BC Conservation Data Centre: Conservation Status Report
Pinus ponderosa - Populus trichocarpa / Toxicodendron rydbergii
ponderosa pine - black cottonwood / poison ivy
| Scientific Name: | Pinus ponderosa - Populus trichocarpa / Toxicodendron rydbergii |
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| English Name: | ponderosa pine - black cottonwood / poison ivy |
| Provincial Status Summary | |
| Status: | S1 |
| Date Status Assigned: | June 17, 1993 |
| Date Last Reviewed: | June 19, 2013 |
| Reasons: | This linear, riparian ecological community is sparsely distributed within an extremely small range. Very few occurrences of this ecosystem exist as intact floodplains. Analysis of Terrestrial Ecosystem Mapping data (TEM: South Okanagan 2009) suggests this ecosystem has declined over the long term. Ongoing threats include the spread of invasive alien species, conversion to agriculture and urban development. |
| Range | |
| Range Extent: | B = 100-250 square km |
| Range Extent Estimate (km2): | 240 |
| Biogeoclimatic Unit: |
BGxh1/06
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| Range Extent Comments: | The range extent estimate of this ecological community is based on Version 9 of the Biogeclimatic Ecosystem Classification (BEC) map (B.C. Ministry of Forests, Lands, and Natural Resource Operations. 2014). It occurs at low elevations at the southern end of the Okanagan Valley, from the north end of Skaha Lake to the U.S. border, and along the Similkameen River from Keremeos to the U.S. border (BEC map Version 9; Lloyd et al. 1990). |
| Area of Occupancy (km2): | AB = <5 km² |
| Area of Occupancy Comments: | This linear community is sparsely distributed within an extremely small range. It occurs on valley bottoms, specifically high bench floodplains, fans and in riparian zones. Based on Sensitive Ecosystems Inventory (SEI) and Terrestrial Ecosystem Mapping (TEM) this community occupies only about 0.94 km2 or 0.4 % of its range. |
| Spatial Pattern: | |
| Occurrences | |
| Number of Occurrences: | U = Unknown |
| Number of Occurrences with Good Viability / Ecological Integrity: | U = Unknown |
| Threats (to population, occurrences, or area affected) | |
| Degree of Threat: | B = High |
| Comments: | This riparian community continues to be threatened by the spread of invasive alien species (pervasive in scope, but moderate severity), and, to a lesser extent, conversion to agriculture (small-restricted scope, moderate-serious severity) and urban development (small in scope but extreme severity). |
| Trend (in population, range, area occupied, and/or condition of occurrences) | |
| Short-Term Trend: | U = Unknown |
| Comments: | Insufficient information is available. |
| Long-Term Trend: | D = Decline of 50-70% |
| Comments: | Terrestrial Ecosystem Mapping (TEM: South Okanagan 2009) shows that there is 68% less of this ecosystem in mature and old seral stages combined, and none left in the old stage, compared to the recommended seral stage distribution for permanent range in the Biodiversity Guidebook (Biodiversity Guidebook 1995), suggesting a decline of this ecosystem over the long term (> 40 years) (Yearsley et al. 2013). |
| Other Factors | |
| Intrinsic Vulnerability: | B=Moderately vulnerable |
| Environmental Specificity: | B=Narrow. Specialist or community with key requirements common. |
| Comments: | This ecological community occurs in a dry climate, on moist to wet sites adjacent to streams and on larger floodplains, on coarse-textured soils over fluvial blankets that can have water less than 50 cm from the surface. |
| Other Rank Considerations: | |
| Information Gaps | |
| Research Needs: | Research on the effects of climate change on water levels and flooding. |
| Inventory Needs: | Occurrence mapping from Terrestrial Ecosystem Mapping (TEM) is needed. |
| Stewardship | |
| Protection: | |
| Management: | |
| Version | |
| Author: | Yearsley, H.K. and C.M. Cadrin |
| Date: | December 13, 2013 |
| References | |
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B.C. Ministry of Forests, Lands, and Natural Resource Operations. Biogeoclimatic Ecosystem Classification (BEC) Map, WHSE_FOREST_VEGETATION.BEC_BIOGEOCLIMATIC_POLY [ESRI ArcSDE format]. Version 9. Ministry of Forests, Lands, and Natural Resource Operations, Forest Analysis and Inventory Branch, Victoria, B.C. Updated Regularly.
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Biodiversity Guidebook. 1995. Forest Practices Code of British Columbia. B.C. Minist. For. and B.C. Minist. Environ., Victoria B.C. ix + 99p.
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Flynn, Samantha. 2000. Plant Association Status Ranking 1999-2000. Access Digital Database. BC Ministry of Environment, Conservation Data Centre. Victoria, BC.
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Lloyd, D., K. Angove, G. Hope, and C. Thompson. 1990. A guide to site identification and interpretation for the Kamloops Forest Region. B.C. Minist. For., Res. Branch, Victoria, B.C. Land Manage. Handb. No. 23. 399pp.
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Terrestrial Ecosystem Mapping [TEM] of the South Okanagan and lower Similkameen Valley: refined and updated 2009b. K. Iverson and A. Haney. 1:20,000 spatial data.
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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. 2013. Conservation Status Report: Pinus ponderosa - Populus trichocarpa / Toxicodendron rydbergii. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Feb 20, 2025).