title: How does the foraging behavior of large herbivores cause different associational plant defenses?
abstract: The attractant-decoy hypothesis predicts that focal plants can defend against herbivory by neighboring with preferred plant species when herbivores make decisions at the plant species scale. The repellent-plant hypothesis assumes that focal plants will gain protection by associating with nonpreferred neighbors when herbivores are selective at the patch scale. However, herbivores usually make foraging decisions at these scales simultaneously. The net outcomes of the focal plant vulnerability could depend on the spatial scale at which the magnitude of selectivity by the herbivores is stronger. We quantified and compared the within- and between-patch overall selectivity index (OSI) of sheep to examine the relationships between associational plant effects and herbivore foraging selectivity. We found that the sheep OSI was stronger at the within- than the between-patch scale, but focal plant vulnerability followed both hypotheses. Focal plants defended herbivory with preferred neighbors when the OSI difference between the two scales was large. Focal plants gained protection with nonpreferred neighbors when the OSI difference was narrowed. Therefore, the difference in selectivity by the herbivores between the relevant scales results in different associational plant defenses. Our study suggests important implications for understanding plant-herbivore interactions and grassland management.
authors: Institute of Grassland Science, Northeast Normal University, Key Laboratory of Vegetation Ecology, Ministry of Education, 5268 Renmin St., Changchun 130024, P.R. China.|State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, P.R. China.
authors: Yue
authors: Y
authors: Huang
authors: Institute of Grassland Science, Northeast Normal University, Key Laboratory of Vegetation Ecology, Ministry of Education, 5268 Renmin St., Changchun 130024, P.R. China.
authors: Ling
authors: L
authors: Wang
authors: Institute of Grassland Science, Northeast Normal University, Key Laboratory of Vegetation Ecology, Ministry of Education, 5268 Renmin St., Changchun 130024, P.R. China.
authors: Deli
authors: D
authors: Wang
authors: State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, P.R. China.
authors: De-Hui
authors: DH
authors: Zeng
authors: Northwest Polytechnical University, Centre for Ecological and Environmental Sciences, Xi'an, 710072, P.R. China.
authors: Chen
authors: C
authors: Liu
mesh_terms: D000818:Animals; D017753:Ecosystem; D060434:Herbivory / Q000502:physiology*; D008954:Models, Biological; D018521:Plant Physiological Phenomena; D012756:Sheep / Q000502:physiology*