EUNIS habitat classification 2012 amended 2019 > A - Marine habitats > A4 - Circalittoral rock and other hard substrata > A4.2 - Atlantic and Mediterranean moderate energy circalittoral rock > A4.25 - Circalittoral faunal communities in variable salinity > A4.252 - Halichondria bowerbanki, Eudendrium arbusculum and Eucratea loricata on reduced salinity tide-swept circalittoral mixed substrata

Halichondria bowerbanki, Eudendrium arbusculum and Eucratea loricata on reduced salinity tide-swept circalittoral mixed substrata

English name: Halichondria bowerbanki, Eudendrium arbusculum and Eucratea loricata on reduced salinity tide-swept circalittoral mixed substrata

Description (English)

This biotope typically occurs on circalittoral mixed substrata (bedrock, boulders, cobbles, pebbles and gravel) in the moderately strong, tide-swept narrows near the entrance of Loch Etive, although not in the extremely tide-swept Falls of Lora. This sea loch is unique in having a substantial freshwater input from the surrounding moorland, yielding the most brackish, large sea loch in Scotland. Large growths of the brackish-tolerant sponge Halichondria bowerbanki cover the cobble and boulder seabed, interspersed with Mycale lobata, the hydroid Eudendrium arbusculum and the bryozoan Alcyonidium diaphanum which are particularly characteristic of these conditions. Tufts of the bryozoan Eucratea loricata are occasional in most areas. Other species recorded include Carcinus maenas, Asterias rubens, Crossaster papposus, Buccinum undatum, Pagurus berhardus, Henricia spp., Onchidoris bilamellata and Palio dubia, tolerant of the low salinity, are found in the circalittoral throughout this area. Ascidians such as Ascidiella scabra and Corella parallelogramma may also be present. A very impoverished low salinity version is present in the upper basin of Loch Etive. Unit A4.251 is similar in several respects to this biotope and will develop in less brackish situations where species-richness is generally greater.

Source: EUNIS habitat classification

Quick facts

EUNIS habitat type code A4.252
Bern Convention Included in a Resolution 4 habitat type at a higher level (A4)

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Species mentioned in habitat description

Invertebrates Alcyonidium diaphanum
Invertebrates Ascidiella scabra
Invertebrates Asterias rubens
Invertebrates Buccinum undatum
Invertebrates Carcinus maenas
Invertebrates Corella parallelogramma
Invertebrates Crossaster papposus
Invertebrates Eucratea loricata
Invertebrates Eudendrium arbusculum
Invertebrates Halichondria bowerbanki
Species scientific name English common name Species group
Alcyonidium diaphanum Invertebrates
Ascidiella scabra Invertebrates
Asterias rubens Invertebrates
Buccinum undatum Invertebrates
Carcinus maenas Invertebrates
Corella parallelogramma Invertebrates
Crossaster papposus Invertebrates
Eucratea loricata Invertebrates
Eudendrium arbusculum Invertebrates
Halichondria bowerbanki Invertebrates

Other classifications

Classification Code Habitat type name Relationship type
Marine Habitat Classification Britain/Ireland 0405 CR.MCR.CFaVS.HbowEud <I>Halichondria bowerbanki</I>, <I>Eudendrium arbusculum</I> and <I>Eucratea loricata</I> on reduced salinity tide-swept circalittoral mixed substrata source
CORINE Land Cover 5.2.3. Sea and ocean n/a
For relation to plant communities (syntaxa), see Vegetation types

History

Classification Code Habitat type name Relationship type
EUNIS Habitat Classification 200410 A4.252 Halichondria bowerbanki, Eudendrium arbusculum and Eucratea loricata on reduced salinity tide-swept circalittoral mixed substrata same
EUNIS Habitat Classification 200308 A3.535 Halichondria bowerbanki, Eudendrium arbusculum and Eucratea loricata on reduced salinity tide-swept circalittoral mixed substrata same
EUNIS Habitat Classification 200202 A3.535 Halichondria bowerbanki, Eudendrium arbusculum and Eucratea loricata on reduced salinity tide-swept circalittoral mixed substrata same
EUNIS Habitat Classification 199910 A3.535 Halichondria bowerbanki, Eudendrium arbusculum and Eucratea loricata on reduced salinity tide-swept circalittoral mixed substrata same
MNCR BioMar 97.06 (Britain & Ireland) ECR.BS.HbowEud Halichondria bowerbanki, Eudendrium arbusculum and Eucratea loricata on reduced salinity tide-swept circalittoral mixed substrata same
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