Edge effects and vertical stratification of aerial insectivorous bats across the interface of primary-secondary Amazonian rainforest

Research ArticleEdge effects, abiotic and biotic changes associated with habitat boundaries, are key drivers of community change in fragmented landscapes. Their influence is heavily modulated by matrix composition. With over half of the world’s tropical forests predicted to become forest edge by the end of the century, it is paramount that conservationists gain a better understanding of how tropical biota is impacted by edge gradients. Bats comprise a large fraction of tropical mammalian fauna and are demonstrably sensitive to habitat modification. Yet, knowledge about how bat assemblages are affected by edge effects remains scarce. Capitalizing on a whole-ecosystem manipulation in the Central Amazon, the aims of this study were to i) assess the consequences of edge effects for twelve aerial insectivorous bat species across the interface of primary and secondary forest, and ii) investigate if the activity levels of these species differed between the understory and canopy and if they were modulated by distance from the edge. Acoustic surveys were conducted along four 2-km transects, each traversing equal parts of primary and ca. 30-year-old secondary forest. Five models were used to assess the changes in the relative activity of forest specialists (three species), flexible forest foragers (three species), and edge foragers (six species). Modelling results revealed limited evidence of edge effects, except for forest specialists in the understory. No significant differences in activity were found between the secondary or primary forest but almost all species exhibited pronounced vertical stratification. Previously defined bat guilds appear to hold here as our study highlights that forest bats are more edge-sensitive than edge foraging bats. The absence of pronounced edge effects and the comparable activity levels between primary and old secondary forests indicates that old secondary forest can help ameliorate the consequences of fragmentation on tropical aerial insectivorous batsinfo:eu-repo/semantics/publishedVersio

The importance of indigenous territories for conserving bat diversity across the Amazon biome

Essays and Perspectivesrainforest for millennia. How-ever, evaluations of how much biodiversity is governed under Indigenous stewardship are scarce. Here,we integrate geospatial data of officially recognized ITs across the Amazon biogeographic boundarieswith the distribution range of >200 Amazonian bat species, to: (i) assess the potential contribution of ITsfor the conservation of this species-rich mammalian group across the Amazon; (ii) investigate which ITshost the greatest number of bat species; and (iii) analyse how threatened and Data Deficient bat speciesare distributed within the ITs of the nine Amazonian countries. Twenty-two bat species were found tohave >25% of their global distribution range within Amazonian ITs, including many forest-dependentspecies with restricted distribution ranges and a highly threatened or Data Deficient conservation status.Some particularly diverse ITs were found to harbour over half of the known Amazonian bat species, par-ticularly in transboundary areas in the North-western Amazon. At the national level, the highest numberof species with over 25% of their national Amazonian distribution within ITs was found in Peru (145), followed by Brazil (136), Colombia and Ecuador (both with 134). This study reveals the potential role of Indigenous Peoples in Amazonian bat conservation and emphasizes the contribution of their stewardship for maintaining the ecosystems in which some of the most rare and unique bat species are foundinfo:eu-repo/semantics/publishedVersio