Surveys take place during the summer months when the growth of aquatic plants is at its height. Our team of botanists rely primarily on their extensive expertise to identify and record species in the in the field, although when necessary specimens are collected for more detailed examination and identification. Quality control is maintained by the use of voucher specimens and an exchange of material with other expert botanists. Survey methods for aquatic plants vary according to purpose. For rivers and streams we use standard methods such as the JNCC protcols our standard practice is to survey a 50 m reach centred on or close to the designated sampling site. We then record plant cover and species composition of the plant assemblages along channel transects every 5 m. The composition of the substrate is also recorded and large-scale sketch maps of major morphological features and plant growth are made.
For lakes our survey methods vary according to purpose, but typically includes (i) an inshore survey to record and map shallow water and fringing stands; (ii) transverse trawls using a double-headed rake; and (iii) transect surveys along lines 50-60 m long perpendicular to the shore with Ekman grab surface sediment samples taken at 10 m intervals. The location of end stations of both lake trawls and transects are recorded by GPS. Where necessary we use scuba diving to identify and map submerged taxa, especially rare taxa
The protocol for sites surveyed under the Water Framework Directive follows the Common Standards Monitoring methodology