Skiff milkvetch (Astragalus microcymbus) | ESA status: candidate for listing

Skiff milkvetch facts

The skiff milkvetch grows to a foot tall and produces clusters of small white flowers tinged with purple from mid-May through July. The “microcymbus” portion of its name means “small boat,” hence the common name, “skiff,” referring to its boat-shaped fruits.

What are the threats to the skiff milkvetch?

The Denver Botanic Garden monitored skiff milkvetch populations for 15 years (1995-2009) and predicted that all populations of the species will fall below 20 individuals and become effectively extinct by 2030. Particularly sharp declines from 1995-2002 may have been caused by drought, to which the skiff milkvetch is susceptible. Climate change will likely worsen droughts and other perils to the plant. The species is also threatened by cheatgrass and other non-native plants; development; grazing by domestic livestock and native species; and a lack of legal protections. Today, the milkvetch’s range has been reduced to just 83 acres.

Still awaiting Endangered Species Act protections

The skiff milkvetch has waited more than 40 years for federal protection despite having been petitioned three times for listing under the Endangered Species Act. The Smithsonian Institute was the first to petition the flower in 1975. The U.S. Fish and Wildlife Service responded by proposing it for listing in 1976, but then withdrew that proposal in 1979, at which time the plant was added to the candidate list. The Biodiversity Legal Foundation and an individual petitioned to list the species again in 1993. The agency ignored that petition, and then dropped skiff milkvetch along with more than 2,000 other species from the candidate species list in 1996. WildEarth Guardians filed a third petition to list skiff milkvetch under the ESA in 2007, and the Service responded by placing the species back on the candidate list.

The skiff milkvetch can be saved, but not without the protections of the Act. It is up to the Fish and Wildlife Service to finally list the species.