n s i v e low pressure storms may deluge the archipelago (Gass, et_ aJ.., 1967). These systems abut the 30 continental subarctic high along the major boundary ranges. There result strong, and often violent, winds passing down the principal valleys and fiords bringing dry, cold air into the warmer, moist air masses of the lows. (The effects of this local phenomenon upon the ecosystems of southeastern Alaska have not yet been detailed.) The chief difficulty in assessing precise climatic variability in southeastern Alaska is that although the number of recording stations is moderately large they are restricted, in general, to elevations near sea level. Most are at lighthouses and at, or near, the larger communities. This placement provides data that are pri-marily sea influenced. Strategic placement of additional stations are needed, especially those in elevated positions, mid-island or otherwise distant from the sea, and along major valleys through the mainland mountain ranges. This sampling bias has been overcome, in part by Bishop (unpublished data) who has utilized runoff data from monitered watersheds. Furthermore, many of the records are for rather limited periods, as brief as 5 years or less. An example of a local deficiency of significant climatic records can be noted in the maps of Andersen (1955). He figures no indication of the important influence of the Fairweather Range massif upon the local rainfall, nor is there any compensation in the mean annual summaries of temperature and rainfall for orographic effect. Utilizing Thornthwaite's classification of climate (Thorn-thwaite, 19^6; Carter and Mather, 1966), Patric and Black (1968) 31 conclude that the bulk of southeastern Alaska is "AC^rc^" — perhumid, warm microthermal, no season of rainfall deficiency, temperature efficiency normal to warm microthermal (symbolism and terminology as used by Patric and Black,1968). East and north of the region the climate quickly changes to "DC'^ dc'-^ " — semiarid, cold microthermal, l i t t l e or no water deficiency, temperature efficiency normal to cold microthermal. The transition zone is best documented in the valley of the Klehini River northward from Haines. A generalized picture of these climatic zones of south-eastern Alaska is presented in Fig. 5. The distribution of the variation among the four Thornthwaite categories within the region are (Patric and Black, 1968): Climatic type based upon moisture index: In addition to the transition zone note above, there is only one variation from type "A" (perhumid), and that is the "B^ " (humid) rating at Angoon. Thermal efficiency: A region of "B*^ " (first or cool mesothermal) extends from coastal British Columbia northward to Wrangell in the inner islands, and to Sitka on the outer islands. The bulk of the remainder of the region is "C'g" (warm microthermal) a cooler climatic type. This merges at higher elevations and with the more continental areas to the north and east becoming 32 F i g u r e 5 C l i m a t i c z o n e s in s o u t h e a s t e r n A l a s k a (Genera l i zed) D a t a f r o m P a t r i c a n d B l a c k , 1968 For a n e x p l a n a t i o n o f s y m b o l s see text 33 "C ' I" ( c o l d microthermal), e s p e c i a l l y i n the v a l l e y s o f the major r i v e r s . A r i d i t y index; The b u l k o f the archipelago and adjacent mainland i s c l a s s i f i e d as " r " ( l i t t l e o r no water d e f i c i e n c y ) and only i n the major v a l l e y s connecting i n t e r i o r regions does t h i s become " s " (moderate summer water d e f i c i e n c y ) or "d" ( l i t t l e or no water s u r p l u s ) . This f e a t u r e i s best documented i n the upper Lynn Canal complex. Summer conc e n t r a t i o n o f thermal e f f i c i e n c y : The p a t t e r n f o l l o w s roughly t h a t o f thermal e f f i c i e n c y w i t h "b'^" (normal t o f i r s t mesothermal) extending northward from c o a s t a l B r i t i s h Columbia t o Guard I s l a n d , C r a i g , and S i t k a . The remainder o f the d i s t r i c t i s " c ^ " (normal t o warm microthermal) merging w i t h " c ' i " ( c o l d microthermal) o f the i n t e r i o r , c o n t i n e n t a l c l i m a t e . No attempt has been made i n t h i s t h e s i s t o assess a l a r g e v a r i e t y o f c l i m a t i c parameters and t h e i r p o s s i b l e r e l a t i o n s h i p t o the d i s t r i b u t i o n o f the r e g i o n a l b r y o f l o r a . Only two of the most b a s i c f a c t o r s have been s e l e c t e d , mean seasonal temperatures and mean annual p r e c i p i t a t i o n . Mean temperatures: Andersen (1955) has presented charts o f mean temperature isotherms f o r southeastern A l a s k a f o r the w i n t e r 3h months of December through February and for the summer months of May through September. During the vinter months the isotherms l i e roughly parallel to the main NW-SE trend of mountain ranges and island axes. The warmest zone extends from Cape Ommaney to Tree Point and southwestwardly, being greater than 36°F. The coldest zones are at the heads of the principal valleys traversing the boundary ranges, especially in the most northerly portion of the region (Skagway has a mean winter temperature of 2k.l°F). This trend is not repeated during the summer months. Although the finer details have not yet been documented, the summer isotherms in the southern half of southeastern Alaskatend to be roughly per-pendicular to the NW-SE orientation of the district. In the southern portion the summer means are in the vicinity of 55°F, whereas the central bulk of the archipelago has means of about 51°-52°F. A tongue of warmer means is mapped by Andersen (1955) extending down the Lynn Canal. Patric and Black (1968) give more recent mean annual temper-atures for the district. Plotted isotherms from these data depict the archipelago as having a decreasing temperature gradient from more than k6°F in the south and southeast to less than kO°F in the north and northwest. This zone of moderate temperatures changes sharply along the boundary ranges to the east and the north as the maritime climate merges with the adjacent continental climate. Mean annual temperatures drop to less than 35°F within a few miles from tidewater, and to less than 25°F within one hundred miles from tidewater. 35 Andersen (1955) has demonstrated t h a t c e r t a i n southeastern Alaskan t r e e species appear t o have t h e i r northern l i m i t s o f d i s -t r i b u t i o n r e g u l a t e d by the summer mean temperatures. As d e t a i l e d elsewhere i n t h i s t h e s i s a number o f bryophytes d i s p l a y s i m i l a r d i s t r i b u t i o n s and may l i k e w i s e be r e g u l a t e d . However, i t i s not p o s s i b l e yet t o say w i t h c e r t a i n t y t h a t any p a r t i c u l a r bryophytes have as l i m i t i n g f a c t o r s e i t h e r mean annual or mean seasonal temper-atures . Mean annual p r e c i p i t a t i o n : The a v a i l a b l e p r e c i p i t a t i o n data are adequate t o permit some treatment and v a r i e t y o f p r e s e n t a t i o n f o r p o r t i o n s o f the a r c h i p e l a g o . However, the d i s t r i b u t i o n a l d e t a i l o f the bryophytes i s s u f f i c i e n t l y g e n e r a l i z e d t h a t only an elementary c o n s i d e r a t i o n i s p a r t i c u l a r l y meaningful. Furthermore, the i s o h y e t p l o t t i n g o f the southeastern Alaskan mean annual p r e c i p i t a t i o n appears t o conform reasonably w e l l w i t h the expected moisture requirements o f a number o f t a x a . Measured average annual p r e c i p i t a t i o n ranges from l e s s than 30" i n f i o r d heads i n the n o r t h and east t o over 222" on Baranof I s l a n d ( P a t r i c and B l a c k , 1968). Average monthly p r e c i p i t a t i o n i n southeastern A l a s k a ranges from about U percent ( o f the y e a r l y t o t a l ) i n June t o 13.8 percent ( o f the y e a r l y t o t a l ) i n October. Even i n the d r i e s t areas c l o s e t o one i n c h o f r a i n f a l l s d u r i n g each summer month. October and November are the wettest months, w i t h the span o f September through January 36 c o n s t i t u t i n g about 56 percent o f the annual mean. June i s the d r i e s t month, w i t h May, June and J u l y being the d r i e s t p o r t i o n o f the year accounting f o r o n ly 13.5 percent o f the annual p r e c i p i t a t i o n . Andersen (1955) h & s p u b l i s h e d a map o f mean annual p r e c i p i -t a t i o n f o r southeastern A l a s k a . I t i s d i f f i c u l t , however, t o implement h i s map i n comparison w i t h the r e g i o n a l d i s t r i b u t i o n o f various bryo-phyte t a x a s i n c e i t i s based s o l e l y upon sea l e v e l data and does not consider topographic e f f e c t s . Furthermore, l i t t l e attempt was made t o e x t r a p o l a t e i n areas where data were u n a v a i l a b l e . The o n ly a l t i t u d i n a l p r e c i p i t a t i o n data a v a i l a b l e are those from the' v i c i n i t y o f Juneau. The p e r i o d o f o p e r a t i o n o f the seven r e c o r d i n g s t a t i o n s (see Table I ) v a r i e s g r e a t l y (the Thane and Per-serverance Camp records are l e s s than 25 y e a r s ) . The Mount Juneau f i g u r e was obtained by comparing r a i n f a l l s i n Juneau C i t y and on the mountain during s e v e r a l summer months, then e x t r a p o l a t i n g f o r a mean annual e s t i m a t i o n (Murphy and Schamach, 1965). Table I. R a i n f a l l v a r i a t i o n w i t h a l t i t u d e i n the v i c i n i t y o f Juneau. S t a t i o n A l t i t u d e Mean Annual P r e c i p i t a t i o n (inches) ( f e e t ) Juneau A i r p o r t Thane Auke Bay Juneau C i t y Mendenhall Perserverance Camp Mount Juneau 1100 3U00 12 20 35 72 85 55 81 58 90 9h 160 285 37 Figure 6 p l o t s these data. T h i s increase i n r a i n f a l l w i t h an i n c r e a s e i n a l t i t u d e i n mountainous regions has been repea t e d l y s u b s t a n t i a t e d throughout southeastern A l a s k a (personal communication, D. Bisho p ) . I f the orographic e f f e c t upon mean annual p r e c i p i t a t i o n , and the d i s t r i b u t i o n o f mountains w i t h i n southeastern A l a s k a i s c o n s i d -ered when p l o t t i n g the r a i n f a l l records o f P a t r i c and Black (1968) i t i s p o s s i b l e t o i l l u s t r a t e the d i s t r i b u t i o n o f y e a r l y r a i n f a l l amounts throughout the archipelago more s p e c i f i c a l l y than was done by Andersen (1955). Bishop has prepared such a d e t a i l e d map (un-pu b l i s h e d a t t h i s w r i t i n g ) . Figure 7 g e n e r a l i z e s the p r i n c i p l e zonations u s i n g the 100" i s o h y e t t o h i g h l i g h t wetter and d r i e r r e g i o n s . The shorelands t h a t immediately abut the open ocean are a reg i o n o f somewhat d r i e r c l i m a t e , due p r i m a r i l y t o the f a c t t h a t i t i s not u n t i l storm clouds proceed i n l a n d t h a t they are l i f t e d s u f -f i c i e n t l y t o drop t h e i r h e a v i e s t r a i n s . These coastlands may, however, have periods o f extensive- sea fog. Of p a r t i c u l a r note are the extensive d r i e r zones i n the l e e s o f the Fairweather, Chichagof-Baranof, and P r i n c e o f Wales mountain ranges. (For example, Angoon has a mean annual p r e c i p i t a t i o n o f only 39 i n c h e s , and both Kake and Gustavus have but 54 inches per year.) These d r i e r areas o f the archipelago are more or l e s s continuous w i t h the d r i e r i n t e r i o r c l i m a t e s v i a major r i v e r v a l l e y s , e s p e c i a l l y i n the v a l l e y o f the Lynn Canal. The wettest areas i n the d i s t r i c t are on the outer -38 3 0 0 — • 1 m -c 200-e e • c o p CL « 100 — a. t 1 I, I 1 < n — U I I i l l 1000 2000 3000 4000 5000 Al t i tude ( in inches) F i g u r e 6 R a i n f a l l v a r i a t i o n w i t h a l t i t u d e in t h e v i c i n i t y o f J u n e a u , A l a s k a (See t e x t for s o u r c e of d a t a ) 39 DIXON ENTRANCE Figure 7 G e n e r a l i z e d a n n u a l p r e c i p i t a t i o n zones in s ou thea s te rn A laska (Based upon the app rox imate l o c a t i o n o f the 100" mean annua l p rec i p i t a t i on i sohyet) ko islands and the elevated regions adjacent to the Dixon Entrance. In order to assess the precipitation distribution in terms of the regional flora the distributions of a number of taxa of vascular plants and bryophytes known to be generally restricted to drier environments have been plotted in Figures 8, 9» and 11. The vascular plant data are based primarily upon the environmental comments on the flora of the nearby Queen Charlotte Islands by Calder and Tayler (1968). Figure 8 illustrates