BUNCHGRASS ECOSYSTEMS AND THE EARLY CATTLE INDUSTRY
IN THE THOMPSON-OKANAGAN

SCOPE AND NATURE OF THE STUDY

This study is intended to form part of the Living Landscapes projet developed and sponsored by the Royal British Columbia Museum (RBCM), which has as its mandate "to explore the human and natural history of the Thompson-Okanagan region". Within this broad mandate, a large number of component studies, surveys and compilations will be conducted to provide information on various aspects of the human and natural history of this region. The Living Landscapes program will provide the impetus for on-going study of the Thompson-Okanagan and, significantly, the provision of access to this body of information to the general public in a meaningful way. It is hoped that this study will provide a component part of the overall picture of the human and natural history of the Thompson-Okanagan.

At the time of contact between European and First Nations people in the study area, and indeed for centuries before that, there existed extensive grasslands in the drier climatic zones of the Thompson-Okanagan. During the gold rush years of colonial times, large herds of cattle were driven into British Columbia from the United States along the former Hudson's Bay Company Brigade Trail. The drovers were quick to realize the potential of the nutritious bunchgrass ranges and began to take up land in the grasslands along the trail and the Cariboo Road. The bunchgrass ranges were effectively used for raising cattle beginning in the 1860s up to the present day. The delicate balance between carefully stewarding the grasslands for grazing and destroying the bunchgrass resource from over-grazing has concerned ranchers ever since.

This study will examine the nature and extent of the bunchgrass ranges of the Thompson-Okanagan at the time of the establishment of the Colony of British Columbia. The species of bunchgrass will be recorded as well as the environments in which they are found. The study will then survey the patterns of land acquisition in the region to determine the correspondence between early settlement and the bunchgrass ranges. Land acquisition legislation during the colonial and early provincial eras will be examined to set the legal parameters of land acquisition. The report will then look at the early ranching history of the region with particular emphasis on the extent and effects of overgrazing. Conclusions will be presented on the inter-relationship of the bunchgrass ranges and the early ranching history and on the ongoing use of this delicate resource.

CLIMATIC OVERVIEW

The bunchgrass ranges of the Thompson-Okanagan are closely tied to the climatic factors at work in the region. The climate of the region is largely influenced by the fact that it is separated geographically from the Pacific Coastal regions by the Cascade Mountains, creating a "rainshadow" effect where precipitation is lessened because warm moist air from the coast is dropped on the coastal mountains. The climate of the Thompson-Okanagan varies considerably depending on latitude, longitude and altitude, with the latter factor being the significant one in determining bunchgrass species. Temperature decreases as altitude increases, annual mean temperature decreasing approximately one degree Fahrenheit every 275 feet moving upward from the valley floors. The climate derives from the interplay of continental highs which develop over British Columbia in the summer and occasionally in the winter; Pacific marine lows evident mainly in the spring and winter; and the prevailing westerly winds.

Precipitation also varies considerably from location to location. Precipitation increases with altitude, increasing approximately one inch every 200 feet. Perhaps more significantly, the precipitation increases as one moves from west to east in the region. The Merritt area receives only ten inches of rainfall per year, while further east, in the Okanagan Valley, the "rainshadow" effect is lessened and more moisture is released, particularly at higher elevations. Evaporation rates are also tied to temperature, so that as temperatures decrease with the increase of altitude and latitude, evaporation rates decrease. This has the effect of magnifying the significant differences in precipitation.

 As the accompanying map will show, the "very dry" moisture regimes are found in the lower altitudes east of  the coastal ranges with the altitude at which they are found decreasing slightly from west to east. All  significant bunchgrass rangelands are found in this moisture regime as the main bunchgrass species,  bluebunch wheat grass (Agropyron spicatum), rough fescue (festuca scabrella), and Idaho fescue (festuca  idahoensis) require very dry conditions to flourish.

 

 

 



Bunchgrass and beef
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