A species’ niche breadth is defined as the suite of environments or resources that the species can inhabit or use. Niche breadth is often invoked to explain the latitudinal diversity gradient. The latitudinal diversity gradient is the increase in species richness or biodiversity that occurs from the poles to the tropics. Despite this pattern having been recognized for over 200 years, the processes that drive and maintain the latitudinal diversity gradient remain unclear. We investigated which processes are important drivers of global lizard dietary niche breadth patterns, focusing on the relationship between niche breadth and species richness.
Overall, our findings are consistent with the notion that climate is an important predictor of dietary specialization, with both less rainfall and more stable temperatures associated with narrower dietary niches. Trophic interactions between lizard species and their arthropod prey are sensitive to climate. It is likely that climatic conditions not only affect these interactions but also alter the functional role of other vertebrate predators in terrestrial ecosystems. The sensitivity of dietary niche breadth to climate has important implications for essential ecosystem functions that maintain increased species richness in the tropics, such as food web stability and energy flow.