The Hidden Crisis at the Base of Mount Kilimanjaro
Mount Kilimanjaro in Tanzania is often celebrated as a symbol of frozen romance and untouched nature. However, the real story lies not at its peak but at its base, where the effects of human activity on biodiversity are most evident. This mountain serves as a critical real-world laboratory for scientists studying how and why ecosystems are changing. With diverse land uses ranging from forests to farms and towns, researchers can observe the impact of human activity on nature directly, rather than relying solely on computer models or theories.
For over 36 years, I have been researching the vegetation of East Africa, particularly around Mount Kilimanjaro. Collaborating with scientists from Tokyo and Helsinki, we analyzed historical maps, 46 years of satellite imagery from 1976 to 2022, census data dating back to 1913, and nearly 3,000 plant species recorded across 1,600 field plots on the mountain.
Biodiversity Loss: A Human-Driven Crisis
Our research aimed to determine whether Kilimanjaro’s biodiversity—defined by the composition and number of plant species—has changed and what factors are driving these changes. We found that in the populated areas below the national park, 75% of the mountain’s indigenous plants have been lost over the last century. The primary causes include intensive land use by farmers and builders, habitat destruction, and the increasing presence of non-native, partly invasive plants.
The findings reveal an uncomfortable truth: the biggest threat to biodiversity on Kilimanjaro is not climate change, but human activity. Our farms, houses, roads, and land conversion efforts are the main culprits. The lower slopes of the mountain, which are visible to most people flying into Kilimanjaro Airport or driving to Moshi, have been stripped of their natural ecosystems at an alarming rate.
In 1911, 90% of the lower slopes were natural habitats, primarily savanna woodlands and forests. Today, only 19% of this area remains, with most of it converted into agriculture and built-up areas. The driving force behind this transformation is a 28-fold increase in population over the last 130 years. In 1890, around 50,000 people lived on and around the mountain; today, the population exceeds 1.4 million.
Climate Change vs. Land Use: A Misplaced Focus
While climate change is often cited as the main threat to biodiversity, our research shows that it is not the primary driver of biodiversity loss on Kilimanjaro. If climate change had been the main factor, we would expect to see negative impacts on subsistence agriculture and agroforestry. Instead, these sectors have grown. Towns around the mountain have expanded rapidly, with house construction outpacing population growth. The savanna grasslands that once surrounded the mountain have been almost entirely converted into smallholder and commercial farms.
Our core conclusion is that the main driver of biodiversity decline on Kilimanjaro is land use change, driven by population growth and economic development. Climate change, while significant, plays a secondary role in the loss of biodiversity on the mountain’s lower slopes.
Shifting Plant Composition: A New Ecological Reality
Although the total number of plant species on Kilimanjaro has not changed much, the mix of plants has. Between 1976 and 2022, native plants from natural areas declined by nearly half, while non-native plants increased by 25%. Many native species are now limited to small areas, with some facing endangerment. In contrast, non-native species can spread widely and sometimes outcompete native plants, further threatening indigenous vegetation.
A Path Forward: Balancing Development and Conservation
Kilimanjaro is not an isolated case. Across tropical Africa, and increasingly in Asia and parts of Latin America, biodiversity loss is driven by intensive land use for farming, grazing, and urban expansion. However, there are solutions. Land can be used in ways that support both productivity and biodiversity. For example, the Indigenous Chagga people of Kilimanjaro have maintained home gardens on the southern and eastern slopes that combine fruit trees and crops. These systems provide shade, attract wildlife, and allow for the cultivation of food and cash crops.
Our research also found that protected areas, such as Tanzania’s Rau Forest Reserve or the private Namalok reserve, show dramatically higher species richness per hectare compared to sugar cane fields or intensive rice farming. This demonstrates that it is possible to balance development with conservation.
Urgent Actions Needed
Governments and local communities must take immediate action to protect the remaining fragments of natural vegetation on Kilimanjaro. Agroforestry should receive more support, and governments should not rely solely on carbon markets or carbon credits to protect nature. Instead, they should directly compensate local people for preserving biodiversity.
Decisions about where to build farms and towns must prioritize environmental protection. This is not just a global issue but a local one, requiring physical labor and on-the-ground efforts. The myth that biodiversity loss is a distant, abstract problem is being challenged by the reality of Kilimanjaro’s story.
Conclusion: A Call to Action
Mount Kilimanjaro embodies the world’s ecological dilemma. Its story is not about altitude and ice, but about people and land. The fastest way to save species is to stop destroying the land they live on. As Andreas Hemp, Research Associate Plant Systematics at Bayreuth University, emphasizes, the solution lies in protecting the land and finding sustainable ways to coexist with nature.
