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bioRxiv · 10.1101/2021.08.06.455481

Temporally auto-correlated predator attacks structure ecological communities

Schreiber, S.
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Abstract

For species primarily regulated by a common predator, the P* rule of Holt and Lawton [1993] predicts that the prey species that supports the highest mean predator density (P*) excludes the other prey species. This prediction is re-examined in the presence of temporal fluctuations in the vital rates of the interacting species including predator attack rates. When the fluctuations in predator attack rates are temporally uncorrelated, the P* rule still holds even when the other vital rates are temporally auto-correlated. However, when temporal auto-correlations in attack rates are positive but not too strong, the prey species can coexist due to the emergence of a positive covariance between predator density and prey vulnerability. This coexistence mechanism is similar to the storage effect for species regulated by a common resource. Negative or strongly positive auto-correlations in attack rates generate a negative covariance between predator density and prey vulnerability and a stochastic priority effect can emerge: with non-zero probability either prey species is excluded. These results highlight how temporally auto-correlated species interaction rates impact the structure and dynamics of ecological communities.

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Schreiber, S.. 2021-08-08. Temporally auto-correlated predator attacks structure ecological communities. https://doi.org/10.1101/2021.08.06.455481

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