Non-native species (NNS) are those which have been spread, either intentionally or accidentally, beyond their natural geographical range because of human activity. Invasive non-native species (INNS) can pose major threats to native biodiversity, human health and ecosystem services.
In 2018/19, NNS were surveyed by timed searches at 14 clusters of sites in the Solent region, each cluster consisting of a marina, a designated shore near to the marina and another designated shore further way. This report concerns re-surveys of four of these 14 clusters in 2022, to:
- monitor for changes in species’ distribution and abundance
- review the persistence of documented differences in the prevalence of NNS between the ‘Near’ and ‘Far’ shores
- assess if the clusters were suitable for ongoing sentinel monitoring
- and continue to refine the shore rapid assessment protocol developed during the earlier surveys.
Colonisation of new shores by a number of NNS was documented as well as a marked increase in abundance on shores by the Tufty-buff bryozoan. Two species, Purple fan-worm and Pink-hearted hydroid, were found that were not recorded in the previous surveys.
The survey method developed for the Solent surveys in 2018/19, and refined during these surveys, has proved effective in providing evidence on the presence and abundance of NNS at such sites, contributing vital information to the designated site condition assessments. Recommendations include wider adoption of the survey method and regular monitoring of identified ‘sentinel’ sites.