What causes benthic invertebrate communities to change?
• The distribution and abundance of benthic invertebrate species may be profoundly influenced by a wide variety of physical parameters (e.g. substrate composition, water temperature, depth, dissolved oxygen concentrations, pH, salinity, sediment C/N ratios [36] and hydrography). Spatial and temporal differences in benthic species composition may also be influenced by a range of biological factors (e.g. primary productivity, competition and acclimatisation). Natural seasonal and inter-annual changes in these variables can also modify recruitment success and mortalities of individual species, and consequently the community structure of the benthos. Such cyclical changes and often random inter-annual variation often make long-term changes in benthic communities caused by humans difficult to detect. • Benthic communities can change in response to nutrient enrichment leading to eutrophication, and this has occurred around the world. The effects of nutrients on benthos are thought to be main
