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UBC Theses and Dissertations

Remote sensing of off-road vehicle impacts to soil and vegetation on the Lac du Bois rangelands, Kamloops,… Allan, Grant Edward 1980

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REMOTE SENSING OF OFF-ROAD VEHICLE IMPACTS TO SOIL AND VEGETATION ON THE LAC DU BOIS RANGELANDS, KAMLOOPS, BRITISH COLUMBIA V»^__X GRANT EDWARD ALLAN B.A. , U n i v e r s i t y of Winnipeg, 1977 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF THE FACULTY OF GRADUATE STUDIES REMOTE SENSING / FORESTRY We accept t h i s thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA by MASTER OF SCIENCE i n October 1980 0 Grant Edward A l l a n , 1980 In presenting th is thes is in p a r t i a l fu l f i lment of the requirements for an advanced degree at the Un ivers i ty of B r i t i s h Columbia, I agree that the L ibrary sha l l make it f ree ly ava i l ab le for reference and study. I fur ther agree that permission for extensive copying of th is thes is for scho la r ly purposes may be granted by the Head of my Department or by h is representat ives . It is understood that copying or pub l i ca t ion of th is thes is fo r f inanc ia l gain sha l l not be allowed without my wri t ten permission. Department of Forest ry  The Univers i ty of B r i t i s h Columbia Vancouver 8, Canada ABSTRACT Land use management to provide areas for o f f - r o a d v e h i c l e (ORV) r e c r e a t i o n a l a c t i v i t y , and to c o n t r o l and reduce the ORV impacts, requires information on the r a p i d l y changing conditions. The o b j e c t i v e of t h i s study was to develop a remote sensing method to monitor ORV impacts to s o i l and vegetation on the open lands of B r i t i s h Columbia. To complement a v a i l a b l e a e r i a l photographs of the Lac du Bois range-land study area f o r 1971, 1975 and 1977, two scales and formats of a e r i a l photographs were flown i n the summer of 1979. A ground survey program was designed to support the a e r i a l photograph i n t e r p r e t a t i o n of ORV impacts. The ORV t r a i l s , which were mapped from the a e r i a l photographs, had an increase i n bulk density and a decrease i n moisture content and organic carbon. Regression a n a l y s i s of the s o i l v a r i a b l e s versus o p t i c a l density values from the 1979 a e r i a l photographs f a i l e d to provide consistent r e s u l t s to permit the i d e n t i f i c a t i o n of v a r i a t i o n s i n s o i l conditions w i t h i n areas of ORV a c t i v i t y . The monitoring program was developed as a multistage remote sensing approach. The f i r s t stage u t i l i z e s large scale (1:4000) a e r i a l photographs to map and measure ORV t r a i l s and associated zones of secondary disturbance w i t h i n a study area. The second stage u t i l i z e s very large s c a l e (1:600) a e r i a l photographs to sample the study area and assess the erosion condi t i o n s . The t h i r d stage c o l l e c t s ground information to a s s i s t the a e r i a l photograph i n t e r p r e t a t i o n of the f i r s t two stages and to provide q u a n t i t a t i v e measures of the changes to selected s o i l and vegetation v a r i a b l e s . To consolidate the monitoring program information, an ORV impact condition scale was developed. The simple f i v e point s c a l e summarizes the varying impact conditions within a study area and can be used to assess general changes over time within land management u n i t s . TABLE OF CONTENTS ABSTRACT TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES ACKNOWLEDGEMENTS 1.0 INTRODUCTION 1.1 Objective . . . . . . . . 2.0 'LITERATURE REVIEW . . . . . 3.0 METHODS 3.1 Study Area and S i t e S e l e c t i o n . . . . 3.2 A e r i a l Photography . . . . . . 3.3 Ground Data C o l l e c t i o n . . . . . 3.4 A e r i a l Photograph I n t e r p r e t a t i o n 3.4.1 V i s u a l A n a l y s i s , Mapping and Measurement 3.4.2 O p t i c a l Densitometry . . . . 4.0 RESULTS AND DISCUSSION . . . . . . 4.1 Ground Survey . . . . . 4.1.1 Bulk Density . . . . . . 4.1.2 S o i l Moisture . . . . . 4.1.3 Organic Carbon . . . . . 4.1.4 S o i l Erosion Transects . . . . 4.1.5 Vegetation and Ground Cover . 4.1.6 Discussion of Ground Survey Results 4.2 A e r i a l Photograph In t e r p r e t a t i o n 4.3 Densitometry . . . 5.0 RECOMMENDATIONS . . 5.1 ORV Monitoring Program . 5.1.1 Introduction . . . . 5.1.2 Stage I . . 5.1.3 Stage II . . 5.1.4 Stage I I I . . . . 5.1.5 Summary of ORV Monitoring Program 5.2 ORV Impact Condition Scale 6.0 SUMMARY LITERATURE CITED APPENDIX A - Erosion Evaluation from A e r i a l Photographs APPENDIX B - S o i l Compaction P r i n c i p l e s LIST OF TABLES Table Page 1. Bureau of Land Management ORV Research Strategy 4 2. Utah State U n i v e r s i t y Ten P r i o r i t y ORV Questions 6 3. Major Problems Associated with Uncontrolled ORV A c t i v i t y i n B r i t i s h Columbia 9 4. Ground Survey Transect Groups for the Lac du Bois Rangeland Study Area 20 5. A v a i l a b l e A e r i a l Photograph Coverage of the Study Area 21 6. The Composition of the Densitometric Spectral Signature of Each Ground Survey Sample Point 24 7. Bulk Density (g/cc) - By Study S i t e and ORV T r a i l 26 8. Bulk Density (g/cc) - By S o i l Condition 27 9. S o i l Moisture (% dry wt.) - By Study S i t e and ORV T r a i l 29 10". S o i l Moisture (% dry wt.) - By S o i l Condition 30 11. Organic Carbon (wt. %) - By Study S i t e and ORV T r a i l 31 12. Organic Carbon (wt. %) - By S o i l Condition 32 13. Vegetation and Ground Cover C h a r a c t e r i s t i c s - By Sample Point Location 35 14. Vegetation and Ground Cover C h a r a c t e r i s t i c s - By S o i l Condition 36 15. Increase of ORV T r a i l Length (km) - 1971 to 1979 44 16. Regression Analysis - S o i l Physical Variables versus O p t i c a l Density 51 17. ANOVA - Study S i t e B 54 18. ORV Impact Condition Scale 63 v i LIST OF FIGURES Figure Page 1. Study Area - Lac du Bois Rangelands, Kamloops, B.C. 16 2. S o i l Loss P r o f i l e s Along a Single T r a i l - Transect Group A 34 3. Invasion of Bromus tectorum i n a Zone of Secondary Disturbance 38 4. ORV T r a i l s at Study Sites C and D - June, 1975 45 5. ORV T r a i l s at Study Sites C and D - June, 1977 46 6. ORV T r a i l s at Study S i t e s C and D - August, 1979 47 7. Area of Exposed S o i l for Transect Group A^ 49 8. Exposure Curves of 1:1000 70mm Colour-Infrared A e r i a l Photographs - J u l y 28, 1979 52 ) v i i . ACKNOWLEDGEMENTS The author expresses sincere appreciation to Dr. Peter A. Murtha, Faculty of Forestry and Department of S o i l Science, U n i v e r s i t y of B r i t i s h Columbia, for h i s guidance during t h i s p r oject, h i s assistance i n acquiring the necessary a e r i a l photographs, and h i s encouragement and support through-out my e n t i r e graduate program. Sincere thanks for t h e i r time and assistance are extended to the thesis committee members, Dr. Robert J . Woodham, Faculty of Forestry and Department of Computer Science, U n i v e r s i t y of B r i t i s h Columbia; Dr. L e s l i e M. Lavkulich, Department of S o i l Science, U n i v e r s i t y of B r i t i s h Columbia; and Dr. Peter J. Dooling, Faculty of Forestry, U n i v e r s i t y of B r i t i s h Columbia. The funding f o r the fieldwork of t h i s project, provided by a Un i v e r s i t y of B r i t i s h Columbia Natural and Applied Sciences research grant under the supervision of Dr. Peter A. Murtha, and the use of the laboratory f a c i l i t i e s at the A g r i c u l t u r e Canada Research Station, Kamloops, B r i t i s h Columbia, i s g r a t e f u l l y acknowledged. F i n a l thanks to my mother, Helen, for her continual encouragement and her typing s k i l l s . 1 1.0 INTRODUCTION The p o p u l a r i t y of off-road v e h i c l e (ORV) r e c r e a t i o n i n North America grew r a p i d l y during the 1960s and maintained i t s popularity through-out the 1970s. The impact of ORV a c t i v i t y on n a t u r a l resources and the con-f l i c t s between ORV enthusiasts and other users of the land was seen by the United States Council on Environmental Quality as "... one of the most serious p u b l i c land use problems that we face. Therefore, ways must be found to accommodate o f f -road v e h i c l e s without s a c r i f i c i n g the i n t e g r i t y of the n a t u r a l environment or the r i g h t s of those who choose non-motorized forms of r e c r e a t i o n . " (Sheridan, 1979, p . i i i ) . The p o p u l a r i t y of ORVs i n several regions of B r i t i s h Columbia has prompted the r e c o g n i t i o n of a problem on both l o c a l and p r o v i n c i a l l e v e l s . At Kamloops, the 1976 Lac du Bois Coordinated Resource Management Plan (CRMP) i d e n t i f i e d the uncontrolled use of the area by motorized vehicles as a major problem to be solved (CRMP, 1976). The Greater Vancouver Regional D i s t r i c t (GVRD) established a task force on motorized r e c r e a t i o n i n October 1978 to assess p o t e n t i a l s i t e s for t r a i l bikes and to develop a plan for motorized r e c r e a t i o n v e h i c l e s i n the Lower Mainland region (GVRD, 1978). At the pro-v i n c i a l l e v e l , an 'off-highway v e h i c l e ' coordinator was appointed and the Environment and Land Use Committee (ELUC) Off-Highway Vehicle p o l i c y was form-ulated to provide for cooperative e f f o r t s by governmental agencies and p r i v a t e groups and i n d i v i d u a l s to overcome s p e c i f i c problems which may be i d e n t i f i e d i n the various resource management regions of the province (ELUC, 1978). The objective of the ELUC Off-Highway Vehicle p o l i c y i s to control environmental and property damage associated with improper v e h i c l e use and to resolve c o n f l i c t s between v e h i c l e operators and other resource users. Meeting t h i s requires a good source of information on the past, present and future ORV environmental damages. The u t i l i t y of remote sensing techniques for informa-t i o n c o l l e c t i o n i s recognized i n the development of the environmental impact statement process and the assessment of change over time (Rosen, 1976). H i s t o r i c a l a e r i a l photographs provide an obj e c t i v e record of past baseline conditions. Subsequent changes can be e f f i c i e n t l y and o b j e c t i v e l y recorded with r e p e t i t i v e a e r i a l photographic coverage. Previous ORV studies i n the United States to measure q u a n t i t a t i v e l y past and present ORV environmental impacts (Davidson and Fox, 1974; Webb et a l . , 1978; W i l s h i r e et a l . , 1978) have not f u l l y u t i l i z e d information content of a e r i a l photographs. System-a t i c monitoring programs have not been developed (Sheridan, 1979). 1.1 Obj e c t i v e The obj e c t i v e of t h i s t h e s i s i s to develop a remote sensing method to monitor ORV impacts to s o i l and vegetation on the open lands of B r i t i s h Columbia. 2.0 LITERATURE REVIEW This t h e s i s concerns the environmental impact to s o i l and vegetation by ORVs, other than snowmobiles. The l i t e r a t u r e on ORV environmental impacts dates to 1948 ( H i l l and Kirby, 1948: as c i t e d by Sheridan, 1979) but did not become a popular subject u n t i l the l a t e 1960s when the use of ORVs i n the United States began to boom. The early papers on ORVs were popular, non-s c i e n t i f i c a r t i c l e s which drew a t t e n t i o n to the environmental impacts and the r e c r e a t i o n c o n f l i c t s caused by ORVs. The e a r l y 1970s saw an increased p o p u l a r i t y of ORVs, an increased p u b l i c awareness of t h e i r impacts as a r e s u l t of the l i t e r a t u r e , and the o f f i c i a l r e c o g n i t i o n by the United States government that an ORV problem existed. In 1972 the United States P r e s i d e n t i a l Executive Order 11644 d i r e c t e d agencies with j u r i s d i c t i o n over public lands "... to e s t a b l i s h p o l i c i e s and provide for procedures that w i l l ensure that the use of off-road v e h i c l e s on p u b l i c lands w i l l be c o n t r o l l e d and d i r e c t e d so as to protect the resources of those lands, to promote the safety of a l l users of those lands, and to minimize c o n f l i c t s among the various users of those lands." (R. Nixon, 1972, p.2877). At the time of the Executive Order, Lodico (1973) noted that only by s t r e t c h i n g the d e f i n i t i o n of a ' s c i e n t i f i c study', which she defined as "... any report of research which planned i n advance to measure any environmental impact by an ORV and which i n -cluded a c o n t r o l area where the ORV was not used" (Lodico, 1973, p . i ) , could i t be said that a s c i e n t i f i c study had been published on the environ-mental . e f f e c t s of off-road r e c r e a t i o n v e h i c l e s other than snowmobiles. As a r e s u l t of the 1972 Executive Order and the l a c k of e x i s t i n g knowledge, the Bureau of Land Management (BLM) organized a research strategy to provide necessary information. The s i x steps of the s t r a t e g y are l i s t e d i n Table 1. Table 1. Bureau of Land Management ORV Research Strategy (McCool and Roggenbuck, 1974, p.6) 1. A systematic i d e n t i f i c a t i o n of the needs of ORV users and the r e a l problems associated with ORV use; 2. A p r i o r i t i z a t i o n of the i d e n t i f i e d needs, and problems f o r evaluation and research; 3. The development of research s t r a t e g i e s to resolve those important problems or issues of c o n f l i c t f o r which answers are not c u r r e n t l y a v a i l a b l e ; 4. The completion of the necessary research; 5. The development of comprehensive ORV p o l i c y and managerial s t r a t e g i e s based upon the systematic problem analysis and research findings, and 6. A meaningful on-going feedback system to evaluate programs and p o l i c i e s . 