When you live on the top of a mountain, you don't have many places to run if the environment of that mountain habitat changes. Look at the American pika, for example. These tiny, rabbit-like mammals have evolved to live in cold, high-elevation habitats and die if exposed to temperatures above 25 degrees Celsius. Unfortunately climate change is warming their mountain habitats, pushing the pikas into higher and higher elevations where they have less space to live and fewer plants to eat. Eventually, they may run out of room entirely.
Will the same thing happen to the iconic, critically endangered mountain gorillas (Gorilla beringei beringei) of central Africa? In 2011 research by the United Nations' Food and Agriculture Organization predicted that the vegetation in mountain gorilla habitat will be dramatically altered by climate change. Warming temperatures will push certain plant species further up the mountains leaving the gorillas, which spend most of their days foraging, with fewer food sources. According to some climate change models, the current habitats for mountain gorillas in Uganda, Rwanda, and the Democratic Republic of Congo could become completely unsuitable for the massive primates for the year 2090.
But now new research published Sept. 23 in Ecosphere indicates that mountain gorillas may be able to avoid the worst effects of climate change. In part, the research suggests, gorillas may be able to adapt to changes in vegetation. That alone may not be enough, though. According to the researchers— from the University of California, Davis; Environmental Planning Institute; International Gorilla Conservation Programme; and EcoAdapt—humans living near the gorillas may need to adapt as well.
So what makes mountain gorillas different from other mountain species such as the pika? For one thing, mountain gorillas did not specifically evolve in their current habitats. Instead they escaped into these regions, climbing high into the mountains to avoid humans who encroached upon their territories. Mountain gorillas can live in the colder temperatures of higher elevations because they have long, thick fur, but they do not rely upon any specific vegetation and pick their food from among dozens of plant species based on availability and nutritional content. This suggests that even if plant species shift further up the mountain or disappear entirely, the gorillas may just move on to different vegetation.
But in the process mountain gorillas may need to expand their current territory beyond the confines of Virunga National Park and Bwindi Impenetrable National Park, the two protected areas set up to preserve the primates. That won't be easy. The two parks are surrounded by people and agriculture. The parks could be expanded, the researchers write, but even a five kilometer shift in their borders would be expensive and require convincing entire human settlements to move. Although much of that territory is already heavily deforested and unsuitable for gorillas, the authors identify several sites in the three countries that could conceivably work as expansions to the existing parks.
Another option would involve relocating some mountain gorillas to entirely new territories. This poses a lot of risk. Relocated gorillas could be exposed to new diseases or predators. They could also have a negative effect on the species in their new habitat. Meanwhile, there is no current research that indicates mountain gorillas would be able to adapt to completely new habitats. And then there's the economic aspect: the communities around Virunga and Bwindi parks rely upon eco-tourism from mountain gorillas, so would moving some of the animals hurt the economies of those regions?
No matter what happens in the future, mountain gorillas face many threats today. Their habitat continues to shrink, they face poachers and violence in the war-torn region, and they continue to catch diseases from humans. Most recently a British company announced plans to drill for oil in Virunga National Park, which could further imperil the rare primates. But at the same time a lot of people and organizations have done good work for mountain gorillas, often putting their lives on the line to protect them.
The mountain gorilla population has increased from just 620 in 1989 to 880 today. That's already a victory, but this new research reminds us that many more challenges remain.
Photo by Lukas Vermeer via Flickr. Used under Creative Commons license
Previously in Extinction Countdown: