Spatial and temporal extent of monitoring water column and seabed habitats indicators, based on their scales of natural variation

The Marine Framework Strategy Directive (MFSD, 2008/56/EC) aims for clean, healthy and productive marine ecosystems within all the EU Members states. The MFSD promotes an holistic, ecosystem based approach to marine conservation and monitoring (Art. 13) Monitoring strategies should: 1) focus on the potential of scale dependence in the observed dynamics and 2) be able to integrate the effect of mediating factors operating at different scale levels. However, present knowledge on spatial and temporal fluctuations in marine ecosystems is scarce. The boundaries of natural variation of several important marine ecosystem processes are still undefined. A major source of complexity is the fact that ecosystem processes are occurred across different spatial as well as temporal scales. The present knowledge gap results in uncertainty on the selection of measured parameters and the definition of sampling frequency and sites. Hereby, we discuss theoretical and applied issues related to definition of optimal cross-scale monitoring strategies. Literature data and existing databases were analyzed, to define the connectivity across nested scales of principal D1 (Biodiversity), D5 (Eutrophication), D6 (Seabed habitat integrity) MFSD descriptors. We conclude that present monitoring strategy does not completely fulfil the scaling issues due to lack of theoretical knowledge on cross-scale processes and poor coordination across monitoring operators. A stronger cooperation among member states and regional environmental agencies is needed to implement efficient cross-scale environmental monitoring. This research was developed by partners of the Integrated Regional monitoring Implementation Strategy in the South European Seas (IRIS-SES, http://iris-ses.eu) Project, a pilot project on new knowledge for an integrated management of human activities in the sea (PP/ENV D2/SEA 2012), funded by the European Union.