Allan Sebata

By Allan Sebata

Part of the book: Herbivory

By Allan Sebata

Woody plants are key components of African savanna ecosystems as they provide wildlife habitats, offer browsing to ungulates and are also a major source of fuel wood. Disturbance events such as herbivory and fire negatively affect woody plant communities. However, some woody plants respond to disturbance events through resprouting. In savanna ecosystems, woody plants co-occur with grasses and disturbance events such as overgrazing result in the proliferation of woody plants at the expense of the grasses. Therefore, an understanding of the factors that influence woody plants is critical for the better management of African savanna ecosystems. This chapter reviewed our current knowledge of the ecology of woody plants in African savanna ecosystems and examined disturbance events such as herbivory and fire that shape woody plant communities. The role of resprouting as a response to disturbance events and the negative effects of woody plant encroachment on African savannas was also investigated. In addition, the consequences of poor management such as woody plants loss and possible restoration measures were explored. Disturbance events such as herbivory and fire were found to play critical roles in shaping the African savanna ecosystems. Interventions such as restoration have a role to play in restoring the productivity of degraded woody plant communities.

Part of the book: Plant Ecology

By Allan Sebata

In Zimbabwe, most livestock are reared by smallholder farmers who live in marginal areas with low rainfall and hence poor forage production. As a consequence, livestock productivity is low and intermittent droughts result in animal mortalities. Forage crops have been widely promoted to provide feed resources to livestock, particularly during the dry season and in years of low precipitation. However, production of forage crops among the smallholder farmers remains low, especially in areas that receive low rainfall (<600 mm per annum). This chapter reviewed work on the production and promotion of forage crops in Zimbabwe in the past 50 years. The production and adaptation of different forage crops viz. improved grasses, herbaceous, and tree legumes to low and high (>800 mm per annum) rainfall areas is highlighted. Planting of improved grasses and herbaceous legumes in fallows and tree legumes as hedges and on contours hold the best promise in terms of improving the availability of forage crops for livestock feeding. Shortage of moisture remains the greatest constraint to increasing the area planted to forage crops. Therefore, the development of irrigation facilities needs to be encouraged to allow for the growing of forage crops.

Part of the book: New Perspectives in Forage Crops