Climate Change Will Harm Older Elephants the Most, With Major Impacts on Ecosystems, Study Finds

Elephant herds are multi-aged and led by a matriarch, the oldest female. Clinton Mwebaze / WCS

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A first-of-its-kind study by researchers from the Wildlife Conservation Society (WCS) and the University of Massachusetts Amherst (UMass Amherst) has found that older elephants will have less chance of survival as the climate warms, and this will reverberate throughout the surrounding landscape.

The research team has developed models for potential mitigation scenarios, which have already begun to be implemented by WCS, a press release from UMass Amherst said.

“We found that the older elephants will be massively affected by warming under every scenario,” said lead author of the study Simon Nampindo, WCS Uganda’s country director, in the press release.

The Greater Virunga Landscape (GVL) of Africa is a 6,062-square-mile region of mountains, lakes and savannas in Rwanda, Uganda and the Democratic Republic of Congo. The land — home to Africa’s largest land animals — is 88 percent protected and contains three wildlife reserves, three tropical high-forest preserves and seven national parks. Three of the conservation areas are world heritage sites.

The African elephant population living in this collection of nature reserves has experienced such a decline in the last century that its members are on the International Union for Conservation of Nature’s Red List as a critically endangered species.

“Elephants are matriarchal — their leaders are the older cows, and the herds depend on their wisdom, long memories and ability to outsmart prey, and if they are lost to changing climate, it will wreak havoc on the surviving, younger herds, as well as change the genetic profiles and structures of the herd. There will also be ripple effects through the GVL’s landscape,” Nampindo said.

Elephants are considered important ecosystem engineers because the way they modify their habitats helps to sustain the landscape. They uproot trees, which then become habitat for thousands of insects and small mammals, disperse seeds from the plants they eat and enrich soil with their dung. They are also culturally important to many Africans.

Not many studies have taken an in-depth look into the interplay between elephant demography, climate change, the environment and how these gentle, intelligent mammals are influenced by their changing habitat over long periods of time.

In order to get a more comprehensive idea of what the future has in store for elephants and what can be done to best safeguard them, Nampindo and Timothy Randhir, a UMass Amherst professor of environmental conservation, put together a systems dynamic model.

“This model can look at all the different environmental and population dynamics within a system. For the first time, we’re able to get a comprehensive vision of what the future might look like for African elephants in the face of climate change,” Nampindo said.

The study, “Dynamic modeling of African elephant populations under changing climate and habitat loss across the Greater Virunga Landscape,” was published in the journal PLOS Sustainability and Transformation.

To build their model, Randhir and Nampindo used data on historical landscape changes, elephant numbers and various future climate change scenarios with warming of 1.6 degrees, 2.8 degrees and 4.3 degrees Celsius over the course of the next eight decades. Then they charted each climate scenario’s effect on five different age ranges: less than 10 years old; 11 to 30; 31 to 40; 41 to 50; and more than 50.

“[A]ny impact on one age class has a community effect throughout the entire population. But this model not only tells us what the threats are, we can also use it to tell us which policy possibilities will be most effective in helping African elephants to survive,” Randhir said in the press release.

Because elephants have such a wide range that can cross national boundaries, understanding how different policies may affect future herds is important so that responses can be coordinated by management agencies.

Randhir and Nampindo found that a locally, regionally and nationally coordinated GVL management plan is necessary to address threats from poaching. They emphasized the importance of education and programs led by communities in villages and towns where interactions between humans and elephants is common, in addition to well-funded anti-poaching strategies.

“These results are very important to WCS,” Nampindo said. “If we can do a good job at protecting elephants, our efforts will reverberate to other species, such as lions and mountain gorillas.”

The landscape of the GVL itself also requires proper management to reduce fires, habitat fragmentation and invasive species.“ More broadly, the most exciting thing about this systems dynamic modeling is that it can be adapted to any migratory species that move across political boundaries, from fish to birds to lions,” Randhir added.

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