多样性高的群落拥有高的功能潜力（如生物量），因为物种可以利用不同的资源和应对不同的环境因子。然而，在高竞争性群落中，由于对共享资源的激烈竞争，个体生长效率往往较低。Maynard等学者的研究表明竞争网络（例如谁打败谁）最终决定多样性的增加会导致功能的增加还是降低。多样性-功能之间的关系取决于群落是否具有“石头-剪刀-布（Rock-paper-scissors）（即不相容）”机制，以及它们是否包括强、弱竞争者。这些结果突出表明竞争网络对于预测生物多样性的丧失对生态系统功能产生积极或消极影响是不可或缺的。
该论文发表在PNAS，2017年114卷43期，doi: 10.1073/pnas.1712211114
论文题目和摘要
Competitive network determines the direction of the diversity–function relationship
The structure of the competitive network is an important driver of biodiversity and coexistence in natural communities. In addition to determining which species survive, the nature and intensity of competitive interactions within the network also affect the growth, productivity, and abundances of those individuals that persist. As such, the competitive network structure may likewise play an important role in determining community-level functioning by capturing the net costs of competition.Here, using an experimental system comprising 18 wood decay basidiomycete fungi, we test this possibility by quantifying the links among competitive network structure, species diversity, and community function. We show that species diversity alone has negligible impacts on community functioning, but that diversity interacts with two key properties of the competitive network—competitive intransitivity and average competitive ability—to ultimately shape biomass production, respiration, and carbon use efficiency. Most notably, highly intransitive communities comprising weak competitors exhibited a positive diversity–function relationship, whereas weakly intransitive communities comprising strong competitors exhibited a negative relationship. These findings demonstrate that competitive network structure can be an important determinant of community-level functioning, capturing a gradient from weakly to strongly competitive communities. Our research suggests that the competitive network may therefore act as a unifying link between diversity and function, providing key insight as to how and when losses in biodiversity will impact ecosystem function.
