And if forests are fragmented, so are vital habitats. Researchers point out that development -- whether urban, suburban or agricultural -- continues to carve up forests, fields and wetlands, and the ecosystems they contain. A single road may not seem like much of an impediment to humans, but a two-lane stretch of pavement can sever a vulnerable piece of habitat.
To quantify habitat fragmentation, researchers at N.C. State used satellite imagery to build a map of global forest cover. Computer analysis showed that very few forests remain unaffected by human development.