Multi-scale examination of stopover habitat use by migrant shorebirds

Abstract

Scope and Method of Study: Surveys of wetland stopover habitats for migrant shorebirds were conducted within broad-scale landscapes in north-central Oklahoma from 2007 thru 2009. The response of wetland shorebird habitat to weather patterns was examined and a metric was developed to measure changes in the composition and configuration of shorebird habitat within landscapes. I subsequently examined the response of shorebirds to the density of wetland habitats at different spatial scales, the amount of different wetland habitats and peripheral land cover types at a landscape level and intra habitat and habitat context characteristics at a patch level.

Findings and Conclusions: Precipitation, temperature, solar radiation and wind speed best explained the occurrence of wetland habitat, but relationships varied with time and among wetland types. Shorebird occurrence patterns within wetland stopover habitats were best explained by habitat density at a 2 km scale and stopover use increased with habitat density at this scale. The abundance and diversity of shorebirds were positively related to the area of wetland habitat within landscapes regardless of the composition of other land cover types, but relationships with wetland habitat types differed among shorebirds based on migration distance and breeding status. Within wetland stopovers, shorebird abundance increased with habitat area, habitat density and grazing intensity and was negatively related to vegetation structure, dominant slope and some land cover contexts. I conclude that broad-scale factors related to the amount and context of wetland habitat are important to explaining migrant shorebird distribution patterns during their stopover at wetlands in north-central Oklahoma.