ESM10.xlsx from A network-based measure of functional diversity in food webs

Biodiversity is measured from various perspectives. One of them, functional diversity, quantifies the heterogeneity in species traits and roles in an ecosystem. One important aspect of species roles is their interactions with other species, i.e. their network role. We therefore investigate here functional diversity from the network perspective. Species differ in their network positions in a food web, having different interaction patterns. We developed a measure for quantifying the diversity in species interaction patterns in a food web. We examined the relationship between interaction diversity and several global network properties for 92 food webs. Our results showed that high interaction diversity occurs in sparsely connected and less cohesive food webs. High interaction diversity also occurred in food webs with more clusters and high network modularity. We also quantified several conventional functional diversity indices and demonstrate that they show little or no correlation with interaction diversity. Our proposed diversity index therefore provides a measure complementary to current concepts of functional diversity.

生物多样性可通过多种视角开展量化评估。其中，功能多样性（functional diversity）用于量化生态系统中物种性状及其生态作用的异质性。物种生态作用的一个重要维度，便是其与其他物种的相互作用，即其网络角色（network role）。因此，本文从网络视角展开功能多样性的相关研究。在食物网中，不同物种所处的网络位置各不相同，其所呈现的相互作用模式也存在差异。为此，我们构建了一种量化食物网内物种相互作用模式多样性的指标。我们针对92个食物网，分析了相互作用多样性与多项全局网络属性之间的关联。研究结果显示，高相互作用多样性常见于连接度较低、聚合性较弱的食物网中。同时，高相互作用多样性也存在于具有更多群落模块以及较高网络模块化程度的食物网中。我们还对多项传统功能多样性指数进行了量化，并证实这些指数与相互作用多样性几乎不存在相关性。因此，本文提出的多样性指标可作为现有功能多样性概念的补充量化手段。