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COSEWIC Assessment and Update Status Report on the Streambank Lupine (Lupinus rivularis) in Canada

Summary of Status Report

No formal protection presently exists for this species in Canada. The single flowering individual found in Sooke occurs on the boundary of a provincial park and may or may not be protected under the Parks Act. All other sites are unprotected. At present it is red-listed in BC. Its heritage status as listed by NatureServe (2002) is listed below:

Global Heritage Status Rank: G4G5 (01Sep1998)

National Heritage Status Rank:

United States: N? (01Aug1993)

Canada: N1

U.S & Canada State/Province Heritage Status Ranks

United States: California (S?), Oregon (SR), Washington (SR)

Canada: British Columbia (S1)

(SR: Species reported by not ranked; S?: Species unranked)

This species is not formally listed in the US as threatened or endangered, although it has been given a G4G5 rank. However, based on our examination of specimens and subsequent re-determination of 75% of these, and based on discussion with Teresa Sholars (2001 pers. comm.) who will be reassessing this species over the next year, this situation may change. In addition, the recent recognition of the major threat to L. rivularis from L. arboreus, and the ongoing efforts at removal of the latter in California and elsewhere, indicate that reassessment of the status of L. rivularis may be overdue.

Lupinus rivularis is found in Canada at only six known stations, and in comparatively low numbers. Only one of these stations might be within the boundaries of a provincial park, and active protection is not presently in place at that site. The other populations occur in unprotected sites which are either privately owned, or owned by railway companies, municipalities, or the Fraser River Port Authority. Site maintenance activities at these sites pose imminent threat to the populations, and indeed one population was severely affected by herbicide spraying this year, wherein most plants that were several years old were killed off, and only seedlings remain.

We believe at present this species is holding on only by virtue of its ability to withstand disturbance, but that its continued existence in Canada is in peril. While the populations appear viable in that they are setting seed, they are unlikely to expand in any way, and dispersal seems limited to the immediate vicinity. Further understanding of this species’ biology is necessary before true viability of the populations can be assessed and, thus, the adequacy of the existing habitat pockets.

It is clear that it would take very little coincident action at all of the known sites to extirpate this species from the Canadian flora.

Adding to this critical picture of Lupinus rivularis in Canada is the possibility that our populations may represent some of the most pure populations that are left in its entire range. Severe genetic swamping by the highly invasive and genetically aggressive L. arboreus has occurred elsewhere throughout its range, where major attempts are being made now to eradicate L. arboreus. The danger of hybridization is strong in our area, and may occur very quickly. Indeed a few plants were found that appear to be unplanted hybrids showing very strong arboreus traits. The biggest hybridization threat in the lower Fraser Valley, however, appears to be wildflower plantings that contain hybrid lupine plants, while on Vancouver Island, the greatest threat comes from the introduction and recent spread of L. arboreus along the coast. Widespread planting is occurring.

This is a species, too, that we believe has suffered extensively from severe habitat loss, and while probably not common prior to this, it may well have been a little more frequent in occurrence prior to dyking of the Fraser River.

In addition, like all lupines, it runs the risk of being picked for the beauty of its flowers. Picking of lupines at one of the six stations was observed in 2001.