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Freshwater invertebrates

Freshwater invertebrates are an important part of the freshwater ecosystem and food chain. Freshwater invertebrates are invertebrates that spend at least part of their lifecycle in freshwater (e.g. rivers, streams, ditches, spring, seepages, ponds and lakes).

Freshwater invertebrates play a vital role in maintaining the quality of our water; they help to breakdown organic matter and provide a food source for other species such as fish, birds and mammals. They can also be used to assess the health of freshwater systems.

Fletton Lakes pollution (c) Greg Hitchcock

Fletton Lakes pollution (c) Greg Hitchcock

Key Issues for Freshwater Invertebrate

  • Pollution poses a significant threat to biodiversity in both flowing and standing waters in the UK. In the lowlands, the most pervasive problem is over-enrichment with plant nutrients such as nitrogen and phosphorus (eutrophication), from both diffuse and point sources. In certain upland areas acidification is a threat.
  • Engineering activities such as flood alleviation schemes, water storage and water abstraction have modified flow in some rivers, changed the periodicity of draw-down in numerous lakes, lowered water tables, and adversely affected wet habitats such as seepages and fens.
  • Recreational activities such as boating and fishing can be a threat to habitat quality and wildlife, especially in small water bodies and canals.
  • Introduced species such as the alien plants New Zealand pigmyweed (Crassula helmsii) and Himalayan balsam (Impatiens glandulifera), invertebrates like the Zebra mussel (Dreissena polymorpha) and the American signal crayfish (Pacifastacus leniusculus), and fish such as the Grass carp, can pose a threat to the native freshwater fauna.