Body mass ratio modulates the effects of temperature on biodiversity and bipartite network structure.

Global climate warming has been threatening community biodiversity and ecosystem stability worldwide. Bipartite network is a type of ecological networks defined by interactions between two trophic level species, such as plants and herbivores, where species connections occur exclusively between these groups. However, the mechanisms underlying the effects of increasing temperature on bipartite systems structure and species richness remain poorly understood. Using 156 bipartite networks analyzed under a dynamic modeling framework, we examined the individual and interactive effect of temperature (gradient from 0 to 50 °C) and mean body-mass ratio (gradient from - 3 to 6) on the community persistence and connectance. We found that ecosystems biodiversity increased linearly with rising temperature when mean body-mass ratio was low (i.e., resource biomass > consumer biomass). Conversely, under high mean body-mass ratios (i.e., consumer biomass > resource biomass), ecosystems biodiversity exhibited a negative response to temperature elevation. Network connectance (i.e., the proportion of possible feeding links that are realized), however, decreased with increasing temperature at low mean body-mass ratios. At high mean body-mass ratios, community connectance displayed a concave relationship with temperature. Overall, our results demonstrate that the body-mass ratio between consumers and resources serves as a key indicator for predicting the response of biodiversity and structure in antagonistic bipartite networks (specifically, herbivore-plant systems) to global environmental change.