alien phytogeographic regions of southern africa numerical classification, possible drivers, and regional threats外星人phytogeographic地区南部非洲的数值分类,可能司机,和地区的威胁.pdfVIP

Alien Phytogeographic Regions of Southern Africa: Numerical Classification, Possible Drivers, and Regional Threats 1 1,2 3 4 Sanet Hugo *, Berndt J. Van Rensburg , Abraham E. Van Wyk , Yolande Steenkamp 1 Department of Zoology and Entomology, DST-NRF Centre of Excellence for Invasion Biology, University of Pretoria, Pretoria, South Africa, 2 School of Biological Sciences, University of Queensland, Brisbane, Australia, 3 Department of Plant Science, University of Pretoria, Pretoria, South Africa, 4 Biosystematics Research Biodiversity Collections Division, South African National Biodiversity Institute, Pretoria, South Africa Abstract The distributions of naturalised alien plant species that have invaded natural or semi-natural habitat are often geographically restricted by the environmental conditions in their new range, implying that alien species with similar environmental requirements and tolerances may form assemblages and characterise particular areas. The aim of this study was to use objective numerical techniques to reveal any possible alien phytogeographic regions (i.e. geographic areas with characteristic alien plant assemblages) in southern Africa. Quarter degree resolution presence records of naturalised alien plant species of South Africa, Lesotho, Swaziland, Namibia and Botswana were analysed through a divisive hierarchical classification technique, and the output was plotted on maps for further interpretation. The analyses revealed two main alien phytogeographic regions that could be subdivided into eight lower level phytogeographic regions. Along with knowledge of the environmental requirements of the characteristic species a