Recovery Success for the First Plants Listed under the Endangered Species Act

by Gary D. Wallace

The U.S. Navy’s commitment to environmental stewardship and conservation of our nation's natural heritage has helped improve the status of two rare plant species in southern California—Acmispon dendroideus var. traskiae (San Clemente Island lotus) and Castilleja grisea (San Clemente Island paintbrush). Both species were among the very first plants to gain Endangered Species Act (ESA) protection 35 years ago. The two perennials, which are unique to San Clemente Island located 75 miles (120 kilometers) west of San Diego, were listed as endangered in 1977 after their habitat was severely degraded from decades of overgrazing by goats and other nonnative herbivores.

Large numbers of sheep grazed the island from 1877 until 1934, when ownership was transferred to the U.S. Navy. Goats also introduced in the late 1800s were still numerous on the island for some time. The concentration and duration of impacts from these herbivores severely altered the extent and distribution of the vegetation on the island. It was not until the 1990s that concentrated efforts were made to remove the last goats from the island. Many years after the reduction and ultimate removal of herbivores the fragile island landscape has started to show signs of recovery.

San Clemente Island lotus is a low growing, sprawling subshrub in the pea family, while the San Clemente Island paintbrush is an erect, hemiparasitic perennial in the broomrape family. Both plants are unique to San Clemente Island, occurring nowhere else in nature.

The first collections of San Clemente Island plants were made in 1885. The island's wide variety of unusual native plants attracted many botanists, who visited and collected on the island. However, it was not until the comprehensive flora of the island was published by Peter Raven in 1963 that the considerable impacts to individuals and habitats of endemic plants and animals from the grazing and browsing was evidenced. These concerns prompted the listing of San Clemente Island lotus and San Clemente Island paintbrush, along with Malacothamnus clementinus (San Clemente Island bushmallow), (Delphinium variegatum subsp. kinkiense (San Clemente Island larkspur), San Clemente loggerhead shrike (Lanium ludovicianus mearnsi), San Clemente sage sparrow (Amphispiza belli clementeae), and Island night lizard (Xantusia riversiana). All of these plants and animals are restricted, or nearly restricted, to this single island. Currently San Clemente Island supports 16 endemic plant taxa, among the almost 300 native plant taxa known from the island.

The U.S. Navy has a long history – over 75 years – of stewardship and conservation efforts on San Clemente Island. The U.S. Navy's conservation efforts on behalf of San Clemente Island lotus and San Clemente Island paintbrush include, support of monitoring efforts, genetic research, habitat restoration, management of fire, control of erosion, removal of invasive nonnative plants, and other species management efforts on the island. This is in addition to their commitment to conservation and recovery of the other listed and sensitive plants and animals on the island. On-island efforts include nursery cultivation of local stock of endemic taxa for outplanting on the island as well as collection of seeds for offsite seed banking. The U.S. Navy monitors native taxa on the island and coordinates closely with the Service to minimize impacts associated with military training activities.

The U.S. Navy plans to continue conservation efforts for listed and other sensitive plant species including finalization of a revised Integrated Natural Resources Management Plan, which will provide an updated framework for conservation and management of biological resources on San Clemente Island; and continued monitoring and management of listed plants and other sensitive plant species on the island.

Ongoing conservation efforts have helped reduce threats to the species, which has resulted in increasing numbers and spatial distribution of the two plants on the Island. Since the apparent abundance and distribution of these two plants on San Clemente Island have improved considerably since the time of listing, the Service has proposed reclassifying the legal status of the two plants from endangered to the less critical threatened category. These plants are just part of the noticeably improved appearance and diversity of the natural landscape on the island.

The U.S. Navy continues to support and promote research, conservation, and recovery of the island's unique flora and fauna. Efforts similar to those to restore San Clemente Island lotus and San Clemente Island paintbrush are likely to benefit nonlisted species, including Poa thomasii (Nuttall's poa), a rare grass that was presumed extinct for almost 100 years, until it was rediscovered on Catalina Island in 2005 and subsequently on San Clemente Island. The change of fortunes of these two listed plants is but one example of the importance of conservation partnerships, through which the ESA can deliver remarkable successes.

 

Gary D. Wallace, a botanist in the Service's Carlsbad Fish and Wildlife Office, can be reached at gary_wallace@fws.gov or 760-431-9440.