Consistent energy-diversity relationships in terrestrial vertebrates

Ecologists have long proposed that environments providing more energy can support more species, yet empirical evidence frequently contradicts this expectation. We argue that such inconsistencies result from confounding geographical influences that mask the true relationship between species richness and energy-related factors. Here, by comparing species richness across different climate conditions, we disentangle the direct effects of temperature, precipitation, and primary productivity from the confounding impacts of the area and isolation of various climates. Using a global analysis of terrestrial vertebrates, we reveal clear and consistent relationships between energy-related factors and species richness. Our findings clarify existing ecological theory and illustrate how adopting a climate space perspective advances biodiversity research, providing critical insights into biodiversity patterns and their responses to environmental change.