McLellan et al. 2010 - Ecology.pdf (217.61 kB)

Predator-mediated Allee effects in multi-prey systems

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journal contribution
posted on 18.09.2020 by B McLellan, R Serrouya, Heiko Wittmer, S Boutin
Allee effects can have significant consequences for small populations and understanding the causal mechanisms for such effects is important for guiding conservation actions. One proposed mechanism is through predation, in which a type II functional response leads to increasing predation rates as prey numbers decline. However, models to support this mechanism have incorporated only a single declining prey species in the functional response, which is probably an oversimplification. We reevaluated the potential for predator-mediated Allee effects in a multi-prey system using Holling's disc equation. We also used empirical data on a large herbivore to examine how grouping behavior may influence the potential for predation-mediated Allee effects. Results based on a multi-prey expression of the functional response predict that Allee effects caused by predation on relatively rare secondary prey may not occur because handling time of the abundant prey dominates the functional response such that secondary prey are largely "bycatch." However, a predator-mediated Allee effect can occur if secondary prey live in groups and if, as the population declines, their average group size declines (a relationship seen in several species). In such a case, the rate at which the number of groups declines is less than the rate at which the population declines. Thus the rate at which a predator encounters a group remains relatively stable, but when a predator kills one animal from smaller groups, the predation rate increases. These results highlight the need to evaluate risks associated with potential changes in group size as populations decline. © 2010 by the Ecological society ot America.

History

Preferred citation

McLellan, B., Serrouya, R., Wittmer, H. & Boutin, S. (2010). Predator-mediated Allee effects in multi-prey systems. Ecology, 9(1), 286-292. https://doi.org/10.1890/09-0286.1

Journal title

Ecology

Volume

9

Issue

1

Publication date

01/01/2010

Pagination

286-292

Publisher

Wiley

Publication status

Published

Contribution type

Article

ISSN

0012-9658

eISSN

1939-9170

Language

en

Exports