A recent study published in the journal Scientific Advances, investigates the effects on ecosystems of habitat fragmentation occurring around the world. This research, led by scientists at North Carolina State University and made up of more than 12 collaborating research teams globally, has found that 70% of existing forested lands are within a half mile of the forest edge. This subjects the habitat to encroachment from agricultural, suburban and urban influences which can negatively affect inhabiting plants and animals.
Covering many different types of ecosystems this studying reflects an unsurprising but still disheartening trend, from forests to savannas to grasslands to forests and more, fragmentation causes losses of plants and animals, changes how ecosystems function, reduces the amounts of nutrients retained and the amount of carbon sequestered, among other deleterious effects.
This study has been monitoring 7 projects on 5 continents to assess the impact habitat fragmentation has on ecosystem health and biodiversity. Results indicate that biodiversity is reduced between 13 and 75 percent when habitat is non contiguous, with the most severe impacts occurring in the smallest, most isolated fragments. Researchers used data collected to assemble a global map of forest cover and found that little continuous habitat remains that has not affected by some type of human development.
Dr. Nick Haddad, William Neal Reynolds Distinguished Professor of Biological Sciences at NC State, co-author of the paper explains, “”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. [However] The results were astounding. Nearly 20 percent of the world’s remaining forest is the distance of a football field — or 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.”
The NC State led study went even further as to include ongoing major experiments on fragmented land, some were more than 30 years old. While the results were initially what the team was expecting, they were surprised by the seemingly cumulative negative effects of habitat fragmentation; Dr. Haddad continues, “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.”
There are some possible methods to mitigate the negative effects of habitat fragmentation, such as; conserving and maintaining larger areas of habitat; utilizing landscape corridors, or connecting fragments has shown to be effective in achieving higher biodiversity and better ecosystem function; increasing agricultural efficiency, as well as focusing on improving urban design efficiencies. However, reversing the trend is a daunting, if not impossible, task and the results of this study should prove a wake-up call.
Nick M. Haddad et al. “Habitat Fragmentation and its Lasting Impact of Earth’s Ecosystems” Science Advances, March 2015 DOI: 10.1126/sciadv.1500052