Biodiversity of intertidal food webs in response to warming across latitudes

Global warming will affect food-web structure and species persistence, and real world data is needed for better prediction. Combining species counts and temperature data from rock pools with dynamic modelling predicts biodiversity increases in arctic to temperate regions and declines in the tropics. Global warming threatens community stability and biodiversity around the globe. Knowledge of the mechanisms underlying the responses to rising temperatures depends heavily on generic food-web models that do not account for changes in network structure along latitudes and temperature gradients. Using 124 marine rock-pool food webs sampled across four continents, we show that despite substantial variation in ambient temperature (mean 11.5-28.4 degrees C), similar empirical food-web and body-mass structures emerge. We have used dynamic modelling to test whether communities from warmer regions are more sensitive to warming and found a general hump-shaped relationship between simulated biodiversity and temperature (gradient from 0-50 degrees C). This implies that an expected anthropogenic global warming of 4 degrees C should increase biodiversity in arctic to temperate regions while biodiversity in tropical regions should decrease. Interestingly, simulations of synthetic networks did not yield similar results, which stresses the importance of considering the specificities of natural food webs for predicting community responses to environmental changes.German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig - German Research Foundation [FZT 118]Portuguese Foundation for Science and TechnologyPortuguese Foundation for Science and Technology [SFRH/BD/109618/2015, UID/MAR/04292/2019, UID/Multi/04326/2019, PTDC/MAR-EST/2141/2012]