Jonatan Rodríguez1,2,3, Adolfo Cordero-Rivera3 and Luís González1,2
1Plant Ecophysiology Group, Department of Plant Biology and Soil Science, University of Vigo, 36310 Vigo, Spain
2CITACA, Agri-Food Research and Transfer Cluster, Campus da Auga, University of Vigo, 32004-Ourense, Spain
3ECOEVO Lab, E. E. Forestal, University of Vigo, 36005 Pontevedra, Spain
Plant invasions alter the composition of native communities by inducing negative effects on biodiversity-ecosystem functioning. Globalization facilitates the mobilization of alien species into non-native ecosystems resulting in new environmental situations and disrupting the taxonomic, behavioural and functional diversities. Native plant communities may be affected by competition with introduced plants. However, the effects of plant invasions on plant-herbivore interactions have been rarely studied. Here, we examined how plant diversity influences the occurrence of herbivores in ten coastal areas with the presence of Carpobrotus edulis in the NW Iberian Peninsula. The aims were to (i) evaluate the abundance of herbivorous invertebrates in different communities (invaded vs native), (ii) assess the effect of the biotic resistance on the performance of C. edulis, and (iii) explore the structure of the plant-herbivore interaction networks. We identified 18 different herbivorous invertebrates feeding on introduced and native plants, of which 12 fed on C. edulis. The herbivore species composition was affected by the invasive status and plots situated at a medium distance to the sea had more beta-diversity. Our results show that snails lead to an increase in the number of damaged flowers of Carpobrotus and hemipterans can affect the leaf thickness or hydration. Native areas had more specialized herbivorous species and higher values for network descriptors than invaded areas. We conclude that the feeding behaviour of the snail, Theba pisana, might act as a natural biological control by reducing the production of seeds in C. edulis. Overall, further research is necessary to understand the impacts of non-native plants as a result of invertebrates and implement long-term management strategies that are key to reduce the spread of C. edulis.