Study finds protected areas for elephants work better if they are connected

Conservation measures have successfully halted the decline of the African savannah elephant population in southern Africa, but the trend varies locally, according to a new study.

Evidence suggests that the long-term solution to elephant survival requires areas not only to be protected, but also connected to allow populations to stabilize naturally, according to an international research team.

Their study, published on January 5 in Scientists progress, collected survey estimates and calculated growth rates for more than 100 southern African elephant populations between 1995 and 2020, representing approximately 70% of the global savannah elephant population. The published article is titled “Protecting and connecting landscapes stabilizes populations of endangered savannah elephants.”

“This is the most comprehensive analysis of growth rates of a large mammal population anywhere in the world,” said co-author Rob Guldemond, director of the Conservation Ecological Research Unit (CERU ) at the University of Pretoria, South Africa.

Overall, the survey results are positive. There are the same number of elephants today as there were 25 years ago, a rare conservation victory at a time when the planet is rapidly losing its biodiversity. However, the trend is not uniform from one region to another. Some regions, such as southern Tanzania, eastern Zambia and northern Zimbabwe, have experienced serious declines due to illegal ivory poaching. In contrast, populations in other regions such as northern Botswana are booming.

“However, uncontrolled growth is not necessarily a good thing,” says Stuart Pimm, study co-author and Doris Duke Professor of Conservation at Duke University in North Carolina. “A rapidly growing population can become too large and damage its local environment and prove difficult to manage, posing a threat to its long-term stability,” says Pimm.

In addition to documenting local growth rates, the team also examined the characteristics of local populations to identify what makes them stable, meaning neither growing nor declining.

Elephant populations living in well-protected but isolated parks, sometimes called “conservation fortresses,” grow rapidly in the absence of threats, but are not sustainable in the long term. These elephants will likely need future conservation interventions, such as translocation or birth control, which are both costly and intensive efforts.

The team found that the most stable populations are found in large core areas surrounded by buffer zones. Core zones are defined by their high levels of environmental protection and minimal human impact, while buffer zones allow certain activities such as sustainable agriculture, forestry or trophy hunting. Unlike island fortresses, core areas are connected to other parks, allowing herds to move naturally.

“What’s crucial is that you need a mix of areas with more stable base populations linked to more variable buffer zones,” said lead author Ryan Huang, a Ph.D. at Duke. is currently doing postdoctoral research at CERU.

“These buffer zones absorb immigrants when core populations become too numerous, but also provide escape routes when elephants face poor environmental conditions or other threats such as poaching,” Huang said.

Connecting protected areas means elephants can move in and out freely. This allows a natural balance to occur without human intervention, saving conservationists from using their limited resources to maintain the balance.

“Calling for connecting parks is not something new. Many have,” Huang said. “But surprisingly, there hasn’t been much published evidence of its effectiveness until now. This study helps quantify why it works.”

“Connecting protected areas is essential for the survival of African savannah elephants and many other animal and plant species,” said Celesté Maré, co-author and doctoral student at Aarhus University in Denmark. “Populations with more options for movement are healthier and more stable, which is important given an uncertain future due to climate change.”