Abstract:
Studies from the temperate zones have shown that artificial lights can either deter
insectivorous bats by disorienting them and increasing exposure to predators, or
attract them by providing concentrations of prey, depending on the life history of the
species in question. This study looked at insectivorous bat responses to light pollution
in the tropics for the first time. Bat echolocations were recorded at 11 pairs of light
and dark sites in premontane and lower montane forest of Monteverde, Costa Rica.
Bat foraging activity was higher at artificially lighted sites (mean ± standard error
123.64 ± 34.77 recorded echolocations per night) than dark sites (mean ± standard
error 49.64 ±12.00 recorded echolocations per night), but species richness was not
statistically different between sites. While the majority of bat species increased their
activity in response to light, Myotis pilosatibialis and an unidentified bat were only
recorded in dark sites, suggesting that like temperate bats, tropical species are
differentially impacted by artificial lights. Increased light pollution in the tropics
concentrates some species around human inhabited areas while harming others via
habitat fragmentation, potentially shifting community structure.
