Plants do not suffer greater losses to seed predation towards the tropics
Plants do not suffer greater losses to seed predation towards the tropics
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DOI：
10.1111/geb.12636
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发表时间：
2017-11-01
影响因子：
6.4
通讯作者：
Moles, Angela T.
中科院分区：
文献类型：
--
作者：
Chen, Si-Chong;Hemmings, Frank A.;Moles, Angela T.
目的：传统上预测生物相互作用在热带地区更强。然而，以往关于种子捕食纬度梯度的研究要么是基于单一物种，要么是从不同生态系统中使用不同方法的研究中收集数据。我们的目标是提供第一个大规模的量化的纬度梯度在种子捕食在跨物种和物种内的水平。位置：25个网站跨越28度纬度的澳大利亚东海岸。方法：使用一致的协议，我们测量了256个物种x地点组合的扩散前种子捕食（共包括170个品种）和126个品种x地点组合（共包括91个品种）的扩散后种子清除，以及每个地点的标准米粒清除。种子捕食和纬度之间的关系进行了量化使用广义混合效应模型和荟萃analysis.Results：与预期相反，种子损失的比例扩散前种子捕食增加与纬度在跨物种水平，并没有表现出纬度的趋势在物种内的水平。有没有显着的纬度和种子的比例之间的关系，传播后的种子去除，无论是在物种内或跨物种。我们发现，在低纬度的标准米粒显着更高的去除，但这种趋势发生逆转，如果我们排除了四个岛屿的网站analysis.Main结论：种子捕食天然种子是不高的低纬度。因此，我们的研究加入了越来越多的证据，与热带物种比温带物种遭受更大的食草动物损失的想法相反。标准米粒的去除率的纬度梯度表明，来自低纬度的天然种子可能已经实现了类似的捕食率高纬度物种通过增加防御投资。然而，需要更多的数据来检验这一假设。
Aim: Biotic interactions have traditionally been predicted to be stronger towards the tropics. However, all previous studies about the latitudinal gradient in seed predation were either based on single species or compiled data from studies that used different methods in different ecosystems. Our goal was to provide the first broad-scale quantification of the latitudinal gradient in seed predation at both cross-species and within-species levels.Location: Twenty-five sites spanning 28 degrees of latitude on the east coast of Australia.Methods: Using consistent protocols, we measured pre-dispersal seed predation for 256 species x site combinations (including a total of 170 species) and post-dispersal seed removal for 126 species x site combinations (including a total of 91 species), as well as removal of standard rice grains at each site. The relationships between seed predation and latitude were quantified using generalized mixed-effects models and meta-analyses.Results: Contrary to expectations, the proportion of seeds lost to pre-dispersal seed predation increased with latitude at the cross-species level and showed no latitudinal trend at the within-species level. There was no significant relationship between latitude and the proportion of seeds lost to post-dispersal seed removal, either within species or across species. We found significantly higher removal of standard rice grains at lower latitudes, but this trend reversed if we excluded the four island sites from analysis.Main conclusions: Seed predation on natural seeds was not higher at lower latitudes. Thus, our study joins a growing body of evidence contrary to the idea that tropical species suffer greater losses to herbivores than do temperate species. The latitudinal gradient in removal rates for standard rice grains suggests that natural seeds from low latitudes may have achieved a similar predation rate to high-latitudinal species through increased investment in defenses. However, additional data will be necessary to test this hypothesis.