Magilton Matthew, Maraun Mark, Emmerson Mark, Caruso Tancredi
School of Biological Sciences and Institute for Global Food Security Queen's University of Belfast Belfast UK.
JFB Institute of Zoology and Anthropology Georg August University Göttingen Göttingen Germany.
Ecol Evol. 2019 Jul 4;9(14):8320-8330. doi: 10.1002/ece3.5409. eCollection 2019 Jul.
The role of niche partitioning in structuring species-rich soil animal communities has been debated for decades and generated the "enigma of soil animal diversity." More recently, resource-based niche partitioning has been hypothesized to play a very limited role in the assembly of soil animal communities. To test this hypothesis, we applied a novel combination of stable isotopes and null models of species co-occurrence to quantify the extent of resource niche partitioning on a diverse oribatid mite community sampled from mature oak woodland.We asked whether species aggregate or segregate spatially and how these patterns correlated with the abundance of estimated trophic guilds. We also estimated the effects of environmental variables on community structure.All measured environmental variables accounted for 12% of variance in community structure, including 8% of pure spatial structure unrelated to measured environmental factors and 2% of pure environmental variance unrelated to spatial variation. Co-occurrence analysis revealed 10 pairs of species that aggregated and six pairs of species that were spatially segregated. Values of δN indicated that five out of the 10 pairs of aggregated species occupied the same trophic guild, while values of δC indicated that species in these five pairs consumed resources of different quality, supporting a significant role of resource-based niche partitioning. Also, one of the five pairs of segregated species occupied the same trophic guild but had overlapping δC values suggesting that these species do not co-occur locally and thus minimize competition for shared resources.Partitioning of resources plays an underestimated role in soil microarthropod communities and different local communities consisted of the same trophic guilds with species identity changing from place to place. The sum of resource partitioning, multi-trophic interactions, and microscale environmental variability in the environment is a viable solution to the enigma of soil animal diversity.
几十年来，生态位分化在构建物种丰富的土壤动物群落中的作用一直备受争议，并引发了“土壤动物多样性之谜”。最近，基于资源的生态位分化被认为在土壤动物群落的组装中作用非常有限。为了验证这一假设，我们应用了稳定同位素和物种共现零模型的新组合，来量化从成熟橡树林地采样的多样化甲螨群落中资源生态位分化的程度。我们研究了物种是在空间上聚集还是分离，以及这些模式如何与估计的营养类群丰度相关。我们还估计了环境变量对群落结构的影响。所有测量的环境变量解释了群落结构中12%的变异，包括与测量环境因素无关的8%的纯空间结构和与空间变异无关的2%的纯环境变异。共现分析揭示了10对聚集的物种和6对在空间上分离的物种。δN值表明，10对聚集物种中的5对占据相同的营养类群，而δC值表明这5对物种消耗不同质量的资源，支持基于资源的生态位分化的重要作用。此外，5对分离物种中的一对占据相同的营养类群，但δC值重叠，表明这些物种不在局部共现，从而最大限度地减少了对共享资源的竞争。资源分化在土壤微型节肢动物群落中发挥着被低估的作用，不同的局部群落由相同的营养类群组成，物种身份因地点而异。环境中资源分化、多营养相互作用和微观尺度环境变异性的总和是解决土壤动物多样性之谜的一个可行方案。
