BC Conservation Data Centre: Conservation Status Report
Ceanothus velutinus - Danthonia spicata
snowbrush - poverty oatgrass
| Scientific Name: | Ceanothus velutinus - Danthonia spicata |
|---|---|
| English Name: | snowbrush - poverty oatgrass |
| Provincial Status Summary | |
| Status: | S1 |
| Date Status Assigned: | April 21, 2023 |
| Date Last Reviewed: | April 21, 2023 |
| Reasons: | |
| Range | |
| Range Extent: | A = <100 square km |
| Range Extent Estimate (km2): | 37.9 |
| Biogeoclimatic Unit: |
ICHxwa/Gb06
|
| Range Extent Comments: | This ecological community has a custom range based on Version 12 of the Biogeclimatic Ecosystem Classification (BEC) map (B.C. Ministry of Forests, Lands and Natural Resource Operations, Biogeoclimatic Ecosystem Classification Map Version 12). It only occurs in part of the ICHxwa on the main stem of the Columbia river as the community requires sandy glaciofluvial deposits on flat terraces typically found in wide valleys. Occurrences have not been found in the Pend Oreille Valley; the valley may be too narrow and shaded as it runs east-west, unlike the Columbia. |
| Area of Occupancy (km2): | BC = 0.1-1 kmē |
| Area of Occupancy Estimate (km2): | 0.43 |
| Area of Occupancy Comments: |
Targeted ecosystem mapping and field verification has been undertaken across the entire range of this ecological community (Teck Metals 2021). The community is uncommon across its range and is estimated to occur across 0.43 km2 (1.1%) of its range. Due to variability in mapping scales, 0.43 km2 may overestimate area occupied by this community. |
| Spatial Pattern: | Small patch |
| Occurrences | |
| Number of Occurrences: | Rank Factor not assessed |
| Number of Occurrences with Good Viability / Ecological Integrity: | Rank Factor not assessed |
| Percent Area with Good Viability / Ecological Integrity: | D = Moderate (11-20%) |
| Comments: |
Very few occurrences of this ecological community are unimpacted by roads, trails, and powerlines. Roads through the Fort Shephard Conservancy are not identified in the Digital Road Atlas and so fragmentation from roads is underestimated (B.C. Ministry of Forests, Lands, and Natural Resources Operations and Rural Development, Digital Road Atlas, accessed March 2023). |
| Threats (to population, occurrences, or area affected) | |
| Degree of Threat: | B = High |
| Comments: |
Several direct and indirect threats to this ecological community warrant a high overall threat rating. Roads and utility lines are a medium threat. Approximately 18% of polygon area containing this ecological community are impacted by power lines (B.C. Ministry of Forests, Lands and Natural Resource Operations, Baseline Thematic Mapping, accessed March 2023) and approximately 8% of polygon area containing this ecological community has been converted to roads (B.C. Ministry of Forests, Lands, and Natural Resources Operations and Rural Development, Digital Road Atlas, accessed March 2023). Maintenance of power lines is ongoing and will continue to impact this community, where repeated mowing impacts vegetation community composition and increases in traffic and vehicle parking on this community during pole replacement compacts soils and impedes recovery (Machmer and Ehman, Pers. Comm.). Numerous roads are not identified in the Digital Road Atlas, and easy terrain in these ecological communities increases area potentially impacted by trails. Pollution is a medium threat. Approximately 100% of this ecological community occurs within an area polluted by metals (lead, zinc, cadmium, arsenic, etc.) (LCEMP 2022), though pollution levels vary. SO2 can raise soil pH and increases the risk of metals becoming unbound in soils. Effects on vegetation include chlorotic foliage and impacted growth. Invasive alien plant species are a low threat and are less frequent across mapped occurrences of this ecological community than other shrubland communities as sites are often very dry. Turkeys and ungulates are vectors for the spread of invasive alien plant species that typically establish in areas with disturbed soil, including recreational trails, roads, utility corridors, intense fires, and areas used by livestock. Invasive alien plant and problematic native species include black locust, bracken, cheatgrass, knapweed, hairy vetch, St. Johns wort, sulphur cinquefoil, dalmatian toadflax, etc. Fires and fire suppression are low threats. Fires that burn through surface organic material expose mineral soil for invasive alien plant infestation and is of particular concern in areas that are already weedy. Hot fires may also volatize pollutants when soil is burned. Fires also likely to be suppressed in areas with infrastructure (power lines, roads, communities). Climate change is anticipated to be a low threat at this time. By the 2050s in the Kootenay-Boundary region of British Columbia, there is a predicted 3.2 degree Celsius annual temperature increase and a decrease of 5.2% in annual precipitation (Pacific Climate Impacts Consortium Plan2Adapt 2012; accessed March 2023). Prolonged end of summer dry season could result in increased vegetation mortality towards the end of August. However, vegetation at these very dry sites are not as susceptible to drought as other shrubland ecological communities in the area. Haughian et al. (2012) predict increased frequency and severity of wildfires associated with climate change in the southern interior of British Columbia. Dams are an unknown threat. A muted hydrologic cycle may have an impact on growth and establishment of this ecological community, though more work is required to assess impacts and threats from altered hydrologic cycles. |
