Consumptive and nonconsumptive effects of cannibalism in fluctuating age-structured populations
Persistent URL
Author(s)
Wissinger, Scott A.
Whiteman, Howard H.
Denoël, Mathieu
Mumford, Miranda L.
Aubee, Catherine B.
Date Issued
February 1, 2010
Abstract
Theory and empirical studies suggest that cannibalism in age-structured populations can regulate recruitment depending on the intensity of intraspecific competition between cannibals and victims and the nature of the cannibalism window, i.e., which size classes interact as cannibals and victims. Here we report on a series of experiments that quantify that window for age-structured populations of salamander larvae and paedomorphic adults. We determined body size limits on cannibalism in microcosms and then the consumptive and nonconsumptive (injuries, foraging and activity, diet, growth) effects on victims in mesocosms with seminatural levels of habitat complexity and alternative prey. We found that cannibalism by the largest size classes (paedomorphs and age 3þyr larvae) occurs mainly on young-of-the-year (YOY) victims. Surviving YOY and other
mall larvae had increased injuries, reduced activity levels, and reduced growth rates in the presence of cannibals. Data on YOY survival in an experiment in which we manipulated the density of paedomorphs combined with historical data on the number of cannibals in natural populations indicate that dominant cohorts of paedomorphs can cause observed recruitment
failures. Dietary data indicate that ontogenetic shifts in diet should preclude strong intraspecific competition between YOY and cannibals in this species. Thus our results are consistent with previous empirical and theoretical work that suggests that recruitment regulation by cannibalism is most likely when YOY are vulnerable to cannibalism but have low dietary overlap with cannibals. Understanding the role of cannibalism in regulating recruitment in salamander populations is timely, given the widespread occurrences of amphibian decline. Previous studies have focused on extrinsic (including anthropogenic)
factors that affect amphibian population dynamics, whereas the data presented here combined with long-term field observations suggest the potential for intrinsically driven population cycles.
Journal
Ecology
Department
Biology
Environmental Science / Studies
Citation
Wissinger, S.A., Whiteman, H.H., Denoël, M., Mumford, M.L., Aubee, C.B. (2010). Consumptive and nonconsumptive effects of cannibalism in fluctuating age-structured populations. Ecology 91(2): 549-559.
Publisher
Ecological Society of America
Version of Article
Final manuscript post peer review, without publisher's formatting or copy
editing (postprint)
Rights
This article was selected and published in Ecology © 2010 Wissinger, Whiteman, Denoël, Mumford, and Aubee. All rights reserved.
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