Ground-Vegetation Clutter Affects Phyllostomid Bat Assemblage Structure in Lowland Amazonian Forest

Abstract

Vegetation clutter is a limiting factor for bats that forage near ground level, and may determine the distribution of species and guilds. However, many studies that evaluated the effects of vegetation clutter on bats have used qualitative descriptions rather than direct measurements of vegetation density. Moreover, few studies have evaluated the effect of vegetation clutter on a regional scale. Here, we evaluate the influence of the physical obstruction of vegetation on phyllostomid-bat assemblages along a 520 km transect in continuous Amazonian forest. We sampled bats using mist nets in eight localities during 80 nights (3840 net-hours) and estimated the ground-vegetation density with digital photographs. The total number of species, number of animalivorous species, total number of frugivorous species, number of understory frugivorous species, and abundance of canopy frugivorous bats were negatively associated with vegetation clutter. The bat assemblages showed a nested structure in relation to degree of clutter, with animalivorous and understory frugivorous bats distributed throughout the vegetation-clutter gradient, while canopy frugivores were restricted to sites with more open vegetation. The species distribution along the gradient of vegetation clutter was not closely associated with wing morphology, but aspect ratio and wing load differed between frugivores and animalivores. Vegetation structure plays an important role in structuring assemblages of the bats at the regional scale by increasing beta diversity between sites. Differences in foraging strategy and diet of the guilds seem to have contributed more to the spatial distribution of bats than the wing characteristics of the species alone.

Does sex matter? Gender‐specific responses to forest fragmentation in Neotropical bats

“…, Rodríguez‐San Pedro & Simonetti ) and local‐scale vegetation structure influences species’ occurrence and abundance by constraining flight and access to food resources (Marciente et al . ). However, no study has yet investigated how male and female bats differ in their responses to local and landscape‐scale characteristics in fragmented landscapes.…”

Subtle changes in elevation shift bat‐assemblage structure in Central Amazonia

“…Vegetation structure has been related to the organization of bat assemblages at wide and local scales in Central Amazonia (Marciente et al . , Bobrowiec & Tavares ). The use of cluttered environments varies among bat guilds (Marciente et al .…”

“…Bat foraging guilds interact in different ways with the physical structure of vegetation (Marciente et al . , Bobrowiec & Tavares ). Gleaning animalivores are more generalist and use environments with different levels of vegetation clutter, while canopy frugivores are more common in sites with more open vegetation (Marciente et al .…”

“…, Marciente et al . , Bobrowiec & Tavares , Rocha et al . ), few studies in Amazonia have attempted to test their effects on species distributions and to test possible direct and indirect effects of these variables.…”

“…Gleaning animalivores are more generalist and use environments with different levels of vegetation clutter, while canopy frugivores are more common in sites with more open vegetation (Marciente et al . ).…”