title: Protected-area boundaries as filters of plant invasions.
abstract: Human 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.
authors.affiliation: Conservation Services, South African National Parks, Skukuza 1350, South Africa. llewellynf@sanparks.org
authors.forename: Llewellyn C
authors.initials: LC
authors.lastname: Foxcroft
authors.forename: Vojtěch
authors.initials: V
authors.lastname: Jarošík
authors.forename: Petr
authors.initials: P
authors.lastname: Pyšek
authors.forename: David M
authors.initials: DM
authors.lastname: Richardson
authors.forename: Mathieu
authors.initials: M
authors.lastname: Rouget
mesh_terms: D044822:Biodiversity; D003247:Conservation of Natural Resources / Q000379:methods*; D058865:Introduced Species; D010944:Plants; D011157:Population Dynamics; D013019:South Africa