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Rapid expansion of protected areas around the world failing to reduce human pressures on land

  • A little over 20 million square kilometers, or about 15 percent, of Earth’s terrestrial surface is currently protected. It is likely the world will achieve the goal set out in Aichi Biodiversity Target 11 of the Strategic Plan for Biodiversity 2010-2020 to set aside “at least 17 per cent of terrestrial and inland water areas” by 2020.
  • But a study published in the Proceedings of the National Academy of Sciences (PNAS) last month finds that the emphasis on rapidly scaling up protected area coverage to meet Aichi Biodiversity Target 11 has led to the establishment of many PAs that are not successfully reducing anthropogenic pressures on the land.
  • Most strikingly, in South America, Southeast Asia, and Sub-Saharan Africa, average pressures from human activities inside PAs, especially conversion of land to agriculture, was found to be significantly higher than in unprotected areas.

As the world races to meet the goal of protecting 17 percent of Earth’s land surface, a new study looks at how effective protected areas are at reducing human pressures — and finds that there is considerable room for improvement.

According to the World Database on Protected Areas, 241,368 protected areas (PAs) have been designated around the world, mostly on land. A little over 20 million square kilometers, or about 15 percent, of Earth’s terrestrial surface is currently protected. It is likely the world will achieve the goal set out in Aichi Biodiversity Target 11 of the Strategic Plan for Biodiversity 2010-2020 to set aside “at least 17 per cent of terrestrial and inland water areas” by 2020.

But a study published in the Proceedings of the National Academy of Sciences (PNAS) last month finds that the emphasis on rapidly scaling up protected area coverage to meet Aichi Biodiversity Target 11 has led to the establishment of many PAs that are not successfully reducing anthropogenic pressures on the land.

Researchers at the University of Cambridge in the UK compiled data from 12,315 PAs in 152 countries to examine how well they reduce pressures from human activities. The researchers used satellite data to assess agricultural expansion and the number of lights visible at night in protected areas, together with census and crop yield data, to determine the extent of human encroachment into the study areas between 1995 and 2010. They then compared the findings for each PA with comparable areas of unprotected land in order to determine whether or not the PAs were actually impeding human encroachment.

The researchers found that human pressures have increased in a majority of PAs in every region of the globe over the past 15 years. “Rapidly establishing new protected areas to meet global targets without providing sufficient investment and resourcing on the ground is unlikely to halt the unfolding extinction crisis,” Jonas Geldmann of the University of Cambridge Conservation Research Institute, the study’s lead author, said in a statement.

Most strikingly, in South America, Southeast Asia, and Sub-Saharan Africa, average pressures from human activities inside PAs, especially conversion of land to agriculture, was found to be significantly higher than in unprotected areas. “Our study suggests that protected areas in more remote and wild parts of the tropics have experienced alarming increases in human pressure since 1995,” Geldmann said. “These places house a disproportionately high amount of the Earth’s biodiversity, and play an irreplaceable role in maintaining our most threatened species.”

Not all of the study’s findings were negative. PAs in the Northern Hemisphere and Australia, for instance, were found to have been effective at slowing human encroachment over the past 15 years when compared to unprotected areas. The researchers say that PAs in nations with higher ranks on the Human Development Index tended to see the smallest increases in human pressures.

Previous studies of the threats human activities pose to PAs have often been limited to forests, and Geldmann and co-authors note in the study that their results largely confirm those studies’ conclusions that protected areas can help reduce rates of deforestation. But PAs in other habitats, like savannahs, are not meeting with similar success, the present study found.

Increases in human activity in the protected areas of East and Central Africa were especially high; for example, cropland inside PAs designated to conserve Sub-Saharan grasslands increased nearly twice as much as it did in unprotected areas. Agriculture inside PAs in grassland habitats in Southeast Asia expanded 8 percent more than in unprotected areas. Similarly, agricultural expansion in forested areas of South America outside of the Amazon was 10 percent higher in PAs than outside of them.

“Our study shows that agriculture is the driving force behind threats to protected areas, particularly in the tropics,” Geldmann said. “Our data does not reveal the causes, but we suspect factors that play a major role include rapid population growth, lack of funding, and higher levels of corruption. Additionally, most unprotected land suitable for agriculture is already farmed.”

Geldmann added that the study’s findings highlight the importance of establishing PAs with “the right funding, management and community engagement that is needed” to ensure their success. “Important ambitions to protect 17% of land by the end of this decade, expected to increase to 30% at a pivotal meeting next year in China, will not mean much if not accompanied by enough resources to ensure the preservation of precious habitats.”

Yosemite National Park in the United States. Photo by King of Hearts, licensed under CC BY-SA 3.0.

CITATIONS

• Geldmann, J., Manica, A., Burgess, N. D., Coad, L., & Balmford, A. (2019). A global-level assessment of the effectiveness of protected areas at resisting anthropogenic pressures. Proceedings of the National Academy of Sciences, 201908221. doi:10.1073/pnas.1908221116

• UNEP-WCMC, IUCN and NGS (2019). Protected Planet Live Report 2019. UNEP-WCMC, IUCN and NGS: Cambridge UK; Gland, Switzerland; and Washington, D.C., USA.