Stoichiometrically Explicit Competition between Grazers: Species Replacement, Coexistence, and Priority Effects along Resource Supply Gradients
Stoichiometrically Explicit Competition between Grazers: Species Replacement, Coexistence, and Priority Effects along Resource Supply Gradients
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食草动物之间化学计量的显式竞争：物种替换、共存和资源供应梯度的优先效应
DOI：
10.1086/422201
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
S. Hall
中科院分区：
文献类型：
--
作者：
S. Hall
假设相互作用之间的关键权衡，几个模型（资源比，基石捕食，intraguild捕食）预测物种组成的变化在资源供应梯度。生态化学计量学也可以预测的组成变化梯度的营养和光供应的机制，涉及（错误）之间的匹配的元素体组成的食草动物和植物。本文使用一套两个食草动物，一个植物模型来探讨这一假设，该模型包含三个关键组成部分：植物生产取决于光照和营养，植物的营养含量可以变化，稳态食草动物可能是碳或营养有限的。该套件的结果非常类似于经典的资源比模型描述植物竞争两种资源。在这里，模型预测的变化，食草动物组成沿着资源供应梯度，如果物种权衡植物碳和养分的竞争能力。考虑到这种权衡，上级营养竞争者应该主导低营养环境，而上级碳竞争者应该主导高营养环境。在中等营养供应下，物种可以在稳定的平衡中共存，或者出现替代的稳定状态，这取决于食草动物如何影响它们的资源。然而，这些结果取决于食物网结构。例如，捕食者可以改变或减少食草动物化学计量介导共存的可能性。
Assuming key trade‐offs among interactors, several models (resource ratio, keystone predation, intraguild predation) predict changes in species composition over resource supply gradients. Ecological stoichiometry could also predict compositional shifts of grazers over gradients of nutrient and light supply through a mechanism involving (mis)matches between elemental body composition of grazers and plants. This hypothesis is explored here using a suite of two‐grazer, one‐plant models that incorporate three key components: plant production depends on light and nutrients, nutrient content of plants can vary, and homeostatic grazers can be carbon or nutrient limited. The results from this suite closely resemble the classical resource ratio model describing plant competition for two resources. Here, the models predict shifts of grazer composition along resource supply gradients if species trade off competitive abilities for plant carbon and nutrients. Given this trade‐off, superior nutrient competitors should dominate low nutrient environments, and superior carbon competitors should dominate high nutrient environments. At intermediate nutrient supply, species can coexist at a stable equilibrium, or alternative stable states emerge, depending on how grazers impact their resources. These results depend on food web architecture, however. For instance, predators can alter or reduce possibilities for stoichiometry‐mediated coexistence of grazers.