BC Conservation Data Centre: Conservation Status Report
Distichlis spicata Estuarine Marsh
seashore saltgrass Estuarine Marsh
| Scientific Name: | Distichlis spicata Estuarine Marsh |
|---|---|
| English Name: | seashore saltgrass Estuarine Marsh |
| Provincial Status Summary | |
| Status: | S1S2 |
| Date Status Assigned: | February 28, 2018 |
| Date Last Reviewed: | February 28, 2018 |
| Reasons: | This community is limited to the lowest vegetated areas of estuaries along the coastline of the Strait of Georgia and southwest end of Vancouver Island. Occurrences are generally small in size with a few exceptions. Some large occurrences have been affected by industrial use for log sorting. Almost all other occurrences in this area have had some form of disturbance, either from old settlements and farms, or as access points with old docks and pilings remaining on the sites. A variety of low level threats exist, including recreational use, shoreline pollution, and, at some sites, harvesting of plant products (Salicornia) for the food industry. The impact of sea level rise in estuarine areas with limited backshore expansion, is a moderate-level threat. |
| Range | |
| Range Extent: | D = 1,000-5,000 square km |
| Range Extent Estimate (km2): | 1809 |
| Biogeoclimatic Unit: |
CDFmm/Em03
CWHxm1/Em03 |
| Range Extent Comments: | The range extent of this ecological community is estimated with a custom range map. This custom map is based on known community distribution and BEC map Version 9. Ryder et al. (2007) approximated a range of 746 km2 for all of B.C. estuaries, the majority of which are intertidal flats (533 km2). This ecological community is known only from the coastal waters of the Georgia Basin, where it is restricted to the lower limits of estuaries, within the intertidal zone. Much of these estuarine areas occur within the Fraser River delta (Ward et al. 1992). |
| Area of Occupancy (km2): | AB = <5 kmē |
| Area of Occupancy Comments: | This saline herbacious community is restricted to the lower limits of estuaries, within the intertidal zone. It occurs within the estuary area identified as marsh/swamp by Ryder et al (2007), which occupies 60 km2 in all of British Columbia's estuaries. The estimated area of occupancy is a very small percentage of most estuaries. Ward et al. (1992) estimated an area of 2.35 km2 of saltmarsh, or 4% of the total marsh area occurring within the Fraser estuary. Other prominent sites in the Strait of Georgia with Seashore Saltgrass Herbaceous Vegetation include the shore of Boundary Bay, the Tsawout wetland near Sidney Spit, Witty's Lagoon near Metchosin, and Sidney Lagoon on Sidney Island (within the Southern Gulf Islands National Park Reserve). Smaller occurrences can also be found in Port Moody, Roberts Bank and in the Burrard Inlet (Page 2011a; Page 2011b). Many very small occurrences are located along the coastline of east Vancouver Island and the Sunshine Coast from Malaspina Peninsula to Howe Sound (Sensitive Ecosystems Inventories; 2004, 2005). |
| 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: | C = Medium |
| Comments: | At this time limited recreational disturbance and boat access affect some sites. Some sites are also affected by adjacent or on-site industrial use. As this brackish community occurs within the intertidal zone, there has been less long term impact associated with conversion to agriculture and urban development. In the future, changes to sea level and ocean currents could have greater impacts where there is limited potential for backshore dispersal of salt-tolerant species. Currently, the effect of invasive species such as Spartina anglica and Lythrum salicaria on this particular saltmarsh community are not well known. The combined effect of all threat categories results in a medium level of threat. |
| Trend (in population, range, area occupied, and/or condition of occurrences) | |
| Short-Term Trend: | F = Decline of 10-30% |
| Comments: | Artificial structures creating land-water access and recreational activity and some industrial/commercial use have resulted in small decline in the recent decades since the analysis by Campbell-Prentice and Boyd (1988) for the Fraser River estuary. |
| Long-Term Trend: | E = Decline of 30-50% |
| Comments: | Almost every estuary along the south coast has been modified in the past, including low impact First Nations 'farming' for selected species, losses due to European settlement and agricultural conversion through dyking and ditching, structures associated with land access (docks and pilings), and the transportation of harvested timber from source to mill sites. The Fraser estuary is reported to have the greatest modifed and converted area (70%) of any estuary in B.C. (Campbell-Prentice and Boyd, 1988). However, Distichlis spicata var. spicata Herbaceous vegetation, which occurs at the lowest margins of marsh vegetation, may be the least likely estuarine marsh to have been converted in the last century of anthropogenic use due to the proximity to exposed mudflats. |
| Other Factors | |
| Intrinsic Vulnerability: | B=Moderately vulnerable |
| Comments: | Depending on degree of disturbance, the ecological community may recover in less than 10 years. |
| Environmental Specificity: | A=Very narrow. Specialist or community with key requirements scarce. |
| Comments: | Fluctuating saline conditions associated with diurnal flooding. |
| Other Rank Considerations: | |
| Information Gaps | |
| Research Needs: | |
| Inventory Needs: | Mapping of element occurrences. |
| Stewardship | |
| Protection: | |
| Management: | |
| Version | |
| Author: | Cadrin, C.M., H.K. Yearsley and C. Schaefer |
| Date: | November 26, 2013 |
| References | |
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Sensitive Ecosystems Inventory [SEI] of East Vancouver Island and Gulf Islands: Sensitive Ecosystems Mapping, Disturbance Mapping and Re-evaluation of Major Riparian Corridors. 2004. Prepared by Axys Environ. Consulting Ltd. for Environ. Can., Can. Wildl. Serv., B.C. Minist. Sustainable Resour. Manage., and B.C. Minist. Water, Land and Air Prot., and the Habitat Conserv. Trust Fund. 66 mapsheets, 1:20 000 scale.
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Sensitive Ecosystems Inventory [SEI] of the Sunshine Coast and Adjacent Islands. 2005. Cadrin, C., C. Erwin, B. Fuller, C. Schaefer and J. Stacey. 1:20 000 spatial data.
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Terrestrial Ecosystem Mapping [TEM] of the Coastal Douglas-fir Biogeoclimatic Zone. 2008. Prepared for B. Zinovich, Integrated Land Management Bureau, B.C. Minist. of Agric. and Lands, Nanaimo B.C. by Madrone Environmental Services, Duncan B.C. 1:20,000 spatial data.
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Ward, P., K.Moore and R.Kistritz. 1992. Wetlands of the Fraser Lowland, 1989: an inventory. Technical Report Series No. 146, Canadian Wildlife Service, Pacific and Yukon Region, B.C. 216pp.
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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: Distichlis spicata Estuarine Marsh. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 10, 2026).