The increasing stability of large food webs: generation time as a possible explanation

Stability is a relevant property of complex food webs, which has been in the focus of studies for a long time. However, it remained an intriguing question how large and complex food webs do relate to smaller and simple ones considering their persistence. We analyzed the relationship between food web size and stability in the case of 450 food webs with a large node interval ranging from 3 to 263. Our results show that both dynamic and topologic stability increases with food web size based both on return times after disturbance and on robustness calculated from secondary extinctions. Our results contribute to the explanation of large and complex food web persistence since their stability at the small node number intervals is smaller than their stability at the large food web size interval. We evaluated stability simultaneously from a dynamic and topological point of view. To explain our results, we hypothesize the contribution of mean food web generation time (mean life span of contributing species) to stability. Thus, we propose a time-scale standardization (min–max normalization) of return times to facilitate comparative stability analyses across food webs operating on different biological time scales. Also, we stress the use of food web generation times in food web stability studies.