Environmental correlates of species diversity for sarcosaprophagous Diptera across a pronounced elevational gradient in central Spain

Measuring the biological diversity in a given area can provide valuable approaches not only to conserve ecological systems, but also to understand their functioning and organization. The current paper analyzes the species richness and diversity patterns of sarcosaprophagous Diptera across an elevational gradient of natural habitats in central Spain, and the relationship between the species diversity and the environmental variables defining each habitat. The calculation of randomized species richness curves and non-parametric estimators confirmed the representativeness of the inventories. Oromediterranean habitats, i.e. those located at highest elevation, showed significantly lower species richness than mesomediterranean and supramediterranean levels. Slope and solar radiation were significantly and negatively correlated with diversity, whereas the correlation between mean temperature and diversity was significantly positive. A significantly negative correlation was found between diversity and the percentage of forest surface, whereas the correlation between diversity and the percentage of urban surface was positive and close to significance. Possible explanations for these observed patterns are considered and discussed. This study also supports the use of different, complementary diversity measurements in order to obtain a proper assessment of the diversity of a given area.