PREDICTING CLIMATE CHANGE IMPACTS ON GREAT BASIN WETLANDS, MIGRATORY BIRDS, AND THEIR PREY

Predicted climate impacts on arid U.S. Great Basin wetlands will alter their number, distribution, and quality (e.g., salinity). The scarcity and isolation of these wetlands make them essential not only to wildlife but to ranchers, farmers, and urban areas that rely on their ecosystem services. Great Basin wetlands are important habitats for migratory birds at high volumes but become concentrated mineral brines at low volumes, narrowing waterbird food resources as salinity rises. Thus, resource managers must be able to answer two questions: How will climate change affect migratory bird species dependent on climate-sensitive wetlands? How should management strategies balance human consumer uses of these water resources with the changing requirements of the ecosystems? We are using the following steps to address these issues: (a) determine the spatial extent of the wetland and waterbird network across the Great Basin, (b) determine climate drivers that alter that extent, (c) use DNA markers to measure the level of key aquatic invertebrate species connectivity throughout the network, and (d) estimate how shifting climate drivers will alter the extent and level of connectivity for Great Basin wetland populations and communities.

We began our efforts by monitoring movements of radio-tagged and color-banded shorebirds (Charadriiformes) throughout the annual cycle throughout Great Basin. The nine breeding shorebird species used space in three general ways: some species breed, then move long distances within the region to spend an extended staging period at a few hypersaline sites; others spend an extended postbreeding time at their breeding site prior to migration; the remaining species breed and quickly leave the region. Here, we summarize movement patterns of three species, one from each category. American Avocets (Recurvirostra americana) remained tightly tied to breeding waterbodies but then most flew 100-300 km north where they staged at saline or hypersaline lakes for 3-6 months. Conversely, Killdeer (Charadrius vociferus) remained within 1 km of their freshwater breeding territory, even during a protracted post-breeding period. Intermediate in space-use, Willets (Catoptophorus semipalmatus) spent a short time on freshwater breeding grounds and moved immediately to coastal areas. These movement data provide perspective on wetland connectivity and are being incorporated into broader climate change models that will help develop future wetland conservation plans for the Great Basin and other similar arid areas.