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C·I·B core team member, Llewellyn Foxcroft, was one of ten recipients of the 2010 Man and Biosphere Programme Young Scientist Awards which are endorsed by UNESCO (The United Nations Educational, Scientific and Cultural Organization). He received the award for a project focussing on the dispersal patterns of invasive alien plants along the Sabie River catchment.

Every year since 1989, the Man and Biosphere Programme has awarded grants up to R 38 000 (US$5,000) to ten young scientists, with the aim of encouraging young scientists to carry out interdisciplinary projects on ecosystems, natural resources and biodiversity in keeping with MAB Programme which focuses on sustainable interaction between people and their environment. The laureates for the 2010 Young Scientist awards were announced by the International Coordinating Council of UNESCO’s Man and the Biosphere programme (MAB), at a meeting held in Paris from 31 May to 4 June 2010.

The main aim of the Dr Foxcroft’s project is to determine the dispersal patterns of invasive alien plants along river corridors, from which suggestions for management may be made. The Sabie River catchment covers an area of about 7096 km2 and contains a large number of different land uses and alien plant control programmes. The headwaters of the catchment are approximately 120km from Kruger National Park, from where the Sabie River flows through the park and into Mozambique, therefore providing a perfect study site. Lantana camara (lantana), a globally problematic invasive plant, is widespread in the upper reaches and across the catchment, and thus was well suited as the focal species.

Using this study the investigators aim to test the assumption that the highly invaded areas in the headwaters of the watershed serve as source areas for these invasions. It is assumed that propagules move downstream during normal flow, but especially during large flood events. Management guidelines generally recommend control programmes to start at the upper watershed areas, working downstream. However, as logical as the assumption is, the areas of some watersheds are immense, making complete control from top to bottom unlikely. Further, this assumption does not consider the high likelihood of multiple introductions for different sources to different areas across the catchment. Thus, if the source of plants can be determined, management interventions can be strategically sited, making better use of limited resources.

The project will aim to track gene flow (the movement of genes in space) as a proxy for dispersal and connectivity between populations of lantana collected from across the Sabie catchment. From the genetic analysis it should be possible to determine the extent to which different populations are related to each other, thus identifying routes of invasion (sources, spread and dispersal). It should also be possible to determine which lantana populations are not related to any others within the catchment, and which have arisen due to introductions from sources outside the catchment. These results will show whether the assumption that the populations in the upper reaches of the catchment are in fact responsible for the invasion patterns in the rest of the catchment. Part of this work will form the basis for the MSc project of C·I·B student Ms Wafeeka Vardien.

Dr Llewellyn Foxcroft is currently based in the Kruger National Park where he holds the position of scientist/ecologist. He is responsible for the Invasion Ecology research and monitoring programme in South African National Parks. His main research interests are in alien plant invasions, investigating the processes and patterns of invasion, and the links to management interventions. He also has wide ranging interests in conservation biology, as well as the use of strategic adaptive management frameworks as a means of connecting science, management and policy. He is the editor of the journal Koedoe: African Protected Area Conservation and Science.

Dr Llewellyn Foxcroft and MSc student Wafeeka Vardien collecting leaf samples of Lantana camara in the Sabie River catchment (Photo: DM Richardson).