The impacts of woody encroachment on nature's contributions to people in North America and Africa: A systematic review

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Abstract Woody encroachment is affecting nature's contributions to people (NCP) in grassy ecosystems around the world, but these impacts have not yet been well summarised. Moreover, the impacts of encroachment are likely to vary depending on the historical ecosystem dynamics, climatic conditions, encroacher species, and the temporal, spatial, cultural and socio‐economic contexts, including the dependence of communities on natural resources. To address these issues, we systematically reviewed the literature on the impacts of woody encroachment in Africa and North America, according to the three broad groups of the NCP framework: material, non‐material and regulating NCP. The material NCP most adversely affected by woody encroachment was the reduction in herbaceous forage availability, leading to reductions in the number and products of livestock on both continents. The benefits of material NCP were largely experienced in Africa and constituted the provision of wood materials for fuel, building and forage. Negative impacts on non‐material NCP, such as recreation, tourism and social amenities, were also reported for Africa. For regulating NCP, negative effects were reported on soil health, habitat availability and the regulation of hydrological NCP (in terms of water loss) in both continents. The regulating benefits were mainly carbon stocks in both continents, with North America reporting more than three times more positive cases than Africa. The benefits of woody encroachment, such as carbon stocks, must be understood in the context of the highlighted diverse impacts on other NCP. Depending on the context (e.g. ecological, spatial, cultural or socioeconomic), the need for certain NCP such as livestock production, tourism revenue and water provision supports efforts to reverse woody encroachment. Read the free Plain Language Summary for this article on the Journal blog.