Bush encroachment and rangeland management in southern Ethiopia

Rangelands in southern Ethiopia have been undergoing a rapid shift from herbaceous to woody plant dominance in past decades, reducing indigenous plant biodiversity, altering ecosystem function and threatening pastoralism. Despite significant rangeland management implications, quantification of the extent of bush encroachment and transitional pathways that result in encroachment remain largely underexplored. The paper “Bush encroachment dynamics and rangeland management implications in southern Ethiopia” by Chuan Liao et al, published in 2018 in Ecology and Evolution 8 (23): 11694–11703, develops a phenology-based approach to map rangeland vegetation states in the Borana Zone of southern Ethiopia, and examines transition pathways among states using the state-and-transition model.

It was found that nearly 80% of landscape was dominated by woody plants in 2013. While stable encroached states have been established in both high and low lands through different transition pathways between 2003 and 2013, the authors identified spatial locations where bush encroachment occurred rapidly. The multiplicity in the transition pathways indicates opportunities for positive transformation in southern Ethiopia and other semiarid regions of Africa. In the highlands where the major pathways are from open canopy woodland and bushland to dense scrubland, a combination of browsing and fire can potentially reduce the woody plant layer and reverse the trend of encroachment. In the drier lowlands where the transition pathway from grassland to bushland dominates, adding more goats and camels while reducing the number of cattle in the herds could be crucial to make better use of the woody forage resources that are well suited for browsing. The authors argue that, rather than simply living with bush encroachment, pastoralists can actively contribute to its mitigation by changing their livestock portfolios.

This is exactly what Borana pastoralists are doing.

Posted on 12 May 2020 in Pastoralism & Natural Resources