Eger Aaron M, Best Rebecca J, Baum Julia K
Department of Biology University of Victoria Victoria BC Canada.
Present address: School of Biological, Earth, and Environmental Sciences University of New South Wales Sydney NSW Australia.
Ecol Evol. 2021 Jul 6;11(15):10489-10501. doi: 10.1002/ece3.7854. eCollection 2021 Aug.
Biodiversity and ecosystem function are often correlated, but there are multiple hypotheses about the mechanisms underlying this relationship. Ecosystem functions such as primary or secondary production may be maximized by species richness, evenness in species abundances, or the presence or dominance of species with certain traits. Here, we combine surveys of natural fish communities (conducted in July and August 2016) with morphological trait data to examine relationships between biodiversity and ecosystem function (quantified as fish community biomass) across 14 subtidal eelgrass meadows in the Northeast Pacific (54°N, 130°W). We employ both taxonomic and functional trait measures of diversity to investigate whether ecosystem function is best predicted by species diversity (complementarity hypothesis) or by the presence or dominance of species with particular trait values (selection or dominance hypotheses). After controlling for environmental variation, we find that fish community biomass is maximized when taxonomic richness and functional evenness are low, and in communities dominated by species with particular trait values, specifically those associated with benthic habitats and prey capture. While previous work on fish communities has found that species richness is often positively correlated with ecosystem function, our results instead highlight the capacity for regionally prevalent and locally dominant species to drive ecosystem function in moderately diverse communities. We discuss these alternate links between community composition and ecosystem function and consider their divergent implications for ecosystem valuation and conservation prioritization.
生物多样性与生态系统功能常常相互关联，但对于这种关系背后的机制存在多种假说。诸如初级或次级生产等生态系统功能可能会因物种丰富度、物种丰度的均匀度，或具有某些特征的物种的存在或优势而达到最大化。在此，我们将对天然鱼类群落的调查（于2016年7月和8月进行）与形态特征数据相结合，以研究东北太平洋（北纬54°，西经130°）14个潮下带鳗草草甸中生物多样性与生态系统功能（以鱼类群落生物量量化）之间的关系。我们采用分类学和功能特征多样性度量方法，来探究生态系统功能是由物种多样性（互补性假说），还是由具有特定特征值的物种的存在或优势（选择或优势假说）能得到最佳预测。在控制环境变异后，我们发现当分类学丰富度和功能均匀度较低时，以及在由具有特定特征值的物种（特别是那些与底栖生境和猎物捕获相关的物种）主导的群落中，鱼类群落生物量达到最大化。虽然先前关于鱼类群落的研究发现物种丰富度通常与生态系统功能呈正相关，但我们的结果反而突出了区域普遍且局部占主导地位的物种在中等多样性群落中驱动生态系统功能的能力。我们讨论了群落组成与生态系统功能之间的这些不同联系，并考虑了它们对生态系统估值和保护优先级的不同影响。
