Reproductive constraints in frugivorous phyllostomid bats: seasonal and elevational variation in reproductive rates in the Brazilian Atlantic Forest

Abstract

Reproductive rates in bats are higher when there is a greater availability of food, and when temperatures and rainfall are higher. Along elevational gradients, variation in these factors occurs over a small area, making them ideal natural laboratories for studies that aim to describe reproductive patterns and to identify possible vertical migrations for reproduction. We characterized the seasonal and elevational variation in reproductive rates of female and male Artibeus spp., Carollia perspicillata, and Sturnira lilium in the Brazilian Atlantic Forest. We sampled bats with mist nets at 13 sites in southeastern Brazil, between 23° and 24° of latitude, at elevations between 60 and 1,800 m a.s.l. The reproductive patterns of Artibeus spp. and S. lilium were seasonal, with higher reproductive rates in the period with higher rainfall, temperatures, and, consequently, greater availability of food. Moreover, elevation influenced reproductive activity in all study species. Reproductive rates for females of Artibeus spp. were higher at intermediate elevations (between 501 and 1,000 m a.s.l.), and for females of S. lilium at high elevations (above 1,000 m a.s.l.) with a less evident peak at intermediate elevations. Similarly, the proportions of reproductively active male Artibeus spp. and S. lilium were greater at intermediate and high elevations, respectively. In the dry season, reproductive rates of all females increased with local abundance of all females. Differences in reproductive rates along elevational gradients could influence population dynamics, and therefore entire elevational ranges should be protected to ensure conservation of the best reproductive habitats for a variety of bat species. Public policies are needed to ensure effective conservation of biodiversity, biological processes, and the ecosystem services provided by local fauna from the lower lands to the mountain peaks.