C4: Diverse seas: condition of seafloor habitats
Short Description
This indicator of diverse seas evaluates the condition of seafloor habitats. Seafloor habitats assessed include soft sediment invertebrate communities and intertidal communities of seagrass, rocky shore macroalgae and saltmarshes. Once developed the indicator will assess the impact of human activities on seafloor habitats.
Data for the seafloor habitat condition indicators come from surveys undertaken on a 6-yearly cycle using methods developed for Water Framework Directive (WFD) classifications, now transposed to the Water Framework Directive Regulations. These include the intertidal rocky shore macroalgae tool, intertidal seagrass tool, Infaunal Quality Index, and intertidal saltmarsh tool.
Readiness and links to data
This indicator is not available for reporting in 2023 in a finalised form. An interim indicator is presented here that shows target achievement for regional sea assessment, status of coastal water bodies and offshore unit assessments. The assessments used for this indicator have been reported under the updated UK Marine Strategy Part One (2019) to assess progress towards the UK Marine Strategy target of achieving and maintaining Good Environmental Status (GES) in UK seas.
Data on benthic (sea floor) habitats, analytical methods and assessment are available, including information on the intertidal rocky shore macroalgae tool, intertidal seagrass tool, Infaunal Quality Index, and intertidal saltmarsh tool.
The indicator will be further developed to include data on the condition of benthic communities. When data are available, C4 may also be based upon data on the condition of sublittoral rock communities (those that occur from the lowest point exposed by low tide to the edge of the continental shelf) and the condition of biogenic reefs (formed by horse mussel and Ross worm). A trial assessment on the condition of benthic communities was reported under the updated UK Marine Strategy Part One (2019) to assess progress towards the UK Marine Strategy target of achieving and maintaining Good Environmental Status (GES) in UK seas. Updates to the method and data underpinning this indicator will be made available as part of the UK Marine Strategy Part 1 Assessment in 2024.
Notes on indicator
While the currently available data predate the 25 Year Environment Plan, they provide the most recently available assessment of the condition of benthic habitats. They enable a better understanding of a baseline from which to measure progress towards the goals of the 25 Year Environment Plan when the indicator is next updated.
Indicator components
Images C4i: Regional sea assessments, and the status of coastal water bodies for seagrass, 2010 to 2015
Trend description for C4i
The UK Marine Strategy target for intertidal seagrass communities was met for all Regional Seas. Four Regional Seas were not assessed due to either an absence of intertidal habitat which is required by the indicator or an absence of existing WFD classification data. The natural conditions required for seagrass beds to exist limits their occurrence in coastal water bodies. However, for those contributing, the quality threshold of ‘Good’ or ‘High’ Ecological Status was met for the majority of surveyed locations. The Irish Sea had the lowest extent of intertidal seagrass meeting the quality target, although the total remains markedly above the indicator quantity threshold of 85%.
Assessment of change
No assessment of change was undertaken for this indicator as a suitable time series is not yet available in the Outcome Indicator Framework.
Images C4ii: Regional sea assessments, and the status of coastal water bodies for rocky shore macroalgae, 2010 to 2015
Trend description for C4ii
The UK Marine Strategy target for the intertidal rocky shore macroalgae was met for all 7 assessed Regional Seas. Two Regional Seas were not assessed due to either an absence of intertidal habitat which is required by the indicator or an absence of existing WFD classification data.
Assessment of change
No assessment of change was undertaken for this indicator as a suitable time series is not yet available in the Outcome Indicator Framework.
Images C4iii: Regional sea assessments, and the status of coastal water bodies for saltmarsh, 2010 to 2015
Trend description for C4iii
The UK Marine Strategy target for the saltmarsh communities was largely met for the Celtic Seas and Northern North Sea but was not met for considerable areas of the Southern North Sea and the Eastern English Channel Regional Seas. Five Regional Seas were not assessed due to either an absence of intertidal habitat which is required by the indicator or an absence of existing WFD classification data.
Assessment of change
No assessment of change was undertaken for this indicator as a suitable time series is not yet available in the Outcome Indicator Framework.
Images C4iv: Regional sea assessments, and the status of coastal water bodies and offshore units for soft sediment invertebrates, 2010 to 2015
Trend description for C4iv
The UK Marine Strategy target for soft sediment (benthic) invertebrate communities was largely met for most Regional Seas including the Minches and western Scotland, Scottish Continental Shelf, Shared Waters between Northern Ireland and Republic of Ireland, Northern North Sea and Eastern English Channel. The Western English Channel and Celtic Seas did not reach the target largely due to the inshore classification results, while the failure of the Southern North Sea to meet the target can be attributed to the offshore results. The Irish Sea did not meet the target due to both inshore and offshore results. The Atlantic North-West Approaches was not assessed due to an absence of data.
Assessment of change
No assessment of change was undertaken for this indicator as a suitable time series is not yet available in the Outcome Indicator Framework.