Less space for the Chagga home garden

The image of snow-capped Kilimanjaro is one of Africa's icons: a white-capped peak rising above the savannah, often with a few elephants or giraffes in the foreground. Above the haze, the mountain massif appears mighty and unchanging on the horizon. But the opposite is the case.

Climate, biodiversity, agriculture, population - the conditions on the slopes of Africa's highest peak are changing on many levels. Science speaks of a socio-ecological system that is on the move. A team led by Prof. Dr. Andreas Thiel from the Department of International Agricultural Policy is researching just how dramatic this change is, what influence humans are having and what consequences humans are bearing.

Thiel and his team have traveled to northern Tanzania countless times. There, right on the border with Kenya, lies Mount Kilimanjaro. "Its slopes are like a piece of tropical rainforest in the middle of the vast dry savannahs of the lowlands," Thiel describes. "It's green, misty, densely populated. The people who live on the mountain, the Chagga, seem proud, enterprising and tradition-conscious. Their culture is closely linked to the mountain."

The Research Group is particularly interested in the fertile and densely populated southern slopes of the mountain massif. The population there has always used the water captured by the mountain and released by the glacier to cultivate the land. "Irrigation ditches run down the slopes like a spider's web," describes the agricultural economist. But the climate is changing, rainfall is becoming more irregular, temperatures are rising and the glacier on the summit is melting. These are not the only changes: Free trade is also having an impact on the landscape; many a farmer who used to grow a range of crops for local consumption now grows avocados for the world market. Coffee exports are being reorganized. What influence do institutions, i.e. formal and informal rules such as disposal and inheritance rights or the regulation of trade, have on these developments? This is the focus of Thiel's project team. Over the past few years, they have gained a number of insights.

Take water, for example: when water becomes scarcer, it is also a question of politics and influence as to how it is distributed. The Kassel scientists have observed that large-scale farmers at the foot of the mountain are increasingly growing pineapples, beans and cut flowers. The cultivation of avocados has grown strongly. The fruit originally comes from Central America, but is now grown on every continent, with annual global production exceeding 8 million tons. In Germany, too, the oily fruit is becoming increasingly popular. The problem: avocado trees swallow up a lot of water. Despite lower rainfall, the influential large-scale farmers in the lower altitudes know how to ensure that more water is diverted from the higher altitudes down to their plantations. At higher altitudes, small farmers are often forced to turn to other sources of income, such as tourism.

Take coffee, for example: Kilimanjaro is one of the oldest cultivation areas in the world for the Arabica variety, the harvests there are high-yielding and the beans are aromatic. In recent years, cooperatives, in which farmers traditionally organize themselves, have provided their members with new varieties that can cope better with the lack of rainfall. However, the power of the cooperatives is waning and their de facto monopoly has been broken by politicians - partly because some were poorly managed and had problems with corruption. Unlike in the past, membership is no longer compulsory. On the one hand, it is good for the farmers not to have to put up with corrupt structures, says Wivina Msebeni, who comes from Tanzania herself and is doing her doctorate on coffee cultivation there. "On the other hand, small farmers have a harder time on the market than large plantation owners." This could lead to a shift in the balance and a concentration of cultivation. This would result in monocultures instead of the traditional mixed farming that has characterized the landscape on the slopes of Kilimanjaro to date: In the so-called "Chagga home gardens", family farms grow coffee bushes alongside banana trees and vegetable patches.

Example of inheritance law: Traditionally in this region, inheritance is divided between all the sons and daughters of a couple. But as the population grows, this means that the plots of land inherited by the young farmers are getting smaller and smaller, and because each unit still has a family home on it, the total usable agricultural area is shrinking. So not only are there more stomachs to fill, there is also less space to produce the necessary food. Will inheritance rights remain untouched or will new forms develop? What ways will governments, municipalities and communities find to maintain long-term stability? The group from the University of Kassel is also investigating these questions.

The Kassel project is part of a DFG Research Group that brings together numerous disciplines and research institutions. While the Kassel sub-project focuses on the influence of institutions and other forms of governance on land use, society and nature, the overall project takes a broader view: What value does nature have for the well-being of people? How can the value of agriculture, biodiversity and tourism magnets be quantified? The researchers are hoping for results that can be transferred to other regions of the world. But that is not easy.

"The difficulty lies in the special characteristics of each region of the world," Thiel points out. Culture, local economic models, climatic conditions - none of this is easy to transfer from one region to another. In the end, however, there should definitely be one thing: a socio-ecological model of the Kilimanjaro system that depicts the role of institutions, governance and power and, in general, the reality of this time - beyond the romanticism of the savannah that can be marketed to tourists.

Kilimanjaro is located in northern Tanzania and, at 5895 meters, is the highest mountain in Africa. There are several national parks in its vicinity with rich biodiversity - including large animals such as elephants, rhinos, lions and giraffes. The province of the same name is densely populated and has almost 2 million inhabitants. In addition to new products such as avocados for export, the rural population mainly grows coffee, bananas, maize and beans.

Text: Sebastian Mense.