University of Bristol, School of Biological Sciences, Woodland Road, Bristol BS8 1UG, United Kingdom; University of Queensland, School of Biological Sciences, QLD 4072, Australia; CSIRO Sustainable Ecosystems, Queensland Bioscience Precinct, 306 Carmody Road, St Lucia, QLD 4067, Australia; South African National Biodiversity Institute, Kirstenbosch Research Centre, Claremont 7735, Cape Town, South Africa
Carvalheiro, L.G., University of Bristol, School of Biological Sciences, Woodland Road, Bristol BS8 1UG, United Kingdom, South African National Biodiversity Institute, Kirstenbosch Research Centre, Claremont 7735, Cape Town, South Africa; Buckley, Y.M., University of Queensland, School of Biological Sciences, QLD 4072, Australia, CSIRO Sustainable Ecosystems, Queensland Bioscience Precinct, 306 Carmody Road, St Lucia, QLD 4067, Australia; Jane, M., University of Bristol, School of Biological Sciences, Woodland Road, Bristol BS8 1UG, United Kingdom
Invasive plants are considered a major cause of ecosystem degradation worldwide. While their impacts on native plants have been widely reported, there is little information on how these impacts propagate through food webs and affect species at higher trophic levels. Using a quantitative food web approach we evaluated the impacts of an invasive plant on plant-herbivore-parasitoid communities, asking specifically how diet breadth influences the propagation of such impacts. Measuring the impact of the alien plant at the plant level seriously underestimated the community-level effect of this weed as it also caused changes in the abundance of native herbivores and parasitoids, along with a decrease in parasitoid species richness. The invading plant affected specialist and generalist subsets of communities differently, having significant and strong negative impacts on the abundance of all specialists with no negative effect on generalist consumers. Specialist consumer decline led to further disruptions of top-down regulatory mechanisms, releasing generalist species from competition via shared natural enemies. Plant invasion also significantly increased the evenness of species abundance of all trophic levels in the food webs, as well as the evenness of species interaction frequency. Extending impact evaluation to higher trophic levels and considering changes in trophic diversity within levels is hence essential for a full evaluation of the consequences of invasion by alien plants. Moreover, information on diet breadth of species in the invaded community should be taken into account when evaluating/predicting the impacts on any introduced species. © 2010 by the Ecological Society of America.
degradation; dicotyledon; diet; food web; herbivore; invasive species; native species; parasitoid; species richness; trophic cascade; animal; article; classification; diet; environmental protection; feeding behavior; food chain; host parasite interaction; insect; parasitology; physiology; plant; United Kingdom; Animals; Conservation of Natural Resources; Diet; Feeding Behavior; Food Chain; Great Britain; Host-Parasite Interactions; Insects; Plants; Avon; Dorset [England]; England; United Kingdom; Gaultheria shallon