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PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES 
Series 4, Volume 65, Supplement I 
particularly in the panhandle, but just three of six caves in the peninsula occupied by females in 
spring 1992 had evidence of volant young by summer. The other three showed signs of disturbance 
(including fires beneath roosting sites) and abandonment. 
Comer et al. (2014) compared detection probabilities for southeastern myotis using acoustic 
sampling versus roost search transects in eastern Texas pine habitat and found that 6 nights of 
acoustic surveys (using two detectors) would yield a detection probability of 90%, whereas 61 one- 
kilometer length transects would be required to attain the same detection probability using roost 
searches. In Mississippi, Fleming et al. (2013b) estimated that searches for roost trees of this 
species had detection probabilities above 90%, but that visual estimates of colony size by inspect¬ 
ing internal cavities underestimated numbers of bats compared to digital imagery, with increased 
error in larger colonies. 
Management Practices and Concerns. — Although some maternity colonies of south¬ 
eastern myotis can be found in buildings (for example, Hermanson and Wilkins, 1986), in Florida 
most young are bom in caves (Gore and Hovis, 1994). These bats are thus very vulnerable where 
populations require caves for reproduction because of disturbance, blocking of entrances, destruc¬ 
tion of cave habitat, and intentional killing. Populations are no doubt at greatest risk in Florida and 
other parts of the southeastern U.S. that are undergoing rapid conversion of habitat to support bur¬ 
geoning populations of people. Humphrey and Gore (1992) reported that one colony of 11,000 
known from the 1950’s had become a public dump filled with trash and lacked bats completely, a 
colony of 2,500 at another site had been displaced because of frequent use of the cave for recre¬ 
ation, and that vandals throwing guano at roosting bats at a third site contracted histoplasmosis, 
resulting in demands to destroy the colony as a public health threat. Some former colony sites sur¬ 
veyed in Florida in 1991-92 had blocked entrances; several active maternity caves in Florida 
showed evidence of malicious disturbance, including fires, spent ammunition, and carcasses of 
killed females and neonates (Gore and Hovis, 1994, 1998). These observations are symptomatic of 
the large encroachments of people into formerly isolated areas of the southeastern U.S., and prob¬ 
ably represent only a fraction of such incidents. Catastrophic mortality from natural sources such 
as flooding can also be an important issue for population dynamics when major segments of pop¬ 
ulations are aggregated at just a few locations (see “Mortality Factors” above). 
Some caves in the Florida panhandle that have been protected for the endangered gray bat are 
also used by southeastern myotis, at least two other caves on public lands harboring primarily this 
species have been gated or fenced, and several caves on private lands have been posted against tres¬ 
pass to protect their colonies (Humphrey and Gore, 1992). Intentional removal of a gate by man¬ 
agement at one of three entrances to Old Indian Cave at Florida Caverns State Park resulted in 
increased nightly egress of a mixed group of gray bats and southeastern bats (largely the latter), but 
with no overall change in abundance of the roosting population (Ludlow and Gore, 2000). The 
removed gate was replaced by a perimeter fence because managers felt it was advantageous to have 
multiple unobstructed entrances to reduce predation and increase efficiency of emergence, while 
still restricting access to the cave by potential trespassers (Ludlow and Gore, 2000). 
Gore and Hovis (1994, 1998) recommend several measures for conservation of colony sites 
for this species in Florida, which may harbor a significant portion of the U.S. population. They 
stress the need for wider efforts at educating both veteran and novice cavers to avoid maternity 
colony sites at critical times of year (15 February to 15 August), to increase emphasis of enforce¬ 
ment of trespass laws, and to develop conservation easements, deed restrictions, special designa¬ 
tions, or purchase of critical caves. The best approach to achieve these goals is development of a 
cooperative unified cave management plan aimed at conservation of all cave-roosting bat colonies 
in Florida (Gore and Hovis, 1994). Additional study of ecology and natural history, including for¬ 
aging habitat requirements and possible impacts of contaminants was also recommended. 
