Foxcroft, Llewellyn C.Jarosık, VojtechPysek, PetrRichardson, D.M. (David Mark), 1958-Rouget, Mathieu2011-08-082011-08-082011-04Foxcroft, LC, Jarosik, V, Pysek, P, Richardson, DM & Rouget, M 2011, 'Protected-area boundaries as filters of plant invasions', Conservation Biology, vol. 25, no. 2, pp. 400-405.0888-8892 (print)1523-1739 (online)10.1111/j.1523-1739.2010.01617.xhttp://hdl.handle.net/2263/17028Human land uses surrounding protected areas provide propagules for colonization of these areas by non-native species, and corridors between protected-area networks and drainage systems of rivers provide pathways for long-distance dispersal of non-native species. Nevertheless, the influence of protected-area boundaries on colonization of protected areas by invasive non-native species is unknown. We drew on a spatially explicit data set of more than 27,000 non-native plant presence records for South Africa's Kruger National Park to examine the role of boundaries in preventing colonization of protected areas by non-native species. The number of records of non-native invasive plants declined rapidly beyond 1500 m inside the park; thus, we believe that the park boundary limited the spread of non-native plants. The number of non-native invasive plants inside the park was a function of the amount of water runoff, density of major roads, and the presence of natural vegetation outside the park. Of the types of human-induced disturbance, only the density of major roads outside the protected area significantly increased the number of non-native plant records. Our findings suggest that the probability of incursion of invasive plants into protected areas can be quantified reliably.enWiley-Blackwell. The definite version is available at www.blackwell-synergy.com. This article is embargoed by the publisher until April 2012.Barriers to invasionNon-native invasive speciesOverland water flowProtected-area boundaryPlant invasions -- South Africa -- Kruger National ParkAlien plants -- South Africa -- Kruger National ParkProtected areas -- ManagementNational parks and reserves -- South AfricaPostprint Article