the distributions of the following vascular plants: Abies lasiocarpa, Acer glabrum subsp. douglasii, Anemone multifida. Arctostaphylos uva-ursi, Carex brunnescens, Cerastium arvense. Collinsia parviflora, Eleocharis kamtschatica, Hieracium albiflorum, Lycopus uniflorus, Myriophyllum spicatum, Polemonium pulcherrimum, Ranunculus hyperboreus. Salix lasiandra, Salix scouleriana, Symphoricarpus albus. Figure 9 maps the combined distributions of the taxa classified in this thesis as "Dry Climate" bryophytes. A special symbol has been used to designate those taxa which are doubtfully included in the classification. Figure 10 maps the combined dis-tributions of the "Wet Climate" bryophytes. These distribution data have been combined in Figure 11. A line separating the "Dry Climate" taxa from the "Wet Climate" taxa has been fitted where possible. This line mirrors the contours F i g u r e 8 Comb ined d i s t r i bu t i on s o f some " D r y C l i m a t e " v a s c u l a r s pec i e s (see t e x t f o r s p e c i e s l i s t ) 1+2 DIXON ENTRANCE Figure 9 Combined distributions of "Dry Climate" bryophyte taxa (The symbol @ indicates taxa doubtfully included in the "Dry Cl imate" classif ication) 43 DIXON ENTRANCE Figure 10 Combined distributions of "Wet Climate" bryophyte taxa (The symbol O indicates locations with subalpine collection sites only) hk DIXON ENTRANCE F i gu r e 11 C o m b i n e d d i s t r i b u t i o n s o f " D r y C l i m a t e " t a x a (•) a n d " W e t C l i m a t e " t a x a (O) (This f i g u r e is a c o m p o s i t e o f F i g u r e s 8, 9, a n d 1 0 ) 45 o f the mean annual p r e c i p i t a t i o n , but some d i f f e r e n c e s occur, esp-e c i a l l y i n the southern p o r t i o n . The l i n e g e n e r a l l y f o l l o w s the 100" contour d e r i v e d by the c l i m a t i c data. Mean annual p r e c i p i t a t i o n ( o r some s i m i l a r moisture parameter), then, appears t o be a dominant f a c t o r i n the l o c a l d i s t r i b u t i o n and composition o f the f l o r a . 1+6 CHAPTER III VEGETATION TYPES OF SOUTHEASTERN ALASKA WITH ESPECIAL REFERENCE TO THE BRYOPHYTES I. INTRODUCTION Palmer (1942) has described the vegetation types of south-eastern Alaska utilizing 7 basic categories, plus several subdivisions. The major vascular plant constituents are enumerated with accompanying density figures. He devised the following floristic summary using Forest Service figures for approximately 75 percent of the region and personal estimates for the remainder: Community Estimated area sq. mi. % Coastal Forest (Hemlock, Spruce, Cedar) Climax (Conifer—moss) 4688 13 Scrub (Conifer—shrub) 3125 9 Muskeg (Lodgepole pine—moss—sedge) . . . . 6250 17 Beach or Shoreline and Tidal Delta Flats (Sedge—grass) 700 2 Shrub (Alder—grass) 3000 9 Alpine Meadow (Ericaceae heath) 11,447 32 Waste or Barren Rock—crustose lichens 1000 3 Glaciers 5000 14 Aquatic 350 1 Total 35,560 100 Krajina (1965) has listed eleven biogeoclimatic zones for British Columbia. Four of these enter southeastern Alaska: Coastal 47 Western Hemlock — 1; Mountain Hemlock ( C o a s t a l Subalpine) — 3; Engelmann Spruce —- Subalpine F i r ( I n t e r i o r Subalpine — 8; and A l p i n e — 11. Numbers 1, 3» and 11 occur throughout southeastern A l a s k a and represent the primary a l t i t u d i n a l d i s t i n c t i o n s i n the r e g i o n . The I n t e r i o r Subalpine Zone occurs only i n the most n o r t h -eastern p o r t i o n of the a r e a , at the heads of the arms of the Lynn Canal. F. R. Stephens, e t a l . (1969) have d r a f t e d a major proposal o u t l i n i n g the s o i l s and a s s o c i a t e d t e r r e s t r i a l ecosystems o f south-eastern A l a s k a : The ecosystems . . . have "been c l a s s i f i e d according t o " f a m i l i e s " , "types", and "subtypes". Ecosystem f a m i l i e s group ecosystems w i t h broad vegetation-soil-environment s i m i l a r i t i e s , such as " F o r e s t " , "Muskeg", " A l p i n e " , e t c . F a m i l i e s are subdivided i n t o "ecosystem types". W i t h i n each t y p e , species composition, p r o d u c t i v i t y , secondary succession a f t e r f i r e o r l o g g i n g , and ecosystem f u n c t i o n -i n g are s i m i l i a r . Ecosystem types are subdivided i n t o "subtypes", based upon c h a r a c t e r i s t i c s r e l a t e d t o p r a c t i c a l management features such as e r o s i o n and l a n d s l i d e hazards, depth t o bedrock, c o m p a c t i b i l i t y , e t c . This c l a s s i f i c a t i o n was designed t o i n c l u d e a l l n a t u r a l ecosystems o f southeastern A l a s k a w i t h the exception o f the heads o f major f i o r d s w i t h c o n t i n e n t a l c l i m a t e s . More than 55 c a t e g o r i e s are t r e a t e d . Successions! v e g e t a t i o n and ecosystems have r e c e i v e d l i t t l e a t t e n t i o n i n southeastern A l a s k a beyond the environs o f G l a c i e r Bay. Cooper (I923a,b,c, 1931, 1937, 1939, 1942), Ta y l o r (1932, 1935), 48 Chandler (1942), Lawrence (1951, 1953, 1958), Lawrence and Hulbert (1950), Lawrence, et al. (1967), Cooke and Lawrence (1959), Crocker and Major (1955), Crocker and Dickson (1957)» Sprague and Lawrence (1959), M. E. Stephens (1963), Welch (1965), P. R. Stephens (I969a,b), Stephens and Billings (1967), Stephens, ejt al. (1969), and Reiners, et al. (1971) have a l l contributed to the description of floristic succession in regions of recent deglaciation and crustal uplift in a variety of southeastern Alaska sites. However, i t is only at Glacier Bay that investigations have reached an advanced stage. There have been several classifications of the successions^ vegetation of Glacier Bay National Monument. Cooper (l923a,b,c, 1931, 1937* 1939* 1942) recognized three stages: Pioneer, Thicket, and Forest. Lawrence (1951» 1953, 1958; Lawrence and Hulbert, 1950; Lawrence, et ai., 1967) has described developmental sequences rather than classifying the vegetation. Decker (1966) has discussed nine divisions: Early Pioneer, Mat Stage, Late Pioneer, Open Thicket Stage, Closed Thicket Stage, Poplar-Pine Stage, Spruce Forest, Spruce-Hemlock Forest Stage. He did not intend his treatment to include vegetation older than Neo-glacial time. Reiners, e_t al. (1971) have utilized eight stages in their study of plant diversity. These in-cluded a forest of at least an age of 500 years old, and a muskeg estimated at 1500 years old. Hence, there are some 93 or more published categories of veg-etation within southeastern Alaska excluding the continental regions h9 at the heads of principal fiords, and the flood plains of the larger trans-montane rivers. As an exercise, the present author has attempted to delimit the significant vegetational types and environments from a bryological standpoint. The current total is approximately lUO di-visions. The treatment of forest types by F. R. Stephens, et al. (1969) appears to be more than adequate for bryophyte considerations. The combined maritime categories of F. R. Stephens, et al. (1969) and Calder and Taylor (1968) (for the nearby Queen Charlotte Islands) are generally sufficient for the bryoflora. Calder and Taylor (1968) have subdivided the regional wetland communities more than any pre-vious workers, but further clarification and subdivision is s t i l l necessary. Insufficient attention has been paid to distinctions in lake and pond types, stream and river forms, and the various peatland phenomena. The complexities of the subalpine and alpine have been almost completely neglected. G. Streveler (personal communication), Park Biologist for the National Park Service and the present author have compiled a tentative breakdown of vegetational types in the upper montane, listing U8 categories. Finally, as F. R. Stephens (1969a,b; personal communication; F. R. Stephens, et al . , (1969) has indicated, essentially nothing is known about the vegetation in many youthful sites throughout southeastern Alaska. Consequently, the following discussion presents a general picture of the vegetation, rather than an exhaustive assessment. 50 As elsewhere in this thesis species lists are presented alphabetically, with the hepatics preceding the mosses. II. MARITIME COMMUNITIES The distinctions made among maritime communities by Calder and Taylor (1968) and F. R. Stephens, et al. (1969) supplemented by Palmer (1942) and F. R. Stephens and Billings (1967) emphasize various aspects of the maritime zone based upon topography, parent material, history, salinity, general physiognomy, and vascular plant floristics. Characteristic bryophytes are few, with the majority of the coastal taxa also common in non-maritime situations. Where the influence of saltwater is great the number of bryophyte species is much reduced. However, in areas of frequent rains with l i t t l e or no drought, and where fresh-water periodically flushes the lower veg-etation, complex bryophyte communities may exist down to the upper limit of the highest tidal zone. Shoreline sites No bryophytes grow in habitats that are periodically submerged by tidal waters. Grimmia maritima is common throughout southeastern Alaska in rock crevices and on surfaces that are often wetted by salit 51 spray. Brachythecium albicans, Campylium adscendens, Eurhynchium praelongum, Hypnum cupressiforme, and Bryum spp. occur on the ex-posed rocks and in the larger crevices of headlands and sea c l i f f s . Where a mature forest abuts tide-vater a line of alders grows in a band between the last Sitka spruce or (occasionally) hemlock and the open shore. Most of the common regional epiphytes can be found on their twigs and bark, but Ulota phyllantha appears to be essentially restricted to this zone, occurring also on neighboring rocks or dead-wood. This species and Grimmia maritima are the only bryophytes within the archipelago which appear to be limited to maritime environments, although Aulacomnium androgynum, Campylium adscendens, and Crumia deciduidentata may be similarily restricted. Raised beaches The successional stages on the many raised or exposed beaches have not yet been documented or thoroughly studied. However, some terrestrial bryophytes are especially common or distinctive in the pre-shrub and/or pre-tree stages: Lophozia barbata Aulacomnium palustre Bryum spp. Drepanocladus uncinatus Hylocomnium splendens-Leptobryum pyriforme Meesea uliginosa Pleurozium schreberi Ptilium crista-castrensis Rhacomitrium canescens var. ericoides Rhacomitrium fasciculare Rhyti di adelphus loreus Rhyti di adelphus squarrosus Rhytidiadelphus triquetrus Tortula ruralis 52 Other species are common on driftwood i n this zone: Blepharostoma t r i chophyHum Cephalozia connivens Lepidozia reptans Ptilidium californicum Ptilidium pulcherrimum Scapania bolanderi Aulacomnium androgynum Orthotrichum speciosum Pohlia nutans Ulota phyllantha Rock Environments A number of taxa are generally characteristic on beaches and shores on rocks, c l i f f s and boulders, or among gravels: Diplophyllum albicans Funaria hygrometrica Antitrichia curtipendula Grimmia maritima Brachythecium albicans Mielichhoferia macrocarpa Brachythecium lamprochryseum Pohlia nutans Bryum spp. Rhabdoweisia denticulata Campylium adscendens Rhacomitrium canescens Ceratodon purpureus var. ericoides Dicranum scoparium sens, l a t . Rhacomitrium fasciculare There are no bryophytes restricted to, or especially character-i s t i c of bir d rookeries. Tide-influenced Meadows Few bryophytes are found in tide influenced meadows (cf. F. R. Stephens and B i l l i n g s , 1967), and only forms of Eurhynchium praelongum and Brachythecium spp. are common. 