Real wilderness has become rare on our planet. How many unspoiled natural areas with natural animal populations still exist today has now been investigated by researchers using a new approach. According to this, only three percent of the earth’s land area is ecologically untouched. Settlement and protection measures can presumably increase this proportion to 20 percent.
Humans have drastically changed the landscape of the earth over time: wilderness became arable land, rainforests became oil palm plantations and more and more areas are shaped by human structures. This change in land use contributes to the impoverishment of the biodiversity of plants and animals – in some locations even more than climate change. That is why wilderness areas, which are almost untouched by humans, are a priority for the preservation and protection of biodiversity and should be more secured in the future.
How many more untouched areas are there?
But how large is the proportion of wilderness areas worldwide that are still intact habitats? Researchers led by Andrew Plumptre from Cambridge University have now got to the bottom of the question. “We know that intact habitats are increasingly being lost, and at the same time the value of intact habitats has been proven both for biological diversity and for humans,” said Plumptre. Earlier studies on this, however, only related to which land areas are free from major human disturbances such as settlements, roads and light and noise pollution and showed that up to 40 percent of the terrestrial surface is still intact in this regard.
In their study, however, Plumptre and his colleagues chose an expanded approach: Instead of focusing only on human influences, they looked for so-called “Key Biodiversity Areas” (KBA). These are regions that, according to standardized criteria, are considered to be essential for the preservation and protection of animal and plant species. These can be, for example, breeding sites, important resting and wintering areas and areas that are used for foraging. The research team tested these regions according to the so-called criterion C. This means that in an intact ecological community all species known there occur in their natural abundance, so there is no loss of animals in this area. In addition, the scientists also assessed the functional integrity of the regions and thus whether losses in species already impair the healthy function of these ecosystems.
The researchers chose the year 1500 AD as a comparative figure for animal populations, as it is the base date for assessing species extinction in the IUCN’s Red List of Threatened Species. Based on their studies, Plumptre and his team then defined the proportion of areas that today fall under the Key Biodiversity Area Criterion C.
97 percent of the land area not intact
The result: In fact, the number of undisturbed land areas worldwide seems to be lower than previously assumed. The scientists found that only two to three percent of the earth’s land surface can be defined as ecologically intact areas according to criterion C – ten times less than the results of previous studies had suggested. Because these did not take into account the fact that animal populations were also decreasing in many places because they were hunted by humans or lost due to invasive species or diseases, according to the researchers. “Areas that can still be identified as functionally intact include eastern Siberia and northern Canada for boreal and tundra biomes, parts of the tropical forests of the Amazon and the Congo basin, and the Sahara desert,” said Plumptre and his team. However, only eleven percent of these regions are currently considered protected areas. Some of the places identified as undisturbed were in territories administered by indigenous communities, which apparently play a crucial role in the preservation of these areas, as the researchers explain.
Interesting, however, is that only a very small part of the earth can currently be described as intact ecosystems. Nevertheless, the proportion could increase again in the future. “The results show that it might be possible to increase the extent of ecologically intact areas to up to 20 percent through the targeted reintroduction of species that have been lost in areas – provided that the threats to their survival can be addressed “, Explains Plumptre. The research team suspects that if only up to five species are settled in places that have so far been rarely used by humans, completely intact habitats could emerge in these areas again.
Identifying the regions under the Key Biodiversity Area Criterion C can, according to the researchers, help identify the natural areas that should be protected or restored as a priority in the future. “There is a need to recognize those special places within intact habitats that are fully functional and to develop plans to focus restoration on areas where ecological integrity can be rebuilt,” concluded Plumptre.
Source: Frontiers, Article: Frontiers in Forests and Global Change, doi: 10.3389 / ffgc.2021.626635 / full