Demographic response to perturbations: the role of compensatory density dependence in a North American duck under variable harvest regulations and changing habitat
Article first published online: 20 MAR 2012
© 2012 The Authors. Journal of Animal Ecology © 2012 British Ecological Society
Journal of Animal Ecology
Volume 81, Issue 5, pages 960–969, September 2012
How to Cite
Péron, G., Nicolai, C. A. and Koons, D. N. (2012), Demographic response to perturbations: the role of compensatory density dependence in a North American duck under variable harvest regulations and changing habitat. Journal of Animal Ecology, 81: 960–969. doi: 10.1111/j.1365-2656.2012.01980.x
- Issue published online: 7 AUG 2012
- Article first published online: 20 MAR 2012
- Received 14 October 2011; accepted 10 February 2012 Handling Editor: Michael Wunder
- integrated population models;
- Leslie matrix;
- Waterfowl Breeding Population and Habitat Survey
1. Most wild animal populations are subjected to many perturbations, including environmental forcing and anthropogenic mortality. How population size varies in response to these perturbations largely depends on life-history strategy and density regulation.
2. Using the mid-continent population of redhead Aythya americana (a North American diving duck), we investigated the population response to two major perturbations, changes in breeding habitat availability (number of ponds in the study landscape) and changes in harvest regulations directed at managing mortality patterns (bag limit). We used three types of data collected at the continental scale (capture–recovery, population surveys and age- and sex ratios in the harvest) and combined them into integrated population models to assess the interaction between density dependence and the effect of perturbations.
3. We observed a two-way interaction between the effects on fecundity of pond number and population density. Hatch-year female survival was also density dependent. Matrix modelling showed that population booms could occur after especially wet years. However, the effect of moderate variation in pond number was generally offset by density dependence the following year.
4. Mortality patterns were insensitive to changes in harvest regulations and, in males at least, insensitive to density dependence as well. We discuss potential mechanisms for compensation of hunting mortality as well as possible confounding factors.
5. Our results illustrate the interplay of density dependence and environmental variation both shaping population dynamics in a harvested species, which could be generalized to help guide the dual management of habitat and harvest regulations.