Abstract:
Over the past century, the Earth has experienced roughly 0.4–0.8
◦C rise in the average
temperature and which is projected to increase between 1.4–5.8
◦C by the year 2100. The increase in the Earth’s temperature directly influences physiological traits of individual species
in ecosystems. However, the effect of these changes in community dynamics, so far, remains
relatively unknown. Here we show that the consequences of warming (i.e., increase in the
global mean temperature) on the interacting species persistence or extinction are correlated
with their trophic complexity and community structure. In particular, we investigate different nonlinear bioenergetic tri-trophic food web modules, commonly observed in nature, in
the order of increasing trophic complexity; a food chain, a diamond food web and an omnivorous interaction. We find that at low temperatures, warming can destabilize the species
dynamics in the food chain as well as the diamond food web, but it has no such effect on the
trophic structure that involves omnivory. In the diamond food web, our results indicate that
warming does not support top-down control induced co-existence of intermediate species.
However, in all the trophic structures warming can destabilize species up to a threshold
temperature. Beyond the threshold temperature, warming stabilizes species dynamics at
the cost of the extinction of higher trophic species. We demonstrate the robustness of our
results when a few system parameters are varied together with the temperature. Overall,
our study suggests that variations in the trophic complexity of simple food web modules can
influence the effects of climate warming on species dynamics
