Biodiversity & Conservation

Overhangs and caves

LR.LR.Ov


LR.Ov

Image Keith Hiscock - A well developed overhang community with pendulous polyclinid tunicates. Image width ca 1 m.
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Distribution map

LR.LR.Ov recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)


  • EC_Habitats

Habitat sensitivity

Physical Factors

Click factor name to view rationale Intolerance Recoverability Sensitivity Species Richness Evidence / Confidence
Substratum Loss High Moderate Moderate Major decline Moderate
Smothering High High Moderate Decline Low
Increase in suspended sediment Low High Low Minor decline Very low
Decrease in suspended sediment
Desiccation Intermediate High Low Minor decline Low
Increase in emergence regime Intermediate High Low Minor decline Low
Decrease in emergence regime
Increase in water flow rate Intermediate High Low No change Low
Decrease in water flow rate
Increase in temperature Intermediate High Low Minor decline Low
Decrease in temperature
Increase in turbidity Low High Low No change Moderate
Decrease in turbidity
Increase in wave exposure Intermediate High Low Not relevant Low
Decrease in wave exposure
Noise Tolerant Not relevant Not sensitive Not relevant Not relevant
Visual Presence Tolerant Not relevant Not sensitive Not relevant Not relevant
Abrasion & physical disturbance High High Moderate Major decline High
Displacement High High Moderate Major decline Moderate

Chemical Factors

Click factor name to view rationale Intolerance Recoverability Sensitivity Species Richness Evidence / Confidence
Synthetic compound contamination Intermediate Low High Minor decline Low
Heavy metal contamination Insufficient information Not relevant Insufficient information Not relevant Not relevant
Hydrocarbon contamination Low Moderate Low Minor decline Low
Radionuclide contamination Insufficient information Not relevant Insufficient information Not relevant Not relevant
Changes in nutrient levels Tolerant Not relevant Not sensitive No change Low
Increase in salinity Intermediate High Low Decline Low
Decrease in salinity
Changes in oxygenation High High Moderate Decline Low

Biological Factors

Click factor name to view rationale Intolerance Recoverability Sensitivity Species Richness Evidence / Confidence
Introduction of microbial pathogens/parasites Insufficient information Not relevant Insufficient information Not relevant Not relevant
Introduction of non-native species Insufficient information Not relevant Insufficient information Insufficient Information Not relevant
Extraction of this species Not relevant Not relevant Not relevant Not relevant Not relevant
Extraction of other species Intermediate High Low Minor decline Very low

Species used to indicate biotope intolerance

Physical factors

Morchellium argus
Important characterizing
Botryllus schlosseri
Important structural
Umbonula littoralis
Important structural
Substratum LossHighHighHigh
SmotheringHighHighIntermediate
Increase in suspended sedimentLowHighIntermediate
Decrease in suspended sediment
DesiccationHighIntermediateIntermediate
Increase in emergence regimeIntermediateIntermediateIntermediate
Decrease in emergence regime
Increase in water flow rateLowIntermediateIntermediate
Decrease in water flow rate
Increase in temperatureLowLowLow
Decrease in temperatureIntermediate
Increase in turbidityLowLowLow
Decrease in turbidity
Increase in wave exposureLowIntermediateIntermediate
Decrease in wave exposure
NoiseTolerantTolerantTolerant
Visual PresenceTolerantTolerantTolerant
Abrasion & physical disturbanceIntermediateIntermediateIntermediate
DisplacementHighHighHigh

Chemical factors

Morchellium argus
Important characterizing
Botryllus schlosseri
Important structural
Umbonula littoralis
Important structural
Synthetic compound contaminationInsufficient informationInsufficient informationInsufficient information
Heavy metal contaminationInsufficient informationInsufficient informationInsufficient information
Hydrocarbon contaminationInsufficient informationInsufficient informationIntermediate
Radionuclide contaminationInsufficient informationInsufficient informationInsufficient information
Changes in nutrient levelsTolerantLowInsufficient information
Increase in salinityIntermediateIntermediateHigh
Decrease in salinity
Changes in oxygenationInsufficient informationIntermediateLow

Biological factors

Morchellium argus
Important characterizing
Botryllus schlosseri
Important structural
Umbonula littoralis
Important structural
Introduction of microbial pathogens/parasitesInsufficient informationInsufficient informationInsufficient information
Introduction of non-native speciesInsufficient informationTolerant*Insufficient information
Extraction of this speciesIntermediateNot relevantNot relevant
Extraction of other speciesIntermediateHighHigh

Species used to indicate biotope recoverability

Physical factors

Morchellium argus
Important characterizing
Botryllus schlosseri
Important structural
Umbonula littoralis
Important structural
Substratum LossHighHighHigh
SmotheringHighHighHigh
Increase in suspended sedimentHighHighHigh
Decrease in suspended sediment
DesiccationHighHighHigh
Increase in emergence regimeHighHighHigh
Decrease in emergence regime
Increase in water flow rateHighHighHigh
Decrease in water flow rate
Increase in temperatureVery highVery highHigh
Decrease in temperatureHigh
Increase in turbidityHighImmediateHigh
Decrease in turbidity
Increase in wave exposureHighModerateHigh
Decrease in wave exposure
NoiseNot relevantNot relevantNot relevant
Visual PresenceNot relevantNot relevantNot relevant
Abrasion & physical disturbanceHighHighHigh
DisplacementHighModerateHigh

Chemical factors

Morchellium argus
Important characterizing
Botryllus schlosseri
Important structural
Umbonula littoralis
Important structural
Synthetic compound contaminationNot relevantNot relevantNot relevant
Heavy metal contaminationNot relevantNot relevantNot relevant
Hydrocarbon contaminationNot relevantNot relevantHigh
Radionuclide contaminationNot relevantNot relevantNot relevant
Changes in nutrient levelsNot relevantHighNot relevant
Increase in salinityHighHighHigh
Decrease in salinity
Changes in oxygenationNot relevantHighHigh

Biological factors

Morchellium argus
Important characterizing
Botryllus schlosseri
Important structural
Umbonula littoralis
Important structural
Introduction of microbial pathogens/parasitesNot relevantHighNot relevant
Introduction of non-native speciesNot relevantNot relevantNot relevant
Extraction of this speciesHighNot relevantNot relevant
Extraction of other speciesHighModerateHigh

This review can be cited as follows:

Hiscock, K. 2002. Overhangs and caves. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 23/07/2014]. Available from: <http://www.marlin.ac.uk/habitatsensitivity.php?habitatid=242&code=1997>