Healthy & Biologically Diverse Seas Evidence Group Technical Report Series: Evaluation and gap analysis of current and potential indicators for Plankton 2010

Abstract

This report identifies the most effective planktonic indicators of marine ecosystem state, pressures, structure and function to allow scientifically robust assessment of Good Environmental Status (GES) in the context of the Marine Strategy Framework Directive (MSFD) as well as fulfilment of HBDSEG monitoring programmes under UKMMAS and the UK marine biodiversity monitoring and surveillance programme objectives. The results were obtained through a process beginning with a review of existing indicators for phytoplankton and zooplankton, which included an evaluation of the scientific and economic effectiveness of these indicators. The indicators were then assessed with respect to relevant pressures and important aspects of ecosystem structure and function. This allowed the identification of gaps in indicator availability and was followed by a recommendation of an effective suite of plankton indicators.

Two classes of indicators were assessed in this work: those derived from data collected by the Continuous Plankton Recorder (CPR) survey and those collected from other, primarily coastal, in situ monitoring programmes as well as remotely-sensed satellite data. In general, the CPR indicators are based on a long time-series which is spatially extensive, are well developed with respect to policy needs and are both cost efficient and scientifically robust. For the most part, the non-CPR indicators focused on localized coastal collection sites and had shorter time-series, but may be more frequently sampled and provide critical information on plankton change in near-shore waters.

The most effective indicator suite for addressing policy and monitoring needs is comprised of both CPR indicators providing comprehensive information on a regional scale and non-CPR indicators which offer information on plankton change at some coastal sites. The combination of the two types of indicators enables effective interpretation of plankton dynamics influenced by anthropogenic pressures against regional-scale climate-driven changes in the plankton.

The most significant gap in plankton monitoring occurs in the lack of an integrated monitoring strategy which would allow a greater understanding of the changes in the plankton of UK waters and would systematically link large scale surveys such as the CPR with inshore and single station sampling programmes. An integrated monitoring strategy would enable the development of more robust ecological indicators which could be used to assess the performance of policy requirements. More effort should also be directed towards developing indicators that are able to detect change in the smallest size classes of plankton, which although are an important part of the plankton (and Harmful Algal Bloom) community, are often under-represented in monitoring programmes.