53 Wharfs S e v e r a l t a x a are common on wharfs, n o t a b l y : l u r t i p e n d u l a serpens a a l b i c a n s Bryum sp. Ceratodon purpureus P o l y t r i c h i a ! formosum Rhacomitrium canescens var. e r i c o i d e s Rhacomitrium f a s c i c u l a r e U l o t a p h y l l a n t h a I I I . AQUATIC AND WETLAND COMMUNITIES The wetland communities o f southeastern A l a s k a have r e c e i v e d v i r t u a l l y no systematic o r d e t a i l e d a t t e n t i o n . Lakes and F l u v i a l Rocks F o n t i n a l i s a n t i p y r e t i c a and other species o f the genus are the o n l y bryophytes commonly found submerged i n l a k e s and the deeper pools o f slower moving streams. S e v e r a l t a x a occur on the rocks o f streams and r i v e r s , t h e i r presence o f t e n dependent upon the type o f ro c k , f l u c t u a t i o n s i n stream h e i g h t , l o a d , and turbulence: Mars u p e l l a emarginata Scapania paludosa Scapania u l i g i n o s a Scapania undulata Solenostoma c o r d i f o l i u m F o n t i n a l i s a n t i p y r e t i c a F o n t i n a l i s d u r i a e i F o n t i n a l i s p a t u l a Hygrohypnum a l p e s t r e Hygrohypnum luridum Hypnum d i e c k i i Rhacomitrium a c i c u l a r e Scleropodium o b t u s i f o l i u m Scoule,ria a q u a t i c a 5h Streambanks The stream bank environments, s u b s t r a t e s , and f l o r a s i n southeastern A l a s k a are as d i v e r s e as the l a r g e r communities and topographies through which they pass, although not n e c e s s a r i l y dependent upon them. The more common bryophytes are: Aneura p i n g u i s A n t h e l i a .lulacea Cephalozia media Chiloscyphus p a l l e s c e n s Conocephalum conicum Diplophyllum a l b i c a n s Harpanthus flotowianus Marchantia polymorpha Ma r s u p e l l a emarginat a Moerckia. h i b e r n i c a Nardia s c a l a r i s P e l l i a neesiana Scapania i r r i g u a Solenostoma hyalinum T r i t o m a r i a p o l i t a Bartrami o p s i s l e s c u r i i Brachythecium r i v u l a r e C a l l i e r g o n sarmentosunr Campylium s t e l l a t u m Climacium,dendroides Dichodontium pellucidum D i c r a n e l l a h eteromalla Drepanocladus badius Drepanocladus exannulatus Drepanocladus f l u i t a n s Drepanocladus revolvens F i s s i d e n s adianthoides F i s s i d e n s bryoides Heterocladium procurrens Hygrohypnum ochraceum Hygrohypnum pseudomontanum Hylocomium splendens Hypnum d i e c k i i L e u colepis m e n z i e s i i Oncophorus wahlenbergii P h i l o n o t i s americana P h i l o n o t i s fontana Plagiomnium i n s i g n e Pogonatum l a t e r a l e Pogonatum macounii P o h l i a wahlenbergii Rhacomitrium a c i c u l a r e Rhizomnium glabrescens Rhizomnium nudum Rhizomnium p e r s s o n i i Scleropodium o b t u s i f o l i u m S c o u l e r i a a q u a t i c a Sphagnum squarrosum P o o l . Pond and Lake Margins A number o f bryophytes are frequent as emergents i n , or along the margins o f , p o o l s , l a k e s and ponds. Depending upon the s p e c i f i c ecology o f the s i t e there may be l a r g e expanses of a s i n g l e taxon (eg., 55 Chiloscyphus p a l l e s c e n s , species o f C a l l i e r g o n , species o f Drepano- c l a d u s , P a l u d e l l a squarrosa, species o f P h i l o n o t i s ) o r complex communities. The more common t a x a o f these zones are: Anastrophyllum minutum Aneutta, p i n g u i s B l a s i a p u s i l l a Chiloscyphus p a l l e s c e n s Harpanthus f l o t o v i a n u s Lophocolea "bidentata Lophozia kunzeana Macrodiplophyllum p l i c a t u m Nardia s c a l a r i s P e l l i a neesiana Scapania paludosa Scapania u l i g i n o s a Brachythecium r i v u l a r e Bryum spp. C a l l i e r g o n c o r d i f o l i u m C a l l i e r g o n giganteum C a l l i e r g o n sarmentosum C a l l e r i g o n stramineum Drepanocladus exannulatus Drepanocladus f l u i t a n s F i s s i d e n s adianthoides F o n t i n a l i s a n t i p y r e t i c a Hygrohypnum ochraceum Hylocomium splendens Hypnum l i n d b e r g i i L e u colepis m e n z i e s i i Oncophorus wa h l e n b e r g i i Plagiomnium i n s i g n e Pogonatum macounii P o h l i a wahlenbergii Rhizomnium glabrescens Rhizomnium nudum Rhizomnium p e r s s o n i i Rhytidiadelphus t r i q u e t r u s Slope Drainage S i t e s A r a t h e r l a r g e number o f bryophyte communities are found i n va r i o u s s p r i n g s , r i l l s , f l u s h e s , seeps and s i m i l a r h a b i t a t s on g e n e r a l l y s l o p i n g t e r r a i n . The p a r t i c u l a r nature o f the f l o r a depends p r i m a r i l y upon the l o c a l topography, the p o s i t i o n o f the water t a b l e , the water source, chemistry, and volume, the type o f free-drainage f l o w , the r e g i o n a l and l o c a l c l i m a t e s , and the a l t i t u d e . S e v e r a l t a x a are es-s e n t i a l l y r e s t r i c t e d t o these h a b i t a t s , w h i l e others are e s p e c i a l l y common. Some o f the more frequent o f the t a x a found i n these e n v i r o n -ments are: 56 Aneura pinguis Harpanthus flotovianus Marchantia polymorpha Microlepidozia setacea Moerckia bl y t t i i Moerckia flotoviana Nardia scalaris Pellia neesiana Scapania irrigua Scapania paludosa Scapania uliginosa Andreaea nivalis Brachythecium 1amprochryseum Bryum creberrimum Bryum pseudotriquetrum Calliergon cordifolium Calliergon giganteum Calliergon sarmentosum Calliergon stramineum Cratoneuron commutatum var. falcatum Cratoneuron filicinum Dicranella pacifica Drepanocladus aduncus. Drepanocladus badius Drepanocladus exannulatus Drepanocladus fluitans Drepanocladus uncinatus Fissidens adianthoides Hygrohypnum luridum Hygrohypnum ochraceum Hypnum dieckii Hypnum lindbergii Oncophorus virens Oncophorus wahlenbergii Orthothe^cium chryseum Philonotis americana Philonotis fontana Polytrichum formosum Sphagnum palustre Sphagnum rubellum Marshes Fresh-water marshes (similar, in part, to the concept of "swamp" in Calder and Taylor, 1968) are infrequent in southeastern Alaska, but of diverse ecology (Worley, unpublished data). There has been no standardization of terminology among marshes, swales, swamps, mires, and similar phenomena in the region, but for the present purpose the following listings include bryophytes common in level, treeless areas where the water table is frequently high or above the substrate surface. Some species are usually restricted to basic conditions (eg., Aneura pinguis, Meesea trifaria,. Paludella, squarrosa. Scorpidium scorpioides. and Tomentypnum nitens). Other 57 common bryophytes belonging t o t h i s general category i n c l u d e : . B i a s i a p u s i l i a C a l l i e r g o n stramineum Chiloscyphus p a l l e s c e n s Drepanocladus aduncus Conocephalum conicum Drepanocladus badius Moerckia f l o t o w i a n a F i s s i d e n s adianthoides Scapania i r r i g u a Hygrohypnum ochraceum Scapania paludosa Meesea u l i g i n o s a Scapania u l i g i n o s a P h i l o n o t i s americana C a l l i e r g o n c o r d i f o l i u m Rhizomnium pseudopunctatum C a l l i e r g o n giganteum Peatlands There has been more research done on peatland phenomena i n southeastern A l a s k a than any other wetland f e a t u r e . Of p a r t i c u l a r note are the papers o f Dachnowski-Stokes (1941), Rigg (1914, 1937), Palmer (1942), Zach (1950), Heusser (1952, 1954b), F. R. Stephens, e t a l . , and R e i n e r s , e t a l . , (1971). The present author has elsewhere (unpublished data) begun a c l a s s i f i c a t i o n o f the peatland t y p e s , but f o r t h i s t h e s i s o n ly the d i s t i n c t i o n o f "hyperoceanic" has been made. Those t a x a unique t o the hyperoceanic environment are t r e a t e d i n Chapter IV. The d e s c r i p t i o n s o f peatland types by Dachnowski-Stokes (1941), Calder and T a y l o r (1968), and F. R. Stephens, et a l . , (1969) are the most complete t o date, and l i s t the major v a s c u l a r p l a n t c o n s t i t u e n t s . The f o l l o w i n g t a x a are among the most c h a r a c t e r i s t i c o f the peatland f l o r a s : 58 Anastrepta orcadensis Anastrophyllum donianum. Anastrophyllum s a x i c o l u s Bazzania p e a r s o n i i Calypogeia sphagnicola Cephalozia b i c u s p i d a t a Cephalozia connivens Cephalozia leucantha Cephalozia media Cephalozia p l e n i c e p s Chiloscyphus p a l l e s c e n s C l a d o p o d i e l l a f l u i t a n s Gymnocolea i n f l a t a Harpanthus f l o t o v i a n u s Herberta himalayana Lophozia kunzeana Lophozia h a t c h e r i M i c r o l e p i d o z i a setacea Moerckia b l y t t i i Moerckia h i b e r n i c a M y l i a anomala M y l i a t a y l o r i Odontoschisma elongatum P l e u r o z i a purpurea R i c c a r d i a l a t i f r o n s R i c c a r d i a m u l t i f i d a Scapania p a l u d i c o l a Scapania undulata Aulacomnium p a l u s t r e Campylopus a t r o v i r e n s Dicranum elongatum Dicranum undulatum Drepanocladus exannulatus Drepanocladus revolvens Hylocomium splendens Paraleucobryum enerve Pleurozium s c h r e b e r i P o h l i a nutans P o h l i a sphagnicola Polytrichum juniperinum var . g r a c i l i u s P t i l i u m c r i s t a - c a s t r e n s i s Rhacomitrium lanuginosum Sphagnum b a l t i c u m Sphagnum compactum Sphagnum f us cum Sphagnum imbricatum .-Sphagnum l i n d b e r g i i Sphagnum magellanicum Sphagnum nemoreum Sphagnum p a l u s t r e Sphagnum pa p i l l o s u m • Sphagnum r i p a r i u m Sphagnum rubellum Sphagnum r u s s o v i i Sphagnum subnitens Sphagnum tenellum Sphagnum t e r e s Sphagnum v a r n s t o r f i i IV. FOREST COMMUNITIES Since t i m b e r i n g i s one o f the primary i n d u s t r i e s i n southeast-ern A l a s k a considerable l i t e r a t u r e has been produced concerning the r e g i o n a l f o r e s t s . Hovever, there are f e v l o c a l p h y t o - s o c i o l o g i c a l o r f l o r i s t i c s t u d i e s , nor are there any corresponding bryophyte treatments. No attempt t o c a t e g o r i z e f o r e s t s , except i n a very general vay, has been 59 made i n t h i s t h e s i s . F. R. Stephens, et. a l . , (1969), Gass, et a l . , (1967), and F. R. Stephens, e t a l . , (1968) have given the most d e t a i l e d c o n s i d e r a t i o n s t o the d i s t i n c t i o n o f f o r e s t types. T h e i r treatments have been based p r i m a r i l y upon the a s s o c i a t e d s o i l t y p e s . Therefore, under the present heading the c h a r a c t e r i s t i c b r y o -phytes o f s e v e r a l s e l e c t e d general h a b i t a t s o f f o r e s t zone e n v i r o n -ments w i l l be l i s t e d , r a t h e r than a l i s t i n g by f o r e s t type. Trunks o f Trees The p a r t i c u l a r bryophytes found upon the trunks o f t r e e s are dependant upon the species and the age o f the t r e e , the p o s i t i o n o f the t r e e w i t h i n the f o r e s t , the l o c a l c l i m a t i c c o n d i t i o n s , the f o r e s t t y p e , and the a l t i t u d e ( a l s o o c c a s i o n a l l y the l a t i t u d e ) . Some t a x a are almost t o t a l l y r e s t r i c t e d t o the trunks o f t r e e s (eg., Homalo-thecium n u t t a l l i i , P lagiothecium p i l i f e r u m and Zygodon r u p e s t r i s ) i n t h i s p o r t i o n o f t h e i r range, many are r e s t r i c t e d t o t r e e s and shrubs (see the next l i s t i n g ) , but the m a j o r i t y are a l s o known from a v a r i e t y o f other h a b i t a t s , e s p e c i a l l y c l i f f s and rocky s l o p e s : Bazzania ambigua P o r e l l a cordaeana Bazzania denudata P o r e l l a n a v i c u l a r i s Bazzania t r i c r e n a t a Radula b o l a n d e r i F r u l l a n i a t a m a r i s c i Radula complanata subsp. n i s q u a l l e n s i s Radula o b t u s i l o b a Herberta adunca subsp. p o l y c l a d a M e t z g e r i a conjugata Amblystegium serpens P l a g i o c h i l a s a t o i A n t i t r i c h i a c u r t i p e n d u l a P l a g i o c h i l a semidecurrens Brachythecium reflexum subsp. alaskana Claopodium b o l a n d e r i 60 Claopodium c r i s p i f o l i u m Dicranum tauricum Homalothecium • fulgescens Homalothecium n u t t a l l i i Hypnum c a l l i c h r o u m Hypnum c i r c i n a l e Hypnum subimponens Isothecium s t o l o n i f e r u m Orthbtrichum c o n s i m i l e Orthotrichum l y e l l i i P l agiothecium p i l i f e r u m Pterigynandrum f i l i f b r m e P y l a i s i e l l a polyantha U l o t a .laponica U l o t a megalospcra U l o t a o b t u s i u s c u l a U l o t a reptans Zygodon r u p e s t r i s Branches and Twigs Shrubs and shrubby t r e e s occur at many f o r e s t margins, i n f o r e s t successions^, stages, i n p e a t l a n d - f o r e s t t r a n s i t i o n zones, on avalanche and snow-slide s l o p e s , and o t h e r , l e s s frequent, circumstances. The presence o f a s s o c i a t e d e p i p h y t i c bryophytes i s dependent p r i m a r i l y upon the same f a c t o r s noted f o r t r e e t r u n k s . I n p a r t i c u l a r , some species are notably l i m i t e d t o a s p e c i f i c t r e e or shrub (eg., Douinia. ovata and Radula b o l a n d e r i t o Alnus) o r t o c e r t a i n e c o l o g i c a l c o n d i t i o n s (eg., Lescuraea a t r i c h a and L. b a i l e y i are r e s t r i c t e d t o the subalpine and a l p i n e ) . The f o l l o w i n g t a x a are common on the branches and twigs o f shrubs and t r e e s : Blepharostoma t r i c h o p h y l l u m Lescuraea b a i l e y i D ouinia ovata Lescuraea s t e n o p h y l l a F r u l l a n i a t a m a r i s c i Orthotrichum c o n s i m i l e subsp. n i s q u a l l e n s i s Orthotrichum l y e l l i i M e t z geria f r u t i c u l o s a Orthotrichum pulchellum P t i l i d i u m c a l i f o r n i c u m Orthotrichum speciosum Radula b o l a n d e r i U l o t a drummondii Radula complanata U l o t a .laponica A n t i t r i c h i a c u r t i p e n d u l a U l o t a megalospora Habrodon l e u c o t r i c h u s U l o t a o b t u s i u s c u l a Hypnum c i r c i n a l e U l o t a p h y l l a n t h a