Biodiversity & Conservation

Beds of dead maerl

Dead maerl beds


Beds of dead maerl
Distribution map

Dead maerl beds recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)


  • EC_Habitats
  • UK_BAP
  • OSPAR

Habitat sensitivity

Physical Factors

Click factor name to view rationale Intolerance Recoverability Sensitivity Species Richness Evidence / Confidence
Substratum Loss High None Very High Major decline High
Smothering Intermediate High Low Decline Low
Increase in suspended sediment Intermediate High Low Decline Very low
Decrease in suspended sediment Not relevant Not relevant Not relevant Not relevant Not relevant
Desiccation Not relevant Not relevant Not relevant Not relevant Not relevant
Increase in emergence regime Not relevant Not relevant Not relevant Not relevant Not relevant
Decrease in emergence regime Not relevant Not relevant Not relevant Not relevant Not relevant
Increase in water flow rate Intermediate High Low Decline Very low
Decrease in water flow rate High High Moderate Major decline Very low
Increase in temperature Low Very high Very low Minor decline Very low
Decrease in temperature Low Very high Very low Minor decline Very low
Increase in turbidity Low Very high Very low Minor decline Very low
Decrease in turbidity Low Very high Very low No change Very low
Increase in wave exposure Intermediate High Low Decline Low
Decrease in wave exposure Tolerant Not relevant Not sensitive No change Very low
Noise Tolerant Not relevant Not sensitive Not relevant Low
Visual Presence Tolerant Not relevant Not sensitive Not relevant Low
Abrasion & physical disturbance High Moderate Moderate Major decline Moderate
Displacement Intermediate High Low Decline Very low

Chemical Factors

Click factor name to view rationale Intolerance Recoverability Sensitivity Species Richness Evidence / Confidence
Synthetic compound contamination Intermediate High Low Decline Very low
Heavy metal contamination Intermediate High Low Decline Very low
Hydrocarbon contamination Intermediate High Low Decline Very low
Radionuclide contamination Insufficient information Insufficient information Insufficient information Insufficient Information Insufficient information
Changes in nutrient levels High Moderate Moderate Major decline Moderate
Increase in salinity Low Very high Low No change Low
Decrease in salinity Intermediate High Low Decline Low
Changes in oxygenation High Moderate Moderate Major decline Moderate

Biological Factors

Click factor name to view rationale Intolerance Recoverability Sensitivity Species Richness Evidence / Confidence
Introduction of microbial pathogens/parasites Low Very high Low No change Very low
Introduction of non-native species High Very low / none Very High Major decline High
Extraction of this species High None Very High Major decline High
Extraction of other species High None Very High Major decline High

This review can be cited as follows:

Tyler-Walters, H. 2013. Beds of dead maerl. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 30/07/2014]. Available from: <http://www.marlin.ac.uk/habitatsensitivity.php?habitatid=999&code=2004>