Conserving Diverse Wet Habitats Keeps Western Rangelands Resilient

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Some mesic habitat is found at higher elevations where it supports wildflowers and other plants that are important for wildlife. Photo: Jeremy Maestas.

New research highlights the importance of wet mesic habitats for sage grouse and other species

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The western sagebrush ecosystem is governed by a semi-arid climate. Vegetation productivity is limited by periodic drought, which makes wet mesic habitats critical for sage grouse and other wildlife. Wet mesic habitats in the Rocky Mountains, Great Plains and Great Basin include riparian areas, wet meadows, irrigated alfalfa fields, and productive rangelands.

During periods of drought, many wildlife, including sage grouse, seek out these last islands of productive green areas. Collaborative whole-watershed conservation strategies that protect a diversity of mesic resources across public and private lands are key to maintaining healthy sage grouse populations.

Wildlife rely on access to different types of wet mesic habitats, such as low-elevation agricultural wetlands during dry years (photo left) and productive high-elevation rangelands during wet years (photo right). Photo credits: Patrick Donnelly, USFWS (left) and Andrew Olsen, Oregon State University (right).

Researchers from the University of Montana and the U.S. Fish and Wildlife Service used more than 15,000 satellite images to analyze late-season (mid-July to mid-September) vegetation productivity across western rangelands from 1984-2016. They then linked these summertime productivity patterns to annual variations in climate and categorized the results into irrigated alfalfa, rangeland, riparian areas, or wet meadows. Finally, they examined land tenure data, which allowed them to detail the proportional mesic abundance by ownership type in three western regions: the Great Basin, the Rocky Mountains, and the Great Plains.

For a great visual of mesic resources, check out our Interactive Map and toggle the mesic resources layer under the ecosystems tab.

Sage grouse populations are partially structured by drought sensitivity, that is the bird’s populations generally boom during wet years when green vegetation is widely available and constrict when these resources are scare during times of drought (which can include the hot, dry summer months).

“Drought-resilient riparian areas and wet meadows provide green refuges that keep sage grouse and other animals alive when water is scarce. But when rain and snow are plentiful, productive upper-elevation rangelands helps populations grow.”

-Patrick Donnelly, IWJV/USFWS

Because of this, wet mesic resources that provide food during drier times play an important role in supporting sage grouse populations. Basically, the landscapes with the highest abundance of wet mesic habitats support the largest sage grouse populations.

Privately owned wet meadows and riparian areas in valley bottoms remain productive in late summer as opposed to high-elevation public rangelands that dry out during drought. Map: Nevada, Credit: Patrick Donnelly, USFWS

This sweeping analysis pinpoints the most productive (and important to sage grouse) habitats across the west, providing a new tool for informing where to invest in mesic resource conservation. For example, in the Great Plains, 87% of wet meadows are found on private lands while 66% of productive rangeland is found on public lands. In sagebrush country, privately owned parcels contain 68% of all mesic resources, even though private lands only make up 40% of the landscape.

This information helps agencies like the USDA Natural Resources Conservation Service most effectively target sage grouse conservation projects. NRCS offers technical assistance for private landowners looking to improve mesic resources like wet meadows and riparian areas – key mesic habitats on private lands. Meanwhile, the Bureau of Land Management can target its mesic conservation efforts on removing encroaching conifers in upper-elevation rangelands across sagebrush country – rangelands that are more likely to be public land.

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