The following sections present an overview of only those fundamental physical attributes and ecological requirements of kelps which affect their basic distribution, with emphasis on information for those species common in UK waters at the present time.

The faunal and floral diversity of kelp biotopes is extremely rich (see Appendix). This is in part associated with the diversity of available food sources as primary production (microscopic and macroscopic algae), secondary production (herbivores and subsequent trophic levels) and microbially recycled production but is also due to the physical and structural diversity within the biotopes, with the many and various exploitable niches available.

Any kelp-bearing area will contain a number of habitats available to other biota. Faunal species may be found restricted to, or moving between, any combination of such associated habitats. A large component of the fauna, such as much of the rock crevice fauna or sediment infauna, may occur more or less independently of the presence of kelp. Similarly some fauna may be mainly or entirely restricted to the kelp plants themselves, as is the case with many species found in the kelp holdfasts. The flora found in kelp beds may also not be restricted to this habitat, but the complex interactions of the grazing species found in kelp beds and the several habitats available for colonisation within the kelp bed may lead to a wide diversity of seaweeds being present within a given area.

However, the following points should be noted:

• For the majority of flora and fauna found within the various kelp biotopes, the specific environmental requirements and the physical attributes of the individual species are not known.
• Within the scope of this report it is not possible to consider the specific requirements for any of the many hundreds of species of animals and plants which are characteristic of the given kelp biotopes. It must be assumed that, if a species is present within a kelp biotope, the local conditions are suitable for it. These conditions may be at the upper or lower limits of tolerance for the species the presence of which may be independent of the presence of kelp species.

Substratum

Light, depth and water clarity

Water movement

Temperature

Chemistry

References