The bat fauna of the Kararaô and Kararaô Novo caves in the area under the influence of the Belo Monte hydroelectric dam, in Pará, Brazil.

Brazil's large territory displays significant richness in caves with about 12 thousand caves already recorded. Nevertheless, studies on bats in these environments are extremely scarce and fragmented. This study characterized the chiropteran fauna from two sandstone caves under the influence of the Belo Monte hydroelectric dam (Belo Monte UHE) in Pará, Brazil. The Kararaô and Kararaô Novo caves are located on the same ridge, 250 m apart. Three expeditions were carried out in 2013 and 2014, with a 4- to 5-month interval in between. A total of 589 animals were caught, 246 in the Kararaô cave and 343 in the Kararaô Novo cave. Fifteen species were recorded (13 in each cave) representing 79% similarity. With the exception of Vampyrum spectrum, which is not a cave species, the remaining recorded species were mostly cave bat species. Some species seemed to use the caves seasonally, although the basis of this pattern is still unknown. The most commonly observed species were Pteronotus personatus (dominant in the Kararaô cave), P. parnellii (dominant in the Kararaô Novo cave), and Lionycteris spurrelli, which accounted for 65% of all captures recorded for the two caves. Natalus macrourus is a species recorded in the Kararaô cave that is regionally threatened with extinction. Both caves are less than 500 m from the future reservoir; however, because the Kararaô cave entry is in an area that is lower than the reservoir, it can suffer alterations that would affect its dynamics. This raises great concern about the cave's associated fauna.