What Happens When Forestry Goes? Lessons from Mariepskop (SAEON Seminar, Nov 2025)

Описание: Presenter: Dr. Tony Swemmer (NRF-SAEON Ndlovu Node)

Title: What happens when forestry goes? Ecological and hydrological dynamics following the abandonment of plantations, and the return of fire, on Mariepskop Mountain

Abstract: Over the latter half of the 20th century large areas of montane grasslands around the world were afforested with timber plantations or transformed to croplands, with catastrophic consequences for river flows and biodiversity. More recently, some plantations and crop fields have been abandoned and this trend is likely to accelerate. Many other mountainous areas have been invaded by alien plants. As a result, significant parts of the mountains in South Africa (and around the world), are covered by abandoned plantations, alien plant infestations or secondary grasslands. What does this mean for the amount of freshwater that flows from these areas, and for the conservation of the high but threatened biodiversity of our montane ecosystems?

To address this question, the SAEON Ndlovu Node initiated long-term research on the slopes of Mariepskop Mountain in north-eastern South Africa. This includes monitoring of vegetation structure and diversity, weather and streamflow, and fire. Clearing of plantations trees and increasing fire frequencies has led to the emergence of secondary grasslands with reasonably high diversity, although still well below what is likely to have been there before. Increases in river flows are not yet evident, and geohydrological modelling is underway to better understand current hydrological changes. These results will be presented as well as the consequences of such changes for local stakeholders, and the implications of major land cover change for the broader region.