Shrinking habitats have adverse effects on world ecosystems

As much as 70 percent of existing forest lands are within a half-mile of the forest edge, meaning they are prone to harm from encroaching urban or agricultural influences, warns a new study.

IANS| Updated: Mar 21, 2015, 15:04 PM IST

New York: As much as 70 percent of existing forest lands are within a half-mile of the forest edge, meaning they are prone to harm from encroaching urban or agricultural influences, warns a new study.

The extensive study of global habitat fragmentation, published in Science Advances, points to major trouble for a number of the world's ecosystems and the plants and animals living in them.

The researchers assembled a map of global forest cover and found very few forest lands unencumbered by some type of human development.

"It's no secret that the world's forests are shrinking. Nearly 20 percent of the world's remaining forest is the distance of a football field - or about 100 metres - away from a forest edge," said corresponding author Nick Haddad from the NC State University.

"Seventy percent of forest lands are within a half-mile of a forest edge. That means almost no forest can really be considered wilderness," Haddad added.

The study also tracks seven major experiments on five continents that examine habitat fragmentation and finds that fragmented habitats reduce the diversity of plants and animals by 13 to 75 percent.

Covering many different types of ecosystems, from forests to savannahs to grasslands, the experiments combined to show a disheartening trend: Fragmentation causes losses of plants and animals, changes how ecosystems function, reduces the amounts of nutrients retained and the amount of carbon sequestered, and has other deleterious effects.

"The key results are shocking and sad. Ultimately, habitat fragmentation will also hurt people. This study is a wake-up call to how much we're affecting ecosystems - including areas we think we're conserving," Haddad concluded.