Avifauna Assemblages in Sand Shinnery Oak Shrublands Managed with Prescribed Fire

Abstract

Sand shinnery oak (Quercus havardii) shrublands are estimated to have once occupied 5−7 million ha across the southwestern United States. As a result of herbicide and plowing, this endemic vegetation community has been significantly reduced in extent. Further, sand shinnery oak shrublands were historically maintained by relatively frequent fires, but recent fire suppression has resulted in substantial changes in plant community composition and structure where this vegetation type remains. Few studies have been conducted to determine wildlife species composition and richness in remaining sand shinnery oak shrublands and how management practices, such as fire, may influence species occurrence. In this study, we conducted breeding bird surveys in an intact sand shinnery oak shrubland managed with prescribed fire in western Oklahoma to describe the breeding bird assemblage and evaluate the effects of prescribed fire on species abundance. We found the breeding bird community varied along a gradient of sites with high tree/tall shrub density to more open sites dominated by grasses and sand shinnery oak. Bird species richness increased with higher tree/tall shrub densities and declined with greater cover of grasses, shrubs, and bare ground. The 10 most common bird species displayed a range of responses to prescribed fire. Species such as northern bobwhite (Colinus virginianus) and field sparrow (Spizella pusilla) had their greatest relative abundance in recently burned patches, and species such as painted bunting (Passerina ciris) and Bewick's wren (Thryomanes bewickii) were most abundant in patches that were > 36 mo post fire, with many of the remaining species having peak abundance in intermediate times since fire. Our findings show prescribed fire can be used to create a diversity of vegetation structure that provides habitat for multiple shrubland and grassland bird species. However, factors such as tree density and precipitation may influence the response of bird species to prescribed fire.