5. The BLM subsequently contracted Utah State U n i v e r s i t y to complete the f i r s t three steps of the research strategy. The major r e s u l t of the Utah State U n i v e r s i t y study, which has helped to d i r e c t ORV research including t h i s t h e s i s , was the i d e n t i f i c a t i o n of ten p r i o r i t y issues concerned with ORV administration, environmental impacts and user behavior. The ten p r i o r i t y questions, i d e n t i f i e d and ordered by BLM personnel, other governmental employees, representatives of resource user groups and academicians, during a s e r i e s of questionnaires and seminars are l i s t e d i n Table 2. The ten questions have been u t i l i z e d by the BLM and other land management agencies to d i r e c t t h e i r research programs p r i o r to the develop-ment of management plans f o r areas with ORV re c r e a t i o n i n t e r e s t s . The research programs and the r e s u l t i n g s c i e n t i f i c papers (using the term of Lodico, 1973) on the environmental impacts of ORVs have dealt p r i m a r i l y with questions 7 and 1, without c a r e f u l consideration of the monitoring approach of question 4. Davidson and Fox (1974) q u a n t i f i e d the impact of motorcycles on vegetation and s o i l but Wi l s h i r e and Nakata (1976) , Wilshire et_ a_l. (1978) , Webb _e_t al_. (1978) and S t u l l e_t_ a l . (1979) q u a n t i f i e d changes i n s o i l only. A l l the above f i v e references studied changes between undisturbed and d i s -turbed areas w i t h i n ORV a c t i v i t y areas whereas Vollmer e_t al_. (1976) , Weaver and Dale (1978), Foster (1977) and Leininger and Payne (1980) studied changes to s o i l , vegetation and w i l d l i f e before, during and a f t e r a c o n t r o l l e d t r a f f i c experiment. In quantifying the ORV impacts, the research has concentrated on data c o l l e c t i o n using ground sampling techniques. They have provided land managers with an understanding of the i n t e n s i t y of the environmental e f f e c t s of ORVs, but management programs s t i l l "... need to monitor the e f f e c t s of ORV use much more 6 Table 2. Utah State U n i v e r s i t y Ten P r i o r i t y ORV Questions (McCool and Roggenbuck, 1974, p.23) 1. What are the r e l a t i v e impacts of various types of ORVs upon the na t u r a l environment? 2. What techniques can be used to more e f f e c t i v e l y communicate with ORV users? 3. What c r i t e r i a should a land manager use to decide whether an area should be open, r e s t r i c t e d , or closed to ORV use? 4. How can the environmental e f f e c t s of ORV use best be monitored? 5. What kinds of data are needed to give a s o l i d b a s i s f o r developing an ORV management plan? 6. What kinds of c o n f l i c t s are occurring between ORV users and other r e c r e a t i o n i s t s ? 7. How can environmental damage due to ORV use be quantified? 8. How can the land manager decide when ORV use becomes misuse or overuse? 9. How can increased cooperation between f e d e r a l , state and l o c a l governmental agencies be achieved i n order to increase ORV oppor-t u n i t i e s and to reduce ORV impacts and c o n f l i c t s ? 10. How can an e c o l o g i c a l and s o c i o l o g i c a l data base be e s t a b l i s h e d to increase the ef f e c t i v e n e s s of ORV management decisions? c l o s e l y and s y s t e m a t i c a l l y than they have done to date." (Sheridan, 1979, p.57). The Los Padres National Forest (USFS, 1976) and the Utah Outdoor Recreation Agency (1977) s p e c i f i e d annual environmental monitoring programs with i n t h e i r ORV management plans to a s s i s t amending the management p o l i c i e s to minimize the adverse e f f e c t s of ORV a c t i v i t y , but no procedures were developed. The only monitoring program that has been attempted was a non-s c i e n t i f i c study by the Tennessee V a l l e y Authority to detect changes i n the Land Between The Lakes ORV area. The o n - t r a i l locations were measured f o r changes i n erosion transects and tree and shrub m o r t a l i t y over a four year period was noted (McEwen, 1978). Based on the approach of the Tennessee V a l l e y Authority and environmental impact assessment guidelines, the Council on Environmental Qua l i t y recommended that "In areas r e g u l a r l y used by ORVs a monitoring system should be employed so that land managers can assess the impact of ORVs on w i l d l i f e , s o i l and vegetation. Under such a system, s o i l l o s s at key check points would be measured on a regular b a s i s (a r e l a t i v e l y simple matter), w i l d l i f e counts would be undertaken p e r i o d i c a l l y , and changes i n vegetation biomass, species, and the area of coverage would be tracked. The eyeball inspections of land managers on the ground are s t i l l v i t a l , but a basic monitoring system would provide objective data on which to base further land use designations and adjustments in e x i s t i n g ORV use plans." (Sheridan, 1979, p.57). To t h i s point, the review of the l i t e r a t u r e has drawn s o l e l y on United States sources to j u s t i f y the o b j e c t i v e of the thesis to develop a monitoring program. The d e c i s i o n to develop the monitoring program for the open lands of B r i t i s h Columbia was the r e s u l t of the presence of ORV a c t i v i t y i n B r i t i s h Columbia and the lack of s p e c i f i c environmental information. The a t t e n t i o n given to ORVs i n B r i t i s h Columbia has dealt with the i d e n t i f i c a t i o n of a v a r i e t y of problems, the development of plans to c o n t r o l the a c t i v i t y and the p r o v i s i o n of s p e c i a l ORV areas (Powers, 1975; CRMP, 1976; GVRD, 1978; ELUC, 1978). The i d e n t i f i c a t i o n of problems associated with the uncontrolled use of ORVs has varied within the province. The l i s t of ORV problems i n published reports for the Greater Vancouver Regional D i s t r i c t (Powers, 1975) and for the Lac du Bois rangelands, Kamloops (CRMP, 1976) indicates the v a r i e t y of concerns and t h e i r emphasis (Table 3). The Greater Vancouver Regional D i s t r i c t was most concerned with the noise disturbance i n r e s i d e n t i a l d i s t r i c t s , whereas the Coordinated Resource Management Plan for the Lac du Bois rangelands was most concerned with environmental f a c t o r s of increased erosion and reduced forage crops for l i v e s t o c k grazing. The i d e n t i f i c a t i o n of the ORV problems was i n conjunction with plans to c o n t r o l the ORV a c t i v i t y and reduce the problems. The plans advocated placement of signs and fences at i l l e g a l use areas and the s e l e c t i o n of the 'designated ORV use' areas. To a s s i s t the implementation of the regional and l o c a l plans, the p r o v i n c i a l ELUC Off-Highway Vehicle p o l i c y was formulated to provide information and education programs, to provide administrative and l e g a l - d e s i g n a t i o n of land for ORV use or r e s t r i c t i o n , and to provide improved enforcement procedures (ELUC, 1978). The d e s c r i p t i o n of the a t t e n t i o n given to ORVs i n B r i t i s h Columbia can be considered as steps 1 and 5 of the BLM research strategy (Table 1). The intermediate steps of i d e n t i f y i n g and conducting research have been neglected but are very important to providing a proper program evaluation at step 6 using q u a n t i t a t i v e information within a pre- and post-plan time frame-work. The development of an e f f i c i e n t ORV environmental monitoring system for the open lands of B r i t i s h Columbia can use as a guideline the recommenda-tions by the Council of Environmental Quality of the general needs of a mon-i t o r i n g system (Sheridan, 1979, p.57), which can be developed for each man-agement area based on s p e c i f i c ground conditions. Table 3. Major Problems Associated with Uncontrolled ORV A c t i v i t y i n B r i t i s h Columbia Greater Vancouver Regional D i s t r i c t (Powers, 1975, p.2-3) " 1. Noise annoyance occurs when t e r r a i n requirements are not optimum » and r e s i d e n t i a l areas are nearby; 2. T e r r a i n disturbance occurs when vegetation and surface materials are eroded by overuse; 3. I n j u r i e s occur due to lack of supervision and distance to immediate f i r s t a i d ; 4. F i r e danger a r i s e s when ve h i c l e s are not equipped with spark a r r e s t o r s ; 5. Recreation use c o n f l i c t s occur when veh i c l e s use h i k i n g t r a i l s , equestrian lanes, and s k i touring t r a i l s , and 6. I l l e g a l use often occurs as most veh i c l e s are i l l e g a l i n most parks and m u n i c i p a l i t i e s . Noise disturbance i s by f a r the most s i g n i f i c a n t problem associated with uncontrolled v e h i c l e use. " B. Lac du Bois Rangelands, Kamloops (CRMP, 1976) 1. Erosion problems caused by s c a r r i n g of h i l l s i d e s ; 2. Harassment of w i l d l i f e and domestic stock; 3. Spreading of weeds (eg. knapweed); 4. Loss of aesthetic viewing; 5. Noise p o l l u t i o n ; 6. C o n f l i c t s with range improvements; 7. Destruction of vegetative cover; 8. C o n f l i c t s with research p r o j e c t s ; 9. Interference with educational pursuits i n area; 10. C o n f l i c t s with other r e c r e a t i o n a l users, and 11. Increased f i r e hazard. 10 Monitoring many forms of environmental conditions and impacts has recently begun'to u t i l i z e remote sensing techniques to increase the e f f i -ciency of information c o l l e c t i o n . A multistage sampling approach combining ground data sampling with remote sensing information of various sensors and scales has been recognized as a b e n e f i c i a l method of data c o l l e c t i o n f or more i n t e l l i g e n t management of resources (Reeves, 1975). Within the format of a multistage sampling approach for remote sensing, the choice of ground data sampling for the monitoring program was developed from the past experience of quantifying ORV impacts i n the western United States. The impacts of ORV a c t i v i t y on s o i l have been measured f o r p h y s i c a l and chemical property changes between o n - t r a i l and o f f - t r a i l l o c a -t i o n s . Varying degrees of change have been measured f o r surface strength, bulk density, s o i l moisture, i n f i l t r a t i o n , s o i l temperature, organic carbon, pH, and exchangeable calcium and magnesium content (Wilshire e_t al^. , 1978; Webb e_t al. , 1978). An a d d i t i o n a l s o i l f a c t o r , the volume of s o i l eroded from ORV t r a i l s , has been c a l c u l a t e d with erosion transects f o r s i n g l e t r a i l s and for e n t i r e h i l l s i d e s (Wilshire and Nakata, 1978; S t u l l ejt al_. , 1979). The q u a n t i f i c a t i o n of changes to vegetation have been sampled f o r changes i n plant number, changes i n plant cover, changes in percent l i t t e r cover and varying degrees of damage to shrubs (Davidson and Fox, 1974; Vollmer et a l . , 1976; Foster, 1977; Weaver and Dale, 1978; Leininger and Payne, 1980). Several weaknesses e x i s t i n the previous research programs. The f i r s t i s that the studies have concentrated on the measurement of changes between o n - t r a i l and o f f - t r a i l l o c a t i o n s without sampling f o r a t r a n s i t i o n zone at the edge of the t r a i l . In a d d i t i o n , the studies measuring vegetation have i d e n t i f i e d changes to e x i s t i n g plant communities but few areas have had to measure the invasion of undesirable vegetation into the zones of ORV disturbance. 11 Both of the above weaknesses could be input i n t o the ground data sampling scheme, which could also draw upon information derived from the prev-ious use of remote sensing for ORV studies, or from the previous use or the theory of remote sensing for environmental monitoring. Five studies represent an i n i t i a l stage i n the u t i l i z a t i o n of remote sensing for ORV a c t i v i t y monitoring following the 1974 suggestion by Utah State U n i v e r s i t y that a "... research program evaluate several p o t e n t i a l l y u seful monitoring systems, which may include remote sensing, ERTS imagery, ground l e v e l photography, as w e l l as the more t r a d i t i o n a l methods of d i r e c t observation." (McCool and Roggenbuck, 1974, p.37). Each of the ORV research projects had u t i l i z e d remote sensing technology for s o i l data c o l l e c t i o n but not to the greatest p o t e n t i a l of remote sensing. Schultink (1977) used a v a i l a b l e a e r i a l photographic coverage to delineate vegetation cover versus ORV barren areas and to c a l c u l a t e the rate of denuda-t i o n over time. Unfortunately no ground studies on the changes of s o i l param-eters- or changes i n vegetation species or vigour were done. Whithurst, Blanchard and Doiron (1977) used c o l o u r - i n f r a r e d a e r i a l photographs to locate and measure the l i n e a r extent of marsh buggy routes. No ground data c o l l e c -t i o n was reported but the a e r i a l photographs allowed a q u a l i t a t i v e estimate of the growth stage of revegetated marsh tracks plus the amount of compaction of the marsh vegetation and s o i l . A t h i r d study u t i l i z i n g remote sensing f o r c o l l e c t i o n of q u a n t i t a t i v e information was done by S t u l l e_t_ a_l. (1979) . Ground photographs of h i l l s i d e s allowed measurement of the area of exposed s o i l , which permitted c a l c u l a t i o n of s o i l erosion losses from s o i l erosion transects and bulk density sampling. The l a s t two studies represent an i n i t i a l p roject (Foster, 1977) and i t s continuation over time (Leininger and Payne, 1980) . Their r e s u l t s of the c o n t r o l l e d t r a f f i c study measured changes to s o i l and vegetation with ground sampling and indicated that some on the ORV t r a i l s could be seen on 1:6000 scale normal colour and c o l o u r - i n f r a r e d a e r i a l photo-graphs. The general approach of the f i r s t three studies was to i d e n t i f y and measure the exposed s o i l of ORV t r a i l s . More s o i l information can be obtained from the a e r i a l photographs i f the proper scale and date of photography are a v a i l a b l e . T u e l l e r and Booth (1975) found that large scale (1:600 to 1:1000) 70mm normal colour a e r i a l photographs can be used to detect and inventory s o i l erosion and movement, plus " A e r i a l photography i s not l i m i t e d by a c c e s s i b i l i t y , allows for a gr e a t l y increased sample s i z e at s i m i l a r cost, provides a permanent record, and i s more objec-t i v e . " ( T u e l l e r and Booth, 1975, p.709). For rangeland areas, which receive pressure from c a t t l e grazing and are pop-u l a r ORV s i t e s (such as the Lac du Bois rangelands), they found that a system of