Isolated forest patches lose species,...( MADISON Failing to see the forest f...)

MADISON Failing to see the forest for the trees may be causing us to overlook the declining health of Wisconsin's forest ecosystems.

Even areas with apparently robust trees and lush canopies are threatened as forests are increasingly fragmented by roads and development, becoming isolated green islands in a sea of agricultural fields, housing tracts, and strip malls, say University of Wisconsin-Madison researchers.

A new study is revealing that decades of fragmentation of Wisconsin's forests have taken a largely unseen toll on the sustainability of these natural ecosystems.

The long generation times of trees and other plants have masked many of the ecological changes already under way in the patches of forest that remain, says study co-author Don Waller, a professor in the Department of Botany and Nelson Institute for Environmental Studies at UW-Madison. "Things may look healthy, but over time we see an erosion of biodiversity," he says.

To better catalog the changes at work, he and colleagues looked beyond the trees to the forest understory the shrubs, grasses and herbs covering the forest floor to witness how Wisconsin's forests are really faring. Their results, published online June 8 and appearing in an upcoming issue of the journal Conservation Biology, show that fragmentation is reducing the abundance and diversity of native plants in southern Wisconsin forests.

The findings highlight the effects of increasing urban development and road density, especially in the southeastern part of the state. Land use changes have a pronounced impact on the islands of forest that remain, even when these are protected as parks or natural areas.

"These forest patches are not just losing species their whole biological nature is changing," says David Rogers, an assistant professor of biological sciences at UW-Parkside who led the study while a UW-Madison graduate student. "Surrounding landscape factors, like
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