O’SHEA, CRYAN & BOGAN: UNITED STATES BAT SPECIES OF CONCERN 
57 
the long-term, tolerated various gate designs, and that the landscape location and structural com¬ 
plexity of a mine were better than gate characteristics as predictors of whether this species would 
continue using a site after gating. 
A study of 1,345 mines and 47 caves surveyed at multiple times of the year in six regions of 
Utah and Nevada (Sherwin et al., 2003; see above) showed that intensive field work and careful 
analysis are required for comprehensive regional management of abandoned mines as roosting 
habitat for Townsend’s big-eared bats. Use of such roosts can follow complex seasonal patterns, 
and sites that are used by this species can be missed without such thorough studies, which unfor¬ 
tunately are seldom possible. 
Resurgence of Mining by Modern Methods: A major conservation issue for Townsend’s 
big-eared bats has arisen in historic mining districts, where renewed mining operations using mod¬ 
em techniques have resulted in complete removal of otherwise suitable abandoned mines; the 
largest then-known mine-roosting hibernating colony of Townsend’s big-eared bat in California 
(166 bats) was destroyed by renewed mining in the 1980s (Pierson and Rainey, 1998a). These 
extensive mining operations have other consequences for bat populations, as pointed out by Clark 
(1991), Brown et al. (1993a,b), and Brown and Berry (1991). Old mine openings can be destroyed, 
surrounding landscapes altered, and water tables reduced by removal of water for mining and 
extraction processes, with resultant elimination of natural drinking sources in streambeds and loss 
of riparian vegetation used for foraging by some bats (Brown et al., 1993a,b; Brown and Berry, 
1991). Mitigation of loss of roosts in historic mining districts through experimental creation of arti¬ 
ficial roosting habitat has taken place at the McLaughlin Mine in northern California, but its 
acceptance by this species at the time was not determined (Enderlin, 2000). In this case, large used 
tires from heavy equipment were placed side to side to form tunnels, radiating in four directions 
from a central concrete hub, then covered with waste rock, clay, and soil. 
Euderma maculatum — Spotted bat (Family Vespertilionidae) 
Conservation Status. — National and International Designations: U.S. Fish and Wildlife 
Service (1994, 1996a,b): Species of Concern (inactive, former Category 2 candidate for listing 
under the U.S. Endangered Species Act). U.S. Forest Service (2005a,b): Sensitive Species. Bureau 
of Land Management (2009a, 2010a,b,c, 2011a,b, 2015a,b, 2017): Sensitive Species (Arizona, Cal¬ 
ifornia, Colorado, Idaho, Nevada, New Mexico, Oregon, Utah, Wyoming state offices). Interna¬ 
tional Union for the Conservation of Nature (2017): Least Concern. NatureServe (2017): Rounded 
Global Status G4, Apparently Secure. 
State Designations: Arizona Game and Fish Department (2012): Tier IB Species of Greatest 
Conservation Need. California Department of Fish and Wildlife (2017): Special Animals List, 
Species of Special Concern. Colorado Parks and Wildlife (2015b): Species of Greatest Conserva¬ 
tion Need, Tier I. Idaho Department of Fish and Game (2005): Species of Greatest Conservation 
Need. Montana Fish, Wildlife, and Parks (2005, 2015a,b): Species of Greatest Concern, Species of 
Greatest Conservation Need. Nevada Department of Wildlife (2013): Threatened Mammal. Nevada 
Department of Conservation and Natural Resources (2015a): Imperiled. New Mexico Department 
of Game and Fish (2006, 2012): State Threatened, Species of Greatest Conservation Need, Vul¬ 
nerable. Oregon Department of Fish and Wildlife (2005, 2008): Sensitive Species, Vulnerable. 
Texas Parks and Wildlife (2012, 2015): Species of Greatest Conservation Need, State Threatened. 
Utah Division of Wildlife Resources (2015; Sutter et al., 2005): Species of Greatest Conservation 
Need. Washington Department of Fish and Wildlife (2015a,b): Species of Concern, Species of 
Greatest Conservation Need. Wyoming Game and Fish Department (2017a,b): Species of Greatest 
Conservation Need, Tier III. 