ground observations combined with a e r i a l photograph i n t e r p r e t a t i o n keys and guidelines allowed f o r the evaluation of several s o i l surface f a c t o r s , such as: flow patterns, wind erosion, l i t t e r movement, v e s i c u l a r horizons, bare ground and r i l l s and g u l l i e s . A l l these factors are important to range man-agement for the determination of vegetation condition and trend plus each fa c t o r can be a l t e r e d by ORV disturbances. To complement the s o i l erosion information, v a r i a t i o n s i n s o i l p r o p e r t i e s and conditions may be i d e n t i f i e d from the s p e c t r a l r e f l e c t a n c e i n -formation recorded by the a e r i a l photographs and represented by o p t i c a l den-s i t y values (Gaucher e_t a l . , 1975; Ci h l a r and Protz, 1977 ; Piech and Walker, 1974). Webb e_t a l . (1978) and Wi l s h i r e et a l . (1978) measured phy s i c a l and chemical changes i n s o i l properties as an e f f e c t of ORV a c t i v i t y . Of the properties measured, a l t e r a t i o n s to the surface properties of s o i l moisture, organic matter content and exchangeable magnesium are known to a f f e c t s o i l s p e c t r a l r e f l e c t a n c e (Shields e_t a l . , 1968; Schreier, 1977; Hoffer, 1978; Stoner e_t a l . , 1980) . Although the research has studied s o i l s p e c t r a l r e -f l e c t a n c e using spectroradiometers over a wavelength range of 0.5 um to 2.4 um, there are v a r i a t i o n s i n the s p e c t r a l r e f l e c t a n c e of s o i l s within the sen-s i t i v i t y range of c o l o u r - i n f r a r e d f i l m (0.5 um to 0.9 um). The c o l o u r - i n f r a -red f i l m records the s p e c t r a l r e f l e c t a n c e on three f i l m dye layers instead of the continuous sampling mode of a spectroradiometer. Each ground feature has i t s s p e c t r a l signature composed of three o p t i c a l density values as measured by a densitometer. Therefore the three o p t i c a l density values or t h e i r r a t i o s (Gaucher e_t al_. , 1975; L i l l e s a n d et_ al_. , 1975) may be used to i d e n t i f y v a r i a -tions i n ground features which are a r e s u l t of a l t e r e d s o i l p roperties. The use of a e r i a l photographs can also a s s i s t the vegetation i n -formation needs of an ORV monitoring system. ORV induced changes to vegeta-t i o n species" and percent ground cover are among the vegetation parameters which have been studied for the a p p l i c a b i l i t y of a e r i a l photography for range-land inventory and monitoring. For herbaceous vegetation, Carneggie (1968), Carneggie and Reppert (1969) and T u e l l e r (1977) a l l found that very large scale (1:600) a e r i a l photographs were suited for a wide range of i n t e r p r e t a -tions and measurements, such as: "... vegetation and species i d e n t i f i c a t i o n , plant species mapping, vegetation mapping, plant cover determination, plant density counts, biomass or range p r o d u c t i v i t y de-terminations, vegetation u t i l i z a t i o n , plant vigor and phenology, range readiness, erosion determinations, rodent a c t i v i t y , off-road v e h i c l e use and/or damage, evaluating herbicide a p p l i c a t i o n s , range condition and trend and evaluating and measuring environmental impact." ( T u e l l e r , 1977, p.1507). Large to medium scale (1:4000 to 1:20,000) normal colour and colour-i n f r a r e d a e r i a l photographs are also u s e f u l f o r vegetation species and commun-i t y i d e n t i f i c a t i o n and mapping and have been tested on the Lac du Bois range-lands for native climax vegetation and for invading vegetation species (Watson, 1977). To summarize the l i t e r a t u r e review, the use of remote sensing 14. technology to supplement a ground data sampling program should allow for the development of a method to e f f i c i e n t l y monitor ORV impacts to s o i l and vegetation for the open lands of B r i t i s h Columbia. 3.0 METHODS 3.1 Study Area and S i t e S e l e c t i o n The Lac du Bois rangelands, Kamloops, B r i t i s h Columbia (Figure 1) were used as a study area representing the open lands of B r i t i s h Columbia. The area was chosen subsequent to the development of a rangeland c l a s s i f i c a -t i o n by Watson (1977) which required the i n c l u s i o n of a 'motorcycle and a l l t e r r a i n v e h i c l e damage' clas s within the legend. The rangelands have an i r r e g u l a r topography formed from the t h i n layer of wind-blown loess covering the drumlinized t i l l which v a r i e s i n t h i c k -ness over the bedrock of the i n t e r i o r plateau (Watson, 1977). The Artemisia  t r i d e n t a t a Nutt., Agropyron spicatum Pursh var. inerroe H e l l e r and Poa secunda P r e s l climax vegetation (Watson, 1977) does not o f f e r any natural b a r r i e r s to off-road t r a v e l by the motorcycle and 4-wheel drive enthusiasts from the c i t y of Kamloops and i t s surrounding population. Within the study area, four study s i t e s (Figure 1) were selected, u s i n g ' e x i s t i n g a e r i a l photographs and a ground reconnaissance, to represent sections of the rangeland which' have received varying h i s t o r i e s of concen-trated ORV a c t i v i t y . Three of the s i t e s were ORV a c t i v i t y areas chosen by the r e c r e a t i o n i s t s . The fourth s i t e represents the 1976 Lac du Bois Coordinated Resource Management Plan's 'designated ORV area'. Study s i t e A represents the area of rangeland which has received the longest and most intensive ORV a c t i v i t y . It i s immediately adjacent to a suburban housing development and serves as a f i r s t stop for most r e c r e a t i o n -i s t s . The t e r r a i n provides a complete range of topography from gently r o l l i n g to very steep and has the greatest concentration of e s t a b l i s h e d t r a i l s . Study s i t e B represents the 'designated ORV area' which provides 700 acres of v a r i a b l e topography s p e c i f i c a l l y for concentrated ORV a c t i v i t y and organized ORV competitions. 16. Figure 1. Study Area - Lac du Bois Rangelands, Kamloops, B.C. Colour Infrared A e r i a l Photograph Stereo T r i p l e t North Thompson To River North Kamloops Scale = 1:83,000 Date of Photography = Sept, 1975 Study S i t e A -Study S i t e B -Intensive use ORV area 'Designated ORV area' Study S i t e C -Study Site D -ORV H i l l c l i m b area Light use ORV area Study s i t e C i s a large h i l l on the rangelands with both moderately steep and very steep slopes. The s i t e i s near the middle of the rangelands and requires extra t r a v e l l i n g time for access. Study s i t e D i s a gently r o l l i n g area adjacent to study s i t e C. The s i t e has received le s s use than the other s i t e s but had been used for ORV motocross races i n i t s e a r l y years of r e c e i v i n g ORV r e c r e a t i o n a l use. It i s the only one of the four study s i t e s which i s within the r e s t r i c t e d use zone for ORV r e c r e a t i o n , as designated i n 1978 under the Province of B r i t i s h Columbia Land Act. 3.2 A e r i a l Photography Two scales and formats of a e r i a l photographs were acquired for a l l four study s i t e s . Both photographic missions used Kodak Aerochrome Infrared 2443 f i l m which was developed to a p o s i t i v e transparency. The o r i g i n a l pos-i t i v e transparencies were used for a l l i n t e r p r e t a t i o n s . The f i r s t photo-graphic mission on July 28, 1979 photographed the study s i t e s at a s c a l e of 1:1000 using wing-tip mounted, Vinten 70mm cameras. The second mission on August 1, 1979 photographed the study s i t e s at a scale of 1:4000 using a Zeiss 2 23cm standard survey camera with a 305.3mm f o c a l length le n s . 3.3 Ground Data C o l l e c t i o n The ground survey program for s o i l erosion, selected s o i l properties and vegetation cover, was completed immediately following the a c q u i s i t i o n of the a e r i a l photographs. The sampling scheme consisted of transects across the selected ORV t r a i l s . Each transect began and ended i n undisturbed areas adja-cent to the t r a i l s and point sampled for o f f - t r a i l , t r a i l - e d g e and o n - t r a i l conditions of s o i l and vegetation plus included a s o i l erosion transect for the o n - t r a i l portions of the transect. Each t r a i l was sampled with a set of transects ranging i n number from two to eight depending on the length and slope changes of the t r a i l . A t o t a l of 31 transects represented eight ORV t r a i l s within the study area. The o n - t r a i l s o i l erosion transects were used to estimate the s o i l removal from the h i l l s i d e s . The method assumed that the o r i g i n a l surface was approximately l e v e l across the t r a i l . A t h i r t y meter surveying tape was stretched across the t r a i l and the distance between the h y p o t h e t i c a l former surface and the present surface was measured at 50cm i n t e r v a l s along the tape to provide a b a s i s f o r the c a l c u l a t i o n of the c r o s s - s e c t i o n a l area of s o i l removed. The area of s o i l removed from each cross s e c t i o n represented the erosion c o n d i t i o n for a section of the h i l l s l o p e . The volume of s o i l removed along a s i n g l e t r a i l was c a l c u l a t e d from the area of s o i l removed, as measured i n the c r o s s - t r a i l transects, and the area of exposed s o i l , measured with a dot g r i d on the 1:1000 s c a l e a e r i a l photographs. A f i n a l value, of the mass of s o i l removed per t r a i l i s the volume of s o i l removed m u l t i p l i e d by the bulk density of the eroded s o i l as measured at an o f f - t r a i l l o c a t i o n . Three standard s o i l tests were used to determine the surface pro-portions of o f f - t r a i l , t r a i l - e d g e and o n - t r a i l sample points at each transect. Bulk density was c a l c u l a t e d f or the surface 7.5cm. S o i l samples were taken using the excavation method because the degree of compaction prevented using a corer, then the volume was measured with a i r - d r i e d sand. S o i l moisture was determined from the bulk density samples following oven drying at 105°C for 24 hours at the A g r i c u l t u r e Canada Kamloops Research S t a t i o n . The t h i r d s o i l property, organic carbon, was measured for each sample s i t e of bulk1- density and s o i l moisture using the Le'co Analyzer i n the U n i v e r s i t y of B r i t i s h Columbia S o i l Science Department laboratory. The vegetation ground cover was determined at each s o i l sample 2 l o c a t i o n using ground photographs of lm p l o t s . The vegetation was i d e n t i f i e d 19 by species and the surface cover proportions of vegetation, l i t t e r and exposed s o i l were measured with the U n i v e r s i t y of B r i t i s h Columbia Forest Harvesting 9830 d i g i t i z e r . The values of each s o i l property and surface cover were, tested by a n a l y s i s of variance (ANOVA) for s i g n i f i c a n t d i f f e r e n c e s between o n - t r a i l , t r a i l - e d g e and o f f - t r a i l sample point l o c a t i o n s within various groupings of the transects. The transects were grouped three ways based on t h e i r l o c a t i o n - by study s i t e , by ORV t r a i l , and by s o i l condition. The transect groupings and a d e s c r i p t i o n of the conditions represented i s shown i n Table 4. 3.4 A e r i a l Photograph I n t e r p r e t a t i o n 3.4.1 V i s u a l A n a l y s i s , Mapping and Measurement The a c q u i s i t i o n of the 1979 a e r i a l photographs was supple-mented with e x i s t i n g a e r i a l photographs of various f i l m types and scales to provide a h i s t o r y of ORV a c t i v i t y within the study area. The a v a i l a b l e a e r i a l photographs, by date, f i l m type, scale and area of coverage are l i s t e d i n Table 5. The v i s u a l a n a l y s i s was the i n t e r p r e t a t i o n of the a e r i a l photographs f o r the i d e n t i f i c a t i o n of zones of vegetation and s o i l disturbance and the invasion of undesirable vegetation species. Combining the vegetation information of the ground photographs and the information on species iden-t i f i c a t i o n f o r the Lac du Bois rangelands (Watson, 1977) allowed the iden-t i f i c a t i o n of disturbed and invading vegetation. The mapping and measurement of ORV t r a i l s recorded the changes between 1971 and 1979. Most ORV t r a i l s were easy to i d e n t i f y on the a e r i a l photographs because of the contrast i n s p e c t r a l r e f l e c t a n c e between the exposed s o i l of the ORV t r a i l s and the vegetation of the undisturbed rangeland. 20. Table 4. Ground Survey Transect Groups for the Lac du Bois Rangeland Study Area Transect Group Representative Condition Number of Transects By Study S i t e study s i t e A. The area of rangeland which has received the longest and most i n t e n s i v e ORV a c t i v i t y . study s i t e B. The motocross track within the 'designated ORV area'. study s i t e C. A popular h i l l c l i m b area of the middle rangeland. study s i t e D. A gently r o l l i n g area with a previous h i s -tory of motocross races and infrequent r e c r e a t i o n a l use. 11 By ORV T r a i l an i n t e n s i v e l y used steeply sloping h i l l c l i m b area 6 an i n t e n s i v e l y used t r a i l accessing the r o l l i n g topography 2 of the h i l l t o p area. a very steep h i l l c l i m b area with a large area of invading 3 undesirable vegetation. same a B of the study s i t e group. 8 a long steep h i l l c l i m b area with a north aspect. 4 a short steep h i l c l i m b area with a south west aspect. 2 a s e c t i o n of a f l a t ORV t r a i l through bunchgrass range. 4 a s e c t i o n of a f l a t ORV t r a i l through a Poa secunda swale. 2 By S o i l Condition BR the area of the lower rangeland with the Brown Chernozem s o i l great group. The s o i l area corresponds to group A. DKBR the area of the middle rangeland with the Dark Brown Chernozem s o i l great group. The s o i l area corresponds to B , C , C 2, and D^. SW the area of a small Poa secunda swale with G l e i Rego Brown Chernozem s o i l . The s o i l area corresponds to D^. 