1.1 Soil erosion challenges in East Africa
The East African region harbours rich natural resources that exist in sharp contrast across the landscape (Veldhuis et al., 2019). These areas are populated with varied human and livestock densities and while the landscape provides many ecosystem services, provision is hampered by human activity and land degradation that include soil erosion. Climate changes, ecosystem degradation, biodiversity losses and sociopolitical pressures all impact development, conservation and livelihoods of socio-ecological systems of which majority of communities rely on across the region.
Soil resources in East Africa are being rapidly depleted by erosion, threatening food-, water- and livelihood security in the region (Wynants et al. 2019; Cobo et al., 2010; Oldeman, 1991). While soil and land resources are progressively being depleted the population, with associated needs for livelihoods, food, fibre, and other resources is expanding (FAO, 2019). Agricultural intensification and economic diversification are hampered by a lack of available knowledge, skills and agricultural technology (Korotayev and Zinkina, 2015) and as a result, an increasing number of farmers are pushed to seek more land to establish agricultural operations, causing a marked shift from naturally vegetated landscapes towards agricultural landscapes (Jayne et al., 2014; Odgaard, 2002). Policies of sedentarisation, privatisation and confinement within administrative boundaries have impeded the mobility of previously nomadic pastoralist communities (Homewood et al., 2004). Moreover, pastoral communities are also experiencing internal pressures due to higher livestock and other inequality existing among gender and other community social groups, rapid changes in herd sizes and stocking densities (both expansion and contraction), shifts towards the need for external employment opportunities and increased competition over grazing resources (Rabinovich et al., 2019; Rufino et al., 2013). A combination of all these and other factors have led to a tripling of the livestock numbers in the last 50 years (FAO, 2019) with increasing the local densities of domestic grazers in many areas, leading to overgrazing and trampling of the soil (Little, 1996; Ruttan and Borgerhoff Mulder, 1999). Furthermore, the high reliance on natural vegetation as a source of fuel, construction materials and fodder in both the urban and rural populations is resulting in substantial exploitation pressures on forests and woodlands (Hiemstra-van der Horst and Hovorka, 2009). The conjunction of these multiple pressures has increased rates of surface runoff, soil erosion, gully incision and downstream sediment transport (Blake et al., 2018; Vanmaercke et al., 2014; Wynants et al., 2020). Furthermore, these processes are potentially amplified by natural rainfall variations (Ngecu and Mathu, 1999) and projected increases in extreme climatic events e.g. drought followed by extreme rainfall (Nearing et al., 2004). East-Africa’s environments/ecosystems are highly dynamic in both time and space, posing substantial challenges to the communities that are dependent on them and the development of sustainable land management plans.