Do riparian forest strips in modified forest landscapes aid in conserving bat diversity?

A multifaceted approach to understanding bat community response to disturbance in a seasonally dry tropical forest

Given widespread habitat degradation and loss, reliable indicators are needed that provide a comprehensive assessment of community response to anthropogenic disturbance. The family Phyllostomidae (Order Chiroptera) has frequently been the focus of research evaluating bats' response to habitat disturbance in seasonally dry tropical forests (SDTFs). However, few studies compare this family to the larger bat assemblage to assess its efficacy as a bioindicator. We compared community and species-specific attributes of understory phyllostomid and all understory bat species: (1) along a gradient of habitat disturbance within a human-modified SDTF landscape; and (2) between forest and riparian habitats within each disturbance level. We captured 290 individuals belonging to 13 species and 4 families. Phyllostomid species exhibited greater sensitivity to disturbance than the understory bat community as a whole based on richness and beta diversity. Both groups were more sensitive to disturbance in forest than riparian habitat, but phyllostomid species were more likely to be lost from highly disturbed forest habitat. The two dominant species declined in abundance with disturbance but variation in body condition was species-specific. These results suggest that Phyllostomidae are more effective indicators of human disturbance in SDTF than the understory bat community as a whole and evaluation of bats' response to disturbance is best accomplished with a multifaceted approach.

Consequences of Replacing Native Savannahs With Acacia Plantations for the Taxonomic, Functional, and Phylogenetic α- and β-Diversity of Bats in the Northern Brazilian Amazon

Across the globe, millions of hectares of native vegetation have been replaced by commercial plantations, with negative consequences for biodiversity. The effects of the replacement of native vegetation with commercial plantations on the functional and phylogenetic diversity of bat assemblages remain understudied, and most studies have focused exclusively on the taxonomic component of diversity. Here, we investigate how the replacement of natural savannahs by acacia plantations affects the α- and β-diversity of bat assemblages. We sampled bats, using mist-nets at ground level, in natural forest, savannah areas and acacia plantations, in the Lavrados de Roraima in the northern Brazilian Amazon. Our results show that, in general, acacia is less diverse than native forests in terms of taxonomic and functional diversity, and is also less taxonomically diverse than the savannah matrix which it substitutes. The observed patterns of α- and β-diversity found in the present study are in large part driven by the superabundance of one generalist and opportunistic species, Carollia perspicillata, in the acacia plantations. Taken together, our results show that the replacement of areas of natural savannah by acacia plantations causes a regional loss in diversity across all diversity dimensions: taxonomic, functional and phylogenetic. However, further studies are required to fully understand the ecological and conservation implications of this landscape change.

LOS ENSAMBLAJES DE MURCIÉLAGOS DE LA SERRANÍA DE LA LINDOSA SON DIVERSOS Y HETEROGÉNEOS

La Serranía de La Lindosa es una formación geomorfológica que presenta heterogeneidad en sus coberturas vegetales. Esta zona se encuentra en una situación contradictoria debido a que presenta una elevada biodiversidad, sin embargo, es uno de los actuales focos de deforestación más grandes de Colombia. A pesar de que se espera una alta diversidad de murciélagos en La Lindosa existe poca información publicada sobre este grupo. Este trabajo presenta los resultados de inventarios de murciélagos realizados durante cinco años en la serranía de la Lindosa. Se compara la diversidad (riqueza, composición y estructura) de los ensamblajes de murciélagos en dos tipos principales de cobertura vegetal, los bosques húmedos y las sabanas casmófitas. Los inventarios recogen información de 735 murciélagos capturados, correspondientes a 46 especies. De éstas, 14 especies se encontraron solamente en sabanas casmófitas, 11 en bosques húmedos y 19 en los dos tipos de vegetación. De esta manera, se evidencia una alta complementariedad en la composición de especies de murciélagos entre los dos tipos de vegetación. Adicionalmente, la estructura de los ensamblajes de murciélagos varió entre los dos ambientes. La abundancia entre las especies es más homogénea en las sabanas casmófitas con un mayor número de especies raras comparado con los bosques húmedos. En general, la alta diversidad de murciélagos de la Serranía de La Lindosa puede estar relacionada con la heterogeneidad en la vegetación, la presencia de diferentes tipos de cuevas, y la historia evolutiva de las especies de murciélagos asociados a la Región Guayana.