11 18 Table 5. Av a i l a b l e A e r i a l Photograph Coverage of the Study Area Film Type Date Scale Black & White July 24/71 1:12,000 Study S i t e Coverage A B C D X X Normal Colour (Kodak 2445) Colour Infrared (Kodak 2443) Normal Colour (Kodak 2445) Colour Infrared (Kodak 2443) Colour Infrared (Kodak 2443) June 9/75 Sept 6/75 June 10/77 Jul y 28/79 Aug 1/79 1:8,000 1:63,360 1:12,000 1:1,000 1:4,000 X X X X X X X X X X X X X 22 The 1979 1:4000 scale a e r i a l photographs were used as a base map for ORV t r a i l measurement. The t r a i l s were mapped at a contact s c a l e using a Bausch and Lomb Zoom Stereoscope. The c u l t u r a l features v i s i b l e on the 1979 a e r i a l photographs were also mapped on the base map. The e x i s t i n g a e r i a l photographs from 1971 to 1977 were matched to the base'map scale of the 1979 a e r i a l photographs using a Bausch and Lomb Stereo Zoom Transfer Scope and the ORV t r a i l s v i s i b l e at the r e s o l u t i o n of the a e r i a l photographs were mapped. For each study s i t e and year of a v a i l a b l e a e r i a l photographic coverage the length of ORV t r a i l s , representing t h e i r changes over time, were measured with the 9830 d i g i t i z e r . Included as a second step of the mapping and measurement of ORV t r a i l s was the c a l c u l a t i o n of the area of exposed s o i l f o r a sample area i n study s i t e A. The measurement of t r a i l length does not consider var-i a t i o n s i n the width of exposed s o i l on i n d i v i d u a l t r a i l s . The c a l c u l a t i o n of the area of exposed s o i l from a four times enlargement of a 1:1000 scale 70mm a e r i a l photograph using a dot g r i d (329 dots per square inch) was done to demonstrate an a l t e r n a t i v e procedure. 3.4.2 O p t i c a l Densitometry The l a s t p o r t i o n of the data c o l l e c t i o n was the measure-ment of the f i l m o p t i c a l density values for each dye layer of the 1:1000 s c a l e a e r i a l photographs. A MacBeth TR-524 spot densitometer with a 1mm diameter aperture measured the yellow, magenta and cyan dye-layer d e n s i t i e s of each sample point as an i n d i c a t i o n of the r e l a t i v e s p e c t r a l r e f l e c t a n c e i n the green, red and near i n f r a r e d regions of the electromagnetic spectrum. Each sample point was accurately i d e n t i f i e d on the a e r i a l photographs with the a i d of f i e l d markers and the ground photographs and the o p t i c a l density values were entered into a computer f i l e at the U n i v e r s i t y of B r i t i s h Columbia. The o p t i c a l density value of each dye layer for each sample point was measured three times and averaged to represent the s p e c t r a l r e f l e c t a n c e data of each s p e c t r a l region of the c o l o u r - i n f r a r e d f i l m . Spectral r a t i o i n g of the s p e c t r a l r e f l e c t a n c e data to negate the e f f e c t of any extraneous f a c t o r s i n the f i l m exposure ac t i n g i n a l l wavelengths of the f i l m s e n s i t i v i t y ( L i l l e s a n d and K i e f e r , 1979) r e s u l t e d i n a s p e c t r a l signature of s i x density values for each sample point. The r e l a t i o n s h i p s among the densitometer f i l t e r s , devel-oped f i l m dye-layers, and the s p e c t r a l s e n s i t i v i t y of the f i l m dye-forming layers are given i n Table 6. Following the c a l c u l a t i o n of the s p e c t r a l signatures, the computer was used to analyze the densitometric information and the p h y s i c a l properties of the s o i l and vegetation. The analysis included a c o r r e l a t i o n matrix of a l l v a r i a b l e s , a backwards regression of each s o i l property against the s i x density value components of each sample point s p e c t r a l signature, and an a n a l y s i s of variance between the o n - t r a i l , t r a i l - e d g e and o f f - t r a i l o p t i c a l density values. 24, Table 6. The Composition of the Densitometric Spec t r a l Signature of Each Ground Survey Sample Point Densitometer Colour Infrared Film Dye Layer F i l t e r Film Dye Layer Spectral S e n s i t i v i t y Blue Yellow Green Green Red Magenta Cyan Red near Infrared Green Blue Magenta Yellow Red Green Red, Green Cyan Magenta near Infrared Red Red Cyan near Infrared Blue Yellow Green •4.0 . RESULTS AND DISCUSSION 4.1 Ground Survey 4.1.1 Bulk Density Table 7 shows the r e s u l t s of the ground survey measure-ments for bulk density. The o n - t r a i l , t r a i l - e d g e and o f f - t r a i l measurements are grouped for t h e i r transect l o c a t i o n by study s i t e and by i n d i v i d u a l ORV t r a i l s . Within each group, the mean bulk density values show an increase for o n - t r a i l l o c a t i o n s . Only study s i t e A, which has received the longest h i s t o r y of ORV a c t i v i t y , shows a t r a n s i t i o n from o f f - t r a i l through t r a i l - e d g e to o n - t r a i l . The impact at the other study s i t e s are confined to o n - t r a i l versus o f f - t r a i l . The ANOVA for each study s i t e i n d i c a t e s s t a t i s t i c a l l y s i g n i f i c a n t increases from o f f - t r a i l or t r a i l - e d g e to o n - t r a i l for study s i t e s A, B, and C. Study s i t e D, which has received l e s s ORV a c t i v i t y and repre-sents' a r e l a t i v e l y f l a t area, does not show a s i g n i f i c a n t change i n bulk den-s i t y following ORV a c t i v i t y . Table 8 i n d i c a t e s changes i n bulk density for the t r a n -sect groups representing the three s o i l conditions within the study area. The data was analyzed for d i f f e r e n c e s between o n - t r a i l and o u t - o f - t r a i l ( t r a i l -edge plus o f f - t r a i l ) only, since Table 7 did not f i n d s t a t i s t i c a l l y s i g n i f i -cant d i f f e r e n c e s between the t r a i l - e d g e and o f f - t r a i l measurements. The t a b l e shows that d i f f e r e n t o u t - o f - t r a i l conditions e x i s t for each s o i l c ondition and the greatest percent increase i n bulk density occurred i n the area of greatest ORV a c t i v i t y , the Brown Chernozemic s o i l great group of study s i t e A. 4.1.2 S o i l Moisture The r e s u l t s of the s o i l moisture measurements are shown i n 26. Table 7, Bulk Density (g/cc) - By Study S i t e and ORV T r a i l Sample Point ANOVA - Pairwise Strata Transect Group N On- T r a i l Off- Trail-Edge T r a i l - O f f Edge-Off T r a i l -Edge T r a i l F S i g n i f . F S i g n i f . F S i g n i f . 55 30 8 17 1.70 1. 76 1.76 1.51 1.41 1.43 1.55 1.32 1.28 1.35 1.05 12.98 11.24 1.85 2.24 .01 .01 19.51. .01 15.81 .01 7.52 .01 2.31 0.69 3.37 33 1.45 1.01 32.74 .01 23 1.29 1.05 1.10 5.71 5 1.69 1.72 0.03 .05 2.09 0.15 33 1.35 1.17 1.18 2.62 23 1.48 1.31 1.34 2.23 10 0.96 0.86 0.87 0.28 2.25 1.46 0.24 0.01 0.08 0.00 Table 8. Bulk Density (g/cc) By S o i l Condition Sample Point Transect Group N On-Trail O u t - o f - T r a i l % Change S i g n i f . Brown (BR) 55 1.70 1.37 + 24.09 .01 Dark Brown (DKBR) 84 1.43 1.17 +22.22 .01 Swale (SW) 10 0.96 0.87 + 10.34 AN OVA Pairwise Strata F S i g n i f . On-Trail BR DKBR 10.11 .01 SW 12.92 .01 DKBR SW 5.55 .05. Ou t - o f - T r a i l BR DKBR 11.42 .01 SW 22.74 .01 DKBR SW 8.88 .01 On-Trail - O u t - o f - T r a i l BR 16.13 .01 DKBR 17.68 .01 SW 0.20 — 28. Table 9. There i s a general trend of a loss of moisture content from o f f -t r a i l to o n - t r a i l sample points but the high l e v e l of variance prevents s i g -n i f i c a n t d i f f e r e n c e s . The two areas with s i g n i f i c a n t changes i n moisture con-tent can be explained topographically. Transects i n group are located on a steep north-facing slope. The reduced amounts of d i r e c t sunlight allows the vegetation to reduce evaporation on the o f f - t r a i l areas. The same vegetation I n t e r a c t i o n i s occurring at the transect group D^. The transects are i n a small swale with a thick sod layer of Poa secunda which i s reducing the amount of s o i l moisture evaporation at the o f f - t r a i l sample point l o c a t i o n s . The grouping of the study area transects by s o i l condition i n d i c a t e s that moisture conditions for the o u t - o f - t r a i l l o c a t i o n s i n each group are s i g n i f i c a n t l y d i f f e r e n t but s i g n i f i c a n t changes do not occur between o n - t r a i l and o u t - o f - t r a i l l o c a t i o n s (Table 10). 4.1.3 Organic Carbon Table 11 shows the r e s u l t s of the organic carbon measure-ments and i n d i c a t e s the same nonsignificant downward trend that the moisture content had between o f f - t r a i l and o n - t r a i l areas. The two s i g n i f i c a n t areas of decreased organic carbon content occurred i n study s i t e s A and B. A s i g n i f i c a n t negative c o r r e l a t i o n i d e n t i f i e d between bulk density and organic carbon with a c o r r e l a t i o n matrix explains the decreased l e v e l of organic car-bon i n the two study s i t e s which have received the greatest amount of s o i l compaction from ORV a c t i v i t y . Table 12 i n d i c a t e s the change of organic carbon for each s o i l condition. Again, the o u t - o f - t r a i l values for each transect group are s i g n i f i c a n t l y d i f f e r e n t but only the Brown Chernozem s o i l area measured a s i g n i f i c a n t decrease of organic carbon for o n - t r a i l c o n d i t i o n s . 29 Table 9, S o i l Moisture (% dry wt.) - By Study S i t e and ORV T r a i l Sample Point ANOVA - Pairwise Strata Transect Group . N On- T r a i l O f f - Trail-Edge T r a i l - O f f Edge-Off T r a i l -Edge T r a i l F S i g n i f . F S i g n i f . F S i g n i f . 55 30 8 17 1.75 1,25 2.41 2.28 1.73 1.38 1.54 2.24 1.99 1.71 2.92 0.00 0.03 0.54 0.00 0.04 0.35 0.26 0.06 0.22 0.40 33 4.58 4.67 0.02 23 5 5.58 8.59 8.28 15.97 .01 3.80 4.50 0.22 7.54 .01 0.10 D, 33 7.98 10.84 10.40 23 5.68 7.38 6.40 10 14.85 18.64 18.39 4.26 .05 3.85 .05 7.10 .01 2.94 0.66 6.20 .05 0. 13 1.50 0.05 30. Table* 10. S o i l Moisture (% dry wt.) - By S o i l Condition Transect Group N Sample Point On-Trail O u t - o f - T r a i l % Change S i g n i f . Brown (BR) Dark Brown (DKBR) Swale (SW) 55 1.75 84 5.01 10 14.85 1.81 6.46 18.51 - 3.43 -22.46 - 19.77 AN OVA Pairwise Strata F Si g n i f . On-Trail BR DKBR SW DKBR SW . Ou t - o f - T r a i l BR DKBR SW DKBR SW 9.31 25.84 15.60 41.35 158.63 85.67 On-Trail - O u t - o f - T r a i l BR 0.00 DKBR 3.62 SW 1.83 ,01 ,01 .01 ,01 ,01 ,01 Table 11. Organic Carbon (wt. %) - By Study S i t e and ORV T r a i l Sample Point ANOVA - Pairwise Strata Transect Group N On- T r a i l Off-T r a i l -Edge T r a i l Trail-Edge F. S i g n i f . T r a i l - O f f F S i g n i f . Edge-Off F S i g n i f . 55 30 8 17 1.37 1.27 1.04 1.83 2.07 1.74 1.26 2.86 2.65 2.23 4.06 3.23 1.09 0.09 2.99 7.96 .01 4.13 .05 8.52 .01 2.11 1.29 3.36 33. 3.15 4.00 5.96 .01 23 3.54 3.75 3.50 0.02 5 2.16 2.72 0.38 0.00 0.17 D 33 2.97 3.46 .3.61 0.84 23 2.33 2.59 2.93 0.24 •10 4.87 5.41 4.97 0.39 1.38 1.22 0.01 0.09 0.48 0.40 Table 12. Organic Carbon (wt. %) - By S o i l Condition Sample Point Transect Group . N On-Trail O u t - o f - T r a i l .% Change S i g n i f . Brown (BR) 55 1.37 Dark Brown (DKBR) 84 3.05 Swale 10 4.87 AN OVA Pairwise Strata F S i g n i f . On-Trail BR DKBR 19.06 .01 SW 14.17 .01 DKBR SW 4.10 .05 ' - T r a i l BR DKBR 19.98 .01 SW 37.66 .01 DKBR SW 14.20 .01 2.26 - 39.38 .05 3.42 - 10.82 5.19 - 6.17 On-Trail - O u t - o f - T r a i l BR 5.62 .05 DKBR 1.83 SW 0.11 33. 4.1.4 S o i l Erosion Transects Figure 2 shows a sequence of s o i l - l o s s p r o f i l e s along a s i n g l e t r a i l i n study s i t e A, transect group A^. The p r o f i l e s are represen-t a t i v e of the ORV t r a i l cross section f o r the selected slope on the h i l l s i d e . The t o t a l s o i l mass removed from the area of bare s o i l of the ORV t r a i l was 2 estimated at 349 metric tons or 114 kg/m . An a d d i t i o n a l c a l c u l a t i o n from the s o i l erosion transects confirms that a p o s i t i v e r e l a t i o n s h i p e x i s t s between s o i l erosion and steep-ness of slope. The amount of s o i l removed per unit t r a i l width for a l l 31 transects c o r r e l a t e s to the transect slope with a c o e f f i c i e n t of 0.70. 4.1.5 Vegetation and Ground Cover Table 13 i n d i c a t e s the change i n average percent ground cover for o n - t r a i l , t r a i l - e d g e and o f f - t r a i l l o c a t i o n s . The amount of exposed s o i l decreases with the distance from the centre of the t r a i l and the change i n proportions i s s i g n i f i c a n t between a l l three sample points. The percent plant cover i s i n v e r s e l y r e l a t e d to the amount of exposed s o i l , with s i g n i f i -cant changes i n plant cover occurring between o n - t r a i l and t r a i l - e d g e and a trend toward an increase between t r a i l - e d g e and o f f - t r a i l l o c a t i o n s . Table 14 i n d i c a t e s the r e s u l t s of separating the ground cover proportions into three categories based on s o i l condition. The i n t e r -e s t i n g r e s u l t i s the s i g n i f i c a n t d i f f e r e n c e which e x i s t s between the Brown Chernozem and Dark Brown Chernozem s o i l for the ground cover proportions of l i t t e r and plant. The Brown Chernozem s o i l proportions of l i t t e r and plant are the inverse of the Dark Brown Chernozem s o i l . The change i n proportion of l i t t e r and plant cover corresponds to a d i f f e r e n c e in t r a i l - e d g e vegeta-t i o n species between the Brown and the Dark Brown Chernozem s o i l great groups. The areas adjacent to the heavily used t r a i l s i n the Brown Chernozem s o i l Figure 2. S o i l Loss P r o f i l e s Along a Single T r a i l - Transect Group A^ The four s o i l erosion transects along a s i n g l e t r a i l (1 = top of t r a i l ; 4 = base of t r a i l ) were combined with the measured area of exposed s o i l to 2 compute a t o t a l mass s o i l loss of 349 metric tons or 114 kg/m . J 1 I L 0 2 4 6 8 10 12 W I D T H (m) 35. Table 13. Vegetation and Ground Cover C h a r a c t e r i s t i c s - By Sample Point Location Sample Point N On-Trail 50 Trail-Edge 70 O f f - T r a i l 29 S o i l 0.82 0.25 0.09 Ground Cover Proportions L i t t e r 0.06 0.38 0.36 Plant 0.06 0.28 0.38 Green Plant 0.05 0.09 0.13 Pairwise Strata On-Trail Trail-Edge O f f - T r a i l Trail-Edge O f f - T r a i l ANOVA S o i l L i t t e r Plant Green Plant F S i g n i f . F S i g n i f . F S i g n i f . F S i g n i f . 