Data Nugget: Stormy Shorelines: Simulating the Effects of Warming and Flooding

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Chevak sits along the Ningliqvak River, about sixteen miles from where the river flows into the Bering Sea. The area around the village is a flat coastal wetland, a landscape of winding river channels, marshes, and saltwater lakes. In the Yup’ik language, this low-lying terrain is called maraq. Here, salt-tolerant grasses and sedges thrive in brackish water, and the wetlands serve as nesting grounds for waterfowl during the spring and summer months.

Higher ground, sitting roughly three meters in elevation, is called nunapik, meaning tundra. Tides or saltwater flooding do not touch these areas, so they hold fresh water and support different plant communities. The tundra is rich with freshwater lakes, berries, and shrubs. Because it experiences less flooding, the upland tundra provides important resources for food and medicine and supports a wider variety of plant species.

However, the landscape is changing. In recent years, coastal flooding near Chevak has become more common. With fewer days of protective sea ice, storm surges and high tides now reach farther inland. These flooding events increase erosion, damage property, and alter the delicate balance of wetland and tundra ecosystems. Western Alaska’s average annual temperature has already increased by 4.3 degrees Fahrenheit over the last 50 years. This warming promotes faster plant growth and helps shrubs expand into new areas, but the combination of warming and flooding creates complex challenges for the plants and animals that live here.

Ecologists Dr. Karen Beard, Dr. Katharine Kelsey, and Dr. Joshua Leffler began studying the plants around Chevak to better understand how these changes affect Arctic ecosystems. They are especially interested in how warming and increased flooding—both separately or together—might shift the kinds of plants that grow in the region. To explore these questions, the scientists designed an outdoor experiment at Old Chevak, the original village site, which was abandoned decades ago due to frequent flooding. Working in collaboration with the Chevak community and the Yukon Delta National Wildlife Refuge, they set up experimental plots to simulate different climate conditions.

At this study site, they examined plant growth at both low and high elevations. In the lowlands, saltwater from storm surges reaches the land more often, encouraging the growth of salt-tolerant sedges. The higher tundra supports a diverse range of vegetation, including important berry-producing shrubs such as salmonberry and tundra tea. In their experiments, the scientists used open-topped chambers to gently warm the plots and pumps, flooding them with brackish water to mimic the effects of climate change.

To understand how plant communities responded, the researchers grouped the vegetation into several categories. Graminoids, which include grasses and sedges, often thrive in salty or wet conditions. Forbs are broadleaf herbs, like salmonberry, that grow in the tundra. Shrubs include species such as blueberries, cranberries, and tundra tea, as well as tundra birch, a larger shrub species. The researchers also tracked standing dead plant matter to calculate the total biomass in each plot.