Species Conservation at a Broad Spatial Scale: Reproductive Success of Golden-Cheeked Warblers Across Their Breeding Range

Authors: A. J. Campomizzi, S. L. Farrell, T. M. McFarland, H. A. Mathewson, M. L. Morrison, R. N. Wilkins

Research conducted near the time a species is listed as threatened or endangered can help inform management guidelines. However, these studies are typically limited in temporal and spatial scope and typically address a limited set of ecological questions. Application of such information can result in misleading management guidelines or ineffective conservation if species-habitat relationships vary across space or if preliminary information fails to provide reliable assessments of habitat quality. We evaluated existing management guidelines that addressed reproductive success of the golden-cheeked warbler (Setophaga chrysoparia), a federally endangered songbird endemic to central Texas, USA. We monitored 1,382 territories in 87 patches of woodland across the breeding range from 2007 to 2011. Ours was the first evaluation of management guidelines addressing reproductive success with data collected across the warbler’s breeding range. Our results did not consistently confirm the commonly accepted management guidelines that habitat quality, based on the presence of offspring in a territory, was positively associated with patch size and territory canopy cover, and negatively associated with patch edge. The relationship between probability of a territory fledging ≥1 offspring and patch size, patch edge-to-area ratio, and territory canopy cover varied by geographic region (level-IV eco-region). Our results suggested future conservation plans that address habitat quality should consider variation among regions to improve conservation efforts and that habitat associations identified with warbler occurrence were not necessarily indicative of reproductive success.

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