Grassland Region
Ecoprovince
Ecosections
Area, ha
Cariboo-Chilcotin and Central Interior
233,335
Central Interior
Central Chilcotin Ranges Western Chilcotin Ranges Chilcotin Plateau Fraser River Basin Cariboo Basin Bulkley Basin
Western Chilcotin Ranges
Chilcotin Plateau
Fraser River Basin
Cariboo Basin
Bulkley Basin
8,440 6,765 39,100 125,275 43,860 5,030
6,765
39,100
125,275
43,860
5,030
The Cariboo-Chilcotin and Central Interior Grasslands lie on the rolling plateau between the high ranges of the Coast Mountains in the west and the lower Cariboo Mountains in the east. Extensive open grasslands hug the Fraser and Chilcotin river valleys and higher benchlands with open, dry Douglas-fir and lodgepole pine forests above them.
A number of plants reach the limits of their distribution in parts of this region, creating some unique plant associations. More than three-quarters of the grasslands in the region occur within 20 kilometres of the two rivers and their tributaries. The elevational range and latitudinal extent found in this region give it the greatest variety of grasslands communities.
The ice sheet and glaciers that covered this central part of the province 12,000 years ago left behind thick layers of glacial deposits when they melted. Drumlins and eskers in many places across the plateau add variety to the landscape. A large lake formed when the Fraser River was dammed, forcing it to flow north, left behind thick silt deposits that are exposed in the Williams Lake Creek valley.
The Coast Mountains on the west capture moisture from the south-westerly weather systems that roll in off the coast, creating a rainshadow effect on the plateau. Winters are cold with precipitation falling as snow while summers in the lower valleys are hot and dry. Grassland plants have adapted to these difficult conditions by blooming early in the spring and completing their life cycle before the summer heat.
Bluebunch wheatgrass is the characteristic grass of these hot, dry grasslands stretching from French Bar north past the Fraser-Chilcotin junction and west to Farwell Canyon. There are similarities between these grasslands and those in the Thompson River and Okanagan valleys and many plant species are found even further south in the Great Basin. Two Bunchgrass communities are identified within the Bunchgrass Zone: Lower and Middle Grasslands.
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Grasslands in the Cariboo-Chilcotin and Central Interior region are protected in parks and other conservation areas where livestock grazing is managed to reduce the impact on plant communities. Research projects are giving grasslands managers a better understanding of grasslands species and their particular needs.
Cliff and talus slopes are found in only a few places along the deep river valleys that dissect the region. The basalt lavas that form the Chilcotin Plateau and older, underlying rocks are exposed in sometimes spectacular formations.
Doc English Bluff in the Fraser River valley below the Chilcotin Plateau. A. Roberts
The cliffs where Dog Creek joins the Fraser River are massive with a healthy riparian zone at the base. Many raptor species nest on the cliffs while white-throated swifts, rock wren, warblers and lazuli bunting may be seen and heard.
