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Influence of grazing and available moisture on breeding densities of grassland birds in the central platte river valley, Nebraska

Wilson Journal of Ornithology

By:
, , , and
DOI: 10.1676/07-153.1

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Abstract

We investigated the relationship between grassland breeding bird densities and both grazing and available moisture in the central Platte River Valley. Nebraska between 1980 and 1996. We also compared species richness and community similarity of breeding birds in sedge (Carex spp.) meadows and mesic grasslands. Densities of two species had a significant relationship with grazing and six of seven focal species had a significant relationship with available moisture. Bobolink (Dolichonyx oryzivorus) and Brown-headed Cowbird (Molothrus ater) densities were lower in grazed plots compared to ungrazed plots, whereas Red-winged Blackbird (Agelaius phoeniceus) densities were greater in sedge-meadow plots compared to mesic grassland plots. Bobolink, Dickcissel (Spiza americana). and Brown-headed Cowbird were negatively associated with available moisture with breeding densities peaking during the driest conditions. Our results suggest that wet conditions increase species richness for the community through addition of wetland-dependant and wetland-associated birds, but decrease densities of ground-nesting grassland birds in wet-meadow habitats, whereas dry conditions reduce species richness but increase the density of the avian assemblage. We propose that wet-meadow habitats serve as local refugia for grassland-nesting birds during local or regional droughts.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Influence of grazing and available moisture on breeding densities of grassland birds in the central platte river valley, Nebraska
Series title:
Wilson Journal of Ornithology
DOI:
10.1676/07-153.1
Volume
120
Issue:
4
Year Published:
2008
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Wilson Journal of Ornithology
First page:
820
Last page:
829