135.81 .01 140.34 .01 7.56 .01 37.68 .01 21.12 .01 0.08 18.55 .01 25.02 .01 2.81 0.87 2.36 0.71 36. Table 14. Vegetation and Ground Cover C h a r a c t e r i s t i c s - By S o i l Condition Ground Cover Proportions Transect : : Group N S o i l L i t t e r Plant Green Plant Brown 55 0.44 0.21 0.30 0.049 Dark Broxm 84 0.43 0.34 0.19 0.021 Swale 10 0.02 0.00 0.16 0.830 AN OVA S o i l L i t t e r Plant Green Plant Pairwise S t r a t a F S i g n i f . F S i g n i f . F S i g n i f . F S i g n i f . Brown Dark Brown 0.01 — 6.35 .01 5.30 .05 2.52 Swale 8.97 .01 4.39 .05 2.05 — 450.32 .01 Dark Brown Swale 9.06 .01 11.53 .01 0.11 — 508.05 .01 j 37. area (Study s i t e A) have a p a r t i a l vegetation cover of Bromus tectorum L. 13. tectorum i s an annual grass which grows as a sod-like ground cover with a l e s s obvious proportion of surface l i t t e r . Its most s i g n i f i c a n t area of growth i s at transect group A^ (Figure 3). The t r a i l - e d g e s i t e s i n the Dark Brown Chernozem s o i l areas have maintained the vegetation cover of native bunchgrasses, although the proportions of exposed s o i l and l i t t e r have increased. 4.1.6 Discussion of Ground Survey Results The r e s u l t s of the s o i l surface sampling i n d i c a t e that ORV a c t i v i t y on the Lac du Bois rangelands caused an increase i n bulk density and a decrease i n s o i l moisture and organic carbon. Although the three pro-p e r t i e s are p a r t i a l l y c o r r e l a t e d , the combined e f f e c t can a l t e r the b i o l o g -i c a l p r o d u c t i v i t y of the s o i l . Previous research has studied the e f f e c t of changes i n bulk density, s o i l moisture and organic carbon on the c o n d i t i o n of the s o i l and on the establishment and development of vegetation i n both q u a l i t a t i v e and q u a n t i t a t i v e terms. The l i t e r a t u r e on the e f f e c t of s o i l compaction, or increases i n bulk density, on a g r i c u l t u r a l s o i l s and t h e i r p l a n t growth was reviewed by the American Society of A g r i c u l t u r a l Engineers (Barnes et_ al_. , 1971). The impetus of t h e i r study was the r e a l i z a t i o n that the "Fundamental knowledge of (1) the behavior of s o i l when subjected to forces, (2) the e f f e c t of the s o i l ' s behavior on i t s s u i t a b i l i t y as a root environment, and (3) the re-sponse of plants to t h i s environment i s la c k i n g and i s needed." (Barnes e_t a l . , 1971, p . i i i ) . Their monograph discusses s o i l compactions i n both b e n e f i c i a l and detrimental terms and provides q u a l i t a t i v e and q u a n t i t a t i v e information on modifications to s o i l and vegetation. One detrimental e f f e c t 38. Figure 3. Invasion of Bromus tectorum i n a Zone of Secondary Disturbance The c o l o u r - i n f r a r e d ground photograph of transect group i l l u s t r a t e s the v i s u a l contrast between three vegetation species - Agropyron  spicatum, Bromus tectorum and Centaurea d i f f u s a . On the date o f photography, June 9, 1979, the A. spicatum i s represented by the d u l l brown colour at the top of the h i l l s l o p e . The jB. tectorum has invaded the ORV disturbed s o i l area of the middle and lower slopes and i s a l i g h t amber colour. The C. d i f f u s a i s the magenta colour occurring as narrow s t r i p s along the t r a i l edges of the middle slope. of s o i l compaction, stated i n the review by H a r r i s ( i n Barnes et_ a l . , 1971) i s that heavy compaction w i l l reduce s o i l water i n f i l t r a t i o n and increase surface runoff and erosion because when a s o i l i s compressed the pore-size d i s t r i b u t i o n tends toward a smaller proportion of l a r g e r pores. A second detrimental e f f e c t i s that s o i l compaction r e s u l t s i n a decrease of the amounts of nu t r i e n t s mineralized from the s o i l organic material (Kemper, Stewart and Porter, i n Barnes e_t al_. , 1971). Both detrimental e f f e c t s may be induced by the increase i n bulk density caused by ORV a c t i v i t y . Unfortun-at e l y t h e i r focus on a g r i c u l t u r a l s o i l s r e s t r i c t s the extrapolation of t h e i r q u a n t i t a t i v e r e s u l t s to the rangeland conditions of the Lac du Bois study area. Also t h e i r r e s u l t s are q u a l i f i e d by an i n d i c a t i o n of the complexity of s o i l and vegetation i n t e r a c t i o n s . "In order to f u l l y understand the reactions of a plant growing i n a compacted s o i l i t i s mandatory that we f i r s t understand p h y s i o l o g i c a l requirements of the plant and the responses of the plant to other environmental f a c t o r s . ... A plant can appear to respond normally as long as a l l i t s current needs are s a t i s f i e d . Since s o i l compaction can a l t e r the a b i l i t y of the s o i l to supply the current needs to the roots and the a b i l i t y of the roots to absorb these current needs from the s o i l , s o i l compaction can e f f e c t i v e l y r e s t r i c t plant development. What co n s t i t u t e s an e f f e c t i v e a l t e r a t i o n to the supplying c a p a b i l i t y of the root system depends upon the requirements of the plant and the a e r i a l environment." (Trouse, i n Barnes et a l . , 1971). A search of the l i t e r a t u r e for information on the a b i l i t y of range vegetation to meet i t s growth requirements under compacted conditions i n d i c a t e s a lack of s p e c i f i c knowledge. Studies on the e f f e c t of grazing on s o i l compaction (Beke, 1961; Laycock and Conrad, 1967) did not i d e n t i f y change i n vegetation growth or y i e l d under the compacted s o i l s . Studies on seedling emergence, growth and root development as influenced by compaction (Barton et_ a l . , 1966; Fryrear and McCully, 1972) f a i l e d to provide,information relevant to conditions of ORV compaction. Fryrear and McCully (1972) found that fewer roots grew under each plant and that the grass roots were shallower and with l i m i t e d development through the s o i l p r o f i l e following compaction by a ten ton road r o l l e r . The road r o l l e r may have simulated surface compaction s i m i l a r i n magnitude to the ORV t r a i l s w ithin the Lac du Bois study area but unfortunate-l y the authors d i d not report any measurements on the amount of compaction causing the changes. Barton et_ al. (1966) measured the amount of compaction and found that y i e l d of seed and forage was i n v e r s e l y r e l a t e d to compaction but u n l i k e ORV impact conditions, the compacted layer was four inches below the surface and the surface s o i l provided a seedbed for the emergence of seedlings without any e f f e c t s from the compacted s o i l . As a r e s u l t , the l i t e r a t u r e allows speculation that the Lac du Bois range vegetation w i l l not be able to meet i t s growth requirements along the ORV t r a i l s , but leaves i n doubt the seriousness of the measured increase i n surface compaction due to ORV a c t i v i t y . W i l l the s o i l i n study s i t e A, compacted to 1.76 g/cc on the surface 7.5cm f a i l to provide a seedbed for grass species or r e s t r i c t t h e i r development following an a b i l i t y to e s t a b l i s h themselves on the ORV t r a i l ? Can the increase i n bulk density be termed damage to future vegetation growth or i s i t j u s t an impact to e x i s t i n g vegetation? The changes i n the s o i l moisture and organic carbon values on the ORV t r a i l s are a cause and e f f e c t s i t u a t i o n with the change i n bulk density. Negative c o r r e l a t i o n s existed between bulk density and organic car-bon. The same e f f e c t was measured by Laycock and Conrad (1967) during t h e i r study of grazing e f f e c t s on s o i l compaction. With the removal of vegetation by ORV a c t i v i t y and a r e s u l t i n g increase i n surface s o i l temperature (Brady, 1974), the organic matter of the s o i l i s reduced. A reduced l e v e l of organic matter w i l l reduce the supply of phosphorus, sulphur and nitrogen, w i l l de-crease the amount of water a s o i l can hold and the proportion a v a i l a b l e f or plant growth, and w i l l decrease the supply of energy to s o i l microorganisms for biochemical a c t i v i t y (Brady, 1974) which can combine to r e s t r i c t the development of new plant growth. The decrease of s o i l moisture as a r e s u l t of ORV a c t i v i t y can be a t t r i b u t e d to several factors previously mentioned. The compaction of the s o i l a l t e r s the pore spaces which increases surface runoff and reduces i n f i l t r a t i o n (Rauzi and Hanson, 1966), the removal of vegetation by ORV d i s -turbance exposes the s o i l which increases the temperature and evaporation (Brady, 1974; Voorhees, 1977), and the reduction of organic matter reduces the a b i l i t y of the s o i l to hold water (Brady, 1974) . A reduction i n s o i l moisture can be a c r i t i c a l f a c t o r to plant growth i n the semi-arid grassland region of the study area. Laycock and P r i c e (1970) i d e n t i f i e d an early seasonal drying of s o i l under drought conditions as responsible for the early drying and maturing of plants which i n turn hastens seasonal changes i n chemical composi-t i o n and reduces the n u t r i t i v e value of the reduced y i e l d . In a d d i t i o n to the i n d i r e c t e f f e c t of ORV induced s o i l changes on vegetation, the d i r e c t e f f e c t s are also important. The i n i t i a l and most obvious d i r e c t e f f e c t i s the mechanical abrasion of ORVs on vegetation, e s p e c i a l l y during the senescence period of J u l y and August when the grasses are very b r i t t l e and e a s i l y damaged. Following the abrasion, wind and water erosion can remove plant and l i t t e r material and expose the s o i l to f u r t h e r erosion. A second e f f e c t on the vegetation, caused by the reduced vegetation cover and vigour and the disturbed s o i l , i s the invasion of un-d e s i r a b l e vegetation species. The main invaders i n the study area are Bromus  tectorum, Centaurea d i f f u s a L. and Centaurea maculosa L. A l l three species are undesirable for grazing and f o r the semi-arid region of i n t e r i o r B r i t i s h Columbia, a l l three have s i m i l a r invasion h a b i t s . From research on the range-lands of i n t e r i o r B r i t i s h Columbia, Watson (1972) characterized the i n v a s i o n habits of both Centaurea species. "The s o i l a n a l y s i s i n d i c a t e s that the Centaurea species r e a d i l y colonize d i f f e r e n t s o i l s with a wide range of chem-i c a l p r o p e r t i e s . Plant density of C_. d i f f u s a and _C. maculosa could only be s i g n i f i c a n t l y (P= 0.05) correlated with the degree of disturbance of the s o i l . The greater the degree of disturbance, the higher the plant' density of the knapweed species. These r e s u l t s i n d i c a t e ... that any s o i l i n the dry i n t e r i o r of the province of B r i t i s h Columbia with a disturbed A horizon i s subject to knapweed i n f e s t a t i o n . " (Watson, 1972, p.13). Watson (1972) also indicated that the a b i l i t y of Centaurea species to invade disturbed s i t e s and withstand competition from other plant species i s a t t r i b u t e d to i t s a l l e l o p a t h i c e f f e c t s . This a l l e l o p a t h i c e f f e c t and t h e i r uselessness as a forage plant reduces t h e i r d e s i r a b i l i t y as a useful pioneer species f o r erosion c o n t r o l and organic matter b u i l d up on ORV t r a i l s . The invasion habits of Bromus tectorum were described by H a r r i s (1967) f o r the rangelands of i n t e r i o r Washington. B_. tectorum i s not as undesirable as the Centaurea species since i t does provide a palatable grazing source e a r l y i n i t s growing season p r i o r to the development of i t s spiny seed awls. H a r r i s (1967) indicated that dominance of B_. tectorum on Agropyron spicatum s i t e s i s only known to occur as the r e s u l t of some form of disturbance - which has been provided on the Lac du Bois rangelands by ORV a c t i v i t y . A d d i t i o n a l r e s u l t s from H a r r i s ' study explains the a b i l i t y of 15. tectorum to maintain i t s e l f i n study s i t e A, e s p e c i a l l y transect group A^, yet i t i s not as prominent i n the other study s i t e s . B_. tectorum's growth and reproduction occurs i n the l a t e f a l l to early spring when moisture i s not l i m i t i n g . This allows the B_. tectorum roots to exhaust the s o i l moisture supply p r i o r to the needs of the A. spicatum plants at i t s l a t e r maturity date (Harris, 1967) . The a b i l i t y of the B_. tectorum plants to reduce the moisture content of the s o i l was documented during the ground survey program of t h i s t h e s i s . With reference to Table 9, the average moisture content at t r a i l - e d g e of transect group A^, which has the largest invasion of 13. tectorum i n a l l the study s i t e s , was reduced below the moisture content of both the o n - t r a i l and o f f - t r a i l sample points. The invasion of ]3. tectorum i n smaller concentrations i n study s i t e C, transect group C^, which has s i m i l a r s i t e c h a r a c t e r i s t i c s as group A^, may be the r e s u l t of a greater moisture content due to i t s l o c a t i o n i n the middle grassland Dark Brown Chernozem s o i l great group. The reduced moisture s t r e s s on the A. spicatum plants provides greater competition to the invading _B. tectorum seedlings. 