Vernon Visser

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Distribution data are central to many invasion science applications. The shortage of good information on the distribution of alien species and their spatial dynamics is largely attributable to the cost, effort and expertise required to monitor these species over large areas. Virtual globes, particularly Google Earth, are free and user-friendly software(More)
Native geographical range extent has frequently emerged as a correlate of invasiveness, especially for plant species. We tested whether dimensions of the native range (measured by the area-of-occupancy and its scaling patterns) of 720 Australian eucalypts (genera Angophora, Eucalyptus and Corymbia) could explain introduction and invasion success. We also(More)
Conifer populations appear disproportionately threatened by global change. Most examples are, however, drawn from the northern hemisphere and long-term rates of population decline are not well documented as historical data are often lacking. We use a large and long-term (1931–2013) repeat photography dataset together with environmental data and fire records(More)
The legume, Pueraria montana var. lobata (kudzu vine) is one of the worst plant invaders globally. Here we present the first study of P. montana in South Africa. We found only seven P. montana populations covering an estimated condensed area of 74 hectares during the height of the growing season. Based on a species distribution model, it appears that large(More)
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