Impacts of climate change on shallow and shelf subtidal habitats, relevant to the coastal and marine environment around the UK

A comprehensive review of the literature identified thirteen new relevant studies published since the MCCIP 2013 report on ‘what is already happening’, of which all but one were conducted in UK waters. A further four studies have been published since 2013 on ‘what is likely to happen in the future’. • North Sea infaunal (burrowing) species have shifted their distributions in response to changing sea temperature, however, most species have not been able to keep pace with shifting temperature, meaning that species are subjected to warmer conditions. Leading (expanding) edges are responding more quickly than trailing (retreating) edges, which has been observed elsewhere in the world. • Analysis of a 40-year data–series found that small, generally shorter lived, infauna experienced some changes in community structure related to changes in Sea-Surface Temperature (SST), but this affect was dampened because increased food availability meant that temperature induced rises in energy use were counteracted. This was not the case for large-bodied species that experienced increased competition leading to altered community structures. This highlights that changes in non-climate drivers may interact with climate change to mediate species – community level responses and that responses may depend on species life-history traits. • A number of UK kelp species have experienced changes in abundance linked to altered SST. In particular the warm-water species, Laminaria ochroleuca, has increased in abundance and expanded its distribution into more wave-exposed conditions. While superficially similar, there are differences between warm-water and cold-water species in terms of life history characteristics (e.g. cold-water species such as L. hyperborea and L. digitata are perennial, whereas the warm-water species Saccorhiza polyschides is a pseudo-annual), and habitat provision (e.g. L. hyperborea supports diverse epiphyte assemblages whereas L. ochroleuca does not)