The Ecology and Management of Invasive Prosopis Trees in Eastern Africa

This book synthesises information on an important environmental problem - the invasion of natural ecosystems in Africa by alien Prosopis trees, and how they should be managed. It addresses how the problem came about, what we know about how it works, and how it can potentially be managed at different scales. The book has a focus on eastern Africa but includes studies from elsewhere. Prosopis trees were originally introduced to Africa as early as 1880 (in South Africa), and later to eastern Africa in 1917 (in Sudan). They are difficult to manage due to their ecological features, such as their ability to produce copious amounts of seed, and to compete successfully with native species for resources, but also because they have both beneficial uses and negative impacts, making them conflict species, where people disagree on goals for management and how they should be achieved. In eastern Africa, Prosopis juliflora invades rangeland, cropland, settlements and riparian ecosystems, causing negative impacts on biodiversity and ecosystem services that rural communities depend on. This book considers the perceptions and conflicting interests of different stakeholder groups, and how engagement can be used to co-design management strategies and implement concrete control measures. The book is therefore not only of interest to those working with this invasive tree species, but also to persons involved in policy development and management of other invasive species, or in the wider field of sustainable environmental management.

Urs Schaffner is Head of the 'Ecosystems Management' section at the CABI Switzerland Centre and affiliate assistant professor at the University of Idaho, USA. His research focuses on soil-plant-herbivore interactions, with particular emphasis on biological invasions, biological control of weeds and grassland restoration. He has 30 years of experience in weed biological control and has worked on aspects such as the ecology and evolutionary ecology of host-specificity of weed biological control agents, pre-release impact assessment, demographic modelling of biological control agents and post-release impact evaluation. He is the coordinator of the 'Woody Weeds' project, a multi-partner project on assessing the environmental and socio-economic effects of invasive trees in Eastern Africa and implementing integrated management strategies, including biological control, that mitigate their negative impacts. Urs participated in more than 10 research projects, (co)authored more than 100 articles, book chapters and other publications, and presented his work in more than 50 scientific meetings, being invited as a keynote speaker, and for workshops, training courses, etc. all over the world.

Ketema Bekele is Assistant Professor In Agricultural Economics and Director of University Enterprises Development at Haramaya University. He received his MA Degree in Development Studies from Addis Ababa University, Ethiopia, in 2008 and his PhD Degree, which he did in the frame of the Woody Weeds project, from Haramaya University, Ethiopia, in 2019. Ketema has 14 years of experience as university instructor and researcher in Ethiopia. His research has generally focused on the nexus between economics and environment. Specifically, he assessed the impacts of ecosystem changes on the livelihoods of rural agricultural smallholder farmers and pastoralists in Eastern Africa. He has advised more than 20 MSc and 4 PhD students. As Director of University Enterprises, Ketema manages several large research, production and community service facilities of the University. He has published more than 20 articles in peer-reviewed scientific journals.

Albrecht Ehrensperger is a senior researcher at the University of Bern's Centre for Development and Environment (CDE). From 2007 to 2024, he held various management positions at CDE and was a member of its executive committee. His research focuses on land system science, agrobiodiversity, and agroecology, with a methodological background in spatial analysis and the use of digital mapping tools for stakeholder engagement. With over 25 years of experience in project coordination and research in Eastern Africa and Southeast Asia, he spends part of the year at CDE's office in Vientiane, Laos. He has published more than 60 peer-reviewed scientific papers and book chapters, and co-edited a special issue on the agrarian transition in the Lower Mekong Basin in the Journal of Land Use Science.

Brian van Wilgen is an Emeritus professor at Stellenbosch University, South Africa, and he has 45 years of experience as an applied ecologist in southern Africa and beyond. His research has focussed on two fields - fire ecology, and invasion ecology. He has conducted work in southern and eastern Africa, and collaborated with others in Australia, Europe, North and South America, and on island ecosystems. He has served on numerous editorial boards, the most recent including the journals Conservation Biology, Fire Ecology, International Journal of Wildland Fire, and South African Journal of Science. He has received numerous awards, most recently the South African Academy of Science Gold Medal for excellence in the application of outstanding scientific thinking in the service of society. He is author of over 200 publications, including four books and 170 peer-reviewed scientific papers. He was the lead editor of a recent comprehensive book entitled Biological Invasions in South Africa, published by Springer in 2020.

Johannes Le Roux is an Associate Professor in the School of Natural Sciences at Macquarie University, Sydney, Australia. He is also an International Research Associate at the Centre for Invasion Biology, Stellenbosch University, South Africa. He is a plant biologist, broadly interested in the ecology and evolutionary biology of invasive species. Jaco's research traverses spatial and temporal scales, from studying the microevolutionary dynamics of populations to interpreting the biogeography of plant species. He is author or co-author of over 130 journal publications and book chapters and is the sole author of the book The Evolutionary Ecology of Invasive Species (Academic Press, 2022). Jaco is a long-standing associate editor for several international journals, including Biological Invasions, Conservation Genetics, Austral Ecology and Oecologia.