Wetlands are valuable ecosystems that benefit society. They allow for gradual recharge of groundwater, control erosion, mitigate water pollution, provide water storage, support food and recreational bases for people and play an important role in biogeochemical cycles. Because wetlands are characterized by seasonal or permanent shallow water, they are especially sensitive to changes in precipitation and temperature.

For the past several hundred years and until very recently, wetlands in the United States have been considered to have little value. This has resulted in the destruction of more than half of our wetlands since pre-colonial times, and surviving wetlands are often under a great deal of stress from multiple directions. These compound stressors, combined with sensitivity to changes in precipitation and temperature, make wetlands especially vulnerable to climate change.

While most natural resources managers realize the importance of planning for climate change impacts in their work, the data and tools to do this have largely been unavailable. Because wetlands are so variable and sensitive, it is necessary to have a granular understanding of each one in order to project how climate change will affect it. This project attempts to map and characterize the wetlands of the Columbia Plateau on a fine enough scale that the effects of climate change on them can be anticipated, and to suggest ways that those effects may be incorporated into conservation planning.

We analyzed the flooding and drying patterns of 5,619 wetlands from 1984 to 2011 across the Columbia Plateau Ecoregion. We created this dataset using methods described in past literature. The basic steps are:
1. Reconstruct wetland hydrographs: We used a time series of Landsat satellite imagery from 1984 to 2011 to detect and delineate wetlands and to reconstruct individual wetland hydrographs.
2. Develop wetland-specific regression models: We then used the reconstructed hydrographs along with the Variable Infiltration Capacity hydrologic model to develop wetland-specific regression models for each wetland relating climate variables to changes in wetland inundation.
3. Classify wetlands: Next, we classified wetlands in two ways: by their hydrologic regime—seasonal, permanent, or semi-permanent wetlands—and by the primary hydrologic input—groundwater or surface water.
4. Hindcast and forecast wetland hydrology: Finally, we used the wetland-specific regression models to hindcast and forecast changes in the hydrodynamics of each wetland, from historical data based on 1980s climate to future data based on 2080s climate
5. Estimate change in key wetland dynamics metrics: We examined the changes between hindcast and forecast hydrographs across the Columbia Plateau for maximum annual surface water area, drying frequency, seasonal drying date, and distribution of wetland types.
6. Identify hotspots of management concern: We mapped regional wetland dynamics across the Columbia Plateau using the historical and projected hydrographs. Patterns of change across the landscape provide guidance on which areas or wetland types are likely most vulnerable to climate change impacts.

We would like to thank the Great Northern Landscape Conservation Cooperative and the Northwest Climate Science Center for making this work possible. We would also like to thank the researchers, managers, and regulators from federal and state agencies, tribes, universities, and non-profit organizations who provided inputs and insights during the two workshops we hosted during this project, and in response to our questions and progress updates.

BioScience: Dried Out: Aquatic biodiversity faces challenges in a drying climate
After several hours of climbing up a rocky trail, two researchers with bulging backpacks peer over a high rocky bluff overlooking the still waters of a pair of turquoise lakes. Left behind thousands of years ago as Pleistocene glaciers receded, these watery jewels dotting the Seven Lakes Basin of Washington's Olympic National Park make it hard to imagine that they are anything but pristine. But these peaceful lakes and ponds belie a hidden struggle. As climate change delivers a drying trend to the region, amphibians are being squeezed out of their watery homes.