Effect of landscape composition and configuration on biodiversity at multiple scales: a case study with amphibians from Sierra Madre del Sur, Oaxaca, Mexico

Context Land use change modifies landscapes' original compositions and configurations, which can have a positive, negative, or neutral effect on species diversity. The direction and magnitude of the effect depends on how each species responds to these conditions and can change depending on the scale in which it is evaluated. Objectives We evaluated the effect of landscape composition and configuration on amphibian diversity at multiple scales in two fragmented regions in the Sierra Madre del Sur, Oaxaca, Mexico, in order to identify the determinant landscape characteristics for amphibian species. Methods We sampled amphibian populations at 16 sites and measured 15 landscape metrics at five different scales from focal patches. We then modelled the association between these metrics and amphibian abundance and richness for each scale. Results We found positive associations between amphibian richness and abundance with Forest Patch Density at the 200 m scale, and negative associations with Urban Total Area and Forest Edge Density at 200 m, 500 m and 1000 m scales. Single-species models revealed different responses to landscape metrics at varying scales, suggesting a differential response to landscape's transformations that could be due to species life history traits. Conclusions Most amphibian species in these regions may be abundant in heterogeneous and fragmented landscapes as long as small forest patches are present. Nevertheless, large scale changes in forest amount and patch size due to fragmentation and urbanization could eventually affect some species negatively. Other variables at finer scales may be important and will depend on species-specific requirements.