EN 16859:2017

European foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Monitoring and assessing the condition of a
  Margaritifera population
5 Monitoring the environmental conditions needed
  to support Margaritifera margaritifera populations
6 Monitoring environmental pressures
7 Information needed to assess plans or projects
  on rivers with Margaritifera
Annex A (informative) - Background information on
        the environmental characteristics important for
        maintaining populations of Margaritifera margaritifera
Annex B (informative) - Targets for assessing whether
        Margaritifera populations are in favourable condition
Annex C (informative) - Range of environmental conditions
        supporting sustainable populations of Margaritifera
Bibliography

This European Standard provides guidance on methods for monitoring freshwater pearl mussel populations and the environmental characteristics important for maintaining populations in favourable condition. The standard is based on best practice developed and used by Margaritifera experts in Europe, and describes approaches that individual countries have adopted for survey, data analysis and condition assessment. While it is recommended that the causes for pearl mussel decline should be urgently investigated, standard methods for restoring populations are beyond the scope of this document.