Threats and knowledge gaps for ecosystem services provided by kelp forests: a northeast Atlantic perspective

Kelp forests along temperate and polar coastlines represent some of most
diverse and productive habitats on the Earth. Here, we synthesize information
from >60 years of research on the structure and functioning of kelp forest habitats
in European waters, with particular emphasis on the coasts of UK and Ireland,
which represents an important biogeographic transition zone that is
subjected to multiple threats and stressors. We collated existing data on kelp
distribution and abundance and reanalyzed these data to describe the structure
of kelp forests along a spatial gradient spanning more than 10° of latitude. We
then examined ecological goods and services provided by kelp forests, including
elevated secondary production, nutrient cycling, energy capture and flow,
coastal defense, direct applications, and biodiversity repositories, before discussing
current and future threats posed to kelp forests and identifying key knowledge
gaps. Recent evidence unequivocally demonstrates that the structure of
kelp forests in the NE Atlantic is changing in response to climate- and nonclimate- related stressors, which will have major implications for the structure and functioning of coastal ecosystems. However, kelp-dominated habitats along much of the NE Atlantic coastline have been chronically understudied over recent decades in comparison with other regions such as Australasia and North America. The paucity of field-based research currently impedes our ability to conserve and manage these important ecosystems. Targeted observational and experimental research conducted over large spatial and temporal scales is urgently needed to address these knowledge gaps.