2 july 2019

Great Plains’ Ecosystems Have Shifted 365 Miles Northward Since 1970

Yale Environment 360, July 2, 2019

Ecosystems in North America’s Great Plains have shifted hundreds of miles northward in the past 50 years, driven by climate change, wildfire suppression, energy development, land use changes, and urbanization, according to a recent study published in the journal Nature Climate Change.

The northernmost ecosystem boundary of the Great Plains, for example, has moved more than 365 miles north since 1970, or 8 miles every year. The region’s southernmost ecosystem boundary has shifted 160 miles north, or 4 miles a year.

The study, conducted by scientists at the University of Nebraska-Lincoln, used bird distribution data as an indicator of shifting ecosystem boundaries. Researchers analyzed 46 years’ worth of data for 400 bird species across a 250-mile-wide transect stretching from Texas to North Dakota. The researchers organized the bird species into groups by body mass and looked for gaps in spatial distribution, allowing them to define the boundaries of various ecosystems. They then tracked how the birds’ distributions changed as a measure of how these ecosystems were shifting.

The scientists concluded that climate change has been a major driver of these ecosystem shifts since the 1970s, but said that several other factors — such as wildfire trends, land use changes, and invasion of tree species into grassland habitat — also played a role. “Like most things in ecology, (these shifts) likely have multiple causations,” Craig Allen, an ecologist at the University of Nebraska-Lincoln and co-author of the new study, said in a statement. “And I think it’s fairly intractable to try to separate, say, tree invasion from climate change, because it has to do with fire but also with changing climate. All of these things are highly related.”

Allen and his colleagues say that using bird distribution patterns for tracking ecosystem shifts could be a useful tool for scientists and land managers in the coming decades, giving them an early warning of how habitats are changing in response to rising global temperatures and allowing them to take action to protect vulnerable species.

“If we can work toward prevention (of changes), we’re going to save ourselves so much money and time,” said Caleb Roberts, lead author of the new study and a postdoctoral researcher at the University of Nebraska-Lincoln. “We won’t have to worry about specific endangered species, perhaps, because we will be protecting the system they require.”

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