Woody Plant Encroachment as a Process of Landscape Change in Arid Rangelands: Effective Control Methods and Enhancing Herbaceous Species Richness: A Review

Abstract

This chapter addresses the process of bush encroachment and control measures for suppressing invasive woody plants to improve range productivity. Bush encroachment is a shift in the ecology of rangeland toward bushland with a decline in grass productivity. Bush encroachment modifies the ecological balance of the rangeland plant community causing a loss of biodiversity. Bush encroachment has been a global concern for several decades. Increased atmospheric carbon dioxide, reduced fire intensity, and seasonal changes are major drivers. Bush encroachment is a major threat to the world’s arid and semiarid rangelands, driving land degradation, economic losses, and food insecurity in sub-Saharan Africa. Conventional explanations for the cause of bush encroachment include changes in fire regimes, increased livestock grazing pressure, and climate variability. Generally, previous studies have shown that global rangelands have been increasingly affected by the proliferation of bush encroachment during the past five to six decades. Bush encroachment includes the invasion of indigenous woody plants and/or introduced alien invasive plants into arid and semiarid rangelands. Such ecosystem alteration considerably affects landscape structure, biodiversity, and the value of ecosystem services delivered from rangelands. Hence, control measures are critical management issues for sustainability and conservation of biodiversity.