Isothecium.stoloniferum U l o t a reptans 61 Forest Floors The bryophyte component of the vegetation on forest floors is diverse and depends upon successions! stage (Reiners, et a l . , 1971) and forest type (F. R. Stephens, et al . , 1969). Some of the more common or outstanding taxa are: Calypogeia integristipula Cephalozia connivens Diplophyllum albicans Lepidozia filamentosa Lophocolea cuspidata Lophozia barbata Pellia neesiana Plagiochila asplenioides Brachythec ium reflexum Brachythecium salebrosum Bryum capillare Dicranum howellii 1 Dicranum ma.jus Dicranum scoparium Eurhynchium oreganum Eurhynchium pulchellum Heterocladium procurrens Hookeria lucens Hylocomium splendens Hypnum callichroum Isopterygium elegans Mnium spinulosum Plagiomnium insigne Plagiomnium medium Plagiothecium denticulatum Plagiothecium laetum Plagiothecium roeseanum Plagiothecium undulatum Pleuroziopsis ruthenica Pleurozium schreberi Pogonatum laterale Pogonatum macounii Polytrichum formosum Ptilium crista-^castrensis Rhizomnium glabrescens Rhizomnium nudum Rhytidiadelphus loreus Rhytidiadelphus squarrosus Rhyti di adelphus triquetrus Sphagnum girgensohnii Sphagnum squarrosum Dead and Decomposing Wood Snags, fallen limbs and trees, and decaying wood are plentiful in many forest habitats and environments. The associated bryophytes are often ecologically dependent upon the state of decomposition, the species of tree involved, the water relations, the local climate, and 62 the forest type. Many of the following taxa are known from a variety of substrates, hut some are essentially restricted to decomposing wood (eg., Lepidozia reptans, Lophozia porphyroleuca, Riccardia palmata, Buxbaumia indusiata, Tetraphis geniculata, and T. pellucida). Representative taxa include: Anastrophyllum minutum Bazzania ambigua Bazzania denudata Bazzania tricrenata Blepharostoma trichophyllum Calypogeia integristipula Calypogeia muelleriana Cephaloziacbicuspldata Cephalozia leucantha Cephalozia media Diplophyllum albicans Herberta adunca Jungermannia lanceolata Lepidozia filamentosa Lepidozia reptans Lophocolea cuspidata Lophozia.incisa-Lophozia porphyroleuca Lophozia ventricosa Microlepidozia setacea Mylia taylori Plagiochila asplenioides Plagiochila satoi Ptilidium califomicum Ptilidium, -pulcherrimum Riccardia latifrons Riccardia palmata Scapania bolanderi Amblystegium serpens Aulacomnium androgynum Brachythecium asperrimum Brachythecium reflexum Brachythec ium salebrosum Bryum capillare Bryum creberrimum Claopodium whippleanum Dicranum fuscescens Dicranum ma.jus Dicranum scoparium Dicranum tauricum Eurhynchium oreganum Eurhynchium praelongum Eurhynchium. pulchellum Heterocladium procurrens Hylocomium splendens Hypnum callichroum Hypnum circinale Hypnum dieckii Hypnum subimponens Isothecitmr stoloniferum Leucolepis menziesii Oncophorus virens Oncophorus wahlenbergii Plagiomnium insigne Plagiothecium denticulum Plagiothecium piliferum Plagiothecium roeseanum Pohlia nutans Rhizomnium glabrescens Rhytidiadelphus loreus- Sharpiella striatella Tetraphis geniculata 63 Roots o f Windthrows Windthrown t r e e s are a common feat u r e o f s e v e r a l f o r e s t types and t o p o l o g i c a l s i t u a t i o n s . A d i s t i n c t s u c c e s s i o n a l p a t t e r n occurs i n the newly exposed s o i l s among the upturned r o o t s . The v a r i a t i o n of the p a t t e r n depends, f o r the most p a r t , upon the composition o f the s o i l o r parent m a t e r i a l . Although a number o f bryophytes occur i n t h i s h a b i t a t , a few are e s p e c i a l l y frequent and abundant: Diplophyllum o b t u s i f o l i u m Pogonatum l a t e r a l e Calypogeia m u e l l e r i a n a Pogonatum macounii Bartramiopsis l e s c u r i i P o h l i a cruda D i c r a n e l l a heteromalla S c h i s t o s t e g a pennata Isopterygium pulchellum Humid and Wet C l i f f s C l i f f and rock outcrops are n o t a b l y abundant i n f o r e s t zones i n southeastern A l a s k a . Exposure, amount of i n s o l a t i o n , water a v a i l a b i l i t y and source, type o f rock and l o c a l c l i m a t e seem t o be the most i n f l u e n t i a l f a c t o r s determining the bryophytes present. The general h a b i t a t types that have been s e l e c t e d f o r comparison here are based upon exposure, a c i d i t y - a l k a l i n i t y , and moisture. r e l a t i o n s . A l a r g e and d i v e r s e assemblage o f bryophytes occur on c l i f f s , r o c k s , and canyon w a l l s i n environments t h a t are shaded, humid, and moist o r wet. The f o l l o w i n g l i s t o f the more common t a x a i n c l u d e s many p l a n t s which grow together but which do not n e c e s s a r i l y share i d e n t i c a l e c o l o g i c a l micro-requirements: 6k Anastrophyllum minutum Aneura p i n g u i s Bazzania denudata Bazzania t r i c r e n a t a Blepharostoma t r i c h o p h y l l u m Calypogeia i n t e g r i s t i p u l a Cephalozia b i c u s p i d a t a C e p h a l o z i e l l a r u b e l l a Chiloscyphus p a l l e s c e n s Conocephalum conicum Diplophvllum a l b i c a n s F r u l l a n i a >. t amar i s c i subsp. nj.squallensis Herberta.adunca, L e p i d o z i a f i l a m e n t o s a M a r s u p e l l a emarginata M i c r o l e p i d o z i a setacea P e l l i a neesiana P l a g i o c h i l a . a s p l e n i o i d e s P l a g i o c h i l a f i r m a subsp. confusa P l a g i o c h i l a semidecurrens subsp. alaskana R i c c ar d i a mult i f i da Scapania americana Scapania undulata Solenostoma a t r o v i r e n s Solenostoma c o r d i f o l i u m . Solenostoma pumilum Takakia l e p i d o z i o i d e s T r i t o m a r i a quinquedehtata Amphidium lapponicum Anoectangium aestivum Barbula c y l i n d r i c a Dry and Mesic C l i f f s Many o f the shaded c l i f f s dry o r mesic. C e r t a i n bryophyte Some are l i m i t e d t o almost x e r i c Bartramiopsis l e s c u r i i B l i n d i a acuta Brachythecium plumosum Campylium s t e l l a t u m Campylopus schimperi Cynodontium j e n n e r i Dichodontium pellucidum Dicranodontium denudatum Dicranodontium uncinatum F i s s i d e n s adianthoides F i s s i d e n s b r y o i d e s F i s s i d e n s osmundioides Grimmia a l p i c o l a Grimmia apocarpa Grimmia t o r q u a t a Heterocladium macounii Heterocladium procurrens Hylocomium splendens Hypnum d i e c k i i Isopterygium elegans Isopterygium pulchellum Oedopodium g r i f f i t h i a n u m O l i g o t r i c h u m p a r a l l e l u m Oncophorus v i r e n s Oncophorus v a h l e n b e r g i i Plagiopus oederiana Plagiothecium roeseanum Plagiothecium undulatum Rhabdoweisia d e n t i c u l a t a Rhacomitrium aquaticum Rhacomitrium f a s c i c u l a r e Rhizomnium glabrescens Sphagnum squarrosum Tetradontium brownianum and rocks o f the f o r e s t e d zone are i are frequent on these h a b i t a t s , c o n d i t i o n s , whereas other t o l e r a t e 65 a larger range of moisture conditions. There are taxa (eg., Dicranum scoparium sens, lat., Hylocomium splendens. Isothecium stoloniferum) which display slightly different morphological forms depending upon the "dryness" of the habitat. Diplophyllum albicans Diplophyllum taxifolium Lophozia floerkei Lophozia quadriloba Porella cordaeana Porella navicularis Porella r o e l l i i Preissia quadrata Ptilidium ciliare Radula complanata Bartramia ithyphylla Bartramia pomiformis Claopodium crispifolium Dicranum fuscescens Dicranum scoparium Grimmia alpicola Grimmia apocarpa Grimmia torquata Heterocladium macounii Hylocomium splendens Isothecium stoloniferum Neckera douglasii Calcareous Cliffs Moist calcareous and basic c l i f f s support a bryoflora that contains many infrequent or otherwise geographically interesting taxa. These habitats occur throughout southeastern Alaska in iso-lated exposures of metamorphic seams or as extensive regions of massive limestones and marbles. Although many of the following characteristic taxa are restricted to basic, mineral substrates, some are also known from tree trunks, or other habitats: Athalamia hyalina Barbula vinealis Lophozia bantriensis Campylium halleri Lophozia gillmanii Cirryphyllum cirrosum Lophozia heterocolpa Claopodium pellucinerve Metzgeria conjugata Cratoneuron commutatum Metzgeria hamata var. falcatum Metzgeria pubescens Distichium capillaceum Radula obtusiloba Distichium inclinatum subsp. polyclada Ditrichum flexicaule 66 Entodon concinnus S e l i g e r i a campylopoda F i s s i d e n s g r a n d i f r o n s S e l i g e r i a doriniana Geheebia gigantea S e l i g e r i a p u s i l l a Gymnostomum aeruginosum. Thamnobryum l e i b e r g i i Gymnostomum r e c u r v i r o s t r u m Thuidium d e l i cat ulum Hypbpterygium f a r u i e i v a r . radicans M y u r e l l a .julacea T o r t e l l a f r a g i l i s Plagiobryum z i e r i i T o r t e l l a i n c l i n a t a P l a t y d i c t y a .lungermannioides T o r t e l l a t o r t u o s a P o h l i a f i l i f o r m i s T o r t u l a m u c r o n i f o l i a , .V . - . SUBALPINE AND ALPINE COMMUNITIES There has been no systematic e c o l o g i c a l study made o f the a l p i n e o r subalpine i n southeastern A l a s k a . F. R. Stephens, e t a l . (1969) i n c l u d e o n l y a few h i g h e l e v a t i o n ecosystems i n t h e i r t r e a t -ment. The best d e s c r i p t i o n o f the zone has been given r e c e n t l y by Calder and T a y l o r (1968) f o r the Queen C h a r l o t t e I s l a n d s . Although p u r e l y d e s c r i p t i v e i t g i v e s some i n d i c a t i o n t o the d i v e r s i t y o f a l p i n e and subalpine h a b i t a t s , and the numerous systems o c c u r r i n g throughout. In southeastern A l a s k a , f o r example, there appear t o be at l e a s t s i x r e a d i l y d i s t i n g u i s h e d meadow (not tundra) phenomena, none o f which have been des c r i b e d i n d e t a i l . S i m i l a r l y , the wetland communities and those communities a s s o c i a t e d w i t h snow banks, ava-lanche paths and g l a c i e r s have yet t o be s p e c i f i c a l l y t r e a t e d . The s t r u c t u r e and extent o f the s u b a l p i n e , and the upper l i m i t s o f f o r e s t and t r e e growth have a l s o not been d e t a i l e d . There i s a r i c h b r y o f l o r a above the f o r e s t l i m i t , many o f the 67 taxa being particularly significant in geographical considerations. The diversity of habitats, and the strict habitat specificity of many of the high elevation constituents precludes any attempt here to consider a larger number of phenomena. A number of bryophyte taxa are known predominently from alpine and subalpine zones in southeastern Alaska: Anthelia .iulacea Anthelia juratzkana -Asterella lindenbergiana Cephalozia pleniceps Gymnomitrion obtusum Gymnomitrion pacificum Haplomitrium hookeri Harpanthus scutatus Lophozia floerkei Lophozia lycopodioid.es Macrodiplophyllum imbricatum Marsupella alpina Marsupella sphacelata Hardia geoscyphus Plagiochila arctica Pleuroclada albescens Sauteria alpina Scapania subalpina Solenostoma atrovirens Andreaea b l y t t i i Arctoa fulvella Aulacomnium turgidum Brachythecium nelsonii Conostomum tetragonum Cynodontium schisti Dicranella subulata Dicranoweisia crispula var. contermina Dicranum pallidisetum Ditrichum zonatum Encalypta affinis Grimmia Olympica Grimmia trichophylla Kiaeria falcata Kiaeria glacialis. Kiaeria starkei Lescuraea atricha Lescuraea baileyi Oligotrichum hercynicum Oligotrichum parallelum Orthothecium strictum Rhacomitrium canescens var. strictum Rhacomitrium sudeticum Rhytidiopsis robusta VI. COMMUNITIES ON EXPOSED MINERAL SUBSTRATES Non-forested, bedrock exposures are frequent throughout south-eastern Alaska at a l l elevations. The bryoflora diminishes, generally, in ocver values and diversity with increases in insolation, xeric con-68 ditions and exposure to wind. Many of the rupestra! taxa mentioned in previous categories can he located in suitable micro-environments among the following bryophytes. Since the altitudinal factor is condensed ecologically in southeastern Alaska (alpine or "pseudo-alpine" (sensu F. R. Stephens, et a l . , 1969) vegetation occurs at sea level under the appropriate circumstances) i t is not easy to categorize the plants in this group. Distinctions have been made between wetter and drier sites, and strongly calcareous systems have been singled out. Exposed Moist and Wet Rock The following l i s t includes the more common bryophytes on wet or moist rocks or c l i f f s in exposed situations: Anthelia .julacea Anthelia .juratzkana Blepharostoma trichophyHum Cephalozia -pleniceps Diplophyllum albicans Gymnocolea inflata Marsupella alpina Marsupella emarginata Marsupella sphacelate Nardia scalaris Andreaea nivalis Grimmia alpicola Grimmia apocarpa Grimmia maritima Hylocomium splendens Rhacomitrium varium Exposed Dry Rock The number of