BEC Zones with grasslands1
Major2 grassland BEC Subzones and Variants
Central Chilcotin Ranges
Interior Douglas-Fir Zone
Montane Spruce Zone
Engelmann Spruce-Sub-alpine Fir Zone
Sub-boreal Pine-Spruce Zone
Bunchgrass Zone
Ponderosa Pine Zone
Sub-boreal Spruce Zone
IDFdw: Dry Warm Interior Douglas-fir Subzone
IDFdk4: Chilcotin Dry Cool Interior Douglas-fir Variant
MSxv: Very Dry Very Cold Montane Spruce Subzone
IDFdk3: Fraser Dry Cool Interior Douglas-fir Variant
IDFxm: Very Dry Mild Interior Douglas-fir Subzone
SBPSxc: Very Dry Cold Sub-Boreal Pine-Spruce Subzone
BGxh3: Fraser Very Dry Hot Bunchgrass Variant
BGxw2: Alkali Very Dry Warm Bunchgrass Variant
IDFdk4: Chilcotin Dry Very Cool Interior Douglas-fir Variant
IDFdk3: Fraser Dry Very Cool Interior Douglas-fir Variant
PPxh2: Thompson Very Dry Hot Ponderosa Pine Variant
IDFxw: Very Dry Warm Interior Douglas-fir Subzone
SBSdk: Dry Cool Sub-Boreal Spruce Subzone
2 Over 3,000 hectares.
Fraser Very Dry Hot Bunchgrass Variant (BGxh3): 20,225 hectares
Lower Grasslands occur below about 650 metres along the Fraser and Chilcotin Rivers as far as Farwell Canyon where the climate is the hottest and driest in the region. Widely spaced bluebunch wheatgrass, big sagebrush and a number of early-blooming flowering plants rarely cover more than 50% of the ground. On the soil surface between the plants is a layer of microscopic lichens called the cryptogamic crust. This layer helps prevent moisture evaporating from the soil, making it available for surrounding plants.
Bluebunch wheatgrass cannot tolerate heavy grazing and tends to be replaced by junegrass, needle-and-thread grass and sand dropseed. Big sagebrush, prickly-pear cactus and low pussytoes increase.
Alkali Very Dry Warm Bunchgrass Variant (BGxw2): 41,695 hectares
Benches above Fraser River rise to the plateau surface. B. Wikeem
Where the land levels off on the plateau above the rivers grasslands merge with dry Douglas-fir forest, aspen groves and wetlands. Four Douglas-fir communities occur in the region.
Very Dry Mild Interior Douglas-fir Subzone (IDFxm): 74,200 hectares
Upper Grasslands near Gang Ranch. B. Wikeem
Very Dry Warm Interior Douglas-fir Subzone (IDFxw): 5,150 hectares
This extension of a subzone in the Cache Creek Hills occurs along the Bonaparte River and Loon Lake valleys, and south of Big bar on the Fraser. Grasslands occur on the driest, south-facing or rocky sites from 600 to 1000 metres elevation. Where conifers occur they are either widely spaced or in groves among open grassland. Bluebunch wheatgrass is the dominant grass with species such as kinnikinnick, common juniper and common rabbit-brush as common shrubs.
Small grassland areas in Loon Lake valley and on Edge Hills are similar to Middle Grassland communities where bluebunch wheatgrass dominates.
Fraser Dry Cool Interior Douglas-fir Variant (IDFdk3): 30,860 hectares
The Douglas-fir forests on the plateau area east of the Fraser River from Clinton to Alexandria are interspersed with large pockets of grasslands, aspen groves, ponds and wetlands such as around 70 Mile House and 100 Mile House to Lac La Hache.
Chilcotin Dry Very Cool Interior Douglas-fir Variant (IDFdk4): 23,7990 hectares
Grasslands in this variant occur in small areas along both sides of the Chilcotin River as far west as Chilanko Forks, on the west side of the Fraser River and in the Taseko valley between 1050 and 1350 metres elevation. Park-like stands of Douglas-fir and lodgepole pine have an understory of pinegrass and kinnikinnick with common juniper, saskatoon and spreading needlegrass.
On steeper slopes open grasslands occur with bluebunch wheatgrass on the driest sites and porcupine grass and other species are found on cooler, moister sites. On north-facing slopes and swales near Churn Creek short-awned porcupine grass and litter almost completely cover the ground.
Dry Warm Interior Douglas-fir Subzone (IDFdw): 5,150 hectares
Small areas of grasslands occur in the Chilko and Tatlayoko valleys on steep south-facing slopes from valley bottom to about 1400 metres. Little is known about their composition.
Very Dry Very Cold Montane Spruce Subzone (MSxv): 4,270 hectares
Level, well-drained sites in the upper Chilcotin and Hungry valley, as well as around Itcha Lake, have species more typically found at sub-alpine and alpine elevations. Cold winters, short, warm summers and frost in every month inhibit the growth of trees. Alpine fescue communities may have widely-spaced lodgepole pine, while timber oatgrass dominates wetter sites in Big Creek Park. Rough fescue and prairie sagewort communities are found on steep, south- facing slopes while more moderate slopes in Churn Creek Park have a mix of dry, southern species, alpine and boreal species.
