Springer Online Journal Archives 1860-2000
Abstract Association analysis was used to assess relationships among 25 important alien plant species and their association with feral pig rooting in Hawaii Volcanoes National Park, Hawaii, U.S.A. Results of the association analysis were summarized by means of a simplified, rank-based, polar ordination which yielded three subjective species assemblages. One group was characterized by an association with the endpoint species, Ehrharta stipoides. A second group consisted of species associated with the other endpoint species, Andropogon virginicus. The third group comprised a diverse assemblage of 14 species in the middle of the ordination. Comparison of ordination scores with each species's association with pig-induced soil disturbance revealed that members of the Ehrharta group were strongly positively associated with pig activity, whereas members of the Andropogon group were generally negatively associated. The third group showed no association with pig-induced soil disturbance. These results suggest a strong relationship between feral pig activity and the composition of the alien portion of the plant community. Analysis of the ecologies of both plants and pigs suggests that some species may both encourage pig activity and benefit from it. Likewise, other alien plants appear to neither require nor benefit from pig-induced soil disturbance. While pigs appear to play an important role in the organization of these communities, their removal may have a negligible impact on the success of many of the common weeds in the area.
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