BC Conservation Data Centre: Conservation Status Report
Hydrophyllum tenuipes
Pacific waterleaf
| Scientific Name: | Hydrophyllum tenuipes |
|---|---|
| English Name: | Pacific waterleaf |
| Provincial Status Summary | |
| Status: | S3S4 |
| Date Status Assigned: | March 31, 2018 |
| Date Last Reviewed: | April 30, 2019 |
| Reasons: | Restricted range in BC, but less threatened and more abundant than previously thought. Currently known from 19-20 sites, with a total population of more than a million plants and a strong ability to disperse in appropriate habitat. Appears to tolerate some disturbance, as populations in Sooke and Abbotsford have survived in the midst of surrounding developments. However, as the population in the Lower Mainland and southern Vancouver Island continues to grow, residential development threatens remaining natural areas and may lead to declines in existing populations. |
| Range | |
| Range Extent: | C = 250-1,000 square km |
| Range Extent Comments: | The range extent in BC is 271 square km, as calculated using GIS tools. Restricted to southwestern BC in two areas: the Lower Mainland centered around Abbotsford and Chilliwack, and on Vancouver Island at Goldstream and Sooke. Also, at Mount Douglas Park in Saanich. |
| Area of Occupancy (km2): | DE = 6-125 |
| Area of Occupancy Comments: | The area of occupancy is 72 square km, as calculated using a 2km x 2km grid. |
| Occurrences & Population | |
| Number of Occurrences: | BC = 6 - 80 |
| Comments: | There are at least 19 extant and one historical occurrence in BC. Not all potential habitat within the species range has not been searched, so additional populations likely exist. |
| Number of Occurrences with Good Viability / Ecological Integrity: | CD = 4 - 40 |
| Comments: | There are at least 12 occurrences with good viability but most of the occurrences have not yet been assessed. |
| Number of Occurrences Appropriately Protected & Managed: | B = 1 - 3 |
| Comments: | Only one occurrence appears to be effectively protected (Goldstream Provincial Park). Five other occurrences are in municipal or regional parks, which can be afforded differing levels of protection. In one of the parks, work done on drainage could have impacted the plants. |
| Population Size: | H = >1,000,000 individuals |
| Comments: | Plants are abundant at several locations, and over a million plants have been enumerated. . |
| Threats (to population, occurrences, or area affected) | |
| Degree of Threat: | CD = Medium - low |
| Comments: | The primary threat facing Hydrophyllum tenuipes in BC is destruction of habitat through residential development. However, the species appears to tolerate some disturbance in surrounding areas as demonstrated by populations in Sooke and Abbotsford. |
| Trend (in population, range, area occupied, and/or condition of occurrences) | |
| Short-Term Trend: | F = Decline of 10-30% |
| Comments: | Some populations in Abbotsford have been disturbed or destroyed by development. |
| Long-Term Trend: | U = Unknown |
| Comments: | Long term trend data is not available, however, the species has been known from the Abbotsford area, Sooke, Victoria, and Goldstream for at least 50 years (89 years for Clayburn). Prior to significant urban and suburban developments, was likely more plentiful. |
| Other Factors | |
| Intrinsic Vulnerability: | U=Unknown |
| Comments: | Research on this species in BC has not been undertaken to fully understand the limiting factors, including any intrinsic vulnerability. This species is not limited in its ability to spread in appropriate habitat, but may be vulnerable to habitat fragmentation as surrounding developments increase in some parts of its range. |
| Environmental Specificity: | CD = Moderate to broad. |
| Comments: | Found along trails and in clearings of moist, shaded alluvial forests and streambanks in the lowland zone. Suitable habitat may be decreasing within the range of this species due to urban development. |
| Other Rank Considerations: | |
| Information Gaps | |
| Research Needs: | |
| Inventory Needs: | |
| Stewardship | |
| Protection: | |
| Management: | |
| Version | |
| Author: | Donovan, M. |
| Date: | April 09, 2018 |
| 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. 2018. Conservation Status Report: Hydrophyllum tenuipes. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Apr 23, 2024).