Post-fire successional effects on breeding grassland birds in mesquite savanna habitats of the Texas rolling plains

North American grasslands and grassland birds have declined drastically due to\nhabitat degradation by fire suppression (i.e., woody encroachment), fragmentation, and\nconversion to croplands. A better understanding is needed of the relationships among\ndisturbance regimes (e.g., fire), resultant vegetation changes, and grassland bird\ncommunities to effectively manage remaining grasslands and grassland birds. I assessed\nthe relationship between post-fire succession, and mean relative abundance and nesting\necology of breeding grassland birds (i.e., nest-site selection and nest success) in\nmesquite-dominated rangeland of the Texas Rolling Plains, where prescribed fire is used\nas a tool to manage shrub encroachment. Brush cover, grass cover, and visual\nobstruction generally increased with post-fire succession, and bare ground decreased\nwith post-fire succession. Species richness, grasshopper sparrows (Ammodramus\nsavannarum), Cassin’s sparrows (Aimophila cassinii), and dickcissels (Spiza americana)\nresponded positively to post-fire succession, and lark sparrows (Chondestes grammacus)\nresponded negatively to post-fire succession.; abundance of these avian groups was low\non the control sites. During 2004–2005, 90 grassland bird nests were monitored. I\nfound conflicting results for vegetation parameters important to nest site selection and probability of nest success. For all species except lark sparrows, nest-site location was\npositively associated with visual obstruction and with grass or forb cover. However, the\nprobability of nest success increased with lower visual obstruction, bare ground cover, or\ngrass cover. Grassland bird abundance, nest-site location, and nest success had differing\nassociations with vegetation variables. These results suggest that to effectively manage\nremaining grasslands for sustainable breeding grassland bird populations, managers\nshould engage in practices that keep habitat in multiple vegetative successional stages.