Climate change causes declines and greater extremes in wetland inundation in a region important for wetland birds

Abstract

Wetland ecosystems are vital for maintaining global biodiversity, as they provide important stopover sites for many species of migrating wetland‐associated birds. However, because weather determines their hydrologic cycles, wetlands are highly vulnerable to effects of climate change. Although changes in temperature and precipitation resulting from climate change are expected to reduce inundation of wetlands, few efforts have been made to quantify how these changes will influence the availability of stopover sites for migratory wetland birds. Additionally, few studies have evaluated how climate change will influence interannual variability or the frequency of extremes in wetland availability. For spring and fall bird migration in seven ecoregions in the south‐central Great Plains of North America, we developed predictive models associating abundance of inundated wetlands with a suite of weather and land cover variables. We then used these models to generate predictions of wetland inundation at the end of the century (2069–2099) under future climate change scenarios. Climate models predicted the average number of inundated wetlands will likely decline during both spring and fall migration periods, with declines being greatest in the eastern ecoregions of the southern Great Plains. However, the magnitude of predicted declines varied considerably across climate models and ecoregions, with uncertainty among climate models being greatest in the High Plains ecoregion. Most ecoregions also were predicted to experience more‐frequent extremely dry years (i.e., years with extremely low wetland abundances), but the projected change in interannual variability of wetland inundation was relatively small and varied across ecoregions and seasons. Because the south‐central Great Plains represents an important link along the migratory routes of many wetland‐dependent avian species, future declines in wetland inundation and more frequent periods of only a few wetlands being inundated will result in an uncertain future for migratory birds as they experience reduced availability of wetland stopover habitat across their migration pathways.

Associations with landscape and local‐scale wetland habitat conditions vary among migratory shorebird species during stopovers

“…Depressional wetlands, such as those found throughout our study area, are particularly vulnerable to climate‐induced changes in precipitation patterns and drought (Mitsch and Gosselink 2015, Uden et al 2015, Londe et al 2022). In fact, seasonal and interannual weather fluctuations have already been shown to dramatically change the extent of shorebird habitat across the landscape between years and migration periods (Albanese and Davis 2012, Steen et al 2018), and these dramatic fluctuations in availability of shorebird habitat will only be exacerbated by climate change due to reduced wetland inundation (Uden et al 2015, Reese and Skagen 2017, Londe et al 2022, 2023). This is important to consider in the context of our findings because, given the strong association of most species with broad‐scale wetland availability and density, landscapes with sufficient densities of wetlands may become increasingly rare or unpredictable for migrating shorebirds as climate change decreases numbers of inundated wetlands in the future.…”

“…This region experiences highly variable seasonal and annual weather patterns, including extreme wet and dry periods (Woodhouse and Overpeck 1998), which can greatly influence the extent, hydroperiod (i.e. duration and permanency of wetland inundation), spatial distribution, and connectivity of wetlands (Albanese et al 2012, Albanese and Haukos 2017, Londe et al 2022, 2023). During spring and fall study periods, average monthly temperature was 14.4°C and 23.0°C, respectively, and average monthly precipitation was 10.1 cm and 8.8 cm, respectively (Oklahoma Climatological Survey 2011).…”

“…The Great Plains region has experienced particularly severe wetland losses attributed mostly to agricultural conversion (Johnson et al 2010, Dahl 2011), and remaining Great Plains wetlands are under threat from agricultural intensification, land cover change, and increasing human demand for water (Johnson et al 2010, Moomaw et al 2018). New challenges posed by climate change, including warming temperatures, greater evapotranspiration, and more variable precipitation (Kloesel et al 2018), are also anticipated to further reduce frequency and duration of wetland inundation, leading to reduced wetland availability for migratory shorebirds (Uden et al 2015, Londe et al 2022, 2023). To address these threats, multiple conservation efforts have worked to protect, restore, and rehabilitate wetlands throughout the Great Plains; however, many of these efforts have focused primarily on creating and protecting habitat for migratory waterfowl (e.g.…”