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 2024 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 assessment results. The assessments used for this indicator have been reported under the UK Marine Strategy (UKMS) Part One (2019) to assess progress towards the UKMS 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 seagrass tool, intertidal rocky shore macroalgae tool, intertidal saltmarsh tool and Infaunal Quality Index.
The indicator will be further developed to include data on the condition of benthic communities. A trial assessment on the condition of benthic communities was reported under the UKMS Part One (2019). Updates to the method and data underpinning the condition of benthic communities indicator was made available as part of the OSPAR Quality Status Report (QSR 2023) and will be further updated as part of the UKMS Part One Assessment in 2024. When available, C4 may also include data 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).
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
Figure C4: Summary of regional sea assessment results for coastal and offshore habitats, 2010 to 2015
Table C4: Summary of regional sea assessment results for coastal and offshore habitats, 2010 to 2015
| UKMS sub region | Habitat | Achieved | No data | Not achieved | Suitable habitat absent |
|---|---|---|---|---|---|
| Celtic Seas | Intertidal saltmarsh | 1 | 4 | 0 | 1 |
| Celtic Seas | Intertidal seagrass | 2 | 3 | 0 | 1 |
| Celtic Seas | Rocky shore macroalgae | 5 | 0 | 0 | 1 |
| Celtic Seas | Soft sediment invertebrates | 3 | 1 | 2 | 0 |
| Greater North Sea | Intertidal saltmarsh | 1 | 0 | 2 | 0 |
| Greater North Sea | Intertidal seagrass | 2 | 1 | 0 | 0 |
| Greater North Sea | Rocky shore macroalgae | 2 | 1 | 0 | 0 |
| Greater North Sea | Soft sediment invertebrates | 2 | 0 | 1 | 0 |
Trend description for C4
In the Greater North Sea, the UKMS target was met in two out of three Regional Seas for intertidal seagrass and intertidal rocky shore habitats, with insufficient data to make an assessment in the third. Targets were achieved for soft sediment invertebrates in two out of the three Regional Seas. Two of three Regional Seas did not meet targets for intertidal saltmarsh.
In the Celtic Seas, the UKMS target was met in all five Regional Seas where habitat is present for rocky shore macroalgae. The majority of Regional Seas where habitat is present did not have data for intertidal seagrass (three of five) or intertidal saltmarsh (four of five), with the remainder having met their target. For soft sediment invertebrates, targets were achieved in three out of six Regional Seas. In the remainder, targets were not achieved in two Regional Seas, and there was not enough data for an assessment in the Regional Sea.
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.
Table C4i: Regional sea assessments, and the status of coastal water bodies for seagrass, 2010 to 2015
| UKMS sub region | Regional Sea | Regional Sea Assessment results | Water body classification results (good) | Water body classification results (high) | Water body classification results (moderate) |
|---|---|---|---|---|---|
| Celtic Seas | Atlantic North-West Approaches | Suitable habitat absent | Suitable habitat absent | Suitable habitat absent | Suitable habitat absent |
| Celtic Seas | Irish Sea | Above GES target | 0 | 1 | 1 |
| Celtic Seas | Minches and Western Scotland | No data | No data | No data | No data |
| Celtic Seas | Scottish Continental Shelf | No data | No data | No data | No data |
| Celtic Seas | Shared waters between N. Ireland and Rep of Ireland | Above GES target | 0 | 2 | 0 |
| Celtic Seas | Western Channel and Celtic Seas | Above GES target | 1 | 1 | 0 |
| Greater North Sea | Eastern Channel | Above GES target | 0 | 1 | 0 |
| Greater North Sea | Northern North Sea | Above GES target | 0 | 1 | 0 |
| Greater North Sea | Southern North Sea | No data | No data | No data | No data |
Images C4i: Regional sea assessments, and the status of coastal water bodies for seagrass, 2010 to 2015
Trend description for C4i
The UKMS target for intertidal seagrass communities was met for all assessed 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 intertidal 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.
