Functional traits are characteristics of an organism that represent how it interacts with its environment and can influence the structure and function of ecosystems. Ecological stoichiometry provides a framework to understand ecosystem structure and function by modeling the coupled flow of elements (e.g. carbon [C], nitrogen [N], phosphorus [P]) between consumers and their environment. Animals tend to be homeostatic in their nutrient requirements and preferentially sequester the element in shortest supply relative to demand, and release relatively more of the element in excess. Tissue stoichiometry is an important functional trait that allows for predictions among the elemental composition of animals, their diet, and their waste products, with important effects on the cycling and availability of nutrients in ecosystems. Here we examined the tissue stoichiometric niches (C:N:P) and nutrient recycling stoichiometries (N:P) of several filter-feeding freshwater mussels in the subfamily Ambleminae. Despite occupying the same functional-feeding group and being restricted to a single subfamily-level radiation, we found that species occupied distinct stoichiometric niches and that these niches varied, in part, as a function of their evolutionary history. The relationship between phylogenetic divergence and functional divergence suggests that evolutionary processes may be shaping niche complementarity and resource partitioning. Tissue and excretion stoichiometry were negatively correlated as predicted by stoichiometric theory. When scaled to the community, higher species richness and phylogenetic diversity resulted in greater functional evenness and reduced functional dispersion. Filter-feeding bivalves are an ecologically important guild in freshwater ecosystems globally, and our study provides a more nuanced view of the stoichiometric niches and ecological functions performed by this phylogenetically and ecologically diverse assemblage.

中文翻译：

---

进化历史推动了公会内化学计量生态位变异和功能影响的各个方面

功能性状是生物体的特征，表示它如何与环境相互作用，并可以影响生态系统的结构和功能。生态化学计量学提供了一个框架，通过对消费者与其环境之间的元素（例如碳 [C]、氮 [N]、磷 [P]）的耦合流动进行建模，来了解生态系统的结构和功能。动物的营养需求往往是稳态的，相对于需求，优先隔离供应最短的元素，并释放相对更多的元素。组织化学计量是一个重要的功能特性，可以预测动物的元素组成、它们的饮食和它们的废物，对生态系统中营养物质的循环和可用性具有重要影响。在这里，我们检查了 Ambleminae 亚科中几种滤食性淡水贻贝的组织化学计量比 (C:N:P) 和养分回收化学计量 (N:P)。尽管占据相同的功能性喂养组并仅限于单个亚科水平的辐射，我们发现物种占据不同的化学计量生态位，并且这些生态位在一定程度上因它们的进化历史而异。系统发育差异和功能差异之间的关系表明，进化过程可能正在塑造生态位互补性和资源分配。正如化学计量理论所预测的那样，组织和排泄的化学计量呈负相关。当扩展到社区时，更高的物种丰富度和系统发育多样性导致更大的功能均匀性和减少的功能分散。滤食性双壳类动物是全球淡水生态系统中一个重要的生态类群，我们的研究为这种系统发育和生态多样性组合所执行的化学计量生态位和生态功能提供了更细致入微的观点。