How does the foraging behavior of large herbivores cause different associational plant defenses?
How does the foraging behavior of large herbivores cause different associational plant defenses?
复制标题
大型食草动物的觅食行为如何导致不同的联合植物防御？
DOI：
10.1038/srep20561
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发表时间：
2016-02-05
影响因子：
4.6
通讯作者：
Liu C
中科院分区：
文献类型：
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作者：
Huang Y;Wang L;Wang D;Zeng DH;Liu C
引诱-诱饵假说预测，当食草动物在植物物种尺度上做出决定时，焦点植物可以通过与首选植物相邻来防御食草动物。排斥植物假说认为，当食草动物在斑块尺度上有选择性时，焦点植物将通过与非首选邻居联系来获得保护。然而，食草动物通常在这些尺度上同时做出觅食决定。焦点植物脆弱性的净结果可能取决于食草动物的选择性程度更强的空间尺度。我们量化并比较了羊的斑块内和斑块间总体选择性指数（OSI），以研究关联植物效应与草食动物觅食选择性之间的关系。研究发现，羊的OSI在斑块内比斑块间更强，但焦点植物脆弱性符合这两种假设。当两个尺度之间的OSI差异较大时，焦点植物用首选邻居来捍卫草食。当OSI差异缩小时，焦点植物获得了非首选邻居的保护。因此，草食动物对相关尺度的选择性差异导致了不同的关联植物防御。我们的研究对了解植物-食草动物相互作用和草地管理具有重要意义。
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.