Ecological Water Stress under Projected Climate Change across Hydroclimate Gradients in the North-Central United States

Abstract

Water balance influences the distribution, abundance, and diversity of plant species across Earth’s terrestrial system. In this study, we examine changes in the water balance and, consequently, the dryland extent across eight ecoregions of the north-central United States by quantifying changes in the growing season (May–September) moisture index (MI) by 2071–99, relative to 1980–2005, under three high-resolution (~4 km) downscaled climate projections (CNRM-CM5, CCSM4, and IPSL-CM5A-MR) of high-emission scenarios (RCP8.5). We find that all ecoregions are projected to become drier as based on significant decreases in MI, except four ecoregions under CNRM-CM5, which projects relatively more moderate warming and much greater increases in precipitation relative to the other two projections. The mean projected MI across the entire study area changes by from +4% to −33%. The proportion of dryland (MI < 0.65) is projected to increase under all projections, but more significantly under the warmer and drier projections represented by CCSM4 and IPSL-CM5A-MR; these two projections also show the largest spatial increases in the arid (33%–53%) and hyperarid (135%–180%) dryland classes and the greatest decrease in the dry subhumid (from −56% to −88%) dryland class. Among the ecoregions, those in the semiarid class have the highest increase in potential evapotranspiration, those in the nondryland and dry subhumid class have the largest decrease in MI, and those in the dry subhumid class have the greatest increase in dryland extent. These changes are expected to have important implications for agriculture, ecological function, biodiversity, vegetation dynamics, and hydrological budget.

Climate Change and More Disturbed Land-Use Types will Further the Invasion of a Non-Native Annual Grass, Ventenata Dubia

“…Climate predictors for the future period from 2011-2040 were averaged from a warm and dry climate scenario predicted by CCSM4 GCM. The CCSM4 moderately captures overall spread of future projections of temperature and precipitation changes across the study area (Adhikari et al 2019a).…”

The patchwork governance of ecologically available water: A case study in the Upper Missouri Headwaters, Montana, United States

“…Humans rely on water for drinking and household use, agricultural production, energy generation, industry, navigation, and recreation. Like people, non‐marine species and ecosystems require freshwater for a wide range of physiological and habitat requirements and are increasingly at risk due to declines in the quality and quantity of available water (Adhikari et al, 2019; Jackson et al, 2001; Sabater et al, 2018; Vörösmarty et al, 2010). Regardless of whether a water shortage results from meteorological drought or anthropogenic drivers, when water is scarce, not all demands can be satisfied.…”

Nossana Spring (Northern Italy) under Climate Change: Projections of Future Discharge Rates and Water Availability

“…With the ongoing climate modeling experiments-for example, the Coordinated Regional Climate Downscaling Experiment (CORDEX, http://www.cordex.org/), WorldClim dataset project (http://www.worldclim.org/), and the Climate Change, Agriculture, and Food Security research program (CCAFS, http://ccafs-climate.org/downscaling/)---future climate projections are made available over several domains worldwide with a horizontal resolution of up to 12.5 km. Some studies (e.g., [49,50]) demonstrated that dynamical downscaling can be applied to achieve an even larger detail (≤4 km). However, these methods are computationally very intensive and often show performance losses over complex terrains [46,51].…”