Dry Cool Sub-Boreal Spruce Subzone (SBSdk): 4,695 hectares Edaphic grasslands mixed with aspen west of Francois Lake. B. Wikeem
Further north in the Nazko Upland and Bulkley Basin grasslands have developed on steep south-facing slopes within a sea of forests. The largest areas are found around the community of Fraser Lake, on the north shore of Fraser lake and along the Stellako River. The dominant grasses are slender wheatgrass, interior bluegrass and stiff needlegrass with fewer flowering plants.
Other Grassland Communities
Small pockets of Engelmann Spruce-Subalpine Fir grasslands occur in high elevation valley bottoms, especially on the east side of the Coast Ranges and in the Camelsfoot Range. Altai fescue and Rocky Mountain fescue are the dominant grasses.
Isolated areas of grasslands of the Sub-Boreal Pine – Spruce zone occur in northern and western areas of the Chilcotin Plateau between 850 and 1300 metres elevation. A variety of grasslands types are found, with variations dependant on slope, aspect, climate and soils. They indicate the northern limit of Great Basin influences. Dry sites on steep, warm slopes have bluebunch wheatgrass and other lower elevation species, with bluebunch wheatgrass possibly at the most northern extent in BC and North America.
Some sub-alpine and alpine grassland communities only occur over small areas, but some are unique in the region. Exposed dry ridges, gentle slopes with southerly or westerly aspects provide drier and warmer conditions than surrounding areas. Complexes of species on these sites usually include Altai fescue with greater or lesser amounts of other grasses, flowering plants, shrubs, mosses and lichens.
Many wetland ecosystems are found throughout the grasslands of the Cariboo-Chilcotin and Central Interior, adding variety and complexity to the landscape. Marshes, fens, shrub-carrs and fens all frequently occur and often create complex systems that may vary as water levels change. Saline meadows are often found in association with shallow lakes, showing characteristic rings of white salts and salt-adapted plants. Cottonwood forests occur on the bottomlands of the Fraser River, Chilcotin River and Churn Creek.
Porcupine Grass occurs in slight depressions surrounded by a matrix of bluebunch wheatgrass communities in Middle Grasslands. R. Coupé
Porcupine Grass (Hesperostipa curtiseta)
The variety of ecosystems found in the region provide habitat for a large number of wildlife species 45 of which are red- or blue-listed, with many are at the limits of their range in the province. Spotted frog, Western toad and Western garter snake are found from grasslands to alpine while the northernmost extent of the gopher snake and the rubber boa coincides with the limits of big sagebrush.
209 bird species are found in the Cariboo-Chilcotin but not all are specifically associated with grasslands. Western meadowlark, vesper sparrow, common nighthawk and long-billed curlew are only a few typical grassland birds. All nest on the ground and are at risk from livestock grazing. Raptors such as Cooper’s hawk, red-tailed hawk and American kestrel nest in the forests and hunt their prey over the grasslands. The Upper Grasslands near Riske Creek are the northern limit for such species as Brewer’s sparrow, Prairie falcon, bobolink and flammulated owl.
The aspen groves, wetlands and riparian areas of the Fraser Plateau attract large numbers of waterfowl species. The area is the world centre for Barrow’s goldeneye, greater yellowlegs and yellow-headed blackbird. Wetlands of the area are important breeding areas for sandhill cranes and resting places for large numbers of swans in migration. The red-listed American Pelican nests at only at Stum Lake in the province and uses many surrounding grassland lakes for foraging.
Moose also rely on shrub-carr and wetlands and are numerous throughout the region. Mule deer are most numerous in the grasslands along the Fraser River, moving up into the montane spruce and sub-alpine areas as the year progresses. The largest population (500) of California bighorn sheep in North America can be seen along the main road switchbacks to the canyon of the Chilcotin River where it meets the Fraser. The area is critical for breeding, lambing, and winter range.
Bats forage over the grasslands and wetlands from the lowest grassland elevations to the sub-boreal spruce zone. Ten species have been identified with only the big brown bat and Townsend’s big-eared bat known to hibernate in the area.
