- Study used high-resolution satellite data to analyze the extent of forest loss within 3,376 tropical and subtropical forest protected areas in 56 countries spread across four continents.
- Overall, tropical and subtropical reserves with steeper slopes and higher elevations protect forests better, study found. But when the effect of this topographic advantage is removed, protected areas still slow deforestation, although to a lesser extent, researchers found.
- Countries like Australia, South Africa, Mexico, Panama and Thailand have the best performing reserves, while Indonesia, China, Honduras, India, Papua New Guinea, Venezuela and the Philippines have the worst performing protected areas, study found.
Over the last few decades, protected areas in tropical forests have expanded rapidly, both in number and extent. But do protected areas actually reduce deforestation?
According to a recent study published in PLoS ONE, protected areas in the tropics do help slow down loss of forest cover, but their performance varies widely.
Countries like Australia, South Africa, Mexico, Panama and Thailand have the best performing reserves, researchers from the University of Leeds in the United Kingdom have found. In contrast, countries such as Indonesia, China, Honduras, India, Papua New Guinea, Venezuela and the Philippines have the worst performing protected areas.
“There have been a number of previous studies looking at the effectiveness of protected areas,” lead author Benedict Spracklen of the University of Leeds, told Mongabay. “Our study is the first to use high resolution data on forest loss across the whole tropics, and to specifically compare the effectiveness of protected areas across different continents and countries.”
Legally designated national parks, wildlife sanctuaries and nature reserves are thought to be critical to the conservation of tropical forests. But their effectiveness has often been debated.
To find out whether protected areas do slow deforestation in the tropics, Spracklen and his team used high-resolution satellite data to analyze the extent of forest loss within 3,376 tropical and subtropical forest protected areas in 56 countries spread across four continents, over the period 2000 to 2012.
The team found that overall, tropical and subtropical forest reserves with steeper slopes and higher elevations protect forests better. This is most likely due to the difficult terrain and low accessibility of these forests. But even when the effect of this topographic advantage is removed — a subset of 1,804 reserves which have similar elevation and slope within, and immediately outside the reserves — protected areas still slow down deforestation, although to a lesser extent, the team found.
“So in an ultimate sense, most protected areas are still performing quite positively in terms of reducing deforestation, even if some of this effect is due to their relatively inhospitable terrain,” William Laurance, ecologist at James Cook University in Australia who was not involved in the study, told Mongabay.
Tropical forest protected areas — unless located on steep slopes, or harsh terrain — typically face high deforestation pressure in areas immediately outside the reserves. This external deforestation pressure can result in forest loss within the reserves.
However, the study found that the amount of forest loss in areas immediately outside the reserves did not greatly impact forest loss inside the reserves. In fact, many reserves, despite high deforestation pressure from outside, seemed to be performing well, the study found.
“That really surprises me,” Laurance said. “I guess it shows that there’s huge variation in protected-area effectiveness, so much so that it overrides the effects of local-scale deforestation around the reserve. However, the authors didn’t discuss this result in much detail, and it’s one element of their analysis that I’d like to examine more closely.”
However, reserves which suffered from “exceedingly high” deforestation pressure — cases in which areas immediately outside the reserves had lost more than 30 percent forest cover in the last 10 years — were ineffective, the study found.
“This suggests that when deforestation pressure is exceedingly high, protected areas struggle to maintain forest cover,” Spracklen said. “However, fortunately this was only the case for a minority — about 60 out of nearly 3400 — protected areas.”
The researchers also found considerable variation in the performance of protected areas between and within countries.
For instance, across the tropics, 41 percent of the subset of 1,804 reserves, with similar slope and elevation, reduced forest loss by at least 25 percent. In Australasia (Australia and Papua New Guinea), nearly 70 percent of reserves reduced deforestation by at least 25 percent, while less than one third of reserves in Asia reduced deforestation by 25 percent.
Overall, the study found that reserves in parts of Asia, West Africa and Central America have some of the worst performing protected areas.
Not all countries in Asia perform poorly. Countries like Thailand and Laos have many effective protected areas, the study found. On the other hand, most reserves in China, India, Indonesia and Philippines are largely ineffective. In these countries, reserves that are located on steeper slopes or higher elevations are better at slowing forest loss, the team found.
“In general, the poorest countries (low per-capita GDP) and those with the highest rural population densities have the worst-performing protected areas,” Laurance said. “It appears that relatively wealthier and less densely-populated countries are better able to defend their protected areas.”
This could be because richer countries have more funding available for protected area management, Spracklen said, “although we were not able to test that idea.”
The richer, and better-performing nations, could also have more effective protected areas due to less corruption and more respect for the rule of law, better on-the-ground protection (such as more and better-paid park guards), less-pervasive poverty, and lower population densities, especially in rural areas, Laurance added. “All of these factors contribute to better protected-area performance.”
Not all countries with high GDP have better performing protected areas, though. “Malaysia for instance has relatively high GDP but has a mix of many very poorly protected areas as well as some very effective protected areas,” Spracklen said.
So the efficacy of reserves widely varies across the tropics. Despite the variation, the study shows that protected areas can and do work, the researchers write. There is however an urgent need to understand why some protected areas do not work and take immediate action to prevent further deforestation, they add.
“This study shows there’s great scope to improve the performance of protected areas in some nations and regions, with parts of Southeast Asia, Central America, and West Africa jumping out as especially worrisome places,” Laurance said. “But we need to remember that protected areas are a cornerstone of our efforts to protect nature in the long term. We need lots of strategies to promote nature conservation but clearly we can’t afford to let our protected areas fail. They’re just too important.”
- Spracklen BD, Kalamandeen M, Galbraith D, Gloor E, Spracklen DV (2015) A Global Analysis of Deforestation in Moist Tropical Forest Protected Areas. PLoS ONE 10(12): e0143886. doi:10.1371/journal.pone.0143886