Assessment of Inactive Mines as Bat Habitat in Northern Idaho: Summary of BLM Research 1994-99

摘要

Federal Lands in Idaho contain an estimated 5,000 inactive or abandoned mine sites, many with open portals. Human intrusion into these mines, whether motivated by curiosity or historical interest, subjects individuals to a variety of hazards that can prove life threatening. Consequently, inventory and closure of inactive and abandoned mines has received increased emphasis. Bats, many of which traditionally use caves and old-growth forests to roost and hibernate, may have become dependent on old mines (Tuttle and Taylor 1994). Recent colonization of mines developed during the past century could be the result of an expansion of bat habitat through selective processes enhancing metapopulations (McCullough 1996) or bats may have been displaced from their native habitat into mines as alternative roosting sites. Additionally, some species may enter mines to feed on insects accumulating near the back at the portal. Irrespective of the factors that have caused mine use, the loss of mine habitat through closures may threaten a number of species that now appear to be mine obligates. One of these species, Townsend's big-eared bat (Corynorhinus townsendii), is generally considered the most sensitive species occupying mines in Idaho (Pierson et al. 1999).