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An appraisal of ungulate habitats in the ashnola resource management unit Scheffler, Eike Gerhard

Abstract

The four major ecological variables, soils, climate, vegetation and fauna, were studied from May 1966 to November 1967 and again for a short period in 1969 on important California bighorn sheep {Ovis canadensis califomiana Douglas) ranges in the Ashnola region. Emphasis in this investigation was placed on completing the basic extensive resource inventory as well as on initiating experimental range rehabilitation practices for future management of critical forage resources on the winter ranges. The soils inventory was based primarily on the survey recently completed for the Canada Department of Agriculture (Green, in print) for the Princeton map sheet. Extrapolation for the eastern half of the study area was accomplished with the use of air photos and some additional ground surveys. The climatic factors measured were: air and soil temperature, precipitation, snow depth and evaporation. This was done by establishing two summer climatic transects and one snow depth transect. These transects were altitudinally spaced along available access roads. The vegetation analysis was conducted with the use of site specific species lists, point quadrat and line transects and air photos. Both the habitat and soil type maps were constructed from available air photo coverage and ground surveys. Ungulate distributions were mapped from ground observations, aerial helicopter surveys and previous reports. Range rejuvenation experiments, using large exclosures, fertilization and reseeding, were conducted concurrently with the inventory. Five sites were chosen for these rehabilitation trials. Soils in the study area vary from Brown and Dark Brown to Alpine Dystric Brunisols. The mid-grasslands occur predominantly on Chernozem!c, the Rego Dark Gray to Orthic Black soils. Related in large measure to the physiography of the region, large areas have nonproductive soils, talus slopes and sheer rocks; vegetative production is extremely limited on such sites. Altitude and exposure greatly affect the temperature and precipitation regime within the area. At low altitudes the moisture supply limits productivity. Summer evaporation is very high on exposed low grassland slopes. With rising elevation the precipitation generally increases, and evaporation and mean temperatures decrease. Exposure greatly affects the overall climatic regime. This is reflected in the variable vegetative cover and productivity. Climatic change, variable between years, caused considerable fluctuation in forage production between years. Vegetative zonation is clearly recognizable in the area. The zones and thus habitat types are altitudinally delimited. Fire, logging and ungulate grazing have caused much disturbance. Reseeding was not very successful, especially on stable plant communities on Juniper and South Slope. Fertilization had considerable effect on forage production on all sites. Standing crop increases, as measured by a single annual clipping during late July, were sustained for at least three years on the Poa sp. and Agropyron spicatum sites. Excluding ungulates from the five fenced sites resulted in changes in species composition, plant vigor and increased forage production. Some progressive trends towards climax were recognized on at least two sites in 1969. Climatic factors, primarily temperature and moisture supply, grazing history and soils, all contributed to local and annual variability in forage yields. Periodic protection of important grasslands from use and fertilization of some slopes show promise as management tools.

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