15 August 2014
Human pressure on land is increasing shows world map
During the past two decades, 64 % of the Earth’s land-based area has experienced an increase in human pressure, shows a new map. It is part of a research study that also reveals agriculture and human settlement to be spreading in protected areas in the mountains, in spite of the more inaccessible terrain. The research is carried out by the Center for Macroecology, Evolution and Climate at the University of Copenhagen.
“We have investigated where on Earth you see the greatest increase or decline of human pressure on land over the past two decades. It provides us with an update on where the changes are greatest and it allows us to assess, for example whether protected natural areas can withstand the pressure or not”, explains Jonas Geldmann from the Danish National Research Foundation's Centre for Macroecology, Evolution and Climate.
Within protected areas, the largest negative change is happening right now on the steeper and higher areas. This is particularly relevant since most of the world's rare and endangered species are located in mountainous regions.
Civilization is making its way into remote natural areas
“From other studies we know that the greatest damages to nature have occurred
in low-lying, accessible areas. That the pressure is now shifting to the more inaccessible areas, we interpret as a sign that natural resources such as timber and land area is being depleted in the lower-lying areas, or that there is not enough to support a growing population”, says Jonas Geldmann about the study, published in the journal Conservation Biology.
The analysis of human pressure is based on changes in human population, crop
land and stable night lights, which is an expression of human settlement. By combining these factors the authors produced a temporal human pressure index (THPI). In total, 64 % of the land surface on Earth has experienced an intensified human pressure over the last two decades. The fact that some areas have experienced a decrease in human pressure is primarily in places where people leave rural areas to move to the cities.
Other sources of pressure such as climate change, forestry, mining and poaching
were not included in the analysis, due to lack of global data appropriate for this context. The authors therefore emphasise that human pressure may have increased significantly more than the study shows in some areas.
Also positive signs
Although the study shows that protected natural areas are under pressure, there
are also positive trends. Neil Burgess from the Centre for Macroecology, Evolution and Climate and the UN Environment Programme UNEP is senior author of the paper. He explains:
“We see that the protected areas in countries with less corruption, better education and a greater understanding of the value of nature is doing better. It may seem obvious, but such a clear relationship has not been shown before. It also means that we see the pressure ease in the more wealthy countries”.
Read the article in Conservation Biology
Post.doc. Jonas Geldmann, Centre for Macroecology, Evolution and Climate, University of Copenhagen