No abstract

Stopover use by migrating shorebirds is affected by patch-level characteristics of habitat, but the relative influence of broadscale factors is poorly understood. We conducted surveys of ten -km-radius landscapes in north-central Oklahoma from  through  to examine the influence of the amount and composition of wetland habitats and surrounding land cover on shorebird use during migration. We used generalized linear modeling and an information-theoretic framework to identify factors that best explained species richness, total abundance, and abundance of four groups of shorebirds classified by breeding status and migration distance. Total abundance and richness both increased with the area of wetland habitat within a landscape, regardless of the composition of semi-natural and developed land cover surrounding wetlands. Abundance of shorebird species with different migration strategies varied in relation to the composition of wetland types within a landscape. The amounts of various permanent and semi-permanent wetlands best explained abundance of resident species. Short-distance migrant abundance was best explained by the amount of permanent lacustrine wetlands. The amounts of temporary and semipermanent floodwater habitats were important predictors for abundance of intermediate-and long-distance migrants, although permanent riverine habitats were also important for intermediate-distance migrants. Shorebird species richness was best explained by the amounts of floodwater habitats and permanent riverine wetlands. Broad-scale studies thus provide important insights on use of stopover habitats by migratory shorebirds. Within this region, conservation of riverine habitats with a large complement of ephemeral habitats is necessary to provide the stopover habitat for migrating shorebirds.

No abstract

Within interior North America, erratic weather patterns and heterogeneous wetland complexes cause wide spatio-temporal variation in the resources available to migrating shorebirds. Identifying the pattern-generating components of landscape-level resources and the scales at which shorebirds respond to these patterns will better facilitate conservation efforts for these species. We constructed descriptive models that identified weather variables associated with creating the spatio-temporal patterns of shorebird habitat in ten landscapes in north-central Oklahoma. We developed a metric capable of measuring the dynamic composition and configuration of shorebird habitat in the region and used field data to empirically estimate the spatial scale at which shorebirds respond to the amount and configuration of habitat. Precipitation, temperature, solar radiation and wind speed best explained the incidence of wetland habitat, but relationships varied among wetland types. Shorebird occurrence patterns were best explained by habitat density estimates at a 1.5 km scale. This model correctly classified 86 % of shorebird observations. At this scale, when habitat density was low, shorebirds occurred in 5 % of surveyed habitat patches but occurrence reached 60 % when habitat density was high. Our results suggest scale dependence in the habitat-use patterns of migratory shorebirds. We discuss potential implications of our results and how integrating this information into conservation efforts may improve conservation strategies and management practices.