According to a study published on Thursday, around 58 percent of the land on earth has declined to below the biodiversity safe limit, says The Christian Science Monitor. This decline is attributed mainly to human land practices.
A diminishing biodiversity makes the ecosystem vulnerable to factors such as the extinction or migration of a species and could threaten the food chain, causing the ecosystem to collapse. Biodiversity also plays an integral role in factors such as crop pollination, nutrient cycling, soil erosion control, waste decomposition, and carbon cycle regulation among others.
"The Newbold study is a huge step in our ability to quantify and to understand biodiversity, the next step is trying to reduce the uncertainty about what the decline in biodiversity might mean for humans," said Tom Oliver, associate professor of landscape ecology at the University of Reading in England.
The study was based on a Biodiversity Intactness Index (BII). It was assumed that any area that had experienced a decline of over 10 percent in species abundance is in the biodiversity "danger zone," where it is feared an extinction of one species would cause a domino effect, resulting in a system collapse.
Dr. Newbold studied a total of 39,100 species across 18,600 locations, finding that 58 percent have dropped below 90 percent, with only 84.6 percent of original species left. When the emergence of new species is considered, a net decline in global diversity is still in excess of 12 percent.
"What falling below the boundary means is that we are entering a space where we are not sure what the consequences will be," Newbold said. "We don't know if we will see problems immediately, but we know that biodiversity is important for making sure that ecosystem functions continue into the future even when the environment changes."
What Newbold also found was that areas with less human interference were less likely to experience a significant decline in their biodiversity. Areas such as the northern tundras and parts of the Amazon Rainforest were less affected than areas such as central North America, which has less than 60 percent of its original biodiversity intact.
"There are also impacts for just the everyday person," Dr. Oliver says. "Whether we know it or not, the environment around us impacts our psychological well-being and although we may be able to survive in reduced conditions in terms of simplified biodiversity, for humans to actually thrive it is going to become much more apparent that an intact nature and a high level of biodiversity can promote that psychological well-being."
The impact on the economy and on the individual will be the two factors most important in encouraging government and people to take positive steps towards fighting the decline of biodiversity.
"We can try to preserve what is left of the natural habitat by creating protected areas and we can also where possible try to restore natural habitat," said Newbold. "People should care, if not for biodiversity's sake itself, because we know that biodiversity supports a lot of important functions, a lot of things we as humans rely on."
The study has received some criticism as it is hard to estimate how some ecosystems were originally, and there is no hard scientific basis that a biodiversity "danger zone" exists, with some scientists saying the results of the study should be taken with caution. It has, however, set a foundation on which more research can be done as to which areas have been most affected and what steps need to be taken to prevent further decline.
[Photo by Damian Dovarganes/AP Images]