Limestone Salamander ACEC
Designated in 1986 as the Limestone Salamander Area of Critical Environmental Concern (ACEC), these BLM-administered lands encompass 1,600 acres of confirmed and potential limestone salamander habitat and adjacent BLM lands along the Merced River and its tributaries in western Mariposa County.
A State-listed threatened species and former Federal Category 2 candidate, the limestone salamander (Hydromantes brunus) is one of California's rarest native amphibians. The species' known range is restricted to 15 population sites along a 20-mile stretch of the Merced River between the headwaters of Lake McClure, near the community of Bagby, and the mouth of Sweetwater Creek, near Briceburg. The species occurs nowhere else in the world. Entirely terrestrial, the species is found only on north and east facing rocky outcrops and talus slopes. It is dependent on moist conditions and good cover; thus, it is vulnerable to surface disturbances within occcupied sites.
Much of what is presently understood about the limestone salamander is based on the work of Tordoff (1980) who undertook the only extensive work with the species completed to date. During that study, funded and administered by the BLM, 63 sites were surveyed for the presence of salamanders. Nine of 15 confirmed population sites and 29 of 38 sites containing suitable habitat were on BLM lands.
Along with a State-administered preserve, designated to protect the species' type locality, designation of the Limestone Salamander ACEC places much of the species' habitat under protective management by public agencies. Other designations in the Merced River drainage, including the Merced Wild and Scenic River and Merced River ACEC, extend BLM protection to the area's overall natural and scenic values.
Threats to the limestone salamander do exist, however, other opportunities for protecting the species' habitat remain. Opportunities for increasing the species' protection by the BLM include land acquisitions to consolidate habitats within designated areas and improved monitoring to prevent surface disturbances or loss of cover which could alter or degrade limestone salamander habitat within the ACEC.