Abstract
Habitat loss and fragmentation are the greatest threats to reptiles and amphibians (herpetofauna) around the globe, but especially in the Neotropics where high diversity and ongoing land-use change coincide. Persistence of biodiversity in fragmented systems relies both on characteristics of habitat patches, and on the permeability of the landscape that separates the patches (the "matrix"). We sought to understand: (a) how the herpetofauna community differs between forest reserves, patches, corridors, and matrices, and (b) the landscape characteristics that increase suitability of a habitat patch. We conducted herpetofauna surveys in patches, corridors, matrices, and preserves (54 total sites) in a fragmented landscape in Costa Rica for three seasons. We recorded 1663 individuals of 52 species. We found that the herpetofauna community differed, and had lower richness and abundance, in the matrix compared to the other three habitat types. Patches and corridors supported a similar community to the forest preserves, demonstrating the conservation value of small forest remnants. Water body presence was an important predictor of richness and abundance in both patches and matrices. While total richness increased in patches with more edge, this was driven by the response of generalist species, whereas the prime indicator species of forest preserves decreased in patches with complex shapes. The differing response to landscape characteristics between specialist and generalist species demonstrates the importance of considering specific taxa when setting conservation goals, rather than using richness measures alone. Our findings can help guide preservation of forest fragments to optimize biodiversity conservation in mixed forest-pastoral landscapes.Abstract in Spanish is available with online material.
La perdida y fragmentacion del habitat son las mayores amenazas para los reptiles y anfibios (herpetofauna) en todo el mundo, pero especialmente en el Neotropico, donde coinciden la alta diversidad y el cambio continuo en el uso de la tierra. La persistencia de la biodiversidad en sistemas fragmentados depende tanto de las caracteristicas de los parches de habitat como de la permeabilidad del paisaje que separa los parches (la "matriz"). Buscamos comprender: (a) Como la comunidad de herpetofauna difiere entre reservas forestales, parches, corredores y matrices, y (b) Las caracteristicas del paisaje que aumentan la idoneidad de un parche de habitat. Realizamos estudios de herpetofauna en parches, corredores, matrices y reservas (54 sitios en total), en un paisaje fragmentado en Costa Rica durante tres temporadas, en donde registramos 1663 individuos de 52 especies. Descubrimos que la comunidad de herpetofauna diferia y tenia menor riqueza y abundancia en la matriz en comparacion con los otros tres tipos de habitat. Parches y corredores sustentaron una comunidad similar a las reservas forestales, lo que demuestra el valor de conservacion de los pequenos remanentes de bosque. La presencia de cuerpos de agua fue un predictor importante de riqueza y abundancia tanto en parches como en matrices. Si bien la riqueza total aumento en parches con mas bordes, esto fue impulsado por la respuesta de especies generalistas, mientras que las especies indicadoras principales de reservas forestales disminuyeron en parches con formas complejas. La diferente respuesta a las caracteristicas del paisaje entre especies especialistas y generalistas demuestra la importancia de considerar taxones especificos al establecer objetivos de conservacion, en lugar de utilizar medidas de riqueza unicamente. Nuestros hallazgos pueden ayudar a guiar la preservacion de fragmentos de bosque para optimizar la conservacion de la biodiversidad en paisajes mixtos de bosque y pastoreo.
We assessed the reptile and amphibian community at 54 sites spanning four habitat types in a fragmented landscape in Costa Rica. Our study revealed that small forest patches and corridors play an important role in herpetofauna conservation, as they support a similar richness, abundance, and community composition to large forest preserves. We also found that while species richness increases in patches with a higher proportion of edge habitat, the forest-specialist species decrease in these complexly shaped patches, indicating a need to consider specific taxa when setting conservation goals.image
