Lotus pinnatus

Today’s entry is written by Bryant. The first photograph is from Charles Thirkill, a resident of Nanaimo who has been prominent in preserving this rare species at this location in British Columbia, and the second image is from Bryant. He writes:

Last Thursday, I was fortunate enough to tag along with Daniel Mosquin and Tony Maniezzo, the curator of the North American Gardens (including the Garry Oak Meadow and Woodland Garden, on their scouting trip to various Garry oak ecosystem sites on Vancouver Island. The main purpose of the trip was to examine different Garry oak landscapes and compare the plants and plant assemblages that are growing in the UBC Botanical Garden with their counterparts in the wild. A secondary purpose was to locate and observe rare plant species, in the hope that the Garden will one day participate in conservation programs for these species.

This photo shows Lotus pinnatus (bog birds-foot trefoil), a member of the Fabaceae, at one of its few locations on Vancouver Island. It is a short-lived perennial that grows from a thick taproot, and can be observed in flower from May to June. It has alternate compound leaves, each with 2-4 pairs of oppositely-arranged leaflets and a terminal leaflet. It is found in moist depressions in shallow soil on exposed coastal lowlands. In Canada, it grows in Garry Oak habitat on southeast Vancouver Island and Gabriola Island.

Elsewhere, Lotus pinnatus is native to California, Oregon, Washington and Idaho. The species is not considered threatened globally; however, it is considered extremely rare in Canada (the northern extent of its distribution). In Canada, it is limited to 5 recorded sites, with 83% of its Canadian population residing on the Harewood Plains in Nanaimo, British Columbia. This highly limited Canadian distribution has earned this species an N1 (nationally endangered) ranking by the Committee on the Status of Endangered Wildlife in Canada. Provincially, it is ranked as an S1 (red-listed/critically imperiled) status in B.C., the highest threatened level that can be applied to a species.

Since Lotus pinnatus usually grows in association with water seepage sites, any activity that could cause drainage through soil compaction, channeling or other methods could cause local extirpations of this species. The biggest threats to the British Columbia populations of this species come from logging, unauthorized 4×4, ATV and dirtbike use, development, and encroachment of invasive species. The site where the pictured specimen was found was not marked in any way and showed recent tracks and disturbance from unauthorized recreational vehicles.

Only 7% of the plants in Canada reside under some official protection, those that are in the Woodley Range Ecological Reserve. The percentage of protected habitat for Lotus pinnatus is small because the majority of the Canadian populations exist on private land. Landowners have made efforts to keep off-road recreationists out of the fragile habitat by placing gates, cement barriers and ditches at potential entrance sites, but to little avail. On the bright side, there are steps being taken to help Lotus pinnatus recover. In 2006, the “Recovery Strategy for Multi-Species at Risk in Vernal Pools and Other Ephemeral Wet Areas Associated with Garry Oak Ecosystems in Canada” was developed for Lotus pinnatus, and five other local species, under the Species at Risk Act (SARA). This recovery strategy is a major step in the protection of the mentioned species; the next step requires a proposed action plan, which is currently in the process of development, to delineate site-specific management goals and objectives.

In other news, Lotus pinnatus was named the floral emblem of Nanaimo in 2010 with the hopes to raise public awareness about its conservation status. For information on the local recovery efforts for this species contact the Garry Oak Ecosystems Recovery Team.

Lotus pinnatus
Lotus pinnatus

10 responses to “Lotus pinnatus”

  1. Daniel Mosquin

    A few photographs taken about 100m away from where Bryant’s image was made. This location was marked — marked for restoration — and the sign was still ignored. We also found some plants near here.

  2. Bill Barnes

    So how far are the Canadian populations from the nearest US populations?

  3. Blake Hodgin

    I do not endorse the use of ATV’s and I agree that they are a threat to the unique and fragile Harewood Plains habitat, but I have seen Lotus pinnatus doing very well in ruts created by ATVs at Harewood Plains. Sometimes disturbed sites, whether old logging roads or tire tracks, end up creating patches that are favourable for rare plants. While ATVs are clearly a very bad idea at Harewood – quickly tearing up the thin mantle of soil above solid bedrock on these seepage sites. Nevertheless, this post is a reminder, for me at least, that there are many puzzling lessons to be learned in rare plant conservation efforts.

  4. elizabeth a airhart

    thank you for this fine piece of writing and the pictures are lovely
    i went over to the gary oaks recovery team web site tis great
    and put myself on the email list– the bluebirds are beautiful
    thank you daniel and company i do love me yellow flowers

  5. Daniel Mosquin

    Bill, looks like the Seattle area:
    Lotus pinnatus via the PNW Herbaria portal.
    Blake, yes, my observation was that the ruts can also cause areas where water settles and I did see some plants growing in those ruts.
    That said, the observation would need to be tested to see if such a disturbance is positively or negatively affecting the population numbers. How many plants would be growing in the same place if it wasn’t rutted?
    If such disturbances prove to be beneficial (and as you point out, this is indeed the case for other rare species, including some on Vancouver Island), the next question becomes how to manage the disturbance for conservation purposes. Factors would include: reproductive biology of the species (presumably after seed set in this instance), frequency of disturbance, extent of disturbance, and impact on other species in the area (including how the disturbance might possibly benefit invasives).

  6. Charles Thirkill

    Thank you for the photos and the thoughtful comments. It is a puzzle to understand why one site should be so favoured by a particular species. With such a high density in one location, protection is important. Populations at two previous locations for this plant in or near Nanaimo, were lost to development.
    The local abundance at Harewood Plains is an amazing phenomenon. It is similar to Muehlenberg centaury, which is found in abundance at one location in Victoria and sparsely at two other sites.
    There are a few Lotus pinnatus on Gabriola and on Woodley Range near Ladysmith, but if one looks at these sites, the rarity of L. pinnatus is evident.
    The ATV traffic has fallen to almost zero on The Plains, and we hope to keep it that way. To see the impact of off-road vehicles, look at the Harewood Plains meadows on Google Earth. The tracks can be seen written in the landscape and there is scarcely a square metre left untouched. A little disturbance can offer opportunities for wild flowers, but a little more than little is by much too much.
    It is a miracle that any flowers persist, but they do, reminding us that Nature is robust and there is always hope for the future. Wild flowers are an inspiration.

  7. Daniel Mosquin

    Harewood Plains, via Google Maps Satellite.

  8. Ed Alverson

    Lotus pinnatus can be still occasionally found in wet places in prairie remnants in Oregon’s Willamette Valley, though it is not particularly common and in some areas of suitable habitat it is replaced by the similar Lotus formosissimus. It appears to be quite uncommon in western Washington, the only collections from the state that are less than 30 years old listed in the CPNW web site are from the E end of the Columbia River gorge in Klickitat County, and many of the western Washington county records are over a century old. Suitable habitats for this species – wet places within a prairie landscape – have become a rare feature in today’s world, and not just in British Columbia.

  9. phillip

    ..when applying for a license for an ATV or off road vehicle..a pamphlet of the dangers of the ecosystem’s damage should be given and then tested..but like said above..’to no avail’..

  10. Stephen Lamphear

    I just don’t “get” the recreational part of ATVs. I have one for use on my private land. It gets me to areas where large vehicles either cannot or should not tread.
    Any rational person can recognize that natural areas and damaging “recreation” do not mix. We make laws so that the less than rational “get it”.

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