4.2 A e r i a l Photograph Inte r p r e t a t i o n The v i s u a l a nalysis of the 1971 to 1979 a e r i a l photographs provided a h i s t o r y of the areas of ORV impact on the Lac du Bois rangelands. Table 15 summarizes the increase of ORV t r a i l lengths for each study s i t e . The t r a i l s were divided into s i n g l e and double tracks during the mapping stage, although each t r a i l type does not specify use by only motorcycle- or 4-wheel drive v e h i c l e s . Many double-track t r a i l s began as access roads to various regions of the rangelands but were subsequently adopted as ORV t r a i l s . This i s shown within the table. The e a r l y h i s t o r y of the study s i t e s had higher proportions of double-track t r a i l s which have decreased over time with increased a c t i v i t y . From Table 15, study s i t e A received the e a r l i e s t ORV a c t i v i t y . Presently i t has the greatest length of t r a i l s , although no increase i n t r a i l -length occurred between 1977 and 1979, which was the time period of the great-est increase i n t r a i l length for study s i t e s B, C, and D. The h i s t o r y of the i n c r e a s i n g p o p u l a r i t y of s i t e s C and D i s shown i n Figures 4, 5, and 6. The fi g u r e s are reductions of the maps used for t r a i l length measurement and the date sequence i l l u s t r a t e s the pattern of ORV t r a i l expansion on the steep h i l l climb area of the north facing slope i n study s i t e C. To complement the t r a i l length measurements which do not consider the varying width of the ORV t r a i l s , a section of study s i t e A, encompassing 44. Table 15. Increase of ORV T r a i l Length (km) - 1971 to 1979 Film Date Scale; Type T r a i l Type Study S i t e A Study S i t e B Study Site C & D Aug, 1979 1:4,000 ; CIR Double Single 11.4 22.7 0.8 19.3 1.9 21.7 June, 1977 1:12,000; NC Double Single 11.4 22.7 3.4 4.0 2.2 9.9 June, 1975 1:8,000 ; NC Double Single * * * * 3.5 6.9 July, 1971 1:12,000; B/W Double Single 7.2 5.9 0.5 0.0 * Study S i t e Area (km2) 1.3 1.0 0.8 CIR - Colour Infrared Photographs NC - Normal Colour Photographs B/W - Black and White Photographs * - A e r i a l Photograph Coverage Not Available Figure 4. ORV T r a i l s at Study Sit e s C and D - June, 1975 Figure 5. ORV T r a i l s at Study Si t e s C and D - June, 1977 Scale = 1:7150 Single Track ORV T r a i l s Contour I n t e r v a l = 20m Double Track ORV T r a i l s Area of A e r i a l Photograph ~ = = = Access Roads Coverage - 1975 , 1977 , 1979 = = Main Roads 47 Figure 6. ORV T r a i l s at Study Sites C and D - August, 1979 X - 1979 Transect Locations transect group A^, was measured for i t s area of exposed s o i l (Figure 7). The dot g r i d provided a tedious but us e f u l way of measuring the area of exposed s o i l when the 1:1000 scale a e r i a l photograph was enlarged four times. The enlargement allowed f o r an easier assessment of exposed s o i l using a dot g r i d . The technique can be applied when enlargements are a v a i l a b l e or when very large s cale a e r i a l photographs are a v a i l a b l e for areas of ORV a c t i v i t y with varying t r a i l widths. The i n t e r p r e t a t i o n s of the a e r i a l photographs for vegetation and s o i l disturbance i d e n t i f i e d two types of disturbance. The major t r a i l s are exposed s o i l , compacted and with a thi n mantle of loess on the surface. They have received the greatest concentration of ORV t r a f f i c . The secondary zones of disturbance l i e adjacent to or between the major ORV t r a i l s and occasion-a l l y are major ORV t r a i l s which have been abandoned. Not a l l major t r a i l s have a secondary zone of disturbance associated with them. The secondary zones are i d e n t i f i e d by a trampled appearance of the native vegetation, an invasion of undesirable vegetation species, p r i m a r i l y B. tectorum which i s r e a d i l y v i s i b l e on the colour i n f r a r e d a e r i a l photographs as a l i g h t yellow to beige hue and also Centaurea species which appear l i g h t magenta, plus a rutted s o i l surface with a reduced l i t t e r cover. Ground photographs of tra n -sect group A^, indicates the la r g e s t zone of secondary disturbance. This zone i s v i s i b l e on both the 1:1000 and 1:4000 July/August 1979 a e r i a l photo-graphs although not as pronounced as on the June colour i n f r a r e d ground photograph (Figure 3) which was taken p r i o r to the summer senescence of most grasses. Smaller zones of secondary disturbance are v i s i b l e on the 1:4000 a e r i a l photographs within study s i t e s A and C, and associated with the h i l l -climb areas. In study s i t e B the areas adjacent to the major t r a i l s and motocross c i r c u i t have received considerable impact to the n a t u r a l vegeta-t i o n , p r i m a r i l y mechanical abrasion, but i t has not resulted i n an invasion 49 Figure 7. Area of Exposed S o i l for Transect Group A_, This photograph i s a 1.8 times enlargement of the o r i g i n a l 70mm colour i n f r a r e d a e r i a l photograph which had been enlarged 4.0 times to measure the area of exposed s o i l using a standard dot g r i d . Scale = 1:2470 Date of Photography = July 28, 1979 2 Area of Exposed S o i l = 10,850 m = 16.4 % of the image of undesirable vegetation species. 4.3 Densitometry The r e s u l t s of the regression analysis to test the p o t e n t i a l of colour i n f r a r e d photographs to i d e n t i f y v a r i a t i o n s i n ground conditions with-2 i n areas of ORV a c t i v i t y are shown i n Table 16. The R c o r r e l a t i o n c o e f f i -cients of regressing the s o i l p h y s i c a l parameters versus the o p t i c a l density values and t h e i r r a t i o s are l i s t e d f o r each data set group. 2 2 For the e n t i r e data set, poor c o r r e l a t i o n s , R =.247 and R =.397, existed between the s o i l p h y s i c a l parameters of bulk density and organic car-bon and the o p t i c a l density values, with only a s l i g h t l y better c o r r e l a t i o n , 2 R =.583, existed f or the moisture content values. Grouping of the data set by o n - t r a i l , t r a i l - e d g e and o f f - t r a i l sample points improved the c o r r e l a t i o n s . Bulk density c o n s i s t e n t l y had the lowest c o r r e l a t i o n c o e f f i c i e n t s and the moisture content maintained the better c o r r e l a t i o n values from the i n i t i a l a n a lysis of the e n t i r e data set. Both moisture content and organic carbon had the best c o r r e l a t i o n at the o f f - t r a i l sample points. This r e s u l t does not support the use of densitometry for ORV areas because the information i s most needed for o n - t r a i l conditions. In a d d i t i o n , there was no consistent s e l e c t i o n of h i g h l y c o r r e l a t e d o p t i c a l den-s i t y values i n the regression a n a l y s i s . A second approach to grouping the data set was t r i e d i n an attempt to improve the o n - t r a i l c o r r e l a t i o n s . The data was grouped according to study s i t e but the a n a l y s i s was r e s t r i c t e d to study s i t e B. The choice of study s i t e B was based on the expo-sure curves on the colour i n f r a r e d f i l m (Figure 8). The f i l m had been s l i g h t -l y overexposed, with the r e s u l t that the average o p t i c a l density values f o r each study s i t e are not On the s t r a i g h t l i n e portion, but near the toe of the log exposure curve. The range of o p t i c a l density values for study s i t e s A, 51. Table 16. Regression Analysis - S o i l P h y s i c a l Variables versus O p t i c a l Density S o i l P h y s i c a l Variables Bulk Density S o i l Moisture Organic Carbon Data R2 S i g n i f . Density R2 S i g n i f . Density R2 S i g n i f . Density Group Values Values Values A l l 149 .247 ltf*?r .583 Y,M,C. -397 J^.M/Y. On- Y, M, C, Y, M, M/Y, M, C, M/Y, T r a i l 5 0 , 3 6 7 M/Y, C/M. ' 3 7 ° C/M. C/M, C/Y. T"11- 70 .187 C/M. .588 1// '^' -345 M/Y,. C/Y. Edge C/M. 29 .356 C/Y. .841 Y, M, C/Y. .667 M * M / Y ' T r a i l C/Y. Study 3 3 4 M / y > < 7 1 8 c C / Y i > 8 4 2 C,, M/Y, C/M, Sit e B C/Y. Y - yellow dye layer of the c o l o u r - i n f r a r e d f i l m ; s e n s i t i v e to r e f l e c t e d energy i n the green s p e c t r a l region of the electromagnetic spectrum. M - magenta dye layer of the c o l o u r - i n f r a r e d f i l m ; s e n s i t i v e to r e f l e c t e d energy i n the red s p e c t r a l region of the electromagnetic spectrum. C - cyan dye lay e r of the co l o u r - i n f r a r e d f i l m ; s e n s i t i v e to r e f l e c t e d energy i n the near-infrared s p e c t r a l region of the electromagnetic spectrum. 52. Figure 8. Exposure Curves of 1:1000 70mm Colour-Infrared A e r i a l Photograph - July 28, 1979 YELLOW Dye Layer CYAN Dye Layer MAGENTA Dye Layer O p t i c a l Density Values by Dye Layer and Study S i t e B Maximum T Mean x Minimum Y MC . i n W 1 Y M C x 1 T YMC L O G E X P O S U R E 53. C, and D are nearest to the toe of the log exposure curve where the reduced o p t i c a l density of the f i l m prevents r e l a t i n g the f i l m density to the s p e c t r a l r e f l e c t a n c e and hence to the ph y s i c a l ground data v a r i a b l e s . Study s i t e B has a range of o p t i c a l density values fa r t h e s t from the toe of the exposure curve. I t has the greatest p o t e n t i a l f o r r e l a t i n g the f i l m density to the ph y s i c a l ground data v a r i a b l e s and also has the l a r g e s t sample s i z e along a s i n g l e ORV t r a i l . C o rrelations did not c o n s i s t e n t l y improve when the study s i t e B o n - t r a i l and t r a i l - e d g e sample points were analyzed. A pos s i b l e explanation was i d e n t i f i e d from the ANOVA for the s i x o p t i c a l density values and the three s o i l parameters (Table 17). The ground survey program for both bulk density and organic "carbon had s i g n i f i c a n t changes between o n - t r a i l and tr a i l - e d g e conditions but there were no s i g n i f i c a n t differences between the o n - t r a i l and o f f - t r a i l o p t i c a l density values, despite the presence of vegetation on the t r a i l - e d g e . The a n a l y s i s for c o r r e l a t i o n s between s o i l v a r i a b l e s and o p t i c a l density values f a i l e d to provide consistent r e s u l t s . Although the c o r r e l a -tions f o r s o i l moisture and organic carbon did improve with the analysis of only study s i t e B, i t i s d i f f i c u l t to provide p o s i t i v e concluding statements on the usefulness of the approach. The major drawback of the ana l y s i s i s the over-exposure of the a e r i a l photographs which l i m i t e d the u s e f u l sample s i z e to one of the four study s i t e s . Another l i m i t i n g f a c t o r to the success of i d e n t i f y i n g v a r i a t i o n s i n s o i l conditions following ORV a c t i v i t y i s the s o i l type of the study area. Although the a e r i a l photographs were acquired during the period of grass senescence when the e f f e c t of vegetation on s o i l r e f l e c t -ance was minimized (Siegal and Goetz, 1977), the highly r e f l e c t i v e nature of the a i r - d r i e d s i l t portion of the rangeland s o i l e f f e c t i v e l y masked the within s o i l v a r i a t i o n s . Table 17. ANOVA - Study S i t e B Sample Point ANOVA Var i a b l e N . On-Trail Trail-Edge F S i g n i f . Bulk Density 33 1.45 1.01 32.74 .01 S o i l Moisture 33 4.58 4.67 0.02 — Organic Carbon 33 1 3.15 4.00 5.96 . 01 Yellow 33 0.733 0.675 1.17 — Magenta . 33 0.632 0.598 0.40 — Cyan 33 0.748 0.714 0.57 — Magenta Yellow 33 0.865 0.888 0.79 — Cyan Magenta 33 1.189 1.197 0.01 — Cyan Yellow 33 1.029 1.064 0.63 — Tf The densitometric approach should not be discounted without an addi-t i o n a l analysis using properly exposed photography and at a time period when the s o i l i s not completely a i r - d r i e d . The analysis of study s i t e B i n d i c a t e s a p o t e n t i a l for densitometry to i d e n t i f y v a r i a t i o n s due to s o i l moisture and organic carbon and the c o r r e l a t i o n s to bulk density, which i s the most s i g n i f -icant e f f e c t of ORVs, may also improve to a more acceptable l e v e l . 5.0 RECOMMENDATIONS 5.1 ORV Monitoring Program 5.1.1 Introduction The procedures and r e s u l t s of t h i s t hesis research, and the modifications developed during the f i e l d research and from other recent research, can be drawn together to form a method for monitoring ORV impacts to s o i l and vegetation. The most e f f i c i e n t format u t i l i z e s the remote sens-ing multistage sampling approach to c o l l e c t data as a continuum from the general to the s p e c i f i c . 5.1.2 Stage I At stage I, la r g e - s c a l e a e r i a l photographs can provide information on the condition of an en t i r e study area plus allow for mapping and measuring the length of a l l ORV t r a i l s within and out of s p e c i f i c study s i t e s . New areas of ORV a c t i v i t y can be i d e n t i f i e d i n order to allow des-ignation of a d d i t i o n a l study s i t e s . The s e l e c t i o n of an a e r i a l photograph scale for monitoring i s a management d e c i s i o n which should be governed by considerations of the optimum s c a l e for maximum information content versus the cost of the a e r i a l photograph a c q u i s i t i o n . Decreasing the scale of the a e r i a l photographs to reduce the cost w i l l l i m i t the r e s o l u t i o n . This governs the a b i l i t y of the i n t e r p r e t e r to i d e n t i f y new ORV t r a i l s which have received only minimum t r a f f i c and serve as s t a r t i n g points to major t r a i l s . Also af f e c t e d i s the a b i l i t y to i d e n t i f y new areas of invading undesirable vegeta-t i o n which are easiest to con t r o l at the early stages of competition for dominance. An e n t i r e range of f i l m scales, types and dates were used during t h i s research to compile a h i s t o r y of ORV a c t i v i t y on the Lac du Bois rangelands. Many ORV t r a i l s were v i s i b l e on c o l o u r - i n f r a r e d a e r i a l photographs at the small scale of 1:63,360 because of the s p e c t r a l contrast between the exposed s o i l on the ORVs and the o f f - t r a i l vegetation. For the Lac du Bois study area which experiences an annual midsummer dry period and grass senescence, the optimum date f o r a e r i a l photo-graphic i n t e r p r e t a t i o n of ORV t r a i l s with c o l o u r - i n f r a r e d f i l m i s June. The healthy undisturbed native grasses are approaching maturity and a contrast e x i s t s among the unhealthy, damaged or dead native grasses, the invading annual grasses such as Broraus tectorum which has begun i t s period of summer dormancy, and the areas of exposed s o i l which have not reached the highly r e f l e c t i v e a i r - d r i e d period of midsummer. The s e l e c t i o n of June as the optimum date d i f f e r s from the a e r i a l photographs acquired at the end of Ju l y for t h i s study. The 1979 choice of dates was an^attempt to reduce the e f f e c t of vegetation on the s o i l r e f l e c t a n c e properties and