bryophytes frequent upon dry rock in exposed sites is not great, although some are restricted to that habitat 69 (eg., Andreaea spp., Grimmia ovalis ciliata, and Ulota curvifolia): Cephaloziella divaricata Chandonanthus setiformis Diplophyllum. albi c ans Gymnomitrion obtusum Gymnomitrion pacificvmi Lophozia hatcheri Lophozia quadriloba Tritomaria-quinquedentata Andreaea b l y t t i i Andreaea rothil Andreaea rupestris Arctoa hyperborea Brachythecium albicans Campylium adscendens Ceratodon purpureus Grimmia trichophylla, Hedwigia Grimmia alpicola Grimrni a apocarpa Grimmia ovalis Grimmia trichophylla Hedwigia ciliata Kiaeria b l y t t i i Kiaeria falcata Lescuraea atricha Rhacomitrium brevipes Rhacomitrium canescens Rhacomitrium lanuginosum Rhacomitrium patens Rhacomitrium sudeticum Rhytidi adelphus squarrosus Ulota curvifolia Exposed, Dry, Calcareous Rock There are a number of bryophytes in the regional flora that are known from dry, exposed calcareous rock. Many of the following are restricted to this habitat in southeastern Alaska, some known only from the most climatically dry districts: Asterella ludwigii Pjeissia quadrata Reboulia hemisphaerica Sauteria alpina Abietinella abietina Antitrichia californica Barbula fallax Barbula reflexa Bryum argenteum Desmatodon latifolius Didymodon rigidulus Distichium capillaceum-Ditrichum flexicaule En.caJ.ypt9, affinJrS, Encalypta ciliata Encalypta procera Enpalyptft vulgaris Encalypta rfrabflocarpa. Entodon concinnus Eurhvnchium puj,chell\W var. barnesii Geheebia gigantea Homalothecium fulgescens Homalothecium nevadense Lescuraea incurvata Lescuraea radicosa 70 Myurella .lulacea Orthotrichum rupestre Myurella sibirica Rhytidium rugosum Orthotrichum anomalum Tortella tortuosa Orthotrichum cupulatum Tortula norvegica Sand, Gravel» T i l l and Mineral Soils Exposed sands, gravels, t i l l s , and other mineral soils occur at a l l altitudes in woutheastern Alaska. Their derivation, structure and microclimate are diverse, and subtle differences are often re-flected in the composition of the bryophyte flora. The following l i s t includes many of the more frequent inhabitants of these habitats, plus some taxa that are locally rare (eg., Aloina brevirostris, Amblydon dealbatus, Campylopus schwarzii, and Weissia controversa): Chandonanthus setiformis Cephaloziella rubella Diplophyllum albicans Lophozia alpestris Lophozia badensis Lophozia barbata Fleuroclada albescens Preissia quadrata Scapania gymnostomophila Solenostoma pumilum Solenostoma rubrum Aloina brevirostris Amblydon dealbatus Aongstroemia longipes Atrichum selwynii Bryum spp,. Campylopus schwarzii Ceratodon purpureus Conostomum,tetragonum Cratoneuron filicinum Dicranella crispa Ditrichum, ambiguum Ditrichum flexicaule Drepanocladus uncinatus Hylocomium splendens Hypnum cupressiforme Kiaeria falcata Leptobryum pyriforme Lescuraea patens Oligotrichum aligerum Oligotrichum hercynicum Pleurozium schreberi Pogonatum alpinum Pogonatum laterale Pogonatum umigerum Pohlia annotina Pohlia drummondii Pohlia proligera Pohlia wahlenbergii Polytrichum juniperinum Polytrichum norvegicum Polytrichum piliferum Rhacomitrium canescens Rhytidiadelphus squarrosus Tortula ruralis Weissia controversa 71 Road Cutbanks The bryophytes found commonly on the cutbanks of roadways, and similar environments, are dependant primarily upon the nature of the substrate and water relations. A few taxa are almost t o t a l l y restricted lo c a l l y to this habitat (eg., Blasia p u s i l l a , Dicranella grevilleana, D. pacifica, Leptobryum pyriforme). The most notable constituents of roadcuts include: Blasia p u s i l l a Cephaloziella rubella Diplophyllum obtusifolium Marchantia polymorpha P e l l i a epiphvlla Solenostoma hyalina Solenostoma obovatum Atrichum selwynii Barbula unauiculata Brachythecium albicans Bryum spp. Ceratodon purpureus Dicranella grevilleana Dicranella heteromalla Dicranella pacifica Dicranella subulata Dicranella varia Ditrichum heteromallum Eurhynchium praelongum Fissidens bryoides Funaria hygrometrica Leptobryum pyriforme Oligotrichum aligerum Philonotis americana Philonotis fontana Pogonatum alpinum Pogonatum capillare Pogonatum laterale Pogonatum urnigerum Pohlia wahlenbergii Polytrichum commune Polytrichum juniperinum Tortula ruralis VII. SUCCESSIONAL COMMUNITIES Reiners, et a l . (1971) have recently presented results con-r cerning bryophytes in various successional stages in the southeastern Alaska vegetation. In their study, the ecologically significant bryophytes i n f l a t and level habitats are noted. While the f i e l d work for that investigation was being undertaken at Glacier Bay, the 72 present author attempted to establish a more complete survey of the bryophyte taxa in each stage. Similar investigations from soils, insects, birds, mammals and fish have been reported from Muir Inlet by several contributors to the publication edited by Mirsky (1966) of the Institute of Polar Studies. For the present thesis only a fev, broad categories from the earliest stages immediately following deglaciation to the establish-ment of mature forests are considered. The importance of these list s has not yet been ascertained ecologically. Furthermore, where a l i s t indicates that a taxon is known only from a particular successional stage the exclusiveness refers only to its known distribution within the boundaries of Glacier Bay National Monument plus the adjacent Pleasant Island. The following bryophytes are known only in the pre-Dryas and Dryas successional stages: Angstroemia longipes Orthotrichum speciosum Most of the taxa known from the Dryas stages occur also in other successional stages, some along seashores, a few in the alpine, Bryum bicolor Bryum caespiticum Dicranella subulata Drepanocladus sp. var. macounii Pohlia drummondii Tortella inclinata A few taxa are known only from the Dryas and Alnus stages: Barbula repans Hygrohypnum luridum Lescuraea patens Scapania curta 73 and most in selected forest habitats. Characteristic species include: Aneura pinguis Cephalozia bicuspidata ' Leiocolea badensis Marchantia polymorpha Moerckia flotowlana Preissia quadrata Solenostoma pumila Barbula vinealis Blindia acuta Brachythecium albicans Brachythecium asperrimum Campylium stellatum Catoscopium nigretum Ceratodon purpureus Cratoneuron filicinum Dichodontium pellucidum Dicranum scoparium Distichum capillaceum Ditrichum flexicaule Drepanocladus exannulatus Drepanocladus uncinatus Grimmia alpicola Grimmia apocarpa Gymnostoma aeruginosum . Hylocomium splendens Isopterygium pulchellum Philonotis fontana Platydictya jungermannoides Pleurozium schreberi Pogonatum umigerum Polytrichum .juniperinum Polytrichum norvegicum Ptilium crista-castrensis Rhacomitrium canescens var. ericoides Rhytidiadelphus loreus Rhytidiadelphus squarrosus Rhytidiadelphus triquetrus Tetraplodon mnioides Tortella tortuosa Tortula ruralis Hypnum callichroum Few bryophytes are common on substrates beneath a dense cover of alders in the Alnus stage except where there are moist c l i f f s and canyons, or there are perennial streams. In these environments a rich flora may develop, one which carries primarily into forest vegetation stages. A limited assemblage of bryophytes are known only from the Alnus or late Alnus stages in Glacier Bay National Monument: Chahdonanthus setiformis Lophozia bantriensis Lophozia gillmanii Lophozia atlanticus Lophozia wenzelii Scapania americana Scapania gymnostomophylla Solenostoma atrovirens Solenostoma sphaerocarpa Abietinella abietina Amblyodon dealbatus Barbula reflexa Bryum capillare Cirrophyllum piliferum 7U Claopodium whippleanum Hylocomium umbratum Drepanocladus aduncus Hypnum bambergerii Encalypta ciliata Plagiothecium roeseanum Hygrohypnum molle Tortula mucronifolia A few taxa are known from the Alnus stage and some additional, non-forested habitats: Scapania curta Crumia deciduidentata Barbula repans Hygrohypnum luridem Brachythecium albicans Meesea uliginosa Brachythecium lamprochryseum Mielichhoferia macrocarpa A considerable proportion (ca. 50$) of the known bryoflora of Glacier Bay National Monument appear first in the Alnus stage and persist in the various forest types. These include most of the taxa treated earlier in this chapter under the section on forest types. Nearly 100 species of bryophytes are known in Glacier Bay National Monument only from mature sites. These environments include those areas having a continuous vegetational cover for at least 1000 years: in particular subalpine and alpine communities, spruce-hemlock forests, and open peatlands. Characteristic taxa include: Anastrepta orcadensis Cladopodiella fluitans Anastrophyllum donianum Conocephalum conicum Anastrophyllum minuturn Gymnomitrion obtusum Anastrophyllum saxicolus Gymnocolea inflata Anthelium .luraztkanum Gyrothyra underwoodiana Asterella lindenbergiana Herberta adunca Bazzania pearsonii Herberta himalayana Bazzania tricrenata Hygrobiella laxifolia Bazzania trilobata Lepidozia filamentosa Cephalozia leucantha Lepidozia sandvicensis Cephaloziella divaricata Lophozia floerkei 75 Lophozia porphyroleuca Lophozia ventricosa Macrodiplophyllum plicatum Metzgeria con.lugata Metzgeria hamata Metzgeria pubescens Microlepidozia setacea Moerckia b l y t t i i Mylia taylori Nardia scalaris Qdontoschi sma elongata Plagiochila major Pleuroclada albescens Pleurozia purpurea Sauteria alpina Radula polyclada Riccardia multifida Scapania.uliginosa Andreaea nivalis Anoectangium aestivum Arctoa fuvella Bartramia pomiformis Bartramiopsis lescureae Campylium halleri Claopodium.bolanderi Desmatodon latifolia Drepanocladus fluitans Encalypta affinis Eurhynchium pulchellum Fissidens bryoides Geheebia gigantea Hypnum plicatulum Isopterygium borrerianum Lescureaea incurvata Leucolepis menziesii Mnium bly t t i i Oligotrichum parallelum Orthothecium strictum Plagiopus oederiana Pohlia wahlenbergii Polytrichum formosum Rhacomitrium squaticum Rhacomitrium brevipes Sphagnum fuscum Sphagnum lindbergii Sphagnum magellanicum Sphagnum palustre Sphagnum papillosum Sphagnum recurvum Sphagnum rubellum Sphagnum tenellum Sphagnum warnstorfii Splachnum ovatum. Tetraphis geniculata 76 CHAPTER IV BRYO-GEOGRAPHY I. INTRODUCTION When considering the hiota of a district i t must be determined which geographical features should be selected that best describe and interpret its origins and history. The problems in circumscribing biogeographical regions are discussed in sever treatises (Schouw, 1823; Wulff, 19^3; Cain, 1944, 1947; Darlington, 1957; Just, 1947; Camp, 1947; Hulten, 1958, 1962; Good, 1964; Schmithuse, 1968; Schuster, 1969b; and others). Most biogeographical texts, however, simply give brief descriptions of the areas treated. The categories selected for use in this thesis have been based primarily upon the elements chosen by Schofield (1969b) in his recent treatment of the vascular and bryophyte flora of northwestern North America, although several alterations have been made. After a brief consideration of the taxa new to Alaska and new to southeastern Alaska, geographical affinities of the bryoflora are examined. Following the treatment considering the total ranges of the taxa, a section considers the distributions of the plants in western North America, and another their distribution within southeastern Alaska. The i n i t i a l section discusses endemic, continuous, and. discon^ tinuous ranges. Endemism is a clearly distinguished concept. An TT endemic can be defined as a taxon which is completely restricted to a specific physiographical or political region. However, the def-inition and relationship between discontinuous (or "disjunct") and continuous ranges of taxa forms the heart of biogeography, offers the greatest difficulty of implementation, and is the keystone of considerable discussion. The classical discontinuous distribution can be defined as a situation wherein a taxon occurs in or is uniformly spread throughout each of two or more widely separated geographical regions. Nevertheless, within an area of more or less continuous distribution there exist inevitable discontinuities, with some indi-viduals or groups isolated from the main body of the population, or with a l l individuals occurring more or less at a distance one from another. In many specific cases there are no complications in deter-mining or describing discontinuous distributions; but in some circum-stances, for example the tree species of the boreal forests of North America (de Laubenfels, 19T0), i t can be a matter of difficult, i f not arbitrary, choice to denote the boundaries of areas of continuity and the regions of discontinuity. In general, i t is not the delimitation of continuous or dis-continuous geographical areas that presents the major difficulties, but i t is the recognition of meaningful, workable categories, and the