The Central Valley of California is renowned globally as a critical part of the Pacific Flyway, yet the essential water resources it provides face threats. The Central Valley supports some of the largest concentrations of shorebirds and waterfowl in the world from fall to spring. This is made possible, in part, by managers flooding wetlands and croplands to create the open water habitat these waterbirds require for roosting and foraging. With water supply likely affected by climate change and land use pressures increasing, managers and decision makers want information about the future of this critical habitat.

A new study recently published in Landscape Ecology by USGS and Point Blue scientists provides insight into changes that may occur with future scenarios of climate change and agricultural conversion. These scenarios were based on narratives of the future of the Central Valley created by a broad community of resource managers for the Central Valley Landscape Conservation Project. Spatial models (maps) of these scenarios show that reduced water supply because of increasing drought is the greatest threat to waterbird habitat loss, particularly in January. On the other end of the scenarios’ spectrum, with wetter conditions, greater water supplies could lead to orchard and vineyard expansion at the expense of cropland that has the potential to be flooded for habitat.

Tools for Conservation and Restoration Planning

Given these future threats to Central Valley waterbird habitat, we created an interactive storymap website to support coordinated conservation, wetland restoration, and climate adaptation planning. The website provides a summary of five scenarios of seasonally flooded waterbird habitat that were modeled spatially.  We modeled a Business-as-Usual scenario plus four scenarios that vary by two key themes: water availability and management for conservation.

In the website, users can switch between tabs to see projections of habitat change for individual Central Valley regions, Central Valley Joint Venture planning basins, groundwater sub-basins, or Water Evaluation and Planning (WEAP) model zones. Summary figures display:

• Change in land use and land cover
• Area of wetlands and croplands with high likelihood of flooding
• Change in flooded wildlife habitat in January caused by change in land use and change in water supply

The data behind the figures provide another planning tool. Users can query and filter these tables in Excel to answer different types of questions, such as: Where will land use change most likely impact habitat? Where is water for wildlife habitat more persistent? Which regions are likely to experience the greatest flooded habitat change? To look at one example, in the Colusa Planning Basin in the Sacramento Valley, about 50% more water will be needed to sustain flooded habitat in a dry climate scenario compared to a wet climate scenario.

Finally, maps from the scenario models can be downloaded for custom use. These maps (from years 2011 to 2101) display at 270-meter resolution: (1) the monthly likelihood of flooded cropland and wetland habitat, (2) opportunities for wetland restoration, (3) annual change in urban development and orchard/vineyard expansion, and (4) annual change in row crop conversion and fallowed farmland.

These maps, datasets, and tools were developed with input from multiple stakeholder partners from across the Central Valley to increase their usefulness in decision making. One partner, Samantha Arthur, Working Lands Program Director of Audubon California, describes the value of this project to their work: “With over 90 percent of wetlands in the Central Valley already lost, this project brings new analysis to the critical question of how the last remaining habitat areas for migratory birds are impacted by future climate and water management scenarios. The accessible maps and data outputs enable our organization to zero in on the importance of management actions, such as wetland restoration and prioritizing water supply for wetlands, under potential future climate scenarios, informing our conservation projects and advocacy.”

This website and data releases also contribute to the tools needed to meet California’s “30×30” climate and conservation goals. Tools support these goals by proving insight into possible changes to California’s Central Valley, a high priority region for the state’s 30×30 and natural and working lands strategies.

For a demonstration on the use of the interactive story map website and the data releases, or more information on the study, please contact Kristin Byrd, kbyrd@usgs.gov.

Funding: NASA Applied Sciences Ecological Forecasting Program (#NNX17AG81G), USGS, and The Nature Conservancy