Habitat types key navigation

You can use the 'key navigation' function to identify a specific habitat by answering a set of questions. Starting from first question to next questions you select one of the possible answers. Here are samples of possible answers:

• No ( 002 ) - Leading to question named '002'
• Yes [ G ] - Leading to another questions subset of level G
• No [ E6 ] - Links directly to factsheet for E6

Additionally the diagram may be used for reference.


Category : (A )Marine habitats
Diagram :

Question i :   Stratum

The criterion distinguishes between strata: the sea bed of non-tidal, inter-tidal and sub-tidal waters; the water column of shallow or deep sea, or enclosed coastal waters; and ice or ice-associated marine habitats.

Answers: bed ( ii ) water column [ A7 ] ice-associated [ A8 ]

Question ii :   Permanently water-covered?

Is the bed permanently covered by water (path = Yes), or either regularly exposed at some stage in the tidal cycle (littoral / inter-tidal), subjected to frequent non-tidal change in water level, or above the high water mark but with a high water table (path = No)? Note that under extreme conditions the uppermost fringe of the ‘permanently water-covered’ zone may be exposed. Note that saltmarsh pools, rockpools (filled by splash and spray) located in the supralittoral and permanent brackish pools affected by spray in the waterlogged Baltic geolittoral zone follow path = No.

Answers: No ( iii ) Yes ( iv )

Question iii :   Substrate

Non-mobile substrates include continuous hard and soft bedrock and also non-mobile boulders, rocks and consolidated cobbles, non-mobile artificial substrates and compacted soft substrates such as clay and peat; mobile substrates include substrates such as mobile cobbles, pebbles, sand and mud. Non-mobile rock which is overlain by some deposited sediments follows path = non-mobile. Biogenic reefs on sediment follow path = mobile. Mosaics of mobile and non-mobile substrates should be considered as complex X31 comprising units from A2 and A1.

Answers: non-mobile [ A1 ] mobile [ A2 ]

Question iv :   Shelf?

This criterion separates sublittoral zones of the shelf (including infralittoral and circalittoral zones) (path = Yes), from the deep seabed, beyond the shelf break (path = No). The shelf break occurs at variable depth, but is generally over 200 m. The upper limit of the deep-sea zone is marked by the edge of the shelf. The Baltic Sea is a shelf sea and follows path = Yes. Areas of the Mediterranean Sea which are deeper than 200 m follow path = No. Note that all sublittoral caves follow path = Yes irrespective of depth.

Answers: Yes ( v ) No [ A6 ]

Question v :   Substrate

Non-mobile substrates include continuous hard and soft bedrock and also non-mobile boulders, rocks and consolidated cobbles, non-mobile artificial substrates and compacted soft substrates such as clay and peat; mobile substrates include substrates such as mobile cobbles, pebbles, sand and mud. Non-mobile rock which is overlain by some deposited sediments follows path = non-mobile. Biogenic reefs on sub-littoral sediment follow path = mobile. Sub-littoral mosaics of mobile and non-mobile substrates should be considered as complex X32 or X33 comprising units from A5 and A3 and/or A4.

Answers: non-mobile ( vi ) mobile [ A5 ]

Question vi :   Characterised by macro-algae?

Infralittoral zones characterised by foliose or filamentous macro-algae, within the euphotic zone in relatively shallow sub-tidal or non-tidal water, are separated (path = Yes) from deeper animal-dominated circalittoral zones (path = No). Circalittoral zones are below deeper sub-tidal or non-tidal water with insufficient light penetration to allow algae to dominate; however encrusting algae and very sparse foliose or filamentous algae may be present in the upper circalittoral. Note that habitats in the euphotic zone, normally dominated by foliose or filamentous macro-algae but which as a result of storm damage or heavy grazing are characterised by encrusting algae, follow path = Yes. Note also that sublittoral caves or overhangs physically located within the infralittoral zone but where conditions are the same as at deeper levels of the seabed (i.e. total darkness, no hydrodynamic action and constant temperature) should follow path = No. Note: for mapping purposes it may be necessary to map combined A3/A4 where the presence of algae cannot be detected by the survey method.

Answers: No [ A4 ] Yes [ A3 ]