A review of subtidal kelp forests in Ireland

The information on this page is a synopsis of

A review of subtidal kelp forests in Ireland: From first descriptions to new habitat monitoring techniques
Kathryn M. Schoenrock,Kenan M. Chan,Tony O’Callaghan,Rory O’Callaghan,Aaron Golden,Stacy A. Krueger-Hadfield,Anne Marie Power. Ecology and Evolution, Volume: 10, Issue: 13, Pages: 6819-6832
First published: 16 June 2020 https://doi.org/10.1002/ece3.6345

Kelp forest, west of Ireland

Kelp forest ecosystems are key parts of the marine environment. Prior to the KelpRes project very little was known on the kelp forest ecosystems in Ireland which are dominated by Cuvie (Laminaria hyperborea). In order to study a species the first step is to examine the distribution of historical and present day records. This was done by examining herbarium samples. journal articles, government reports, online databases as well as soliciting information from dive clubs and citizen science groups.

Historic distribution of Laminaria hyperborea in Ireland
From Ecology and Evolution, Volume: 10, Issue: 13, Pages: 6819-6832

An examination of the historic records led to a number of key indicator species associated with healthy kelp ecosystems throughout the year. This information was then used to update the National Marine Monitoring Scheme / Adopt a Site species list to allow the health of kelp ecosystems to be monitored. A lack of these species could indicate the kelp ecosystem is unhealthy or that the habitat is too small (kelp park vs kelp forest).

Laminaria hyperborea is a long-lived species reaching ~15 years of age in the west of Ireland. Kelp ecosystems and their resilience to disturbance is an important aspect of the health of the inshore marine environment in Ireland. As well as hosting a high biodiversity kelp forests also serve as a nursery ground for a number of important fish species particularly juvenile gadoids. Based on initial studies of populations genetics Irish sites are genetically distinct from sites in Brittany France, but that there is also greater genetic structure in populations along the west coast of Ireland. The KelpRes project has collected samples from 48 sites and the results of that work should give us a much better understanding of population structure of kelp in Ireland.

What’s next?

Initial studies of kelp ecosystems indicated that the most important aspects of recording effort are focusing on where kelp ecosystems exist (presence of a forest) and then the measuring of the indicator species present. Citizen scientists and Seasearch divers in particular can play a key part in helping us to better understand this fascinating ecosystem. If you aren’t already find out how you can get involved in Seasearch recording here.

Full list of indicator species of kelp ecosystem

SpeciesAverage abundance m−2Trophic function
Sponge, encrusting Suberites spp.0.26Filter feeder
Hydroid, Obelia geniculata0.27Filter feeder (on kelp)
Anemone, Urticina feline1.54Predator
Cnidarian, Caryophyllia smithii0.59Filter feeder
Annelid, Eupolymnia nebulosa0.02Filter feeder
Crustacean, Palaemon serratus0.016Predator
Mollusc, Gibbula umbilicalis0.86Grazer
Mollusc, Gibbula cineraria0.06Grazer
Echinoderm, Asterias rubens (<3 cm diameter)1.22Predator
Echinoderm, Marthasterias glacialis0.41Predator
Echinoderm, Holothuria forskali0.39Suspension feeder
Echinoderm, Echinus esculentus0.2Grazer
Ascidian, Aplidium punctum0.78Filter feeder
Ascidian, Distomus variolosus4.99Filter feeder
Ascidian, Diplostoma spongiforme0.08Filter feeder
Vertebrate, Pomatoschistus spp.0.015Predator
Vertebrate, Gobiusculus flavescens0.39Predator