Nature - River Mel Group

Nature

River Mel group

Have you seen the kingfisher lately? This is the question most frequently asked of us by people walking along the river. Fortunately we can report that a pair of kingfishers has been seen this year. However, the question underlines the importance of the river and its wildlife to many of the residents of Melbourn and the surrounding area.

In the seven years that we have been working on the Mel, we have seen the pressures on it increase. Many factors have the potential to have a detremental effect on the river. This ranges from natural hazards such as last year’s drought, to those that are man-made. New building in the area, although necessary, increases the demand on the local sewage treatment plant, leading to the possibility of partially treated sewage to be discharged directly into the river at times of heavy rainfall. Many of us enjoy walking along the riverside; however every extra person walking the path is a potential disturbance to the wildlife that lives along the riverbank. Improved access must be balanced against preservation of habitat.

So, apart from the sightings of the kingfisher, how do we know that these pressures are not becoming too much for the river? How do we know that the river is in good health? A number of ‘early warning systems’ are in place to show when things are amiss so that mitigating action can be taken as early as possible.

Routine monitoring of invertebrate populations is an effective way to check water quality and enables action to be taken at the earliest opportunity should any drop in numbers be detected. Riverflies, along with other freshwater invertebrates, are at the heart of any freshwater ecosystem and are a vital link in the aquatic food chain. Riverfly populations are affected by many factors, predominately water quality, habitat diversity, water level and flow rate. They live most of their lives as larvae on the bed of rivers and still waters, emerging as short-lived adult flies mostly in spring and summer, often en masse. Their common characteristics of limited mobility, relatively long life cycle, presence throughout the year and specific tolerances to changes in environmental conditions make them sensitive biological indicators to monitor water quality, and are commonly referred to as ‘the canary of our rivers.’ Following training, these surveys can now be performed by members of the group at sites that have been determined by the Environment Agency.

Further up the food chain, fish surveys are periodically carried out by the Environment Agency. The most recent of these surveys was a detailed electro-survey carried out in early summer on a representative stretch of the river. The fish were stunned and collected for examination and once they had been measured and checked they were returned unharmed to the river. They found sticklebacks, bullheads and two trout. These findings were encouraging, especially following the prolonged drought of last year that saw the upper stretches of the Mel dry for many weeks.

This monitoring is a side of our work that is less obvious to the public, but it is important as it strengthens our partnership with the overstretched statutory bodies that have a duty to protect our rivers and water supplies. Working in partnership in this way ensures that our river and its needs are recognised.

For further details about volunteering or the dates of future working parties, please telephone Maureen Brierley on 01763 262752.

Caddiss fly larvae

waters, emerging as short-lived adult flies mostly in spring and summer on a representative stretch of the river. The fish were stunned and collected for examination and once they had been measured and checked they were returned unharmed to the river. They found sticklebacks, bullheads and two trout. These findings were encouraging, especially following the prolonged drought of last year that saw the upper stretches of the Mel dry for many weeks. the public, but it is important as it strengthens our partnership with the overstretched statutory bodies that have a duty to protect our rivers and water supplies. Working in partnership in this way ensures that our river and its needs are recognised. working parties, please telephone Maureen Brierley on 01763 262752.