Norkko Alf, Villnäs Anna, Norkko Joanna, Valanko Sebastian, Pilditch Conrad
1] Tvärminne Zoological Station, University of Helsinki, FI-10900 Hanko, Finland [2] Marine Research Centre, Finnish Environment Institute, PO Box 140, FI-00251 Helsinki, Finland.
Sci Rep. 2013;3:2646. doi: 10.1038/srep02646.
Size is a fundamental organismal trait and an important driver of ecosystem functions. Although large individuals may dominate some functions and provide important habitat structuring effects, intra-specific body size effects are rarely investigated in the context of BEF relationships. We used an in situ density manipulation experiment to explore the contribution of large, deep-burrowing bivalves to oxygen and nutrient fluxes across the sediment-water interface. By manipulating bivalve size structure through the removal of large individuals, we held species identity constant, but altered the trait characteristics of the community. The number of large bivalves was the best predictor of ecosystem functioning. Our results highlight that (a) accounting for body size provides important insights into the mechanisms underpinning biodiversity effects on ecosystem function, and (b) if local disturbances are recurrent, preventing individuals from reaching large sizes, the contribution of large adults may be lost, with largely unknown implications for ecosystem functionality.
体型是生物体的一个基本特征，也是生态系统功能的重要驱动因素。尽管大型个体可能主导某些功能并产生重要的栖息地构建效应，但在生物多样性与生态系统功能关系的背景下，种内体型效应很少被研究。我们通过一项原位密度操纵实验，探究大型穴居双壳类动物对沉积物 - 水界面的氧气和养分通量的贡献。通过移除大型个体来操纵双壳类动物的体型结构，我们保持物种身份不变，但改变了群落的性状特征。大型双壳类动物的数量是生态系统功能的最佳预测指标。我们的结果表明：（a）考虑体型为理解生物多样性对生态系统功能影响的潜在机制提供了重要见解；（b）如果局部干扰反复发生，阻止个体生长到大型，大型成年个体的贡献可能会丧失，这对生态系统功能的影响在很大程度上未知。
