|Release from native root herbivores and biotic resistance by soil pathogens in a new habitat both affect the alien Ammophila arenaria in South Africa|
|Knevel, I.C.; van den Putten, W.H.; Lubke, R.A. (2005). Release from native root herbivores and biotic resistance by soil pathogens in a new habitat both affect the alien Ammophila arenaria in South Africa, in: Herrier, J.-L. et al. (Ed.) (2005). Proceedings 'Dunes and Estuaries 2005': International Conference on nature restoration practices in European coastal habitats, Koksijde, Belgium 19-23 September 2005. VLIZ Special Publication, 19: pp. 179-189|
|In: Herrier, J.-L. et al. (Ed.) (2005). Proceedings 'Dunes and Estuaries 2005': International Conference on nature restoration practices in European coastal habitats, Koksijde, Belgium 19-23 September 2005. VLIZ Special Publication, 19. Vlaams Instituut voor de Zee (VLIZ): Oostende. XIV, 685 pp., more|
|In: VLIZ Special Publication. Vlaams Instituut voor de Zee (VLIZ): Oostende. ISSN 1377-0950, more|
Abdomen; Invasive plants; PSW, South Africa [gazetteer]; Marine
The European dune pioneer Ammophila arenaria (marram grass) was introduced in the 1870’s in South Africa and has ever since been used to stabilise Cape coastal dunes. At present the alien grass is still an important drift sand stabiliser. Recently, however, the use of A. arenaria has been criticized due to its foreign origin and the proven facts of invasiveness in other parts of the world. One of the major explanations of the success of introduced species in recipient communities is their release from natural enemies (Enemy Release Hypothesis - ERH). On the other hand, when exotic plant species fail to invade new habitats this has been related to biotic resistance from the native communities to be invaded (Biotic Resistance Hypothesis - BRH). In its area of origin A. arenaria dominates the fore dune plant community of mobile dunes, but it disappears naturally when dunes become stabilised mainly due to growth control by soil-borne pathogens. We examined ERH and BRH in relation to the invasiveness of the exotic fore dune grass A. arenaria in South Africa. The results from our study support both ERH and BRH in the case of soil pathogens of the introduced A. arenaria in South African dunes, indicating that ERH and BRH may be active simultaneously. Possibly a number of exotic plant species that does not become highly invasive, such as A. arenaria in South Africa, experience both ERH and BRH. The balance between enemy escape versus biotic resistance will determine the invasiveness of a species in a new habitat. In the case of A. arenaria, the generalist nematodes and the negative soil feedback apparently originate from the local grasses, whereas the dicots were less important in sharing potential pathogens. Our results further suggest that not only the local plant species diversity, but also the type of plant species present will determine the potential for biotic resistance. The biotic resistance against invasive plant species may depend on plant competition, but also on the presence of plant species that are hosts of potential soil pathogens that may negatively affect the invaders.