Nebraska: Wetland Studies Provide Insight into Bird Habitat in a Changing Climate

During spring migration, as shorebirds, waterfowl and waterbirds make their way from wintering habitats to their northern breeding grounds, the broad Central flyway migratory corridors constrict in central Nebraska, funneling millions of birds through the state’s Rainwater Basin Wetland Complex. 

Rainwater Basin wetlands are shallow playa wetlands that fill each spring with snowmelt.  The flooded wetlands provide critical foraging habitat for millions of waterfowl and shorebirds annually.  While in the Rainwater Basin, birds acquire significant energy and nutrient reserves that they will need to continue migration and initiate nesting.   

In addition to providing critical resting habitat for birds, Rainwater Basin wetlands are the major source of groundwater recharge to the region’s aquifer – meaning they help replenish underground water, ensuring a sustainable supply for birds and humans.

During the past decade, the Rainwater Basin Joint Venture has acquired geo-referenced aerial photographs and is analyzing them in a Geographical Information System to monitor and delineate available habitat and contemporary wetland function.  With funding provided by the Great Plains Landscape Conservation Cooperative, joint venture scientists and their colleagues with Nebraska Game and Parks Commission and the Nebraska Cooperative Fish and Wildlife Research Unit are analyzing these data in the context of climate change. 

Current climate models project increases in temperature and winter precipitation and decreases in summer precipitation for this region during the next century.  Both maximum and minimum temperatures are projected to rise, with minimum temperatures showing the greatest increases.  It is also expected that a higher percentage of precipitation will come during major storm events. 

Based on the preliminary results of climate-based habitat assessments, this could be catastrophic for Rainwater Basin wetlands.  Current results suggest a strong relationship between flooded wetland habitat during spring migration and cold season (October – February) temperature, precipitation, and annual snow storage.  Higher winter temperatures would reduce snow storage, increase evaporation, and ultimately reduce surface runoff that fills these wetlands just prior to migration. 

“Because of this sensitivity to temperature and precipitation, we expect that climate change will cause the Rainwater Basin wetlands to undergo changes in both ponding duration and frequency during spring migration,” said Andy Bishop, coordinator for the Rainwater Basin Joint Venture.  “As a result, the joint venture has prioritized several conservation actions to help the landscape adapt to changing conditions.” 

Last year, a watershed initiative was developed to remove concentration pits, plug surface drainages and recontour waterways, all of which will improve hydrologic function of the watersheds that fill Rainwater Basin wetlands.  These actions will enable hydrologic function and increase resilience of these wetlands to climate change. Building resilience into the system will in turn ensure that even in drier, warmer climates, wetlands will have some level of function to support the millions of birds that depend on this region every spring, providing connectivity between the birds’ wintering and breeding grounds.

Author: Andy Bishop, Rainwater Basin Joint Venture Coordinator

 

This article re-posted from US Fish and Wildlife Service's Open Spaces blog. The USFWS will be posting new stories about climate impacts every day for 50 days. 

Photo: Long-billed Dowitchers feeding. Joel Jorgensen, Nebraska Game and Parks Commission.