I have a focus on the vegetation within the miombo region, particularly on the open ecosystems like tropical grasslands and savannas. Here, I studied the diversity of geoxylic plants, i.e. low-growing plants that have a high belowground woody biomass. By investigating how many species there are, where they occur and what the environmental drivers of their evolution and distribution are, I am able to show that geoxylic plants are a key element of disturbance-prone savannas. They contribute greatly to the richness and resilience of (humid) savannas.
In the miombo region, people use fire as a tool for their agricultural practises (slash and burn agriculture). They clear patches of woodland by cutting the trees at waist height and burning the understory, to make space for their crops. The cut trees are used for construction or for charcoal production, which generates some income for the families. Besides, the woodlands offer other important resources for their livelihood, e.g. honey from wild bees or edible plants. Usually, miombo trees are resprouting and are able to recover after some years of protection. However, growing human population and increased need to generate income in countries that are developing rapidly leads to an excessive pressure on the miombo woodlands. Fallows are not able to fully recover because wood is extracted too often and fires are set too frequently. Trees are therefore trapped in a small state and will not reach maturity. In this state, the trees will not flower and fruit, and old-growth trees are needed by bees for their colonies. People have to spend more time and energy to find these resources. Therefore, long-term supply of natural resources, on which the people depend, is compromised by the current land use.