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Density-dependent nest predation in waterfowl: the relative importance of nest density versus nest dispersion

Oecologia

By:
, ,
DOI: 10.1007/s00442-011-2228-1

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Abstract

When nest predation levels are very high or very low, the absolute range of observable nest success is constrained (a floor/ceiling effect), and it may be more difficult to detect density-dependent nest predation. Density-dependent nest predation may be more detectable in years with moderate predation rates, simply because there can be a greater absolute difference in nest success between sites. To test this, we replicated a predation experiment 10 years after the original study, using both natural and artificial nests, comparing a year when overall rates of nest predation were high (2000) to a year with moderate nest predation (2010). We found no evidence for density-dependent predation on artificial nests in either year, indicating that nest predation is not density-dependent at the spatial scale of our experimental replicates (1-ha patches). Using nearest-neighbor distances as a measure of nest dispersion, we also found little evidence for “dispersion-dependent” predation on artificial nests. However, when we tested for dispersion-dependent predation using natural nests, we found that nest survival increased with shorter nearest-neighbor distances, and that neighboring nests were more likely to share the same nest fate than non-adjacent nests. Thus, at small spatial scales, density-dependence appears to operate in the opposite direction as predicted: closer nearest neighbors are more likely to be successful. We suggest that local nest dispersion, rather than larger-scale measures of nest density per se, may play a more important role in density-dependent nest predation.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Density-dependent nest predation in waterfowl: the relative importance of nest density versus nest dispersion
Series title:
Oecologia
DOI:
10.1007/s00442-011-2228-1
Volume
169
Issue:
3
Year Published:
2012
Language:
English
Publisher:
Springer
Contributing office(s):
Western Ecological Research Center
Description:
8 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Oecologia
First page:
695
Last page:
702