Quantitative estimates of isopod resource utilization using a Bayesian fatty acid mixing model
Quantitative estimates of isopod resource utilization using a Bayesian fatty acid mixing model
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DOI：
10.3354/meps10860
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发表时间：
2014-07-17
影响因子：
2.5
通讯作者：
Brett, M. T.
中科院分区：
文献类型：
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作者：
Galloway, A. W. E.;Eisenlord, M. E.;Brett, M. T.
草食性初级消费者是微藻、大型植物和维管植物的初级生产与高级消费者之间的关键中间营养联系。脂肪酸 (FA) 生物标志物可用于评估水生生态系统中的营养相互作用，因为藻类 FA 特征具有清晰的系统发育分离。我们使用基于 FA 的贝叶斯混合模型 (FASTAR) 对美国华盛顿州普吉特湾 6 个地点的潮间带草食性等足类动物 Idotea wosnesenskii 的 3 个藻类进行了定量饮食估计。我们生成了一个在 10 周喂养试验中喂养不同藻类饮食的等足动物 FA 特征的“资源库”，并使用这些经验数据对 FASTAR 进行参数化，从而解释了饮食 FA 的等足动物修改。快速生长的幼鱼 Idotea 的 FA 谱与其饮食特征密切相关，并且几种多不饱和 FA (PUFA) 在饮食和消费者之间高度相关（例如 Sigma C-18 omega 6 + C-18 omega 3、20:4 omega 6 和 20:5 omega 3）。我们使用该模型来表征地点内个体等足类动物饮食的变异性，并测试等足类动物是否优先利用特定的藻类或与田间现有藻类的比例相似。结果确定了某些地点内个体等足类动物资源利用的差异，以及地点水平与可用藻类总覆盖度的相似性。野生等足类动物的体重指数在模型显示绿藻和褐藻利用率高（例如>30%）且红藻支持率低的地点最高。这种基于 FA 的新颖混合模型方法证明了对快速生长的水生草食动物进行定量饮食估计的潜力。
Herbivorous primary consumers are a key intermediate trophic linkage between primary production from microalgae, macrophytes, and vascular plants and higher-level consumers. Fatty acid (FA) biomarkers are useful for evaluating trophic interactions in aquatic ecosystems because of clear phylogenetic separation of algal group FA signatures. We used a FA-based Bayesian mixing model (FASTAR) to generate quantitative diet estimates of 3 algal phyla for an intertidal herbivorous isopod, Idotea wosnesenskii, at 6 sites in Puget Sound, Washington, USA. We generated a 'resource library' of FA signatures of isopods fed diverse algal diets in 10-wk feeding trials and used these empirical data to parameterize FASTAR, thus accounting for isopod modification of dietary FA. The FA profiles of fast-growing juvenile Idotea were closely related to the signatures of their diets, and several polyunsaturated FA (PUFA) were highly correlated between diet and consumer (e.g. Sigma C-18 omega 6 + C-18 omega 3, 20:4 omega 6, and 20:5 omega 3). We used the model to characterize individual isopod diet variability within sites and to test whether isopods utilize specific algal phyla preferentially or in similar proportions to algae available in the field. The results identified both variation in resource utilization among individual isopods within certain sites, and site level similarities with total available algal cover. Body mass index of wild isopods was highest at sites where the model indicated high utilization (e.g. >30%) of both green and brown algae and low support from red algae. This novel FA-based mixing model approach demonstrated the potential for quantitative diet estimations of fast-growing aquatic herbivorous consumers.