Conservation Ecology of Cave Bats

Abstract

Caves and other subterranean sites such as mines are critical to the survival of hundreds of bat species worldwide, since they often provide shelter for most of a nation's bat fauna. In the temperate zone, caves provide roosts for hibernation and for some species, breeding in summer, whereas in warmer regions, they support high species richness year round and enormous colonies that maintain substantial ecosystem services. Due to the solubility of the substrate, the highest densities of caves occur in karst landscapes. Given their importance for bats, relatively few studies have investigated factors involved in cave selection, although current evidence suggests that the density and size of caves are the best predictors of species diversity and population sizes. Thermal preferences have been established for some cave-dwelling species as well as their vulnerability to disturbance, particularly during hibernation and reproduction. Growth in limestone quarrying and cave tourism industries worldwide severely threatens cave-dwelling bats, in addition to loss of foraging habitat, hunting for bushmeat, incidental disturbance and disruptive guano harvesting. Apparent declines of cave bats in Europe and North America also pose serious concerns, as do global climate change predictions. The main conservation response to threats to cave bats in these continents

Reproductive Ecology of Wrinkle-Lipped Free-Tailed Bats Chaerephon plicatus (Buchannan, 1800) in Relation to Guano Production in Cambodia

“…Although rates of guano accumulation should reflect the size of bat colonies [4], their utility as a proxy for population size at our study site was compromised by the practical difficulty of ensuring consistent harvest methods (due to safety concerns related to ammonia levels in the cave) and the fact that unquantified amounts of guano are flushed from accessible areas of the cave by percolating waters during the wet season [22]. The latter may explain why guano harvests were significantly greater in the 2011-2017 dry seasons when the opposite might be expected due to greater food availability during the wet season.…”

“…This is particularly true in Southeast Asia, a region supporting >25% of global bat diversity [1], which has one of the highest deforestation rates in the tropics [2], and where human populations doubled in under four decades to reach 593 million people in 2010 [3]. As a consequence, information regarding the specific vulnerabilities of regionally diverse and threatened taxa such as cave-roosting bats [4] is of considerable interest and can be used to guide efforts to protect and sustainably manage their populations.…”

“…The wrinkle-lipped free-tailed bat Chaerephon plicatus (synonym: Tadarida plicata) (Molossidae) is a widely-distributed insectivorous species occurring from India and Sri Lanka through mainland Because cave-roosting bats are vulnerable to human disturbance during critical reproductive periods (late pregnancy, lactation and weaning) [4], documentation of these periods has clear conservation relevance [13]. Although a wide variety of reproductive patterns have been described for molossid bats [14], the similar climate and monsoon seasons of Thailand and Myanmar [15] led us predict that reproductive phenology of C. plicatus in Cambodia would match patterns documented in these countries [16][17][18].…”

“…Due to the influence of climate and specifically rainfall on insect biomass and hence food availability for insectivorous bats [14,19,20], we further hypothesized that differences in the latter between the dry and wet seasons in Cambodia would be reflected in seasonal differences in body condition and consequently permit identification of periods when the species may be subject to energetic stress. Lastly, we quantified guano harvests at the largest known and most closely Because cave-roosting bats are vulnerable to human disturbance during critical reproductive periods (late pregnancy, lactation and weaning) [4], documentation of these periods has clear conservation relevance [13]. Although a wide variety of reproductive patterns have been described for molossid bats [14], the similar climate and monsoon seasons of Thailand and Myanmar [15] led us predict that reproductive phenology of C. plicatus in Cambodia would match patterns documented in these countries [16][17][18].…”

A Comparative Analysis of Viral Richness and Viral Sharing in Cave-Roosting Bats

“…For example, Monfort Cave in the Philippines houses a colony of frugivorous bats (Rousettus amplexicaudatus) estimated at 2 million individuals with a roosting density of 452.3 individuals/m 2 [4], while Bracken Cave in the United States is occupied by roughly 20 million insectivorous bats (Tadarida braziliensis) [5]. Caves are often structurally complex (e.g., passageways, cracks and crevices, chambers), providing a range of roosting opportunities that can accommodate species-specific preferences and support aggregations of a high diversity of cave-roosting species [6]. Particularly in the tropics, caves have been reported to house bats of more than 10 species [3,7,8].…”