Loss of biodiversity alters ecosystem function in freshwater streams: potential evidence from benthic macroinvertebrates

Particular attention has been paid on the evidence that ecosystem function can be impacted by changes of biodiversity. However, how the loss of biodiversity alters the ecosystem function in aquatic ecosystems remains unclear. Here, the effects of benthic macroinvertebrate community structure on ecosystem function and the possibility of which being shifted by ecological threshold along the habitat condition gradient were examined by quantifying community structure and ecosystem function in streams of Lake Dianchi basin. The results demonstrated that the relative abundance of Oligochaete was significantly linear correlated with ecosystem multifunctions, especially N and P cycling functions, as well as the dominant taxon% and Gather-Collectors% closely affected P cycling function and multifunctions, respectively, while no remarkable nonlinearities were observed. Besides, there was a distinct shift from sensitive taxa-dominated healthy state to tolerant taxa-dominated degraded state with an increase in habitat pressure. The nonlinear transition of benthic macroinvertebrate community structure in combination with altered ecosystem function clearly indicated the present of extinction threshold in the process of stream habitat degradation. The findings contribute to the growing evidence for fully understanding the implications of biodiversity loss in ecosystem function.