PARENT SESSION
Oral Session #63: Invasive Species: Terrestrial.
Presiding: D. Larson
Wednesday, August 7. 1:00 PM to 4:45 PM. Graham Meeting Room, TCC.
Plant ecology of Opuntia stricta (Haworth.) Haworth., an invasive alien plant in the Kruger National Park.
Foxcroft, Llewellyn*,1, Hoffmann, John2, Viljoen, Jozua3, Kotze, Koos3, 1 South African National Parks, Kruger National Park, South Africa2 University of Cape Town, Cape Town, South Africa3 Pretoria Technicon, Pretoria, South Africa
ABSTRACT- Opuntia stricta is the most problematic invasive alien plant species in the Kruger National Park (KNP) where over 66 000 ha have been invaded to varying degrees. O. stricta, indigenous to North and Central America, is a widespread invasive species in Australia and is expanding its range in South Africa. Studies on basic plant ecology of this species should highlight whether the same or different drivers in its native and invaded habitats influence distribution. We report on studies conducted to determine which factors significantly influence distribution and density of O. stricta in the non-native KNP. Analysis of variables collected under field conditions links distribution and abundance of O. stricta to age of invasion and habitat type in the Skukuza region. Data collected from a 25000 ha invasions are subject to GIS analyses and ordination methods to determine contribution to distribution and abundance outcomes. The strongest determinants are fire regime, substrate, soil texture and depth, which indicate a strong ability of O. stricta to invade most areas of the KNP. These outcomes are linked to the management plan for this species and have implications for its effective implementation and control operations.
KEY WORDS: Opuntia stricta, Invasive alien plant, Distribution, Environmental influences