Washington: A new study has revealed that shrinking habitats have adverse effects on world ecosystems.
The North Carolina State University study of global habitat fragmentation, the division of habitats into smaller and more isolated patches, points to major trouble for a number of the world's ecosystems and the plants and animals living in them.
The study shows that 70 percent of existing forest lands is within a half-mile of the forest edge, where encroaching urban, suburban or agricultural influences can cause any number of harmful effects, like the losses of plants and animals.
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, with the largest negative effects found in the smallest and most isolated fragments of habitat.
Researcher Nick Haddad said that it's no secret that the world's forests are shrinking, so this study asked about the effects of this habitat loss and fragmentation on the remaining forests.
Haddad added that the results were astounding as nearly 20 percent of the world's remaining forest is about 100 meters away from a forest edge. Seventy percent of forest lands are within a half-mile of a forest edge. That means almost no forest can really be considered wilderness.
Covering many different types of ecosystems, from forests to savannas 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.
Haddad noted that these negative effects became even more negative with time. Some results showed a 50 percent or higher decline in plant and animals species over an average of just 20 years, for example, and the trajectory is still spiraling downward.
Haddad points to some possible ways of mitigating the negative effects of fragmentation: conserving and maintaining larger areas of habitat; utilizing landscape corridors, or connected fragments that have shown to be effective in achieving higher biodiversity and better ecosystem function; increasing agricultural efficiency; and focusing on urban design efficiencies.
The study is published in Science Advances.