Page 66 - Alderney Regional Environmental Assessment of Renewable Energy: Environmental Report

Alderney Regional Environmental Assessment of Renewable Energy:
Environmental Report
5. Biological Environment
Alderney is exposed to the full force of the sea and weather conditions that prevail in the
western approaches. This is reflected in the fauna and flora recorded around Alderney and the
associated nature conservation designations. This section provides an assessment of the
potential effects of the Draft Plan on benthic and pelagic ecology as well as fish and shellfish,
ornithology marine mammals and turtles, nature conservation and terrestrial ecology. Each
section contains a baseline description of the biological environment and also identifies data
gaps and limitations that will need to be considered further at the EIA project-level by the
developer. An assessment of the potential effects that could arise from the various elements
and phases of the Draft Plan is included together with any mitigation measures that are
required to reduce significant impacts to acceptable levels.
5.1 Benthic Ecology
5.1.1 Baseline Description
The marine life found within the waters around Alderney is typical of that associated with strong
tidal streams and high energy environments with a range of encrusting animals (animals fixed
on or in the seabed), including soft corals, hydroids (sea firs), bryozoans (sea mats), large
sponges and anemones. In shallow water, bedrock and boulders often support kelp and sea
oak macroalgae, which grow very long in the tidal currents, and have a variety of animals
growing on them (UKBAP, 2008; Wood, 2007; 2008; 2010).
The macrofauna associated with the Alderney South Banks Subtidal Sandbank has low
species diversity and abundance and is dominated by tide-swept communities associated with
coarse and mobile sand. Rocky reefs are dominated by turf fauna and tide-swept communities,
the latter being of some interest due to the relative scarcity of this habitat across the UK and
Europe as a whole (Axelsson et al., 2011).
5.1.1.1 Subtidal benthic ecology
There is limited survey data of subtidal benthic habitats within Alderney territorial waters and
the wider study area. Predicted broadscale benthic habitats within Alderney territorial waters
and the wider study area, based on EUSeamap modelling, are shown in Figure 10. Based on
this model, the main broad scale habitat around Alderney is likely to comprise moderate energy
circalittoral rock (EUNIS Level 3 classification A4.2) in which faunal communities on deep
moderate energy circalittoral rock dominate (EUNIS A4.27), and circalittoral coarse sediment
(A5.14). An area of deep low energy circalittoral rock, dominated by faunal communities
(A4.33) is predicted off the south coast of Alderney. To the south west of Alderney and
between Alderney and the French coast, areas of deep circalittoral sand are predicted to occur
(A5.27).
A number of species and habitats exist in the waters around Alderney which are listed as
having important conservation value under UK and EU directives. Although these do not apply
to the Channel Islands, the importance of these species and habitats in terms of their level of
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