assigning of taxa to the categories, that creates the bulk of the practical and theoretical problems. These become important consider-7 8 ations of the geographer (eg., Hertzog, 1926; Wulff, 1943; Cain, 1944, 1947; Camp, 1947; Darlington, 1957; Hulten, 1958, 1962, 1968; Polunin, i960; Szweykowski, 1961-69; Gleason and Cronquist, 1964; KUcher, 196U; Good, 1964; Schuster, 1969b; and Stormer, 1969), the evolutionist (eg., Stebbins, 1959, 1966; Mayr, 1963, 1964; Davis and Heywood, 1965; Briggs, 1966; and others), and the ecologist (eg., Braun-Blanquet, 1932; Cain, 1947; Whittaker, 1953, 1962, 1970; Dansereau, 1957; McMillan, 1959; Eyre, 1963; Billings, 196U; and others). To illustrate the difficulties that arise in selecting which categories to use in a given study, consider the recent classification of the world into floristic regions by Good (1964). He lists 37 regions "... which may, at least for theoretical purposes be regarded as roughly equivalent in floristic value ...", and further subdivides these into 130 sub-regions. At least 100 of these sub-regions contain species that are found in southeastern Alaska. The possible different combinations of these sub-regions which would contain the Alexander Archipelago is on the order of 1 X 10^, and the possible combinations considering just the regions is on the order of 1 X 10-1-0. Systems such as these can be handled easily only via the use of computer techniques. Furthermore, they require species citations at least as specific as the boundaries of the regions or sub-regions. In order to apply a particular flora to such a schema further 79 factors must be imposed upon the categories. This reduces them to a small enough number of categories to permit discussion, and yet numerous enough so as not to suffer from over-simplification. Examples of the numerous categories that exist in floristic studies include a work by BBcher (1943), who utilized over 60 cate-gories in treating the Arctic and European portions of the Boreal flora. Hulten (1950) in classifying the distributions of vascular plants from just northwestern Europe recognized 48 groups. He further (Hulten, 1958) required 16 subcategories to treat the Amphi-Atlantic group. Stflrmer (1969) considered just the European distributions of only 70 species with a limited Norwegian range (those with a western and southern distribution). Twelve categories were established, of which more than half (7) contained three or fewer species. Were similar proportions to be applied to the southeastern Alaska bryoflora (considering the world distribution of the species) there would be a minimum of between 100 and 200 geographical categories required, of which 50 to 100 or more would contain fewer than 17 species, and many would have but a single species. An endeavour to undertake such a study, although admirable and ultimately desirable, is totally impractical considering the general unattainability of consistently precise and verified citation data. Therefore, at present i t appears to be most expedient to treat the flora in terms of already delimited (and demonstrably useful) categories, hence allowing con-8o tinuing, accumulative and comparative results; and to recognize only additional categories that are compatible with the existing ones, especially on the levels of data specificity and significance. The selection of the endemic categories in this thesis is straightforward and is based, in part, upon political boundaries rather than natural ones as the delimiting borders. Although containing inherent biological difficulties, the categories "Cosmopolitan" and "Bipolar Disjunct" are relatively succinct, and are discussed under their respective headings. These two compartments are adequate to treat the bulk of the southeastern Alaska bryoflora that occurs in the Southern Hemisphere. At least 85 percent of the bryoflora of southeastern Alaska is restricted to or centered in the Northern Hemisphere north of the tropics. Good (196U) divides this part of the world into 10 major regions and subregions under the heading "Boreal Kingdom": 1. Arctic and Subarctic Region 2. Euro-Siberian Region A. European Subregion B. Asiatic Subregion 3. Sino-Japanese Region 4. Western and Central Asiatic Region 5. Mediterranean Region 6. Macaronesian Region 81 7. Atlantic North American Region A. Northern Subregion B. Southern Subregion (including the Prairies) 8. Pacific North American Region The establishment of most of these regions i s based upon vascular plant distributions (Schouv, 1923; Engler and Diels, 1936) , and they are separated (very roughly) by north-south boundaries; the notable latitudinal exception being the Arctic and Subarctic Region. ("Boreal" has been variously u t i l i z e d to include the Arctic — Campbell, 1926; Herzog, 1926; Hulten, 1962; Good, 196U, or to be distinct from the Arctic — Polunin, i 9 6 0 ; SJors, 1963; Schmithusen, 1968; and Schofield, 1969b). For this thesis i t was decided to reduce these ten units to seven. The seven consist of the Arctic and Subarctic region, plus six others based upon oceanic vs_. continental d i s t r i c t s . Hence, the two continents are divided into eastern and western oceanic di s t r i c t s plus the interior regions. Good's regions basically define the six: Eastern North America (7A) Continental North America ( 7 B ) Western North America (8) Eastern Asia (3) Continental Eurasia ( U , 2B) Western Eurasia (2A, 5,. 6) 82 The fits are not perfect, especially in "Eastern Asia" which in-cludes the oceanic parts of "2B" (that which is east of Lake Baikal and the Lena River), and excludes portions of "3" (the Himalayas, Tibet, and Szechwan and Yunnan, China), placing them in "Continental Eurasia". The whole of the Tibetan Plateau and the adjacent mountains from the Pamirs and the Hindu Kush to western Szechwan probably de-serves regional.status itself, especially when considering the bryo-phytes (this was done by Herzog (1926) whose geographical categories were of similar division and extent to those of Good). These six regions, then, may be combined into 63 different geographical categories, some continuous except for intervening bodies of water, others disjunct; however, only 32 of the categories include southeastern Alaska. Eight of these categories are essentially without bryophyte representation, four of them are discussed under the ti t l e "Circumboreal", four under "Circumboreal (Missing in Eastern Asia)", three under "Disjunct Western North America - Western Eurasia", two under "Disjunct Western North America - Western Eurasia - Eastern Asia", five under "Disjunct North Pacific", two under "Disjunct Eastern Asia - North America", three under "Endemic to North America", and one under "Endemic to Western North America". Four of the categories are grouped under "Unique Distributions". Most of the Boreal subclassifications chosen for treatment here have been considered previously by various plant geographers; however, 83 depending upon which biotic sector is being emphasized the scope and limits of the classification vary from author to author (summarized in part by SjBrs, 1963). In this thesis there have been segregated for special consideration those boreal species which are essentially circumboreal, but are missing from eastern Asia. "Cir-cumboreal Maritime" and "Boreal through Anthropogenic Introduction" of Schofield (1969b) have been included within "Circumboreal". Furthermore, although "Circumboreal (Missing in Eastern Asia)" and "Disjunct Western North America - Western Eurasia - Eastern Asia" are essentially parallel categories (the latter could be considered "Circumboreal (Missing in Eastern North America)"), they have been titled as such to emphasize that most species in the former are common in the interiors of the continents, whereas the majority of the species which comprise the latter have more limited ranges and are often re-stricted to generally oceanic or coastal districts. The categories "Circumarctic", "Circumalpine" and "Arctic-Alpine" pose some problems when applied to the southeastern Alaska bryoflora. They are treated under their respective headings. In addition to the consideration of the total ranges of the southeastern Alaska flora there are four sections pertaining to the pattern of occurrence of taxa within the western North American portion of their range, and eight sections concerned with regional distri-butions within southeastern Alaska itself. The categories were chosen to demonstrate two aspects in western North America: climatic-8k ally controlled tendencies, and latitudinal and/or longitudinal boundaries. The western North American portion of the text is necessitated primarily due to some taxa exhibiting different eco-logical or geographical tolerances or restrictions in various por-tions of their ranges. Furthermore, the present western North American patterns are particularly useful in the determination of the recent history of the distribution of many of the bryophytes. The southeastern Alaska categories chosen are those which have been the most useful in the search for local trends which could yield information on the historical or ecological causes of specific distributions. Those categories dealing with latitudinal factors present fewer problems than those concerning ecological factors. Table II summarizes the constituents of each of the geograph-ical areas discussed. The numbers and proportions of hepatics, of mosses, and of a l l bryophytes are listed for each area. II. NEW RECORDS New to Alaska Eleven species of liverworts can be cited'for the first time from Alaska. One, Cephalozia loitlesbergeri. has not been reported previously from western North America. One, Solenostoma pumilum. is to be expected from throughout Alaska based upon the remainder of its TABLE II NUMBERS OF TAXA AND PERCENTS OF THE SOUTHEASTERN ALASKAN BRYOPHYTE FLORA IN EACH GEOGRAPHICAL CATEGORY GEOGRAPHICAL CATEGORY HEPATICS MOSSES BRYOPHYTES TAXA PERCENT OF HEPATICS TAXA PERCENT OF MOSSES TAXA PERCENT OF BRYOPHYTES Species in southeastern Alaska 155 378 533 Additional varieties in southeastern Alaska 4 35 39 Taxa in southeastern Alaska 159 100. 413 100. 572 100. New to Alaska 11 6.9 27 6.5 38 6.7 New to southeastern Alaska (including "New to Alaska) 27 17. 67 16. 94 16. Endemic to southeastern Alaska 1 0.6 0 0.0 1 0.17 Endemic to Alaska — Yukon 0 0.0 1 0.24 1 0.17 Endemic to Western North America (EWNA) 12 7.5 42 11. 54 9.4 Endemic to North America (ENA) 0 0.0 6 1.4 6 1.1 Table II (continued) Circumboreal (CB) 92 58. 202 49. 294 51. Circumboreal (Missing in Eastern Asia) (CB(MEA)) 21 1 3 - 53 1 3 - 74 1 3 -Circumarctic (CA) 1 0.6 6 1.4 7 1.2 Circumalpine (CAL) 6 3-8 6 1.4 12 2.1 Arctic — Alpine (AA) 2 3 14. 29 7.0 5 2 9.1 Cosmopolitan (COS) 4 2.5 21 5.1 25 4.4 Disjunct North Pacific (DNP) 10 6.3 18 4.8 28 4.9 Disjunct Western North America — Western Eurasia (DWW) 6 3-8 25 6.0 3 1 5.4 Disjunct Western North America — Western Eurasia — Eastern Asia (DWWE) 9 5.7 11 2.7 20 3-5 Disjunct Eastern Asia — North America (DEANA) 0 0.0 3 0.7 3 0.51 Disjunct Bipolar (DBP) 9 5.7 5 2 1 3 . 61 11. Unique Distribution (DU) 12 7.5 28 6.8 40 7.0 Table II (continued) Widespread in Western North America (W) 95 58. 284 69. 379 67. Oceanic in Western North America (0) 56 35. 91 2 2 . 147 26. Interior in Western North America (I) 1 0.6 24 5.8 25 4.4 Hyperoceanic in Western North America (HO) 12 7.5 4 0.97 16 2.8 Widespread in Southeastern Alaska (WS) 92 58. 237 57. 329 58. Wet Climate in Southeastern Alaska (WC) 12 7-5 8 1.9 20 3-5 Dry Climate in Southeastern Alaska (DC) 4 2.5 38 9 . 2 42 7.3 Northern Distribution in Southeastern Alaska (ND) 12 7-5 43 10. 55 9.6 Southern Distribution in Southeastern Alaska (SD) 4 2.5 15 3.6 19 3-3 Northern Limit in Southeastern Alaska 32 20. 75 18. 107 19. Southern Limit in Southeastern Alaska 3 1.9 15 3-6 18 3.1 Limited Records in Southeastern Alaska (LR) 45 28. 102 25. 147 26. 