Late Lunch Talk: Size dependent temperature effects and ontogentic omnivory in intraguild predation systems

Late Lunch Talk by Viktor Thunell

Ambient temperature structures ectotherm animal communities as it can change size dependent individual energy assimilation and expenditure but also resource conditions. Temperature also modulate the strength of both competition and predation as it affects feeding rates, which also are size dependent. Consequently, accounting for individual size variation is necessary to understand effects of temperature on community dynamics. Another aspect of size in most ectotherm animals is that growth commonly involve changes in diet. Such ontogenetic shifts in diet (or ontogenetic omnivory) commonly result in intraguild predation (IGP) as young or small predators compete with, and predate on another species through ontogeny. However, there is a lack of knowledge in how temperature affects stability and coexistence in the community of ontogenetic omnivores in spite of that they are universal in freshwater, marine and terrestrial ecosystems. Therefore, we construct a stage structured biomass model that mimics the bioenergetics of an ontogenetic omnivore IGP community. We account for size and temperature dependent individual differences in vital rates and study community structure resulting from food and temperature dependent growth under varying scenarios of ontogenetic omnivory and competition. We add novel insights on the effect of temperature to existing theory of community dynamics under variable environmental conditions. Importantly, considering the ubiquity of this combination of competition and predation interactions in nature, our findings broadens the ecological understanding of community dynamics in a warming climate.

Published Mar. 17, 2019 1:05 AM - Last modified Mar. 17, 2019 1:05 AM