to reduce the cost of a e r i a l photograph a c q u i s i t i o n with a mul t i p l e use approach. Unfortunately the s l i g h t overexposure of the f i l m and the lack of contrast between the a i r - d r i e d s i l t s and the dormant vegetation reduced the usefulness of the a e r i a l photographs. The s e l e c t i o n of June i s based on the information content of the co l o u r - i n f r a r e d ground photo-graphs taken during f i e l d reconnaissance for t h i s research, on the information content of the e x i s t i n g June a e r i a l photographs for the study area, on the recommendations by Watson (1977) f or vegetation species i d e n t i f i c a t i o n , and on the recent research by Leininger and Payne (1980) that selected June as the best time of c o l o u r - i n f r a r e d photography to i d e n t i f y ORV t r a i l s which had r e -ceived only l i g h t use during a c o n t r o l l e d t r a f f i c experiment. The s e l e c t i o n of 1:4000 as an optimum scale for ORV t r a i l monitoring was based on the i n t e r p r e t a t i o n experience of mapping the ORV h i s -tory of Lac du Bois with 1:4000, 1:8000 and 1:12,000 a e r i a l photographs. The r e s o l u t i o n of the 1:4000 a e r i a l photographs permitted easier and more accur-ate i d e n t i f i c a t i o n of the secondary zones of ORV disturbance, plus the scale 58. i s large enough to allow the mapping of most secondary zones of disturbance within the cartographic l i m i t s of the a e r i a l photographs. The choice of scale i s also supported by research t e s t i n g the information content of medium to l a r g e - s c a l e a e r i a l photographs. For vegetation i d e n t i f i c a t i o n and c l a s s i f i c a -t i o n on the Lac du Bois rangelands, Watson (1977) recommended 1:10,000 s c a l e a e r i a l photographs for vegetation mapping but indicated that 1:4000 scale was required for species i d e n t i f i c a t i o n . The recent work on ORV t r a i l i d e n t i f i c a -tion on Montana rangelands by Leininger and Payne (1980) found that 1:6000 co l o u r - i n f r a r e d a e r i a l photographs could detect disturbances to vegetation a f t e r eight t r i p s along a s i n g l e t r a i l but the r e s o l u t i o n l i m i t e d the iden-t i f i c a t i o n of two t r i p t r a i l s . A i r d (1980) matched the a e r i a l photograph ground r e s o l u t i o n to surface features and c o r r e l a t e d t h i s to the a e r i a l photo-graph scale. The r e s u l t i s the recommendation of a e r i a l photograph a c q u i s i -t i o n from a 600 metre a l t i t u d e above ground l e v e l (0.16m ground r e s o l u t i o n or approximately 1:4000 scale) for monitoring environmental impacts from p i p e l i n e construction. "For environmental monitoring, a minimum ground r e s o l u t i o n of 16cm i s e s s e n t i a l i n order to obtain s u f f i c i e n t l y d e t a i l e d coverage. This degree of ground r e s o l u t i o n ensure that v e h i c l e t i r e tracks, erosion g u l l i e s , stones or any l a r g e r feature would be recorded and could be i n t e r p r e t e d . Any increase i n a l t i t u d e would r e s u l t i n the l o s s of d e t a i l e s s e n t i a l to provide the required information." (Aird, 1980, Appendix I ) . The u t i l i z a t i o n of the 1:4000 scale c o l o u r - i n f r a r e d a e r i a l photographs for monitoring changes i n ORV t r a i l s does not require that a l l i d e n t i f i a b l e t r a i l s be mapped and measured, due to the p o t e n t i a l l y enormous nature of the task. Mapping of major t r a i l s and providing sequential a e r i a l photographs as a permanent record of changes to the minor t r a i l s , through development to major t r a i l s , invasion of undesirable vegetation or recovery would be an e f f i c i e n t u t i l i z a t i o n of the a e r i a l photographs. The use of smaller-scale a e r i a l photographs to map the major t r a i l s would r e s t r i c t the monitoring of the minor t r a i l s . 5.1.3 Stage II At stage II of the monitoring system, very l a r g e - s c a l e a e r i a l photographs can provide more d e t a i l e d information on the study s i t e s w i t h i n the study area. Recommendation of 1:600 scale 70mm normal colour or co l o u r - i n f r a r e d a e r i a l photographs i s based on the previous research on rangeland inventory and i n d i r e c t l y supported by the 1979 70mm a e r i a l photo-graphs. T u e l l e r and Booth (1975) evaluated several a e r i a l photograph scales l a r g e r than 1:1000 and found that 1:600 scale sequential a e r i a l photographs i n stereo p a i r s could be used to detect and inventory s o i l movement and evalu-ate erosion conditions. The 1979 1:1000 scale 70mm c o l o u r - i n f r a r e d a e r i a l photographs of the study s i t e s at Lac du Bois were at the l i m i t of acceptable r e s o l u t i o n for erosion evaluation under conditions of good contrast ( T u e l l e r and Booth, 1975). Unfortunately the s l i g h t overexposure and date of photo-graphy res u l t e d i n poor contrast on the 1979 a e r i a l photographs and prevented the evaluation of erosion conditions associated with the ORV a c t i v i t y areas on the Lac du Bois rangelands. A c q u i s i t i o n of June a e r i a l photographs at 1:600 scale w i l l allow for erosion evaluation with T u e l l e r and Booth's (1975) method (Appendix A) and the pr o v i s i o n of a permanent record of the changing conditions. The i n c l u s i o n of t h i s stage of data c o l l e c t i o n i n a method which should attempt to provide information with a minimum of expense i s based on the e f f i c i e n c y of data c o l l e c t i o n using remote sensing. Both T u e l l e r and Booth (1975) and Ai r d (1980) assessed the costs of data c o l l e c t i o n from ground survey and from large scale a e r i a l photographs and concluded that remote sens-ing was considerably l e s s expensive and provided a permanent o b j e c t i v e data source. The a c t u a l a c q u i s i t i o n of the a e r i a l photographs f o r open lands i n B r i t i s h Columbia could be accomplished at a reduced cost by coordination with the new forest and range inventory program developed by the B r i t i s h Columbia M i n i s t r y of Forests (1979). The inventory program proposes to use a remote sensing multistage sampling program which includes as i t s stage I I , c o l l e c t i o n of very l a r g e - s c a l e (1:200 to 1:1000) f i x e d base 70mm a e r i a l photographs. Photography of selected ORV study s i t e s during the f l i g h t s to or from the fo r e s t sampling s i t e s would be the most cost e f f e c t i v e data c o l l e c t i o n method for any ORV research. 5.1.4 Stage I I I The t h i r d stage of the monitoring program i s ground data c o l l e c t i o n w i t h i n each study s i t e . The sample s i t e s should be based on ORV management plans, and the sample s i t e s could represent areas of a c t i v e ORV use, r e s t r i c t e d ORV use and areas closed to ORVs to allow for s o i l and vegetation recovery. Following the procedures of the ground survey f o r t h i s t h e s i s , i n -formation on s o i l erosion, s o i l condition and vegetation cover i s c o l l e c t e d . The erosion transects should be permanently located along an ORV t r a i l representative of conditions i n the study s i t e . Each .transect should represent a section of slope along a sing l e t r a i l and be used to pro-vide q u a n t i t a t i v e measurements which can be used i n conjunction with erosion evaluations and measurements from the stage II large scale a e r i a l photographs. The s o i l condition measurements should maintain a monitor-ing program of bulk density, s o i l moisture and organic carbon f o r the surface horizons. The date of measurement should s t i l l coincide with the a c q u i s i t i o n of the a e r i a l photographs but should also be tested f o r v a r i a t i o n s due to sampling date, such as the monthly sampling schedules of Leininger and Payne (1980). This sampling schedule would provide quantitative data on the app-l i c a b i l i t y of the s o i l compaction p r i n c i p l e s (Appendix B) to s p e c i f i c study s i t e conditions. Some of the p r i n c i p l e s r e l a t i n g compaction to moisture con-61. tent, organic carbon, texture and i n i t i a l density should be tested and used by management to co n t r o l ORV a c t i v i t y at s p e c i f i c times of the year when maximum impact from ORV a c t i v i t y would occur. The vegetation survey should continue to provide informa-t i o n , regarding vegetation type and surface proportions of vegetation, l i t t e r and bare s o i l f o r improving the accuracy and r e l i a b i l i t y of the a e r i a l photo-graph i n t e r p r e t a t i o n for s o i l and vegetation conditions. Ground photographs, preferably stereo p a i r s , are an e f f i c i e n t method for vegetation cover surveys of grasses and also provide permanent records of changes along the permanent erosion transects. The e x i s t i n g a e r i a l photographs should be used as a r e f e r -ence to ensure that the transects extend far enough from the t r a i l to reach the undisturbed range areas. D i f f i c u l t i e s were experienced during the f i e l d research of 1979 i n l o c a t i n g the most appropriate undisturbed vegetation s i t e near the ORV t r a i l while standing on the ground. At t e n t i o n should also be given to l o c a t i n g sample points to record the edge e f f e c t s of the major ORV t r a i l s , since the edges of t r a i l s can migrate away from the t r a i l centre with increased ORV a c t i v i t y or towards the t r a i l centre with revegetation encroach-ment. 5.1.5 Summary of ORV Monitoring Program As a summary, the recommended procedure for monitoring ORV a c t i v i t y on open lands includes three stages of information c o l l e c t i o n . Stage I u t i l i z e s 1:4000 June, c o l o u r - i n f r a r e d a e r i a l photographs to provide an overview of the study area and permit mapping and measuring ORV t r a i l lengths and zones of secondary disturbance. Stage II u t i l i z e s 70mm 1:600 scale June, normal colour or c o l o u r - i n f r a r e d a e r i a l photographs for d e t a i l e d information of s p e c i f i c study s i t e s and s p e c i f i c a l l y the evaluation of changes in t h e i r erosion conditions. Stage III i s the ground data c o l l e c t i o n to support the i n t e r p r e t a t i o n of both stage I and II a e r i a l photographs and to provide q u a n t i t a t i v e measurements of the volume of s o i l erosion, changes i n the s o i l v a r i a b l e s of bulk density, s o i l moisture and organic carbon, and changes i n the surface vegetation cover proportions. 5.2 ORV Impact Condition Scale The purpose of developing an impact condition scale i s to draw together the information c o l l e c t e d by the monitoring program for use at a rangeland management l e v e l . The impact condition scale can be used to main-t a i n an inventory of the conditions within each of the three popular ORV management u n i t s : open, r e s t r i c t e d , and closed. The s c a l e was developed from the ideas of an impact condition scale for improving the management of wilderness campsites (Merriam et a l . , 1973; F r i s s e l l , 1978). F r i s s e l l (1978) i d e n t i f i e d a pattern of change within a camp s i t e as i t deteriorated with increasing use, and provided suggestions of poss i b l e management actions at each of f i v e condition c l a s s e s . The e a r l i e r approach by Merriam et a l . (1973), which F r i s s e l l (1978) had s i m p l i f i e d , i s more a p p l i c a b l e to the qu a n t i t a t i v e approach developed as the ORV monitoring program. Merriam ejt al_. (1973) measured changes i n f i v e campsite conditions. Each of the f i v e conditions were rated on an impact stage value of 1 to 5 and the average stage value score determines the impact stage, I to V. The ORV impact condition s c a l e (Table 18) was developed for measure ment i n d i c a t o r s within the monitoring program. Each of the f i v e i n d i c a t o r s represent measured changes from an undisturbed o f f - t r a i l l o c a t i o n . The 1:4000 stage I a e r i a l photographs can be used to i d e n t i f y homogeneous units within the study area and the monitoring system procedures used to assess the ORV impact condition within each u n i t . Table 18. ORV Impact Condition Scale Measurement Indicators Length of Area of Erosion Percent Percent ORV T r a i l s Secondary Condition Increase i n Decrease i n per km^ Disturbance Class Bulk Organic % per km^ Density Carbon (b) (c) (d) (e) .(f) Impact Stage Value (a) 1 0.0-4.9 0.0 Stable 0.0 0.0 2 5.0-9.9 0.1-2.9 S l i g h t 0.1-4.9 0.1-4.9 3 10.0-17.9 3.0-9.9 Moderate 5.0-14.9 5.0-19.9 4 18.0-24.9 10.0-24.9 C r i t i c a l 15.0-29.9 20.0-39.9 5 25.0 + 25.0 + Severe 30.0 + 40.0 + (a) Add the stage value scores of a l l measurement i n d i c a t o r s used. The average stage value score determines the Impact Stage. Impact Stage Average Impact Stage Value I 1.0-1.99 II ' 2.0-2.99 III 3.0-3.99 IV 4.0-4.59 V 4.6-5.00 (b) Measured on Stage I, 1:4000 Colour-Infrared a e r i a l photographs. (c) Measured on Stage I, 1:4000 Colour-Infrared a e r i a l photographs. (d) Assessed from Stage I I , 1:600 a e r i a l photographs using T u e l l e r and Booth's (1975) methodology (Appendix A); or assessed from s o i l erosion transects. (e) Measured during Stage I II ground survey as the d i f f e r e n c e between o n - t r a i l and o f f - t r a i l sample points. (f) Measured during Stage III ground survey as the d i f f e r e n c e between o n - t r a i l and o f f - t r a i l sample points. 