88 range. The other nine species are northern range extensions. Most of these species are common in adjacent, coastal British Columbia and extend southward and/or eastward into unglaciated portions of North America. Herberta himalayana and Treubia nana are otherwise known in North America from only oceanic British Columbia. Twenty five species and two varieties of mosses can be cited for the first time from Alaska. A l l are species that could have been predicted from the region based upon their previously known ranges. Al l but Plagiobryum zierii and, possibly, Meesea longiseta (which are known transcontinentally in northern North America) are northern range extensions in western North America. Eight are endemic to western North America, six have disjunct western North American populations, and the remainder are transcontinental in North America. Both Calliergon wickesiae and Campylopus schwarzii are restricted to the hyperoceanic districts of British Columbia and Alaska in western North America. Of the 38 species new to Alaska (6.7 percent of the southeastern Alaska flora, and h.k percent of the Alaskan bryophyte flora) only Cephalozia loitlesbergeri can be considered truly unexpected (although other taxa, recently discovered likewise could not have been predicted: for example, some of the reports "by Schofield (I968a,b,c,d), and Haplomitrium hookeri (Worley, 1969)). In fact, considering the nature of the area, and the lack of previous, thorough collections from a l l 89 elevations i t is surprising that only 6 .7 percent of the flora is new to the state. Further additions can be anticipated from among numerous species that are known from western North America northward to north coastal British Columbia and the Queen Charlotte Islands (eg., Sphagnum mendocinum. Porotrichum bigelovii, Polytrichadelphus l y a l l i i , Tremato- don boasii, and others). There are also several species of bryophytes known only from the Queen Charlotte Islands in North America (eg., Ancanthocladium carlottae, A. sp., Chandonanthus hirtellus, Seligeria sp., Mastopoma? sp., and Radula auriculata (Schofield, 19690)) that may yet be located in southeastern Alaska, when the specialised, hyperoceanic habitats have been more thoroughly investigated. It does not seem unreasonable to predict that an additional 30-50 species of bryophytes new to Alaska are yet to be found in the southeastern district, species probably of similar geographical affinities as the 38 reported here. New to southeastern Alaska In addition to the species reported as new to Alaska some 16 hepatics and 40 mosses can be cited for the first time from south-eastern Alaska. Hence a total of 94 species and varieties are new to the region, 16 percent of the total bryoflora. Most of these taxa were to be expected in southeastern Alaska as they had been reported previously from adjacent Alaska and/or British Columbia. Some (ca.-15) are not otherwise known from coastal 90 environments, especially in non-Arctic latitudes. Others (ca. 10) have been reported previously but once, or infrequently, from the state. Encalypta affinis, Hypnum bambergeri and Meilichhoferia macrocarpa have their southernmost coastal report in western North America in southeastern Alaska. Scapania gymnostomophila and Ortho- thecium strictum are otherwise considered species of more northern latitudes in western North America. Trachycystis flagellaris and Crumia deciduidentata are known in North America only from coastal districts westward about the Gulf of Alaska. Of this group i t is apparent that the majority of species were to be anticipated from the region, and that the records essentially f i l l gaps in known distributions. Of particular note is the paucity of northern or Arctic species with range extensions entering south-eastern Alaska; furthermore, only 3.1 percent of the known flora of the district has its southern limit of distribution in the region. There are probably an additional 100 or more species of bryo-phytes to be added to the flora of southeastern Alaska. There are at least 850 species of bryophytes now known from the state (Worley, 1970; Worley and Iwatsuki, 1970), although only 572 of these are reported from the southeastern district. 91 III. DISTRIBUTIONAL DIVISIONS A. WORLD DISTRIBUTIONS Endemic distribution Category 1. Endemic to southeastern Alaska. Only one bryo-phyte Frullania chilcootiensis, is endemic to southeastern Alaska, and the validity of the taxon is in serious doubt. It is probable that there are no species of bryophytes endemic to the region, and, likewise, no subspecies or varieties. Two vascular plants, Poa norbergii and Castilleja chrymactis, and four small mammals, Microtus longicaudus. M. coronarius, M. oeco- nomus and Sorex obscurus malitiosus (KLine, 1965), are endemic to the region. The almost total lack of local endemism, supplemented by the small percentage of species (72 bryophytes and 182 vascular plants) which have distributional limits within the region support the con-tention that southeastern Alaska is not a distinctive biogeographical (and especially bryogeographical) unit. However, the restricted distribution of the various hyperoceanic and "Wet Climate" species in north coastal British Columbia, the Queen Charlotte Islands and southeastern Alaska may be duplicated by some endemic taxa (such as the small mamals Peromyscus sitkensis, Sorex obscurus elassodon, and S_. obscurus prevostensis (Kline, 1965)). There are already several 92 endemic bryophytes and vascular plants known from the Queen Charlotte Islands, and these may also occur in appropriate regions of the Alex-ander Archipelago, but are unknown at present. Nevertheless, i t would appear that in southeastern Alaska there has been virtually no species segregation since the last deglaciation (cf. Schuster, 1958), or that the ecological boundaries of the region are not strict enough to contain taxa. Category 2. Endemic to Alaska-Yukon. Only two species of bryophytes, Crumia deciduidentata and Frullania chilcootiensis (pre-viously discussed under southeastern Alaskan endemism) in the south-eastern Alaskan flora are endemic to the Alaska-Yukon district. Scho-field (1969b) summarizes the pertinent literature of this group of plants and l i s t an additional four bryophytes endemic to the area. He further lists some 76 vascular plants endemic to Alaska-Yukon, and in-dicates that the majority of these were derived from polymorphic cir-cumpolar genera (plus a possible Tertiary relic, Boykinia richardsonii (Hook.) Gray) in the large, unglaciated regions of the district. That the number of corresponding bryophytes is so small, and since none of the northern or Arctic endemics extend into southeastern Alaska, in-dicates that there has been insufficient time for post-glacial migration into southeastern Alaska, or that the climatological or ecological conditions are unsuitable for these species. 93 Category 3. Endemic to western North America. Schofield (1969b) delimits "Northwestern North America" as including Alaska, the Yukon, British Columbia, Washington, northern Oregon and Idaho, and the Rocky Mountains portion of Alberta and Montana. To facilitate the treatment of the distributions of a number of bryophytes here, "Western North America" is expanded to include also the regions west of the Rocky Mountains south to the Mexican — United States boundary. However, since the primary concern in this section is with those species found in Alaska, i t w i l l , for the most part, deal with "North-western North America" as defined by Schofield. Twelve of the species of hepatics found in southeastern Alaska (7«5 percent of the regional.hepatic flora).are endemic to western North America. Frullania chilcootiensis is known only from southeast-ern Alaska. Plagiochila firma subsp. confusa and Macrodiplophyllum imbricatum are known from coastal British Columbia to the Aleutian Islands. Four of the species extend from California to southeastern Alaska, while the remainder range from California to Alaskan points west and/or north of the Alexander Archipelago. Most of the species are coastal, but there are three known inland to Idaho, Montana and (in one case) Wyoming. Forty two of the species of mosses known from southeastern Alaska ( l l percent of the regional moss flora) are endemic to western North America. Crumia deciduidentata is known only from south coastal 9k Alaska. Brotherella sp. is known only from coastal British Columbia and the Alexander Archipelago. Two species are known from British Columbia to Alaska, seven from Washington to Alaska, four from Oregon to alaska, and the remainder (27) from California to Alaska. Half (22) of the species extend no farther north than southeastern Alaska, and slightly over half (26) range variously eastward to the Rocky Mountains. As in other geographical groups in this study the hepatics are predominantly oceanic, whereas many of the mosses are known also from continental regions. Schofield (1969b) l i s t s 11 bryophyte genera and almost 100 vascular plant genera endemic to western North America. He further l i s t s , in several sub-categories, some 113 bryophyte species and over 825 vascular plant species endemic to western North America. A sig-nificant portion of the bryophytes (four of the genera and 55 of the species) are known from southeastern Alaska, most of which are found well into regions south of the Pleistocene glacial boundary. About 20 percent of these are rare everywhere in their range, 20 percent are rare in southeastern Alaska and common further south, and the remainder are frequent and characteristic of the local flora. Some of the most abundant bryophytes in the archipelago are in this grouping: Frullania tamarisci subsp. nisquallensis, Porella navicularis, Brachythecium asperrimum, Dicranum howellii, Eurhynchium oreganum, Heterocladium 95 macounii, Hypnum circinaie, Isothecium stoloniferum, Lescuraea baileyi, Leucolepis menziesil, Plagiomnium insigne, Rhizomnium.glabrescens, Rhytidiopsis rohusta; Scouleria aquatica, and Ulota obtusiuscula. These are species of the forest zones and of the subalpine, and most are commonly fertile. Overall, the majority of the endemic species are from forest habitats, a few are from subalpine and alpine zones, and most are widely distributed. This is unlike the vascular flora which has an increase of endemism in the alpine zone, and which also displays mountainous "island endemism". Calcareous, hyperoceanic, and peatland species are essentially absent from this group of endemics, these species generally belonging to either circumboreal or disjunctive cate-gories. Considering that "The forest is entirely of endemic trees and mainly of endemic shrubs, and the herbaceous vegetation is dominated by endemic species" (Schofield, 1969b), i t is not surprising that most of the endemic bryophytes are forest species. Nonetheless, not a l l of the bryophytes are especially or intimately dependant upon the partic-ular vascular flora either as epiphytes or in other restricted habitats determined specifically by the vascular plants present. The greater share are species of the forest floor and of rocks in shaded forest habitats, hence indirectly reflecting the same climatic and geological zonation displayed by the combined macrovegetation. With rare exceptions these taxa are known from regions south of 96 the glacial boundary, and they would have been able to persist there during the maximum ice advances, subsequently reinvading the archi-pelago upon deglaciation and the re-establishment of the forests. In Glacier Bay (Reiners, et a l . , 1971) many of these species are found in the young successional forests only a few decades after the stagnation or disappearance of the ice, while a few do not appear for, perhaps, several centuries (such as Eurhynchium oreganum, Leucolepis menziesii, and Scouleria aquatica). With the "pulsations" of the ice front to the north and east, and the climatic — physiographic barriers to the mountainous east and the more arid south, there were many opportunities for Pleistocene isolation and speciation. If the development of the western North American vascular flora is a meaningful guide (Wolfe, 1969), a number of the taxa were established during the Pleistocene. While such a derivation is probable for some species (especially those which have close, extant relatives (eg., Atrichum selwynii, Dicranella pacifica, Dicranum nowellii. Pogonatum macounii, Rhacomitrium brevipesy Frullania tamarisci subsp. nisquallensis, Plagiochila firma subsp. confusa, Porella r o e l l i i . and Scapania americana). some species and genera are sufficiently remote to require, perhaps, an explanation of their, origins.in.the.late Tertiary* or earlier, (eg.