Influence of Disturbance on Avian Communities in Agricultural Conservation Buffers in Mississippi, USA

Abstract

Introduction:Periodic disturbance of agricultural conservation buffers is required to maintain early successional plant communities for grassland birds. However, a disturbance may temporarily reduce the availability of vegetation cover, food, and nesting sites in a buffer.Objective:Our objective was to determine how the type of disturbance (i.e., prescribed burning, light disking) and time since the last disturbance event in agricultural conservation buffers influence the grassland bird community.Methods:Data collected during line-transect surveys conducted in 46 agricultural conservation buffers in northeast Mississippi during the 2007-2009 breeding seasons (May-early August) demonstrate periodic disturbance through prescribed burning and light disking does not influence breeding bird diversity or density in the buffers.Results:Density of Dickcissels (Spiza americana), Red-winged Blackbirds (Agelaius phoeniceus), and Indigo Buntings (Passerina cyanea) did not differ in the buffers regardless of the type of or time since disturbance.Conclusion:Large effect sizes, however, indicate a potential type two error resulting from this conclusion. Thus, based on relative effect sizes, avian density in undisturbed buffers may be greater than in buffers during their first growing season post-disturbance. Relative effect sizes among estimates also indicate disturbance, namely prescribed burning, may lead to greater densities of breeding birds in agricultural conservation buffers. Though disturbance may initially reduce avian density, it is necessary to maintain long-term early-successional herbaceous habitat in agricultural conservation buffers.