Special Groups

Chironomid Pupal Exuvial Technique (CPET)

This technique can be used to both monitor and assess the quality of both still and flowing freshwater waterbodies.

Floating chironomid exuviae are netted from where they passively accumulate as flotsam and are identified microscopically in the laboratory.

To counteract seasonal emergence patterns, collections are made over three or four months between spring and autumn.

Knowledge of a species tolerance to organic enrichment and habitat preferences allows an assessment of the habitat.

Desmoulin’s Whorl Snail Vertigo moulinsiana

Vertigo moulinsiana is scheduled on Annex II of the European Habitats Directive and is listed as Vulnerable.

This species inhabits calcareous lowland wetlands; swamps, fens and marshes typically bordering rivers, canals, lakes and ponds.  It climbs amongst tall emergent vegetation, living over a large vertical range throughout the year.

It is vulnerable to modifications to the hydrology of its habitat, heavy grazing, successional changes and to developments on flood plains.

Specific surveys for this species can be undertaken using Conserving Natura 2000 Rivers monitoring protocol.


Targeted species surveys

Bespoke surveys are undertaken where specific species or groups of species are to be investigated within an aquatic or wetland habitat.

Trapping methods can be suitable where target species are large and active.