Catchment Invertebrate Fingerprinting
The Wessex Chalk Stream and Rivers Trust (WCSRT) has received significant funding from the Esmée Fairbairn Foundation for 2014 in support of our pioneering work on river catchment improvement. The rivers benefitting in the first year are the Hampshire Avon, the Test and the Itchen. The fingerprinting research is focused on insects and other aquatic animals that live on the river-bed and react characteristically to particular types of water quality pollution and habitat damage. The intention is to identify pollution hotspots which will then be addressed by WCRST and partners.
The first phase of the work has included analyses of long-term (up to 30 years) Environment Agency (EA) river quality sampling data on numbers and types of aquatic invertebrates by Dr Nick Everall of the Aquascience Consultancy (Chesterfield, Derbyshire). These samples were collected by standarised 3-minute kick-samples which makes them comparable over the years and between rivers.
Maps of the outputs from these studies are presented below. On each map, for each sampling site, indices have been calculated to assess the impact of the following four common river pollution factors: Fine sediment level, Flow regime, Phosphate enrichment and Organic pollution. Also, for each of these indices, an arrow has been added to indicate trends over time; an upwards arrow indicates a worsening effect, downwards an improving effect and level no discernible trend.
Phase 1 Results:
For all three river catchments there are clear widespread indications of adverse impacts on invertebrate communities due to both fine sediment and phosphorus pollution. The sources of these pollutants are likely to include non-mains sewerage, riparian farmland, fish and water cress farms, sewage treatment works and other forms of catchment industry.
As of September 2014, we have embarked upon the next phase of our work to collect around 55 invertebrate samples of our own and have them analysed to species-level. This new suite of samples will allow a finer level of analysis of invertebrate communities (and correspondingly water quality) than has been available before, as the older EA data are largely comprised of samples identified to family or genus, rather than species-level. We will be repeating our sampling programme in Spring 2015 to further refine our understanding of catchment water quality. Autumn and Spring sampling allows us to include all invertebrate species that emerge at different times of the year.
We are beginning to identify pollution hot-spots and are formulating strategies to address these problem areas via the respective River Catchment Partnerships, through active advisory and restoration projects.
Subject to a satisfactory conclusion of the first years' programme we are hoping to extend this programme over the next year to include the Meon and the Dorset Stour.
WCSRT intend this project to continue indefinitely and will be seeking funding to enable ongoing annual or biennial sampling across our river systems.
For more information please contact Nick Giles, Project Development Officer, Wessex Chalk Stream and Rivers Trust by email: firstname.lastname@example.org