research suggests shrinking forest habitats could be a major problem for ecosystems across the globe.

The findings show 70 percent of existing forest lands are within a half mile of a forest edge, meaning they are more likely to be influenced by urban, suburban, and agricultural effects that can kill off species, the National Science Foundation reported.

"The results are stark," said Doug Levey, program director in NSF's Division of Environmental Biology and a co-author of the paper. "No matter the place, habitat or species, habitat fragmentation has large effects, which grow worse over time."

To make their findings the researchers assembled a map of global forest cover, revealing most forest land across the globe is subject to some form of human influence. They also determined that habitat fragmentation reduces plant and animal species diversity by between 13 and 75 percent.

"Nearly 20 percent of the world's remaining forests are the distance of a football field--or about 100 meters--away from forest edges. Seventy percent of forest lands are within a half-mile of forest edges. That means almost no forests can really be considered wilderness," said Nick Haddad, a biologist at North Carolina State University and corresponding author of the paper.

 The findings show that fragmentation changes the way nutrients are retained by the ecosystem as well as how much carbon is sequestered. Some of the results showed a 50 percent or higher decline in plant and animal diversity over a period of only 20 years.

"Ultimately, habitat fragmentation has harmful effects that will also hurt people," Haddad said. "This study is a wake-up call to how much we're affecting ecosystems--including areas we think we're conserving."

The findings were published in a recent edition of the journal Science Advances.