This report has been prepared as a summary of the biological and
ecological information available to date (1998) on the kelp beds in European, and more
specifically in UK, coastal waters. It is one of a series of nine reviews on coastal
marine habitats that have been identified as being of significance in terms of the EU
Habitats Directive and which are included in the UK Marine SACs Project.
The "kelp forests" have been selected as biotope complexes to
be scientifically reviewed for the UK Marine SACs Project for the following reasons:
- Kelp forests occur in 8 of the proposed demonstration marine SACs within the UK (see
- Kelp forests have considerable conservation value because they harbour a very high
diversity of organisms, confined to a very narrow fringe along the coastline.
- The kelp forests throughout Europe are threatened by the effects of several forms of
human activity, including harvesting and eutrophication
- Laminaria hyperborea and Laminaria digitata are regarded as commercially
valuable species and demand for exploitation is increasing; this should be counterbalanced
by the provision of reserve areas.
What is kelp and why is it important?
Kelp is the colloquial name given to the large, brown seaweeds of the
order Laminariales which dominate much of the shallow sublittoral in temperate parts of
the world. Kelp plants are physically large, from several metres to several tens of metres
tall, and when they are present in dense stands known as "kelp forests" they
form an important habitat for other organisms. The kelp forests that are found fringing
the temperate sea shores of the world are possibly the most ecologically dynamic and
biologically diverse habitats on the planet. These marine forests are the underwater
equivalent of the terrestrial rain forests and, just as there are African, Asian and
American tropical and temperate rain forests, so in the various oceans of the world are
there different species assemblages and ecological linkages in the kelp forests. In
north-west Europe the major kelp species is Laminaria hyperborea although others
may be locally dominant in particular ecological situations e.g. Laminaria saccharina,
Laminaria digitata, Alaria esculenta and Saccorhiza polyschides.
There are many thousands of animal species that live within the kelp
forests of the world, either on the rock substratum or on the kelp plants. There are also
thousands of different species of seaweeds in these forests, forming layers of plant life
in the same way that terrestrial forests have layers of plants (canopy, epiphytes,
sub-canopy, understorey, etc.). However, the kelp forests differ from the terrestrial
forests in that kelp forests, with their very high productivity, provide the food source
for most of the animals in the areas surrounding the kelp forests as well as within them.
The material that is continually being lost from the kelp plants feeds into a complex
recycling system of herbivores, detritivores, and bacteria, all of which form part of an
immense web of interacting species of plants and animals that extend the influence of kelp
forests far beyond the habitat of the kelp plants themselves.
In the same way that terrestrial forests supply timber and valuable
food species for humanity - and so are threatened to destruction by over exploitation -
kelp forests are also under threat. Kelp species themselves are harvested as feedstock for
fertiliser and chemical industries and for food, at a present rate (world-wide) of about
2.5 million tons per year. Kelp extracts have a multitude of applications as homogenising
and gelling agents (toothpaste, non-drip paint, etc.) and demand for these chemicals is
increasing. Other species of algae in kelp beds also have commercial value as human
foodstuffs or as a fodder crop in aquaculture (e.g. Dulse, Palmaria palmata in
Ireland). Many of the animal species found in kelp forests are also commercially
exploited, lobsters, crabs, crayfish, abalone and many fish species are all harvested from
kelp beds in different parts of the world.
Conservation significance of kelp forests
Kelp distribution in European and UK waters
Kelp beds - the advantages and limitations of the MNCR biotope