Where are can I go to watch wildlife in Cariboo-Chilcotin and Central Interior grasslands?
Check the list of wildlife viewing sites publications.
Red- and Blue-listed grassland elements in the Cariboo-Chilcotin and Central Interior:
Element
Red List*
Blue List**
Vascular Plants
Plant Communities
Insects
Reptiles and Amphibians
Birds
Mammals
Total Elements
27
16
0
10
2
55
39
4
6
21
76
*Red list: List of ecological communities, and indigenous species and subspecies that are extirpated, endangered or threatened in British Columbia.
**Blue list: List of ecological communities, and indigenous species and subspecies of special concern (formerly vulnerable) in British Columbia.
The variety of plant communities and habitats in the Cariboo-Chilcotin and Central Interior grasslands results in a higher number of listed species than in the adjacent Thompson-Pavilion grasslands. 14% of red-listed species and 39% of blue-listed species occur in this region.
Although there are few plant species unique to Cariboo-Chilcotin and Central Interior grasslands, many unique plant communities occur where grasslands with southern and northern influences merge. Some listed species are at their northern or southern limits while others occupy unusual habitats.
Two blue-listed willow species exist together in wetlands of the Upper Grasslands: Booth’s willow from the south and autumn willow from the north. The red-listed blue grama is found in small patches in the Gang Ranch area of the Fraser River, although it is otherwise abundant east of the Rocky Mountains. Research surveys of species in the cryptogamic crust found four species new to North America and five species new to BC.
All the listed amphibians and reptiles reach their northern limit in the region, with rubber boa and gopher snake distribution closely matching that of big sagebrush in the Fraser and Chilcotin valleys. Many listed bird species, such as Brewer’s sparrow, prairie falcon, bobolink, Lewis’s woodpecker and white-throated swift follow a similar pattern, reaching their northern limit near Riske Creek. The yellow-breasted chat, a red-listed species more associated with the south Okanagan, has been recorded from Alkali Lake while Sprague’s pipit, upland sandpiper and common poorwill have only recently been added to the local list of species.
Listed mammals include badger, California bighorn sheep, grizzly bear and five species of bats. The badger is been sighted many time in the last ten years in the southern portion of the region, but its distribution and numbers are not well understood. Grizzly bear use the higher elevation grasslands openings for foraging and cover during the summer.
Bats forage over the grasslands searching for insects and use cliffs, crevices and caves for roosting and maternal colonies. California bighorn sheep are found in a number of groups in the Fraser-Chilcotin and Churn Creek areas. They use the grasslands year round for foraging while steep slopes and breaks are escape terrain and protected places for lambing. A Species At Risk Profile: American White Pelican
Red-listed in BC
Stum Lake in the Sub-Boreal Spruce Zone is the only known nesting site in BC for this intriguing bird. The surrounding grassland-associated lakes, ponds and wetlands provide foraging habitat.
American White Pelicans feeding at Alkali Lake in July. Liz Twan
After arriving in mid-April, pelicans lay 1-4 eggs, with hatching in late June. Actual clutch size ranges from 1.95 to 1.69 depending on whether or not the birds were disturbed. Young are fledged by late July or early August and the pelicans leave the Chilcotin between late September and mid-October.
Pelicans are highly susceptible to disturbance, especially during the nesting period. Changes in the water level of Stum Lake can make nesting sites more available to predators, or flood low-lying nests. Overflights by aircraft and human or wildlife activity on shore can create sufficient disturbance to affect breeding success.
Alkali Lake is an important stopover lake in both spring and fall migration and for feeding. From 1-100 birds are reported to feed there throughout the summer. Pelicans also feed on Williams Lake, Abuntlet, Chilcotin, Kluskus and Pantage lakes, among others. Pelicans in migration are reported from Okanagan valley lakes, Nicola valley lakes, Tranquille Wildlife Management Area in the Thompson valley and Williams Lake.
This population of pelicans overwinters in southern California. Loss of wintering habitat and hunting are two major threats to populations in their wintering grounds.
For more information on species at risk in BC, visit our SAR page.
For definitions of technical terms, please see the GLOSSARY.
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