A review of allodiversity in Lake Naivasha, Kenya: Developing conservation actions to protect East African lakes from the negative impacts of alien species
Gherardi J, Francesca
Harper, David M
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The biodiversity of developing countries is increasingly threatened by introductions of invasive alien species. This study on the allodiversity in Lake Naivasha, Kenya reviews the pathways, establishment rates and outcomes of introduced species, and provides the basis for determining conservation actions that, if implemented, could prevent potentially harmful effects of similar events in other East African lakes. Introductions into Naivasha commenced in the 1920s with the release of a sport fish and have since produced an allodiversity of 23 species. This includes species that are no longer present (e.g., some tilapia species), presumed no longer present (e.g., the Nile perch Lates niloticus) or whose distribution is highly localised and ecologically neutral (e.g., the coypu Myocastor coypus). It also includes species that established successfully and invoked major changes in lake ecology (e.g., the red swamp crayfish Procambarus clarkii) and a species that is producing apparent economic benefits to the local population (i.e., the common carp Cyprinus carpio). The most frequent donor continents were the Americas and most species were the result of secondary introductions. The main introduction vector was active release that aimed to enhance fishery production. Alien species now dominate each main level of the lake’s food web and produce impacts that are rarely restricted to a single ecosystem service. With a few exceptions, the majority of introductions translate into socioeconomic costs that contribute to rising social conflicts and exacerbating poverty. Development of appropriate conservation management tools within a regulatory framework could help protect Naivasha from further damage and could be used elsewhere in East African lakes to ensure that subsequent introductions enhance ecosystem services without affecting biodiversity.
CitationBiological Conservation Volume 144, Issue 11, November 2011, Pages 2585–2596
ScienceDirectDipartimento di Biologia Evoluzionistica “Leo Pardi”, Università degli Studi di Firenze, Via Romana 17, 50125 Firenze, ItalySchool of Conservation Sciences, Bournemouth University, Poole, Dorset BH12 5BB, UKSchool of Biological Sciences, University of Nairobi, Nairobi, KenyaSchool of Biological Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UKDepartment of Biology, University of Leicester, University Road, Leicester LE1 7RH, UKDipartimento di Ecologia, Università degli Studi della Calabria, 87030 Arcavacata di Rende, Italy