The Dwindling & Endangered Lane Mountain Milkvetch

The Lane Mountain milkvetch is very possibly San Bernardino County’s most endangered plant.
Known by its scientific name, Astragalus jaegerianus, the Lane Mountain milkvetch exists nowhere in the world outside of San Bernardino County. It is endemic to northeastern San Bernardino County, where it is limited to four populations within 17 square miles in the vicinity of Fort Irwin. It is a federally listed endangered species.
A rare species of milkvetch, Astragalus jaegerianus is a perennial herb with thin stems coated in scaly hairs. The stems reach 30 to 70 centimeters in length and grow tangled in the herbage of adjacent shrubs. In dry years the plant grows only a few centimeters long before flowering, but after abundant rain it may climb to the tops of neighboring shrubs. The leaves are 2 to 5 centimeters long and are made up of several widely spaced narrow leaflets with hairy upper surfaces.
The inflorescence is an open array of up to 15 pale purple, dark veined flowers. Each flower is up to one centimeter in length. The flowers are insect-pollinated, with the most common pollinator being the megachilid bee, Anthidium dammersi. The fruit is a hanging legume pod up to 2.5 centimeters long. It is hairless and dries to a leathery or thick papery texture.
In addition to its aboveground presence in which it is sometimes intertwined among the branches of other shrubs for support, the Lane Mountain milk vetch is able to subsist underground for years, surviving on a minimal amount of water, which its taproots access. Without that capability, it would most likely have died out.
The plant seeks the protective embrace of a limited number of certain desert shrubs. In this way, the Lane Mountain milkvetch is difficult to spot as it grows hidden inside the dense tangle of stems and leaves of its host. It will remain hidden for two years or even longer while it fortifies itself and matures, at which point it will emerge out of host shrub and flower on its own.
Concern that military maneuvers and other activity on Fort Irwin would destroy the only known habitat for the plant resulted in legal action by the Center For Biological Diversity, which resulted in the U.S. Fish and Wildlife Service, after what the Center For Biological Diversity characterized as “foot dragging,” moving to protect the Lane Mountain milkvetch under the Endangered Species Act by proposing to designate 30,000 acres as critical habitat. Subsequently, however the U.S. Fish and Wildlife Service issued a final decision that excluded the entire proposed area from protection — so the Center For Biological Diversity in 2007 sued the agency, and in 2011 the Service designated 14,069 protected acres. The Army has set aside three small patches of land where vehicular travel is now forbidden and where it is hoped the plant can be preserved.
The perennial plant can live 20 to 25 years if the right conditions prevail. It dies back each summer and is capable of re-sprouting the next year. It can also go dormant for up to three years. But drought conditions wreak havoc on the plant and for the past 16 years, as botanists have closely monitored the four remaining colonies of the plant, it has been losing the survival battle, with its population steadily declining, with rare exceptions where there were a few relatively wet years in the desert.
Humans have attempted to intervene, in particular students and faculty at Department of Ecology and Evolutionary Biology, who have made an effort to cultivate Lane Mountain milkvetch by germinating the plant’s tiny seeds and planting them in areas that closely resemble the rocky terrain of the desert where the plant naturally exists and where host plants are established.
Another factor endangers the Astragalus jaegerianus. It has an inability to grown in any soil that is occupied by the Larrea tridentate, otherwise known as the creosote bush, one of the more prolific shrubs in the Mojave Desert.
Between the creosote bushes, Army vehicles and the drought, this plant may be extinct by mid-century.

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