Division Specifications and standardised methods for monitoring and assessment

1. 1..

   ‘Newly-introduced’ non-indigenous species shall be understood as those which were not known to be present in the area in the previous assessment period.

2. 2..

   ‘Established’ non-indigenous species shall be understood as those which were known to be present in the area in the previous assessment period.

3. 3..

   For D2C1: where it is not clear whether the new arrival of non-indigenous species is due to human activity or natural dispersal from neighbouring areas, the introduction shall be counted under D2C1.

4. 4..

   For D2C2: when species occurrence and abundance is seasonally variable (e.g. plankton), monitoring shall be undertaken at appropriate times of year.

5. 5..

   Monitoring programmes shall be linked to those for Descriptors 1, 4, 5 and 6, where possible, as they typically use the same sampling methods and it is more practical to monitor non-indigenous species as part of broader biodiversity monitoring, except where sampling needs to focus on main vectors and risk areas for new introductions.

Units of measurement for the criteria:

• D2C1: the number of species per assessment area which have been newly introduced in the assessment period (6 years),

• D2C2: abundance (number of individuals, biomass in tonnes (t) or extent in square kilometres (km²)) per non-indigenous species,

• D2C3: the proportion of the species group (ratio of indigenous species to non-indigenous species, as number of species and/or their abundance within the group) or the spatial extent of the broad habitat type (in square kilometres (km²)) which is adversely altered.