Table C4ii: Regional sea assessments, and the status of coastal water bodies for rocky shore macroalgae, 2010 to 2015
| UKMS sub region | Regional Sea | Regional Sea Assessment results | Water body classification results (good) | Water body classification results (high) | Water body classification results (moderate) |
|---|---|---|---|---|---|
| Celtic Seas | Atlantic North-West Approaches | Suitable habitat absent | Suitable habitat absent | Suitable habitat absent | Suitable habitat absent |
| Celtic Seas | Irish Sea | Above GES target | 9 | 8 | 1 |
| Celtic Seas | Minches and Western Scotland | Above GES target | 5 | 4 | 0 |
| Celtic Seas | Scottish Continental Shelf | Above GES target | 6 | 1 | 0 |
| Celtic Seas | Shared waters between N. Ireland and Rep of Ireland | Above GES target | 0 | 3 | 0 |
| Celtic Seas | Western Channel and Celtic Seas | Above GES target | 4 | 3 | 1 |
| Greater North Sea | Eastern Channel | Above GES target | 2 | 0 | 0 |
| Greater North Sea | Northern North Sea | Above GES target | 5 | 2 | 0 |
| Greater North Sea | Southern North Sea | No data | No data | No data | 0 |
Images C4ii: Regional sea assessments, and the status of coastal water bodies for rocky shore macroalgae, 2010 to 2015
Trend description for C4ii
The UKMS 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.
Table C4iii: Regional sea assessments, and the status of coastal water bodies for saltmarsh, 2010 to 2015
| UKMS sub region | Regional Sea | Regional Sea Assessment results | Water body classification results (good potential) | Water body classification results (good) | Water body classification results (high) | Water body classification results (moderate) |
|---|---|---|---|---|---|---|
| Celtic Seas | Atlantic North-West Approaches | Suitable habitat absent | Suitable habitat absent | Suitable habitat absent | Suitable habitat absent | Suitable habitat absent |
| Celtic Seas | Irish Sea | No data | No data | No data | No data | No data |
| Celtic Seas | Minches and Western Scotland | No data | No data | No data | No data | No data |
| Celtic Seas | Scottish Continental Shelf | No data | No data | No data | No data | No data |
| Celtic Seas | Shared waters between N. Ireland and Rep of Ireland | No data | No data | No data | No data | No data |
| Celtic Seas | Western Channel and Celtic Seas | Above GES target | 0 | 2 | 0 | 0 |
| Greater North Sea | Eastern Channel | Below GES target | 0 | 0 | 0 | 1 |
| Greater North Sea | Northern North Sea | Above GES target | 0 | 2 | 0 | 0 |
| Greater North Sea | Southern North Sea | Below GES target | 1 | 1 | 0 | 2 |
Images C4iii: Regional sea assessments, and the status of coastal water bodies for saltmarsh, 2010 to 2015
Trend description for C4iii
The UKMS target for the saltmarsh communities was largely met for the Western Channel and 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.
Table C4iv: Regional sea assessments, and the status of coastal water bodies and offshore units for soft sediment invertebrates, 2010 to 2015
| UKMS sub region | Regional Sea | Offshore assessment results (good) | Offshore assessment results (high) | Offshore assessment results (moderate) | Offshore assessment results (poor) | Regional Sea Assessment results | Water body classification results (good) | Water body classification results (high) | Water body classification results (moderate) |
|---|---|---|---|---|---|---|---|---|---|
| Celtic Seas | Atlantic North-West Approaches | No data | No data | No data | No data | No data | No data | No data | No data |
| Celtic Seas | Irish Sea | 12 | 2 | 5 | 0 | Below GES target | 16 | 5 | 7 |
| Celtic Seas | Minches and Western Scotland | No data | No data | No data | No data | Above GES target | 5 | 3 | 2 |
| Celtic Seas | Scottish Continental Shelf | 3 | 0 | 0 | 0 | Above GES target | 4 | 0 | 0 |
| Celtic Seas | Shared waters between N. Ireland and Rep of Ireland | No data | No data | No data | No data | Above GES target | 3 | 0 | 0 |
| Celtic Seas | Western Channel and Celtic Seas | 3 | 0 | 0 | 0 | Below GES target | 12 | 2 | 3 |
| Greater North Sea | Eastern Channel | 1 | 1 | 0 | 0 | Above GES target | 1 | 1 | 0 |
| Greater North Sea | Northern North Sea | 27 | 28 | 1 | 0 | Above GES target | 7 | 2 | 0 |
| Greater North Sea | Southern North Sea | 51 | 14 | 28 | 1 | Below GES target | 4 | 0 | 2 |
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 UKMS 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 Sea Region 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.