Abstract
This study characterizes the structure of a plant–pollinator network in a temperate rain forest of Chiloé Island, southern Chile, where woody species are strongly dependent on biotic pollinators, and analyzes its robustness to the loss of participating species. Degree distribution, nestedness, and expected species persistence were evaluated. In addition, we assessed the roles of predefined subsets of plants (classified by life forms) and pollinators (grouped by taxonomic orders) in the network’s structure and dynamics. For this, we simulated the complete removal of each plant and pollinator subset and analyzed the resultant connectivity patterns, as well as the expected long-term species losses by running a stochastic model. Finally, we evaluated the sensitivity of the network structure to the loss of single species in order to identify potential targets for conservation. Our results show that the plant–pollinator network of this Chilean temperate rain forest exhibits a nested structure of interactions, with a degree distribution best described by a power law model. Model simulations revealed the importance of trees and hymenopterans as pivotal groups that maintain the core structure of the pollination network and guarantee overall species persistence. The hymenopterans Bombus dahlbomii and Diphaglossa gayi, the shrubs Tepualia stipularis and Ugni molinae, the vines Mitraria coccinea and Asteranthera ovata, and the entire set of tree species exerted a disproportionately large influence on the preservation of network structure and should be considered as focal species for conservation programs given current threats from selective logging and habitat loss.
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Acknowledgements
The authors thank J. D. Flores for his valuable help in scientific computing, M. A. Fortuna for his help with the dynamic model, M. A. Rodríguez-Gironés for specially implementing a batch version of his software BINMATNEST, and M. Franco for improving the readability of this paper. All the experiments and sampling comply with the current laws of the country (Chile) in which they were performed. Work started by an Endowed Presidential Chair in Sciences to J. J. A. We acknowledge support from FONDAP–FONDECYT 1501-0001, P05-002 ICM and PFB-23 CONICYT, Chile. This is a contribution to the research program of Senda Darwin Biological Station, Chiloé, Chile. We appreciate the company and assistance in the field of M. Nuñez-Ávila, L. Suárez, P. Martínez and el Negro.
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Communicated by Miguel Franco.
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Ramos-Jiliberto, R., Albornoz, A.A., Valdovinos, F.S. et al. A network analysis of plant–pollinator interactions in temperate rain forests of Chiloé Island, Chile. Oecologia 160, 697–706 (2009). https://doi.org/10.1007/s00442-009-1344-7
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DOI: https://doi.org/10.1007/s00442-009-1344-7