Macrophytes - coastal waters

Current criteria for assessing macrophytes in coastal waters are based on the depth distribution of selected common, perennial, and eutrophication-sensitive species. It has been difficult to apply the assessment criteria to existing field data mainly due to the lack of data from sufficiently deep bottoms with suitable substrates.

The assessment criteria have also not been adequately evaluated since suitable data from areas with quantified pressures have not been available. In addition, current macrophyte monitoring involves few time series, and is based on a variety of field methods that yield somewhat different types of data. Much of the available macrophyte data were collected in inventories of protected areas, while data from recipients is lacking.

Macrophytes in WATERS
In WATERS we will continue collating existing data on macrophytes, compile information on various indicators and their theoretical background, and compile properties (e.g., sensitivity and functional group identity) of macrophytes along the Swedish coast. Based on this information and available data, existing and new indicators will be evaluated. The sub-project will focus on indicators based on depth distribution and/or species or functional groups sensitive to anthropogenic impact.

Since there are only a few long time series covering macrophytes along Swedish coasts, tests will focus on the correlation between indicators and pressures along spatial gradients. Strong gradients in structuring factors (e.g., depth, substrate, exposure, and salinity) mean that there is a need to evaluate what strata are most suitable for status assessment and how we should design field monitoring to achieve sufficient amounts of data for robust assessments.

In the common gradient study, which is scheduled for the coastal waters focal area, we will collect field data to test the selected indicators.

The goal is to improve and/or develop new indicators for coastal zone macrophytes, develop type-specific class boundaries for these indicators, and identify what field data the indicators require.