Indigenous Grasses for Rehabilitating Degraded African Drylands

Abstract

Drylands provide an important livelihood stream to its inhabitants across the globe through a range of products and ecosystem services. However, these fragile ecosystems are threatened and believed to experience various degrees of land degradation. Estimates of the landmass affected by land degradation in the global drylands range from 10 to 20%, a percentage that is increasing at an annual global rate of 12 million ha of soil lost from desertification and drought. African drylands are especially highly susceptible to severe degradation because of their poor soil structure aggravated by scarce vegetation cover. Causes of degradation in these environments are both natural and anthropogenic in nature.Change in vegetation cover, decline in soil fertility, biodiversity loss and soil erosion demonstrate degradation in African drylands. Grass reseeding using indigenous species is one of the promising sustainable land management strategy to combat degradation in the drylands. Reseeding programmes are aimed at improving vegetation cover, biomass and conserve the soil to an extent not possible by grazing and land management alone. Indigenous drought tolerant grasses notably African foxtail grass (Cenchrus ciliaris), Bush rye grass (Enteropogon macrostachyus) and Maasai love grass (Eragrostis superba) have produced promising rehabilitation outcomes. Previous studies in African drylands have demonstrated the potential of such indigenous forage grasses in improving both vegetation cover (plant frequency and densities, basal cover) and soil hydrological properties (increased infiltration capacity, reduced runoff and sediment production) as indicators of rehabilitation success. Despite their comparative and widespread success, natural and anthropogenic challenges persist. This makes reseeding programmes a risky and often expensive venture especially for the resource poor pastoral communities in African drylands. Despite the risks, grass reseeding using indigenous pastures remains a viable sustainable land management option to combat degradation in African drylands. However, to ensure its continued success in the long-term, multifaceted approaches and strategies that will integrate land and water management and seed systems suitable for African drylands need to be developed, strengthened and promoted.

Cabo Verde’s Poaceae Flora: A Reservoir of Crop Wild Relatives Diversity for Crop Improvement

“…In drylands, the importance of Poaceae species extends from the cultivation of grasslands and erosion control to, and especially, uses by humans (e.g., supply of cereals) and livestock (e.g., fodder and forage) ( Capstaff and Miller, 2018 ; Mganga et al, 2019 ). More than half of the population’s food supply is provided by three grass crops (i.e., rice, wheat, and maize) which are particularly important in developing countries where they provide food security and nutrition to local populations ( Tadele, 2016 ).…”

Plant Morphoecological Traits, Grass-Weed Interactions and Water Use Efficiencies of Grasses Used for Restoration of African Rangelands

“…Moreover, taller plants of E. macrostachyus compared to C. ciliaris and E. superba suggest its higher capacity in absorbing the kinetic energy of raindrops and subsequently protecting the ground from the explosive impact that breaks soil aggregates and weakening its structure. Rainfall simulation studies conducted in semi-arid African rangelands (e.g., Nyangito et al, 2009;Mganga et al, 2019) have demonstrated that grass height contributed significantly to reducing sediment loss in reseeded African rangelands. Moreover, taller grasses are more suitable for reducing grazing pressure because they are readily accessible to grazing herbivores.…”

Assessing Context-Specific Factors to Increase Tree Survival for Scaling Ecosystem Restoration Efforts in East Africa

“…A key aspect of RinD that was implemented by the restoration project, is the use of planned comparisons, an approach where farmers compare and test promising options, and variations thereof, in their fields across a varying range of ecological and socioeconomic conditions [3][4][5]24,25]. Ref.…”

“…However, low survival rates of planted trees, especially species highly valued by farmers, is a major limitation in the drylands [19,20]. This is partly due to unreliable rainfall, high levels of land degradation resulting in low soil productivity, planting of ecologically unsuitable tree species, and poor tree seedling management practices [18,19,24].…”