Linking snake habitat use to nest predation risk in grassland birds: the dangers of shrub cover

摘要: Extremes in rangeland management, varying from too-frequent fire and intensive grazing to the suppression of both, threaten ecosystems worldwide. Intensive denude homogenize vegetation whereas their increases woody cover. Although habitat loss is implicated grassland bird declines, degradation through management or neglect also decreases breeding may reduce nesting success increased rates nest predation. Snakes are important predators, but little known about how use snakes relates predation risk for birds within tallgrass prairie subjected different frequencies. We evaluated survival context used by songbirds two bird-eating snakes, eastern yellowbelly racer Coluber constrictor flaviventris Great Plains ratsnake Pantherophis emoryi. Daily decreased with increasing shrub cover decreasing height, which characterize grasslands that have been neglected intensively managed, respectively. Discriminant function analysis revealed snake habitats were characterized higher cover, successful nests more likely occur areas tall grass forbs reduced Because often habitat, be at addition other predators (e.g., mid-sized carnivores avian predators). Depredated occurred outside discriminant space indicating ground squirrels Spermophilus spp. bullsnakes Pituophis catenifer) denuded Targeted removal shrubs increase minimizing activity attracted