6.0 SUMMARY The Lac du Bois rangelands have become a popular area f o r ORV rec r e a t i o n a c t i v i t i e s . The r e s u l t i n g environmental impacts to s o i l and vegetation has forced management agencies to develop p o l i c i e s to attempt to co n t r o l the a c t i v i t y and reduce i t s impacts. Proper p o l i c y development and subsequent r e v i s i o n s to meet chang-ing conditions requires a monitoring program which can assess the extent and degree of ORV impacts. An ORV monitoring program for the open lands of B r i t i s h Columbia has been developed from the conditions cn the Lac du Bois rangelands. The monitoring program u t i l i z e s the remote sensing multistage sampling approach and has three stages of information c o l l e c t i o n . Stage I uses 1:4000 scale a e r i a l photographs to i d e n t i f y and map ORV t r a i l s within a study area. Stage II assesses the erosion conditions w i t h i n s e l e c t e d study s i t e s and stage I I I c o l l e c t s ground Information to a s s i s t the a e r i a l photo-graph i n t e r p r e t a t i o n of stage I and II and to provide q u a n t i t a t i v e measures of the changes to selected s o i l and vegetation v a r i a b l e s . Based on the information measured by the monitoring program, an ORV impact condition scale was developed. The simple f i v e point s c a l e provides a summary of the varying impact conditions within a study area. The scale can be used at a management l e v e l to assess general changes i n the c o n d i t i o n of areas designated e i t h e r open, r e s t r i c t e d , or closed to ORV t r a f f i c . 65. LITERATURE CITED A i r d , W.J. 1980. U t i l i z a t i o n of A e r i a l Photography for Monitoring Environ-mental Impacts from P i p e l i n e Construction. Proc. Sixth Cdn. Symp. Remote Sensing, Cdn. Aero. Space Inst., Ottawa ( i n press). Barnes, K.K., W.M. Carleton, H.M. Taylor, R.I. Throckmorton, and G.E. Vanden Berg. 1971. Compaction of A g r i c u l t u r a l S o i l s . ASAE Monograph, Amer. Soc. A g r i . Eng., St. Joseph, Michigan, 471p. Barton, H., W.G. McCully, H.M. Taylor and J.E. Box J r . 1966. Influence of S o i l Compaction on Emergence and F i r s t - Y e a r Growth of Seeded Grasses. J . Range Mgmt., 19(2):118-121. Beke, G.J. 1961. The E f f e c t s of Heavy Grazing on Some S o i l s and t h e i r Vege-t a t i o n of the Grasslands i n the Southern I n t e r i o r of B r i t i s h Columbia. B.Sc. Thesis, Dept. S o i l S c i . , U.B.C., Vancouver, B.C., 67p. Brady, N.C. 1974. The Nature and Property of S o i l s . 8th Ed., Macmillan Pub. Co., New York, 639p. B r i t i s h Columbia M i n i s t r y of Forests. 1979. Forest and Range Inventory: A paper for discussion. B.C. Min. of Forests, V i c t o r i a , 15p. Carneggie, D.M. 1968. I n t e r p r e t a t i o n of Color Photography for Range Manage-ment, pp. 408-409, i n Smith J r . , J.T. and A. Anson, (ed.). Manual of Color A e r i a l Photography, Amer. Soc. Photogramm. Carneggie, D.M. and J.N. Reppert. 1969. Large Scale 70mm A e r i a l Color Photos. Photogramm. Eng., 35(3):249-257. C i h l a r , J . and R. Protz. 1977. Color-Film Densities for S o i l s P.I. Photo-gramm. Eng., 38(11):1091-1098. CRMP. 1976. Coordinated Resource Management Plan for Lac du Bois/Batchelor H i l l s . B.C. Min. of Forests, Kamloops. Davidson, E. and M. Fox. 1974. E f f e c t s of Off-Road Motorcycle A c t i v i t y on Mojave Desert Vegetation and S o i l . Madrono, 22(8):381-412. ELUC. 1978. Environment and Land Use Committee P o l i c y Regarding Off-Highway Vehicle Use. ELUC, Min. of Env., Prov. of B.C. Foster, J.W. 1977. The Impact of Off-Road Vehicle T r a f f i c on S o i l s and Vege-t a t i o n on Rangelands i n Southeastern Montana and Photographic Mon-i t o r i n g of the E f f e c t s . M.S. Thesis, Montana State Univ., 168p. F r i s s e l l , S.S. 1978. Judging Recreation Impact on Wilderness Campsites. J . Forestry, 76(8):481-483. Fryrear, D.W. and W.G. McCully. 1972. Development of Grass Root Systems as Influenced by S o i l Compaction. J . Range Mgmt., 25(4):254-257. 66. Gaucher, D.W., J.D. T u r i n e t t i and K.R. Piech. 1975. Special Color Analysis of Runway Conditions. Photogramm. Eng. Remote Sens., 41(10)1259-1268. GVRD. 1978. Motorized Recreation Task Force: An Assessment of P o t e n t i a l T r a i l Bike S i t e s . Gtr. Vane. Reg. D i s t . : Parks. H a r r i s , G.A. 1967. Some Competitive Relationships between Agropyron spicatum and Bromus tectorum. E c o l . Monog., 37:89-111. H i l l , R.R. and F.L. Kirby. 1948. Tread Ruts Lead to G u l l i e s . Colorado Conserv. Comm., 10(7):11-12. Hoffer, R.M. 1978. B i o l o g i c a l and P h y s i c a l Considerations i n Applying Computer Aided Analysis Techniques to Remote Sensor Data - Chapter 5, i n Swain, P.H. and S.M. Davis (ed.) Remote Sensing: The Quantitative Approach. McGraw H i l l , Inc, 396p. Laycock, W.A. and D.A. P r i c e . 1970. Environmental Influences on N u t r i t i o n a l Value of Forage Plants, pp.37-47, i n Range and W i l d l i f e Habitat Evaluation - A Research Symposium. U.S.D.A. For. Serv. Misc. Pub. 1147. Laycock, W.A, and P.W. Conrad. 1967. E f f e c t s of Grazing on S o i l Compaction as Measured by Bulk Density on a High E l e v a t i o n C a t t l e Range. J, Range Mgmt., 20(3):136-140. Leininger, W.C. and G.F. Payne. 1980. The E f f e c t s of Off Road Vehicle Travel on Rangeland i n Southeastern Montana. Montana A g r i . Expt. Stn., Montana State Univ., Bozeman, Res. Report 153, 47p. L i l l e s a n d , T.M., R.H. Brock, J.L. Roberts and W.L. Johnson. 1975. Tree Stress Detection through Spectral Ratioing of Color Film Records. 5th Work-shop, Color A e r i a l Photography i n Plant S c i . , Amer. Soc. Photogramm.: 79-108. L i l l e s a n d , T.M. and R.W. K i e f e r . 1979. Remote Sensing and Image Interpret-a t i o n . John Wiley and Sons, New York, 612p. Lodico, N.J. 1973. Environmental E f f e c t s of Off Road Vehicles: A Review of the L i t e r a t u r e . Res. Serv. Br., O f f i c e of L i b . Serv., U.S.D.I., Wash. D.C., B i b l i o g . Series No. 29, 112p. L u l l , H.W. 1959. S o i l Compaction of Forest and Range Lands. U.S. Govt. P r i n t . O f f i c e , U.S. For. Serv. Misc. Pub. 768, 33p. McCool, S.F. and J.W. Roggenbuck. 1974. Off Road Vehicles and Public Lands: A Problem A n a l y s i s . Dept. Forest, and Outdoor Rec. and Inst, for Study of Outdoor Rec. and Tourism, Utah State Univ., Logan, 109p. McEwen, D.N. 1978. Turkey Bay ORV Area at Land Between The Lakes: An Example of New Opportunities for Managers and Riders. South. 111. Univ. Carbondale, Dept. R e c , Res. Report No. 1, Carbondale, 64p. Merriam, L.C., C.K. Smith, D.E. M i l l e r , C.t. Huang, J.C. Tappeiner, K. Goecker-man, J.A. Bloemendal and T.M. C o s t e l l o . 1973. Newly Developed Campsites i n the Boundary Waters Canoe Area: A Study of 5 Years Use. Minn. A g r i . Stn. B u l l . 511, Univ. of Minn., Minn., 27p. 67. Nixon, R. 1972. Use of Off Road Vehicles on the Public Lands, Executive • Order 11644. Fed. Register, 7(27) :2877-2878. Piech, K.R. and J.E. Walker. 1974. I n t e r p r e t a t i o n of S o i l s . Photogramm. Eng., 40(1):87-94. Powers, M.G. 1975. Recreation V e h i c l e s : S i t e Inventory and A n a l y s i s . Gtr. Vane. Reg. D i s t . , Vane. B.C., Rauzi, F. and C.L. Hanson. 1966. Water Intake and Runoff as A f f e c t e d by Intensity of Grazing. J . Range Mgmt., 19(6):351-356. Reeves, R.G. (ed.). 1975. Manual of Remote Sensing. Amer. Soc. Photogramm., F a l l s Church, Va. Rosen, S.J. 1976. Manual for Environmental Impact Evaluation. P r e n t i c e - H a l l , Inc., New Jersey. Schreier, H. 1977. Quantitative Predictions of Chemical S o i l Conditions from M u l t i s p e c t r a l Airborne, Ground and Laboratory Measurements. Proc. 4th Cdn. Symp. Remote Sensing, Cdn. Aero. Space I n s t . , Ottawa, 106-112. Schultink, G. 1977. Impact Analysis of Off-Road Vehicle Use on Vegetation i n the Grand Mere Dune Environment. Proc. 6th Workshop A e r i a l Color Photo, i n Plant S c i . , Amer. Soc. Photogramm.:132-140. Sheridan, D. 1979. Off-Road Vehicles on Public Lands. Council on Env. Qual., Wash. D.C., 84p. Shields, J.A., E.A. Paul, R.J. St. Arnaud, and W.K. Head. 1968. Spectrophoto-metric Measurements of S o i l Color and Its Relationship to Moisture and Organic Matter. Cdn. J. S o i l S c i . , 48(10):271-280. Si e g a l , B.S. and A.F.H. Goetz. 1977. E f f e c t of Vegetation on Rock and S o i l Type D i s c r i m i n a t i o n . Photogramm. Eng. Remote Sensing, 43(2) : 191-196. Stoner, E.R., M.F. Baumgardner, L.L. B i e h l and B.F. Robinson. 1980. A t l a s of S o i l Reflectance Properties. A g r i . Expt. Stn. Res. B u l l . 962, Purdue Univ., West Lafayette, Ind. , 75p. S t u l l , R., S. Shipley, E. Hovanitz, S. Thompson and K. Hovanitz. 1979. E f f e c t s of Off-Road Vehicles i n B a l l i n g e r Canyon, C a l i f o r n i a . Geol. 7(1):19-21. T u e l l e r , P.T. 1977. Large Scale 70mm Photography for Range Resource Analysis i n the Western United States. Proc. 11th Int. Symp. Remote Sensing of Env., Ann Arbor, Mich.:1507-1514. T u e l l e r , P.T. and D.T. Booth. 1975. Large Scale Color Photography for Erosion Evaluation on Rangeland Watersheds i n the Great Basin. Proc. F a l l Conv., Amer. Soc. Photogramm., Phoenix, Ariz.:708-753. USFS. 1976. Environmental Report - Off Road Vehicle Management Plan - Los Padres National Forest. U.S. For. Serv., C a l i f . Region, 51p. Utah Outdoor Recreation Agency. 1977. Utah Off-Highway Resource Inventory and OHV user. State of Utah, Dept. Nat. Res., 68p. 68. Vollmer, A.T., B.G. Maza, P.A. Medica, F.B. Turner and S.A. Bamberg. .1976. The Impact of Off Road Vehicles on a Desert Ecosystem. Env. Mgmt., 1(2) :115-129. Voorhees, W.B. 1977. S o i l Compaction: how i t influences moisture, temperature, y i e l d , root growth. Crops and S o i l s , 29:7-10. Watson, A.K. 1972. The Biology and Control of Centaurea D i f f u s a Lam, and Centaurea Maculosa Lam. M.Sc. Thesis, Dept. Plant S c i . , U.B.C., Vane, l O l p . Watson, E.K. 1977. A Remote Sensing Based M u l t i l e v e l Rangeland C l a s s i f i c a t i o n for the Lac du Bois Rangelands, Kamloops, B.C. M.Sc. Thesis, Dept. S o i l S c i . , U.B.C., Vane, 85p. Weaver, T. and D. Dale. 1978. Trampling E f f e c t s of Hikers, Motorcycles and Horses i n Meadows and Forests. J . Appl. E c o l . , 15:451-457. Webb, R.H., H.C. Ragland, W.H. Godwin and D. Jenkins. 1978. Environmental E f f e c t s of S o i l Property Changes with Off Road V e h i c l e Use. Env. Mgmt., 2(3):219-233. Whitehurst, C A . , W.A. Blanchard and L.N. Doiron. 1977. The Use of Color Infrared Imagery for the Study of Marsh Buggy Tracks. Photogramm. Eng. Remote Sensing, 43(8):1049-1050. W i l s h i r e , H.G. and J.K. Nakata. 1976. Off Road Vehicle E f f e c t s on C a l i f o r n i a ' s .Mojave Desert. C a l i f . Geol., 29(6) : 123-132. W i l s h i r e , H.G., J.K. Nakata, S. Shipley and K. Prestegaard. 1978. Impact of Vehicles on Natural T e r r a i n at Seven Sit e s i n the San Francisco Bay Area. Env. Geol., 2(5):295-319. APPENDIX A Erosion Evaluation From A e r i a l Photographs P.T. T u e l l e r and D.T. Booth, 1975 The methodology developed f o r erosion evaluation defines and explains erosion and e r o s i o n a l terms and ratings with s p e c i a l reference to t h e i r detection and i n t e r p r e t a t i o n on large scale a e r i a l photographs. Seven s o i l surface f a c t o r s are used to determine the erosion condition c l a s s . Each f a c t o r i s rated according to i t s c h a r a c t e r i s t i c s which are i d e n t i f i e d and/or measured on the a e r i a l photographs. The sum of the seven ratings determines the erosion condition c l a s s . The seven f a c t o r s and t h e i r r a t i n g scales are shown i n the table below. Eroeicn Condition Class Stable* Slight Moderate ' C r i t i c a l Severe Bare Ground SI or less Rating 3 10 15 20 4 5 6 30 40 45 7 8 9 50 60 65 10 11 12 70 75+ 13 14 Vesicular Crust Nora Seme present but «5% 5-101 11-20% 21-40% Above 40% 0 4-5 6-7 B-9 10-11-12 13-14 Li t t e r f t m t t u s it Slight Movement Deposited Bttrtre movement L i t t l e ronaining <4 4 5 6 7 8 ? IS 11 12 13 14 win! JSroeion Bar-ground Sane drifting Active d r i f t s Active sand dunes 6 7 8 9 10 11 12 13 14 ricw Patterns tto erosion <4 Removal and/ or disposition 4 5 6 Moderate s o i l movement 7 8 9 Moveraent occurs w/ each, event 10 11 12 Becoming channeled or large Barren Fans 13 14 IS R i l l s r i l l s 1 interval > 50 f t . interval 20-50 ft . interval 5-20 f t . interval < 5 f t . 0 4 5 6 7 8 9 10 U U 13 14 Gullies and B.C. Stable condition Sere erosion no* 10 to 50% >50 Headcutting 3 4 5 6 7 8 9 10 11 12 13 14 15 •Statue - an erosion condition class of "stable", does not mean the range i s in stable condition; i t means as far as pan be detected from the photography there l a no recent erosion. Erosion Condition Classesi Stable O-JOrSITght 21-40) Moderate 41-60i C r i t i c a l 61-60) Severe 81-100 70. APPENDIX B S o i l Compaction P r i n c i p l e s By H.W. L u l l , 1959 (p.25) The amount of compaction w i l l depend on the degree to which the stress applied to the s o i l overcomes the resistance the s o i l o f f e r s to deformation. The resistance that the s o i l o f f e r s depends on i t s moisture content, texture, s t r u c t u r e , density and organic content. As t h i s resistance i s overcome, the e f f e c t i s to pack i n d i -v i d u a l s o i l p a r t i c l e s c l o s e r together and to crush s o i l ag-gregates, thus reducing pore space. Resultant a d d i t i o n a l s o l i d materials per unit volume increase the resistance of the s o i l to deformation to a point where resistance and stress are i n equilibrium and no further com-paction occurs. As s o i l moisture content increases, resistance to stress de-creases and compaction can be acheived with progressively reduced loads. Maximum density i s obtained at a moisture content about mid-way between f i e l d capacity and w i l t i n g point. Increasing moisture content beyond that point further lowers the resistance to compaction and reduces the maximum density. S o i l s that have the greatest range of p a r t i c l e - s i z e ( i . e . , medium-textured s o i l s ) compact to greatest d e n s i t i e s , f i n e r p a r t i c l e s f i l l i n g the voids between coarser p a r t i c l e s . The less dense the s o i l , the greater opportunity for compac-ti o n . The greater the organic content, the smaller the maximum com-paction and the greater the moisture content required for max-imum compaction. S o i l f r e e z i n g tends to compact s o i l by breaking down water-stable aggregates and tends to loosen compacted s o i l s . Duration of compaction depends l a r g e l y on the stresses the s o i l undergoes by swelling and shrinking from changes i n moisture content and temperatures. Compaction increases bulk density, reduces t o t a l pore space by the same proportion, reduces noncapillary pore space a greater amount, and has i t s greatest e f f e c t on i n f i l t r a t i o n and p e r c o l a t i o n . 

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