- Spanning more than 40,000 square kilometers (15,400 square miles), the Serengeti-Mara ecosystem in East Africa is one of the largest protected areas in the world.
- A new study shows that human activities at the edges of the ecosystem are affecting wildlife migrations and pushing the animals deeper into the core of the protected area.
- The displaced wildlife have less available land, triggering a cascade of events impacting soils and vegetation, putting the whole ecosystem at risk.
- The study authors are calling for broader conservation strategies that address not only protected areas, but also their surroundings and local communities.
Every year, millions of wildebeests, gazelles and zebras migrate between Serengeti National Park in Tanzania and Maasai Mara National Reserve in Kenya, in one of the most iconic wildlife shows on the planet. Preserving this great migration was one of the reasons why almost 40,000 square kilometers (15,400 square miles) in East Africa were designated as protected areas in the 1950s. Communities such as the Maasai, who had lived in the region for hundreds of years, were evicted and forced to relocate. The impact of that controversial move is still felt today.
Now, new research suggests that simply creating protected areas and keeping humans away from them might not be enough to preserve biodiversity.
A study published in March in Science shows that the presence of livestock at the edges of the Serengeti-Mara ecosystem is pushing wildlife away from the margins. As a result, wild species are becoming “squeezed” into the core of the protected areas. In one of the regions analyzed, for instance, wildlife numbers within 15 kilometers (9 miles) of the boundary dropped by 50 to 75 percent between the 1970s and the 2000s.
Human activities are already having an impact on the great migration. GPS data collected over the past 20 years indicate that wildebeests now avoid the margins of protected areas. Instead, they’ve started to graze in more internal areas, with dire consequences for the ecosystem.
Vegetation, dry and wet seasons, fire, and the migration of grazing animals are some of the interconnected pieces of the Serengeti-Mara ecosystem. Changes in one can potentially affect others. For example, natural fires at the end of the dry season consume the old pasture and enrich the soil, making room for lush new grass that attracts the migrating herbivores.
But now, the presence of livestock at the edges is causing intensive grazing in these areas and displacing the wildebeests. With less available land, the wild herds are also overgrazing areas at the core of the protected areas. As a consequence, the area that is annually burned by natural fires has diminished, the grass isn’t as green, and the soil is becoming impoverished and less efficient at sequestering carbon dioxide.
“This is an important example of how humans can alter and potentially reduce animal movements, which can then impact ecosystem functioning,” said Robert Fletcher, a researcher at the University of Florida’s Department of Wildlife Ecology and Conservation, who was not involved in the study. Fletcher said these “edge effects” at the boundaries were pervasive across the world.
“Recent work suggests that 70 percent of the world’s remaining forest is within 1 kilometer [0.6 miles] of a forest edge,” he said.
Beyond protected areas
One of the conclusions of the study is that conservation strategies have to go beyond the boundaries of protected areas.
“This finding alters our view on what is needed to protect biodiversity,” said Michiel Veldhuis, from the University of Groningen in the Netherlands, who is the lead author of the study. “There is an urgent need to rethink how we manage the boundaries of protected areas to be able to conserve biodiversity.”
In their paper, the authors argue that mutual agreements between local populations and governments are the way forward.
A crucial point to tackle is human population growth in the region, which has been steadily increasing in recent decades. The problem isn’t new in the Serengeti, and researchers have been warning about it for a long time. Jafari Kideghesho, a researcher from Tanzania’s Sokoine University of Agriculture, raised the point back in 2010: “[Population] has barely been accorded adequate attention in the conservation policies [of the Serengeti]. This factor is often neglected, thus making dealing with conservation problems similar to treating the symptoms rather than the real cause of the disease.”
Banner image: The savannah and grasslands of the Mara conservancies are home to a spectacular abundance of wildlife, lying at the northern end of the greater Serengeti ecosystem. Photo Credit: Maasai Mara Wildlife Conservancies Association..
Ignacio Amigo is environmental journalist and editor based in Brazil with a PhD in molecular biology from the University of Sao Paulo. He is a multimedia specialist at Climate Tracker. Follow him on Twitter at @IgnacioAmigoH.
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