The importance of range edges for an irruptive species during extreme weather events

Landscape Ecology
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Threats to wildlife species from extreme events, such as droughts, are predicted to increase in frequency and magnitude with climate change. Extreme events can cause mortality and community-level changes, but for some mobile species, movement away from areas affected may be a viable option.


We examined the effect of extreme weather on spatial patterns of abundance for an irruptive grassland bird species, the Dickcissel (Spiza americana).


We calculated route-level annual abundances and abundance anomalies from 1980 to 2012 from North American Breeding Bird Survey data, and classified the Dickcissel’s range into core and edge regions using these abundances. We then compared abundances in the core and edge regions to the standardized precipitation evapotranspiration index, a measure of drought, in linear regressions.


We found that Dickcissel irruptions in the northern range edges were related to drought conditions in the range core, potentially a consequence of birds being ‘pushed’ to the range edge when weather was unsuitable. Specifically, Dickcissels moved into refuge sites containing a high proportion of cultivated crops, with higher vegetation greenness, than those areas they leave during drought years.


In a changing climate where more frequent extreme weather may be more common, conservation strategies for weather-sensitive species may require consideration of habitat in the edges of species’ ranges, even though non-core areas may be unoccupied in ‘normal’ years. Our results highlight the conservation importance of range edges in providing refuge from extreme events, such as drought, and climate change.

Publication type Article
Publication Subtype Journal Article
Title The importance of range edges for an irruptive species during extreme weather events
Series title Landscape Ecology
DOI 10.1007/s10980-015-0212-6
Volume 30
Issue 6
Year Published 2015
Language English
Publisher Springer
Contributing office(s) Upper Midwest Environmental Sciences Center
Description 16 p.
First page 1095
Last page 1110
Online Only (Y/N) N
Additional Online Files (Y/N) N
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