Deforestation and slash-and-burn agriculture in the tropics affect (hillslope) hydrological processes. It can reduce the amount of rainwater that infiltrates into the soil, which in turn can lead to a decreased availability of water in the dry season. However, the effects are highly variable and depend on spatial scales. To better understand and predict the hydrological effects of tropical land use change, field and model-based research is needed. The proposed research will contribute to the discussion regarding the extent to which the original hydrological processes can be restored through reforestation or natural regrowth of the vegetation on degraded soils, with a focus on Eastern Madagascar.
The proposed research seeks to use data on vegetation water use, soil moisture and overland flow dynamics, and soil physical characteristics for four locally important land-cover types (degraded fire-climax grassland, young regenerating shrub, regenerating forests and semi-mature forest) to answer the following overarching research questions:
1) Will continued slash-and-burn cultivation lead to gradually diminishing infiltration and dry season flows?
2) Will a longer period of vegetation recovery or active reforestation (tree planting) have a positive effect on infiltration and dry season flow?