Too many Deer = Wisconsin Enviromental Disaster
Study finds North Woods losing native species 11:30 PM 6/09/04 Ron Seely Wisconsin State Journal
Biologists at UW-Madison have studied sites in a 1950s plant survey of Wisconsin's North Woods and found a changed world. (
Tramping the same parcels that famed UW-Madison botanist John T. Curtis explored 50 years ago, modern-day botany researchers have found that native species are disappearing at an alarming rate and invasive species are altering the landscape. (
The findings appear in the June issue of the journal Conservation Biology. The study was done by UW-Madison botanist Don Waller and botany students Tom Rooney and David Rogers. (
The work is scientifically important, according to Waller, because it is among the first studies in the world to thoroughly document one example of what many scientists believe is the sixth and latest mass extinction event in the history of the Earth. (
But for those who simply enjoy spending time in Wisconsin's green north country, the study is further proof that the landscape from which the state derives a big part of its identity is changing, perhaps forever. (
"Things are vanishing before our eyes," says Waller. "The natural world is getting less interesting." (
The study blames high deer populations, development and the dramatic spread of non-native species for the changes, although Waller said climate change, the very gradual warming of the north country, may also be a factor. Interestingly, sites surveyed on tribal reservations, where development is better controlled and deer herds are smaller due to year-round hunting, showed an actual increase in native species. (
By studying plant growth on the same 62 sites across northern Wisconsin that Curtis studied, the botanists were able to compare their survey data with the earlier information, kept safely all these years in gray file cabinets in Birge Hall. (
They discovered: On average, each site surveyed had lost nearly 20 percent of its native plants from 50 years ago. (
Species diversity declined at 45 of the 62 sites surveyed. (
Invasive species showed up on two-thirds of the sites resurveyed. Fifty years ago, they appeared only on one site. (
Areas faring the worst are those where hunting is restricted, such as Brunet Island State Park in northwest Wisconsin. A native plant called the rosy twisted stalk had declined by 80 percent there, largely because of heavy deer browsing. ( The study is already getting the attention of natural resources managers in Wisconsin and elsewhere, according to Darrell Zastrow, a forest ecologist with the Department of Natural Resources. Information on the impact of deer as well as the threat of invasive species will be especially useful for planning, he said. (
"I do think this is going to be a very significant paper that's referred to a lot," Zastrow said. (
Waller said no studies have looked at such an extensive number of sites to survey plant losses. Such studies are important, he added, if scientists are to understand what some believe is a slow, worldwide extinction of plants and animals, driven by human impacts, that would rate as the sixth-largest mass extinction in the history of the Earth. (
The more immediate impact, however, is simply the alteration of a much-beloved landscape. (
"People flock to northern Wisconsin because it is a beautiful environment," Waller said. "They come for the lakes and for the forests. But it's changing and they don't even know it. (
"People don't go to the North Woods to see garlic mustard." (