Climate, habitat, and species interactions at different scales determine the structure of a Neotropical bat community

Abstract

Climate, habitat, and species interactions are factors that control community properties (e.g., species richness, abundance) across various spatial scales. Usually, researchers study how a few properties are affected by one factor in isolation and at one scale. Hence, there are few multi-scale studies testing how multiple controlling factors simultaneously affect community properties at different scales. We ask whether climate, habitat structure, or insect resources at each of three spatial scales explains most of the variation in six community properties and which theory best explains the distribution of selected community properties across a rainfall gradient. We studied a Neotropical insectivorous bat ensemble in the Isthmus of Panama with acoustic monitoring techniques. Using climatological data, habitat surveys, and insect captures in a hierarchical sampling design we determined how much variation of the community properties was explained by the three factors employing two approaches for variance partitioning. Our results revealed that most of the variation in species richness, total abundance, and feeding activity occurred at the smallest spatial scale and was explained by habitat structure. In contrast, climate at large scales explained most of the variation in individual species' abundances. Although each species had an idiosyncratic response to the gradient, species richness peaked at intermediate levels of precipitation, whereas total abundance was very similar across sites, suggesting density compensation. All community properties responded in a different manner to the factor and scale under consideration.

Mobility explains the response of aerial insectivorous bats to anthropogenic habitat change in the Neotropics

“…and N. albiventris, clearly preferred or avoided certain habitat types. In general, our findings, covering a very large geographic scale, confirm habitat preferences identified on geographically more restricted scales (Estrada-Villegas et al, 2012;Jung andKalko, 2010, 2011). In order to sustain a species-rich AIB community, which will provide crucial ecosystem functions and services including insect control on a regional scale, it is critical to secure a diversity of different habitat types.…”

“…(3) We calculated tree distance as the average distance from our sampling point to the four nearest trees (more than 10 cm diameter at breast height) in four opposite directions, using the same method of visual estimation. (4) As proxy for climate we included orientation to the ocean (categorizing each sampling point as either Atlantic or Pacific, with the central cordillera as the dividing line), as Estrada-Villegas et al (2012) found precipitationdependent distribution patterns in AIB in the Panama Canal area. These measurements helped us to characterize the four habitat types used for site selection in the field: (1) Mature forest, the habitat type with least anthropogenic influence, was characterized by extensive canopy cover, a high canopy and reduced distance between trees (see Table A1 and Fig.…”

“…Other relevant factors may include abundance of preferred prey items (e.g. Gonsalves et al, 2013) or climatic preferences (Estrada-Villegas et al, 2012).…”

“…While some AIB species disappear with urbanization (urban avoiders), others seem rather unaffected (urban adapters) or might even profit from human settlements, where they find high numbers of roosting sites (urban exploiters, Jung and Kalko, 2011). Most studies on AIB in the Neotropics, however, have focused on geographically restricted areas like national parks or cenotes (Delgado-Jaramillo et al, 2011;MacSwiney et al, 2008;Rydell et al, 2002) or the canal area in Panama (Estrada-Villegas et al, 2012;Jung andKalko, 2010, 2011). Working across broader geographical scales is important to reveal broad scale patterns and to test the validity of ecological hypotheses in multiple habitat contexts.…”

Forest Structure and Composition Affect Bats in a Tropical Evergreen Broadleaf Forest

“…)-came from narrow-or edge-space families and genera [8,23,64,65]. These bats fly more slowly but are much more maneuverable and able to fly easily in areas of high structural complexity and clutter [66,67]; as a result, they tend to prefer edge or narrow space typically found in less disturbed areas, often with denser overstories, midstories, understories, and ground layers [30]. Their echolocation calls are also higher in frequency and of shorter duration, as insects are typically being detected over shorter distances [31].…”