| Trend (in population, range, area occupied, and/or condition of occurrences) | |
| Short-Term Trend: | E = Decline of 30-50% |
| Comments: |
There are approximately 3.3 km of roads within polygons mapped with this community (B.C. Ministry of Forests, Lands, and Natural Resources Operations and Rural Development, Digital Road Atlas, accessed March 2023). Road density within this ecological community is 3.79 km/km2. When a 10-meter buffer is applied to roads, 0.07 km2 (8%) of this ecological community is directly impacted by roads and trails. However, impacts associated with roads are underestimated as additional roads are present in the Fort Shepard Conservancy and are not reported within the Digital Road Atlas. Roads and trails contribute to direct area loss and are also a vector for invasive alien plant species. There are 1.19 km of transmission lines within polygons mapped with this ecological community (B.C. Ministry of Forests, Lands and Natural Resource Operations, Baseline Thematic Mapping, accessed March 2023). Transmission line density within this ecological community is 1.37 km/km2. When a 100-meter buffer is applied to transmission lines, 0.16 km2 (18%) of this ecological community is directly impacted by transmission lines. Maintenance of transmission lines is ongoing and includes brushing and use of machinery and contributes to direct loss of area, soil disturbance, and is a vector for invasive alien plant species. Planting inappropriate tree species on sites that support this ecological community may also contribute to losses associated with restoration. Repeat fires during the 1920?s have burned 0.51 km2 of the area mapped with this ecological community (B.C. Ministry of Forests, Lands, and Natural Resources Operations and Rural Development, Historical Fire Mapping, accessed March 2023). Since then, no documented fires have occurred at locations mapped with this ecological community, suggesting active fire suppression, especially around infrastructure. The ICHwxa is NDT4, suggesting that the brushland sites should have a shorter fire return interval than observed in the past century. Approximately 0.87 km2 (100%) of polygons mapped with this ecological community occur within an area polluted by SO2, lead, zinc, cadmium, arsenic, etc. (LCEMP 2022), though pollution levels vary within this area. SO2 can impact soil pH. Soils within the impacted area were documented to have a pH of 4 where a pH of 6.5-7 was expected. Impacts of pollution include chlorotic foliage, decreased vegetation growth and vigor, and exclusion of species not tolerant of pollution. Invasive alien plant species are less frequent across polygons mapped with this ecological community than other shrubland communities as sites are often very dry. Dispersal of weeds largely occurs via historical cattle grazing, turkeys, wildlife, heavy machinery, and vehicles. Impacts from weeds are persistent and require intensive management. Manual pulling has limited success as it creates additional soil disturbance. Moisture is required to maintain and establish shrubs that shade out weeds and may be limited during dry summers or when adjacent forested land cover is harvested. |
| Long-Term Trend: | D = Decline of 50-70% |
| Comments: |
SO2 pollution in the 1920-30's impacted 100% of the ecological community, reducing resilience of these ecological communities and killing most vegetation within impacted areas (LCEMP). Cultural burning was also restricted during the past century. Soils have lingering effects from presence of metals and altered pH. |
| Other Factors | |
| Intrinsic Vulnerability: | B=Moderately vulnerable |
| Comments: | Soils are vulnerable to compaction and weed encroachment. |
| Environmental Specificity: | AB=Very narrow to narrow. |
| Comments: | This ecological community requires north-south exposure on level glaciofluvial terraces with sandy substrate. |
| Other Rank Considerations: | There may have been additional occurrences of this ecological community in the U.S.A, but they may have been inundated when the Columbia River was dammed. |
| Information Gaps | |
| Research Needs: | |
| Inventory Needs: | |
| Stewardship | |
| Protection: | |
| Management: | |
| Version | |
| Author: | A. Ehman, M. Machmer, E Cameron |
| Date: | April 21, 2023 |
| References | |
| No references available | |
Please visit the website Conservation Status Ranks for information on how the CDC determines conservation status ranks. For global conservation status reports and ranks, please visit the NatureServe website http://www.natureserve.org/.
Suggested Citation:
B.C. Conservation Data Centre. 2023. Conservation Status Report: Ceanothus velutinus - Danthonia spicata. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 5, 2026).