Article

Spatial variation in direct and indirect effects of climate and productivity on species richness of terrestrial tetrapods

Barreto et al. (2021) – Global Ecology and Biogeography

We aimed to dissect the spatial variation of the direct and indirect effects of climate and productivity on the global species richness of terrestrial tetrapods. We used a geographically weighted path analysis to estimate and map the direct and indirect effects of temperature, precipitation and primary productivity on species richness of terrestrial tetrapods across the globe. We found that all relationships shift in magnitude, and even in direction, among taxonomic groups, geographical regions and connecting paths. Direct effects of temperature and precipitation are generally stronger than both indirect effects mediated by productivity and direct effects of productivity. Richness gradients seem to be driven primarily by the effects of climate on organismal physiological limits and metabolic rates rather than by the amount of productive energy. Reptiles have the most distinct relationships across tetrapods, with a clear latitudinal pattern in the importance of temperature versus water.

http://www.doi.org/10.1111/geb.13357