Fragmentation from agriculture and sprawl is ‘dooming species to extinction’
Laura Ingalls Wilder’s beloved series of novels about life in the American frontier begins in Wisconsin with the novel Little House in the Big Woods. Less than a hundred years since its publication, a study in Conservation Biology finds that these Midwestern ‘big woods’ are experiencing a worse-than-expected decline and would likely be unrecognizable to Wilder herself.
The new study of forest patches in Wisconsin finds that the temperate forests are losing abundance and diversity of native species due to increasing land-use changes and fragmentation. Bordering Canada, Wisconsin is apart of the Midwest region of the United States where temperate forests were first felled for agriculture beginning in the 1800s. Since then remaining forests have been lost due to housing developments, sprawling suburbs, roads, and strip malls.
Researchers from the University of Wisconsin, Madison looked to the forest floor—surveying shrubs, grasses, and herbs—to determine the impact of humans on the ecosystem. Checking their findings against detailed records made by ecologist John Curtis in the 1940s and 1950s, what the researchers discovered was worse than they expected: even when the patches of forests appeared healthy, they were no longer capable of preserving the region’s biodiversity. They found a widespread decline in abundance and diversity of native plants, especially in southern Wisconsin where forests have been increasingly lost due to land-use changes.
“Things may look healthy, but over time we see an erosion of biodiversity,” co-author Don Waller says, a professor of botany
Furthermore, the researchers found that biodiversity was even in decline in state parks and other protected areas.
“These forest patches are not just losing species — their whole biological nature is changing,” says David Rogers, an assistant professor of biological sciences who led the study. “Surrounding landscape factors, like urbanization and agricultural dominance, are now determining which species can survive in these little patches.”
Waller explains that the forests still appear healthy because there has been a time-lapse between the loss of forests and the visible affect on the ecosystem. “When we isolated these forest patches 50 or 100 years ago, we were dooming species to extinction,” he explains. “It may not happen right away — and in that sense it’s an ‘extinction debt’ — but it will accumulate over time.”
The isolation of these forest patches into small islands has made it difficult, if not impossible, for native plants to re-colonize areas where their populations have been lost, according to the researchers. With increasing distance between local plant communities, one community is no longer able to mix with another.
“Plant species might go locally extinct for lots of different reasons,” Waller explains. “But typically the area will be re-colonized very soon by nearby populations of the same species. That’s what does not happen once a habitat becomes isolated or that patch becomes smaller.”
While the researchers have a general idea as to why the forests are hemorrhaging native diversity and abundance, they are working next to determine the specific factors behind the decline.
“People are a really important part of the system,” Rogers says. “We are having a greater influence over our local ecology, whether we want to or not. That puts the responsibility on people to take care of it, protect it and maintain it.”
(05/14/2009) A new study shows that mammals in the state of Michigan are moving north because of climate change, pushing out other species on the way. Researchers studied the distribution and population of nine small mammals from live-trapping data over 30 years and notes from research museums covering the past hundred years. They utilized over 14,000 records covering the nine species.
(03/29/2009) Having studied plant communities across three continent and within widely varied ecosystems—lowland tropics, deciduous forests, grasslands, and enclosed ecosystems on hill-tops—graduate student Sasha Wright has gained a unique understanding of shifts in plant communities worldwide as they respond to pressures from land use and global climate change. “Plant communities are certainly changing,” Wright told Mongabay.com in a March 2009 interview. “These changes are undoubtedly affected by an increased occurrence of extreme weather events, temperature fluctuations, atmospheric CO2 concentrations, human land use, and in some cases urbanization of populations.”
(01/27/2009) New home size is shrinking in the U.S., reports the Wall Street Journal.
(10/28/2008) Matt Filsinger is driving his white pickup headed northeast from Sterling to look at two of his projects. This self-described introvert speaks enthusiastically about his job. “Ducks, ducks, ducks, that’s what I love!,” says Filsinger, grinning broadly. Filsinger is a wildlife biologist with the Partners for Fish and Wildlife Program of the U.S. Fish and Wildlife Service. He works with private landowners to set aside land and create attractive habitat for imperiled species. Specifically, he designs wetlands to attract waterfowl. Partners for Fish and Wildlife is a successful program that has been around since 1987. Landowners, including farmers and ranchers, form partnerships with the program because they reap a variety of benefits from it. Nonprofit organizations such as Ducks Unlimited, Audubon and the Rocky Mountain Bird Observatory are also partners. Collaboration between the federal government and private landowners is essential to preserving habitat and species, as 73 percent of the country’s land is privately owned, and most wildlife lives on that land.