^ Gyrothyra.underwood-iana, Crumia?, Grimmia Olympic a?, and Leucolepis menziesii). Hence, the bulk of the western North American endemic bryo-97 phytes in osutheastern Alaska probably evolved concomitantly with the largely endemic coastal coniferous forest, with the centre of the development south of or beyond glacial limits. A notable lack of endemism of bryophytes occurs in more specialized habitats, and a similar, remarkable lack of endemism exists among peatland constit-uents. Furthermore, virtually none of the endemics is as highly restricted in range as many of the vascular endemics, although they may have no apparent specialized reproductive structures and are limited to highly specific microenvironments. Endemic derivatives from circum-polar, Arctic, or Aleutian species appear to be infrequent or lacking. Category h. Endemic to North America. Five species and one variety of mosses known from southeastern Alaska are widely distributed in North America and are endemic to the continent. Only Fontinalis patula and Philonotis americana are common and widespread, although Mielichhoferia macrocarpa is relatively frequent in the Arctic, from Alaska to Greenland. The others are restricted to the eastern and western coastal districts, with Calliergon wickesiae and Hygrohypnum pseudomontanum being poorly known in their ranges. With the possible exception of Mielichhoferia macrocarpa none of these is highly distinctive or isolated. This may indicate that they are youthful species. In contrast to the paucity of bryophytes in this element there are numerous regional vascular plants restricted to, but widespread in, North America; however, many of the most dominant 98 and conspicuous species noted "by Schofield (1969b) are missing or of limited distribution in coastal environments. This is not a significant segment of the bryoflora, except in that i t can be inferred that, in general, bryophytes are restricted to rather limited physiographical and climatological zones, or are wide-spread globally. Thus, should a species evolve that is capable of dispersing across or throughout the North American continent i t is likewise capable of intercontinental dispersal. Widespread distributions Category 5 . Circumboreal. In the broadest sense about 83 percent of the hepatic flora and 69 percent of the moss flora of south-eastern .Alaska are widely distributed in the Northern Hemisphere. This includes the following categories of this thesis: "CB" (Circum-boreal), "CB(MEA)" (Circumboreal — Missing in Eastern Asia), "CA" (Circumarctic), "CAL" (Circumalpine), "DWWE" (Disjunct Western North America — Western Eurasia — Eastern Asia), and "DEANA" (Disjunct Eastern Asia — North America), plus selected individuals of "COS" (Cosmopolitan) and "DU" (Unique Distribution). In this thesis the category "Circumboreal" has been used in a somewhat less broad sense, similar to the treatment by Good (1964) in his chapter "The Distribution of Species — II". In Good, those species which are essentially limited to the Arctic or the subarctic are dealt with separately, but in which are included many species that 99 are incompletely circumglobal — in particular those which are notably absent from: a) central North America, b) central Eurasia, c) western Eurasia, d) central North America and central Eurasia, or e) less well-difined or-scattered areas not easily categorized. Those species which are essentially circumboreal, but missing in either eastern North America or eastern Eurasia are separately treated, as are some of the more singular distributions. With the exceptions of a few species in the categories "COS" (Cosmopolitan), "DNP" (Disjunct North Pacific) and "DWW" (Disjunct Western North America — Western Eurasia) the most widespread, fre-quent and abundant hepatics of southeastern Alaska belong to the cir -cumboreal element. Fifty eight percent of the regional flora is in-cluded in this category (and an additional lk percent in "CB(MEA)"). Anastrophyllum assimile and Nardia compressa are restricted in eastern North America to Greenland. Anastrophyllum saxicolus, Bazzania tricrenata, Cladopodiella fluitans, G. coralloides, G. con- cinnatum, Lophozia wenzelii and Pellia neesiana are known from oceanic and continental regions of Eurasia, but are unknown or of limited distribution in central North America. Jungermannia lanceolata. Lophozia lycopodioides, L. obtusa. Pellia endiviifolia and Radula complanata are similarly widespread in North America, but are unknown or of limited distribution in central Eurasia. Several of the most common southeastern Alaska liverworts are included in the following 100 group, species which are restricted to the oceanic portions of the continents: Anthelia julacea. Bazzania denudata, B. trilobata, Caly- pogeia muelleriana, Cephalozia leucantha. Diplophyllum albicans, Harpanthus scutatus, Herberta adunca, Lophocolea cuspidata, Lophozia floerkei., Marsupella emarginata?, M. sphacelata, Mylia taylorii, Hardia scalaris, Pleuroclada albescens. Riccardia multifida, R. palmata?, and R. sinuata. The remaining 60 or so species in the circumboreal element are generally widespread throughout the Northern Hemisphere. Many of the most common and abundant mosses in southeastern Alaska are circumboreal (including "CB" and "CB(MEA)"), but a large number occur also among the Cosmopolitan, Disjunct North Pacific, and Endemic to Western North America elements. Approximately 42 percent of the regional mosses are included in the present category (and an additional 19 percent in "CB(MEA)"). Of these, Anoectangium aestivum. Cirriphyllum cirrosum. Dicranella crispa, Dicranum spadiceum, Lescuraea incurvata. Paraleucobryum enerve, Philonotis seriata. and Rhacomitrium aquaticum are restricted in eastern North America to Greenland. Abietinella abietina. Amblystegium varium. Brachythecium plumosum, Bryhnia novae-angliae, Dicrahodontium asperulum, Isopterygium muellerianum, Plagiobryum z i e r i i . Pohlia sphagnicola, Sphagnum palustre, and S_. quinquefarium are known from oceanic and continental regions of Eurasia, but are unknown or of limited distribution in central North 101 America. Cynodontium polycarpon and Fissidens adianthoides are similarly widespread in North America, hut are unknown or of limited distribution in central Eurasia. Several species are restricted to the oceanic portions of the continents: Arctoa fuvella, Campylopus atrovirens, Dicranella palustris, Grimmia maritima, Hylocomium umbratum, Kiaeria b l y t t i i , K. glacialis, Mnium spinulosum, Rhabdoweisia denticu- lata, Sphagnum imbricatum, S_. tenellum, Ulota crispa, and U. drummondii. Most circumboreal species are known from south of the glacial boundary in western North America, and/or from the large, unglaciated (Coulter, et al., 1965) regions of Alaska and the Yukon to the north. However, a few are not now known from these areas of major Pleistocene refugia: Bazzania trilobata, Gymnomitrion apiculatum. Harpanthus scutatus, Mylia taylorii, Brachythecium plumosum, B. starkei, Dicrano-r dontiurn asperulum, Hylocomium umbratum. Neckera pennata, Philonotis seriata, Pohlia elongata?, Sphagnum lindbergii, S_. papillosum, S_. quinquefarium and S. tenellum. Many of this group are discussed else-where in this thesis, but i t is pertinent to note that several of the species are dioecious and sterile in western North America, including a l l of the hepatics and Hylocomium umbratum. Dicranodontium asperulum is likewise dioecious and sexually sterile, but numerous gemmae formed of deciduous leaves axe common. The remainder are occasionally to usually fertile. Furthermore, Bazzania trilobata, Gymnomitrion apicu- latum -and- Harpanthus scutatus appear to be infrequent or of limited 102 distribution in the region. Hence, the bulk of the bryophyte flora of woutheastern Alaska is composed of species that are widespread in the Northern Hemisphere, and which have been capable of re-entering formerly glaciated terrain within at least a few thousand years after deglaciation, commonly within a few years or decades (Reiners, et_al., 1971) . Furthermore, the presence or absence of sporophytes and/or specialized reproductive structures is not necessarily predictive of the dispersal ability of widespread species, nor the breadth of their ranges (Schuster, 1969b). Good (196U, p. 177) summarizes the Boreal flora in terms of vascular plants, but which are also generally applicable to bryophytes: The great extent of the land surfaces in the colder parts of the northern extratropical world...; the arrange-ment of these lands in an almost continuous circumpolar belt; and, doubtless, the marked climatic vicissitudes to which most of them have been subjected since the end of the Tertiary, combine to give their plant l i f e a rare degree of floristic unity, of which the most notable expression is the unusual prevalence of species with wide distributions and a comparative paucity of narrower endemics of a better-marked sort, a characteristic which points clearly to the main feature of this northern flora, which is that i t i s , in broad terms, a diminished extension northwards of the various floras in the latitudes immediately south of i t . He further suggests that the unique geography of the Northern Hemisphere, in placing such an extensive land area in a climatically stressful zone has tended to " s i f t " out those plants from their more tropical ancestors which possessed or evolved the necessary tolerances. It is suggested that the same mechanisms that often permit northward 103 existence also provide mechanisms for widespread dispersal. Hulten (1962) gives a brief but comprehensive outline of the effects of the Pleistocene upon the species which were presumably widespread in the period of more uniform Northern Hemisphere climate during the Tertiary. Extant species, in general, are regarded to have had an ancestral circumboreal Tertiary distribution which was established under less severe climatic and geological conditions, then fractioned during the Pleistocene by the expansion of the glacial ice and the associated climatic alterations. These conditions also permitted the southerly expansion of the ranges of many species, to sites where they have sometimes persisted, especially in the mountains and upon lakeshores (Butters and Abbe, 1953; Schuster, 1958), while eradicating the same species from other sites. The catastrophic events of the Pleistocene, the accompanying dissections of more continuous distributions, plus the subsequent retreat of the ice, provided climat-ically and edaphically similar regions around the globe that were "suddenly" available for colonization by numerous species. Those capable of aggressive, rapid, and long range dispersal and migration were able to establish or regain their circumboreal distribution pattern. In certain cases the expansion has apparently been more vig-orous in some areas than in others, yielding a contemporary distribu-tion wherein the species is common and widespread in certain regions and otherwise widely distributed but highly local. 104 The maps of Szweykowski (1961-68) illustrate the phenomenon of a scattered, discontinuous, but widespread, circumboreal distri-bution for several hepatics: Anastrophyllum minutum, Anthelia julacea, Lophozia barbata, Metzgeria pubescens., Mylia taylori and Sauteria alpina. Few bryophytes have been mapped with the detail that Hulten (1958, 1 9 6 2 , 1 9 6 8 ) has applied to the circumboreal and northern vascular plants. He ( 1 9 6 2 ) stresses the inadequacy of presenting distributions (as has been done for total ranges in this thesis) in words ("The Himalayas", "Siberia", "Quebec", etc.); a practice which tends to yield impressions of continuity. Most taxa, in fact, have intricate and complex distributions which often contain many gaps and local populations, as a glance at any of his maps will demonstrate. Good ( 1 9 6 U ) carefully considers the inherent problems encount-ered when attempting to circumscribe areas based upon point citations. He concludes that a style of presentation should be chosen based upon the scope of the study and the extent of the geographical region to be treated. The elaboration should be adequate to the purposes of the study, whereas the detail should be similarly restrained so as not to mask the intended results. E>r example, Raup (1941, 1947) and Good (1964) point out this weakness in Hulten's (1937) "Isochore" map proposal, in which the judgements placed upon the choosing of contin-uous areas are fundamental to the application of the "Theory of Equiformal Progressive Areas". By altering a decision of the bounds 105 of an area the theory could he strengthened or weakened, a possibility that in itself tends to diminish the values of the conclusions. Circumboreal species are generally considered to have dis-tributions resulting from a modification of a widespread pre-Pleisto-cene distribution. That a taxon can exist in one area and not in another is determined not only by historical events, but also by the ecological acceptability of the site, the dispersal capacity of the organism, and the time of arrival in terms of niche competition (van der P i j l , 1969). In this regard, upon individual inspection of these factors with respect to particular circumboreal taxa i t is possible that some of the distributions may be explicable only in part by major Pleistocene geological and climatological events; some, indeed, may be expanding their territories. The assemblage of circumboreal bryophytes known from southeast-ern Alaska demonstrates primarily that the region is basically a typical segment of the boreal zone, notably oceanic, and not especially dis-tinctive as a bryological unit within the flora of the circumboreal z
UBC Theses and Dissertations
The bryo-geography of southeastern Alaska Worley, Ian Almer 1972
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