Thesis (Ph.D.)--Mississippi State University, 2011
Periodic disturbance in CP33 habitat buffers is required to maintain early-successional plant communities for grassland birds. However, effects of disturbance on habitat suitability and nesting success of grassland birds are unknown. Furthermore, the grassland bird community and reproductive performance in CP33 habitat buffers may be influenced by the landscape context (e.g., edge habitat, surrounding land cover). My objectives for this study were to determine how periodic disturbance and the agricultural landscape mosaic influence the breeding grassland bird community in buffers, and how these same factors influence grassland bird nesting success and density in buffers
Data collected during line-transect surveys conducted in CP33 habitat buffers in northeast Mississippi during the 2007-2009 breeding seasons demonstrate periodic disturbance through prescribed burning and light strip-disking does not influence breeding bird diversity or density in buffers. Buffers with woodland at the non-crop edge, however, had the least grassland bird diversity. Dickcissels, one of the most abundant grassland bird species detected in buffers, had a lesser, though non-significant, density in woodland-bordered than in grassland-bordered buffers
I estimated nest success of Dickcissels and Red-winged Blackbirds using maximum likelihood approaches modeling daily survival rates of nests in Program MARK. Analysis results indicated periodic disturbance did not inform models of nest success for either species to an extent requiring inclusion in the best approximating model. Both species, however, had greater nest densities in control and burned buffers than in disked buffers, as well as adjacent to grassland and crop edges. Dickcissel nest success was associated negatively to proximity of developed areas and amount of land cover in crop production, and associated positively with nest height. Red-winged Blackbird nest success decreased with increasing distance from a crop edge and decreasing height of surrounding vegetation, but increased with greater amounts of ground cover
Results from this study will assist land managers with selecting land for enrollment in CP33 that will maximize producers' conservation goals while minimally impacting crop production, as well as assist with development and refinement of USDA-NRCS Practice Standards, documentation of ecological benefits of federally subsidized conservation practices, and enhancement of wildlife benefits in agriculture-dominated landscapes
