Tuesday, August 09, 2016

Sagebrush-covered landscapes keep water on the land

According to the Sage Grouse Initiative (SGI)’s newest Science to Solutions report – which summarized research from USDA’s Agricultural Research Service (ARS) – a sagebrush-dominated watershed holds water in snow drifts an average of nine days longer than one dominated by juniper trees.  Removing invading conifer trees improves the health of sagebrush ecosystems, providing better habitat for wildlife and better forage for livestock. And now, new science shows these efforts may also help improve late-season water availability, which is crucial for ecosystems in the arid West. Researchers with ARS analyzed snow and streamflow data from a snow-dominated sagebrush steppe ecosystem in southwest Idaho to evaluate the impact that juniper-dominated landscapes might have on water availability in the system. They found that areas with more juniper had earlier snow melt and less streamflow relative to sagebrush-dominated landscapes. The water retention in sagebrush systems comes from the increased water storage within snow drifts and delayed release of the melting snow back into the soils. Water delivery is delayed by an average of nine days in sagebrush systems compared to juniper-dominated systems. While many juniper-removal studies have demonstrated value to wildlife species, this research adds an entirely different dimension to the practice – the improvement of ecosystem services provided by sagebrush habitats. Rangelands in the West face harsh, dry conditions with plenty of wind, and in higher elevations the vast majority of precipitation comes in the form of snowfall. Holding water later into the summer season helps the sagebrush system become more diverse, benefiting vegetation, wildlife and ranchers. This is one of the greatest services that an ecosystem can provide in the West, the report notes. Since parts of the sagebrush landscape hold water longer, the soil has more water available later in the season to grow “green groceries” – succulent grasses and wildflowers that make for high quality habitat and grazing lands. This ARS research also shows that snow-covered, sagebrush-dominated watersheds are better at turning limited precipitation into streamflow. Timing of snowmelt influences riparian and wet meadow areas that are critical for many species, including sage grouse, as the arid sagebrush ecosystem dries up during the summer...more

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