Experimental prosopis management practices and grassland restoration in three Eastern African countries

• Published in: CABI agriculture and bioscience 2023-07, Vol.4 (1), p.21-21, Article 21
• Main Authors: Eschen, René, Bekele, Ketema, Jumanne, Yohana, Kibet, Staline, Makale, Fernadis, Mbwambo, John Richard, Megersa, Berhanu, Mijay, Mahamood, Moyo, Francis, Munishi, Linus, Mwihomeke, Mickfanaka, Nunda, Winnie, Nyangito, Moses, Witt, Arne, Schaffner, Urs
• Format: Article
• Language: English
• Subjects: Bark; Biodiversity; Biomass; Carbon sequestration; Charcoal; Climate change; Composition; Dry season; East Africa; Ecosystem services; Environmental degradation; Environmental economics; Environmental management; Environmental restoration; Fodder; Forage; Grasses; Grassland restoration; Grasslands; Herbicides; Introduced species; Invasive alien plant management; Livestock; Management methods; Mulching; Permanent establishment; Plant introductions; Planting; Prosopis; Prosopis juliflora; Rangelands; Seed banks; Seeds; Service restoration; Soil erosion; Species composition; Trees; Uprooting; Vegetation; Vegetation establishment; Weeds; Woody invasive species
• ISSN: 2662-4044; 2662-4044
• DOI: 10.1186/s43170-023-00163-5

Woody species have been introduced in many parts of the world to provide economic benefits, but some of those species are now among the worst invaders, causing widespread economic and environmental damage. Management of woody species to restore original ecosystem services, such as biodiverse grassland that can provide fodder and sequester carbon, are needed to limit the impacts of alien species. However, the best management methods, i.e., the most economically efficient and effective way to remove trees and the most effective way to restore or rehabilitate the cleared land, are not developed for many species. In Eastern Africa, prosopis ( ) has invaded large areas of savanna and grassland, thereby affecting, among other things, fodder and water for livestock, access to dry season grazing lands and ultimately pastoral livelihoods. We tested three prosopis treatments (manual uprooting and cut stump and basal bark herbicide application) in combination with three incremental restoration interventions (divots, divots + mulching, divots + mulching + grass seed sowing). The three-year study was replicated in Ethiopia (Afar National Regional State), Kenya (Baringo county) and Tanzania (Moshi district). Prosopis survival and vegetation development, both diversity and biomass, were recorded. The prosopis treatments were all highly effective (between 85 and 100% tree mortality in almost all cases), but the two treatments that involved the complete removal of the aboveground biomass (manual and cut stump) yielded a more productive and more diverse vegetation than the treatment that killed the trees standing (basal bark). Compared to the effect of prosopis removal, the effect of restoration interventions on vegetation composition was small, indicating that most species re-established from the soil seed bank. The results show that it is possible to restore land previously invaded by prosopis. Despite the different rates of vegetation establishment and variation in species composition, the restoration interventions resulted in vegetation that in some cases contained a substantial fraction of perennial grasses. The method chosen to control prosopis depends on the availability of resources, including herbicides, and the need to remove rootstocks if the intention is to plant crops. The online version contains supplementary material available at 10.1186/s43170-023-00163-5.