Growing Land Use Pressure Puts Mount Kilimanjaro’s Biodiversity at Risk

Aerial view of the southern foothills of Kilimanjaro. Over the past hundred years, the original savannah in this area has been almost entirely converted into agricultural land. In the foreground are sugarcane plantations, surrounded by smallholder farms and rice fields. © Andreas Hemp

“Between 1911 and 2022, 75 percent of natural plant species per square kilometre disappeared from the lower slopes of Kilimanjaro. This has a profound impact on other groups of organisms, as plants play a fundamental role in ecosystem functioning,” says Dr. Andreas Hemp from the University of Bayreuth and lead author of the study. While previous research mainly focused on climate change and its effects rather than the causes of biodiversity decline, the international research team led by Dr. Hemp looked into several possible causes.

“In our study, we were able to show that land use change, driven by rapid population growth, was the main driver of biodiversity loss on Kilimanjaro. In contrast, climate change had no discernible impact on the observed biodiversity trends,” says Hemp.

Mount Kilimanjaro is home to an extraordinary diversity of natural habitats with rich flora and fauna, while some of its slopes are densely populated and intensively used. “Nowhere else does one find such a high number of different climate and vegetation zones in such a small area – ranging from dry-hot savannah and moist cloud forests to glaciers at the summit. At the same time, some rural regions have population densities of up to 1,500 people per square kilometre. This contrast is also unique,” Hemp explains. Kilimanjaro is therefore an excellent example of the challenges posed by global change, but also of the opportunities and prospects for other tropical regions.

To mitigate biodiversity loss, the researchers propose the establishment of protected areas and the use of traditional and diverse agroforestry systems. In particular, the sustainable and species-rich land use system of the Chagga people could serve as a blueprint: In the “Chagga homegardens”, which are structured like a natural forest, cultivated and wild plants grow side by side. Under a loose canopy of avocado, mango, and forest trees, bananas are grown, with coffee beneath them and vegetables or medicinal plants at ground level. This structure promotes a favourable microclimate and biodiversity. “This land use system can be transferred to many other rural areas in the tropics to enhance both human and ecological well-being,” says Hemp.

The study was conducted as part of the research group “The role of nature for human well-being in the Kilimanjaro Social-Ecological System (Kili-SES)”, funded by the German Research Foundation (DFG) and led by Dr Andreas Hemp at the University of Bayreuth. More information: https://kili-ses.de