Army's Compatible Use Buffer Program Partners Produce Conservation Plan to Ensure Continued Military Readiness Through Recovery of Candidate Species

Like many in the nation, the Fort Lewis Military Installation has become a habitat island within a sea of development. Situated in the southern Puget Lowlands of western Washington State, Fort Lewis provides some of the largest expanses of remaining grassland habitat in the region. The region's grasslands are threatened by incompatible human uses of the land and the absence of fire across the landscape, resulting in encroachment of conifers and non-native vegetation. Four species that occur on these rare grasslands are federal candidates for listing under the Endangered Species Act (ESA): the streaked horned lark, Mazama pocket gopher, Taylor's checkerspot, and mardon skipper. If any of these species was to become listed, significant military training restrictions could be imposed by the U.S. Fish and Wildlife Service.

Proactive Efforts: Supporting the Mission

Working proactively to ensure uninterrupted military training and readiness, Fort Lewis has partnered with The Nature Conservancy, the Washington State Department of Natural Resources, and the Washington State Department of Fish and Wildlife to enact an Army Compatible Use Buffer (ACUB) program aimed at recovery of the candidate species. Traditionally, ACUB program funding has been used to purchase lands surrounding military installations to act as lifeboats for rare species. At Fort Lewis, Army funds are being used instead for on-site land management and habitat restoration. The non-military partners have provided funds for land purchase and some management of off-post grassland sites. By initiating restoration and reintroduction actions around Fort Lewis, the burden of recovery is shared among the Army and other regional grassland land owners. ACUB, along with other cooperative, regional conservation efforts, decreases the likelihood that the candidate species will become listed under the ESA.

How We Work

The Fort Lewis ACUB Partners have cooperatively produced a five-year implementation plan with conservation actions aimed at achieving the goal of continued military readiness through recovery of candidate species. Projects are selected by consensus of all partners and follow logical, temporally and spatially explicit, species-specific strategies to achieve recovery. The conservation actions funded through the Fort Lewis ACUB include land acquisition, habitat maintenance and restoration, increasing the size and numbers of candidate species' populations, monitoring, planning, and research.

Land Acquisition. The program has acquired privately-owned parcels containing native prairie at various locations in the southern Puget Sound lowlands outside Fort Lewis. The ACUB program and cooperators will continue to pursue additional acquisitions of important habitat.

Habitat Restoration and Maintenance. To provide habitat for reintroduction of candidate grassland species on ACUB lands, the land must be in suitable condition to sustain those animals. Several first- and second-year projects focus on controlling the invasive vegetation that prohibits occupation by the candidate species. Two of the biggest non-native threats are Scotch broom, a nitrogen-fixing shrub that modifies the structure of the prairie, creating unsuitable conditions for native plants and animals, and turf-forming grasses, such as tall oatgrass and colocasenial bentgrass, that outcompete the native prairie bunchgrasses and forbs.

The partners are also working to enhance native vegetation on ACUB sites by growing and outplanting native grasses and forbs that are important to the overall structure and diversity of the grasslands and/or that fulfill specific requirements of the candidate species (e.g., butterfly nectar sources).

Increasing the Size and Numbers of Candidate Species' Populations. The ACUB program is funding captive rearing efforts for both candidate butterflies: the Taylor's checkerspot and the mardon skipper. By developing methods to collect, rear, and release these animals, we are moving toward the goal of reintroduction of these species on currently unoccupied lands outside Fort Lewis. On those grasslands where the candidate species occur, the above-described habitat restoration activities are expected to increase the sizes of the populations.

Monitoring. Standardized, long-term monitoring is an integral aspect of the ACUB program. The tracking of both habitat quality and species status is essential to judge the effectiveness of land management activities, reintroductions, and species status trends. To date, the program has funded work to assess habitat quality ACUB lands, predict occurrence of the Mazama pocket gopher, and track population size of Taylor's checkerspot and mardon skipper.

Planning and Research. Action plans are in development to direct conservation and restoration activities on each ACUB property. The plans are essential to ensure that funds are spent wisely, that conservation actions are targeted to specific sites, and that conservation actions are implemented in a consistent and coordinated manner across all ACUB lands.

Several important research projects have been initiated under the Fort Lewis ACUB that will help inform and direct recovery actions. For instance, existing research has shown that the streaked horned lark is subject to very high nest predation rates, resulting in low reproductive success. However, the primary predators are unknown. An ACUB-funded project is using remote sensing cameras on streaked horned lark nests to identify predators and provide recommendations to reduce nest predation rates.

Other research projects include habitat selection studies for both the Taylor's checkerspot and mardon skipper. By identifying which habitat components these animals are selecting for as egg-laying sites, as well as important life-history traits, such as in which life-stage they spend the winter, we will better know how to create and enhance their habitat.

A technical review panel comprised of scientists and biologists from the ACUB partners and independent (non-ACUB) organizations reviews all project proposals to ensure that a high standard of scientific integrity is maintained.

Eco-regional Efforts: The ACUB program and its associated management and restoration projects are just one piece of a broad-scale, multi-partner effort to restore and recover these candidate species on the grasslands throughout their historic range. Efforts extend from the Georgia Basin in British Columbia, south through the Puget Trough in Washington to the Willamette Valley in Oregon.

Partners in the south Puget Sound area, including the Washington Departments of Fish andWildlife and Natural Resources, Fort Lewis, The Nature Conservancy, Thruston County, and private landowners, have come together to sign a Candidate Conservation Agreement (CCA). The CCA is a formal agreement among participating partners and the U.S. Fish and Wildlife Service. The participants voluntarily commit to implementing specific actions that will remove or reduce the threats to these species, thereby contributing to stabilizing or restoring the species so that listing is no longer necessary.

In addition to the formal agreements such as the CCA, partners are engaged in local working groups throughout the eco-region, informal statements of unity that link partners together through common goals, active participation in species-specific workshops, as well as on-the-ground restoration and protection work across the ecoregion. This cooperative approach boosts chances of regional recovery of the species while assuring that Fort Lewis maintains its soldier training capacity.