Dense aggregations of brittlestars, sometimes covering hundreds of square metres and comprising hundreds or thousands of individuals m-2, can be found on a variety of substrata in UK coastal waters. Although found widely around the British and Irish coasts, beds of this kind are uncommon on a global scale and are of considerable interest to scientists studying the evolutionary history of marine benthic communities. The spatial extent of these aggregations, and the animal biomass they represent, mean that brittlestar beds may play an important role in the ecology of British coastal seas. They may also have some potential as indicators of natural or human-induced changes in the marine environment. The important scientific and ecological aspects of these beds justifies a review of their dynamics and sensitivity characteristics from a conservation-related perspective.

The objective of this report is to summarize and review the available information on the ‘Subtidal brittlestar beds’ biotope complex, focusing on the fundamental environmental and biological attributes of the system, its sensitivity to natural and human-induced changes, and options for monitoring such changes that are relevant to the management of candidate SACs.

Nature and importance of the biotope complex

Status within the MNCR biotope classification

Distribution within the British Isles

Distribution outside the British Isles