A multi-scaled analysis of avian response to habitat amount and fragmentation in the Canadian dry mixed-grass prairie |
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Authors: | Nicola Koper Fiona K K Schmiegelow |
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Institution: | (1) Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2H1, Canada;(2) Present address: Natural Resources Institute, University of Manitoba, 70 Dysart Road, Winnipeg, Manitoba, R3T 2N2, Canada |
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Abstract: | Previous research has suggested that ducks and songbirds may benefit from prairie landscapes that consist primarily of contiguous
grasslands. However, the relative importance of landscape-level vs. local characteristics on mechanisms underlying observed
patterns is unclear. We measured effects of grassland amount and fragmentation on upland and wetland songbird and duck density
and nest success, and on some nest predators, across 16 landscapes in southern Alberta, Canada. We compared these landscape-level
effects with local-scale responses, including distance to various edges and vegetation characteristics. We also evaluated
several statistical approaches to comparing effects of habitat characteristics at multiple spatial scales. Few species were
influenced by grassland amount or fragmentation. In contrast, distance to edge and local vegetation characteristics had significant
effects on densities and nest success of many species. Previous studies that reported effects of landscape characteristics
may have detected patterns driven by local mechanisms. As a corollary, results were very sensitive to statistical model structure;
landscape level effects were much less apparent when local characteristics were included in the models. |
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Keywords: | Akaike's Information Criterion Canada habitat loss and fragmentation Mixed-effects models Mixed-grass prairie Model selection Nest success Prairie birds Spatial scale |
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