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Environment | Land

Mountain Meadows Dwindling In The Pacific Northwest

Ask researcher Harold Zald why he’s concerned about shrinking alpine meadows and he gives two reasons. First, he says, meadows are home to a suite of species that aren’t found anywhere else, and it’s important to preserve this pocket of biodiversity.

But Zald is also an avid hiker; he says the high country in the mountains is part of what makes the West, and Oregon, great:

“You feel like you’re on top of the world. You have this gorgeous view, and these wildflowers. And you have space.”

Zald, a post-doc researcher at Oregon State University, recently published a study documenting climate change in Jefferson Park, a 333 acre meadow in the central Oregon Cascades.

He says grasses and wildflowers thrived in the meadow for about 400 years. But in 1950 trees started to sprout, and as the trees matured, they started blocking the sun.

“Alpine aster, black sedge or certain lupines, they can’t survive in a shaded environment under a forest canopy,” Zald said.

If the snowpack melts just a week or two earlier each year, it can allow trees to take root, and other light=loving meadow species to die out.

Mountain bog gentian is
threatened by tree invasion.
Credit: Harold Zald.

The findings of that research, which was funded by the Pacific Northwest Research Station of the USDA Forest Service, were published in the journal Landscape Ecology.

The study suggests meadow species may be able to hang on in some places, even during a period of warming climate. Zald says features of mountain topography- like the shade cast by a ridge line- can have a powerful effect on how long snowpack lingers. Some particularly cold areas will remain unsuitable for trees, providing refugia where meadow species could persist.

Zald says his study of Jefferson Park adds to an established body of research, which began with studies on Mt Ranier in the 1970s, connecting climate change to shrinking mountain meadows in the west. He says in spite of the research, he finds minimal public awareness of the threats to meadows.

“ We focus on older forests, we focus on salmon, and endangered species in areas that are more accessible. But there are a lot of important vegetation types like these meadows, that have really high biodiversity and conservation value, that have simply received much less attention.”

A lidar transect showing how changes in soil type and topography can impact
where trees will begin to grow in an alpine meadow. Credit: Howard Zald

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