Ecology of Freshwater Species and Habitats of European Importance

These documents consist of the results of a recent review of relevant literature, research work, expert opinion and field observations by a range of recognised experts, and have been subject to extensive peer review. It is important to note that many of the species have not been studied in great detail before, and the empirical information presented may have been gathered from a small number of sites. The conclusions reached and the targets suggested may, therefore, not be applicable to every river.

It is envisaged that the information will be used to identify key issues to be addressed in river conservation strategies, to inform conservation-led management action and develop monitoring programmes to ensure the species are in favourable condition on individual rivers. The information will also help to inform the review of consents and assessment of new proposals under the Habitats Directive, thus ensuring that decisions are taken on the basis of best available scientific information.

In some sites there will inevitably be situations where the needs of one species or habitat conflicts with those of another, or the ecosystem as a whole. Before implementing management measures to benefit an individual species, consideration should always be given to balancing the needs of the species with those of the biological community as a whole. This will include consideration of habitat mosaics, rotational management and the provision of a full range of hydroseral stages.

Monitoring Protocols

The monitoring protocols are based on the ecological requirements of the species and have been designed following a review of available survey techniques and monitoring programmes. Cost-effectiveness has been an important consideration, but has not been allowed to out-weigh the requirements of sound science. Rivers are the most dynamic ecosystems in the UK, and the population fluctuations that might be expected under conditions of low anthropogenic disturbance are poorly understood. For this reason, the frequency of monitoring and the targets recommended may need to be reviewed once further data have been collected over time.

The documents suggest survey methodologies and monitoring protocols for use in condition assessment of SAC (Special Areas of Conservation) rivers. The starting point is an attempt to define favourable conservation status, in terms of population and habitat parameters (population size, health and reproductive success) and key supporting processes (water quality, flow regime and food availability).

Techniques to Address Key Conservation Issues

Several issues have been identified that are potential barriers to achieving favourable conservation status. These include the historical impacts of past river engineering, the impact of siltation from agriculture, the loss of native crayfish from certain rivers and the low reproductive success of the freshwater pearl mussel.

Life in UK Rivers investigated the restoration of rivers to improve conditions for SAC species and habitats. For example, a complete survey was undertaken of plant communities on the River Avon, and has been correlated with a geomorphological survey. The results can be used to target future river restoration work to bring features of European importance back into favourable condition.

Life in UK Rivers also reviewed the impact of silt on salmon, lamprey and aquatic vegetation, and identified cost-effective techniques for silt reduction. Research was also carried out into the captive breeding of pearl mussels and their relationship with their host salmonid fish. Other projects included clearance of rhododendron where this affected pearl mussels by preventing the establishment of riparian oak woodland. Guidance has also been produced on reintroduction of the white-clawed crayfish, and techniques for this were trialled on the River Lathkill SAC in Derbyshire.