15.
SANDY AND SHINGLE BEACHES
In the inner firth, where the coastline is a bit less exposed, sand and shingle have been able to settle between the rocky headlands, forming clean, sandy beaches or long shingle bars.
Sandy Beaches
The
beaches are still battered by winds from the north, and the sand is moved about
by waves. Some of the sand is moved out to deeper water offshore. Life under
the open beach is tough. It can be a hostile environment - at low tide the sun
and wind can quickly dry out small animals; and when the tide comes back in,
the shifting sands do not allow animals to settle. Yet hidden armies of banded
wedge shells, razorshells, striped venus shells and many others lie safe only
a few centimetres under your feet. The innocent sounding necklace shell is a
specialised killer - it bores through the shells of other molluscs with an acid
gland to suck out their insides. Cockles are smashed open or prised apart by
wading birds (41) and gulls feast on the thousands of animals
stranded on the beaches after a storm.
Where washed up driftwood and seaweed create a strandline, there is food and shelter for animals such as the centimetre long sandhopper, a land dwelling relative of crabs and lobsters, which will bounce away if you go near them.
The sand also blows inland, forming sand dunes. These dunes provide a place for land plants to grow. This coastal environment is greatly influenced by tides, salty sea spray, drying winds and often poorly developed soils. It is therefore a difficult place for land plants to live. However, some species are specially adapted to cope with these conditions and can thrive here as there is little competition for space with other plants.
A sand stabiliser - Marram grass
There are few plants that can grow in the constantly shifting sand of the seashore,
which either buries them or exposes their roots to the elements. Marram grass,
however, can grow in pure sand above the drift line of the high tide on sandy
shores, where its deep roots anchor it firmly. Sand blown in the wind is trapped
by the plant and builds up around it. Marram can grow quickly upwards and also
sideways by 'runners' to keep pace with the growing dune. The runners and roots
inside, which can grow up
to 12 metres deep, help stabilise the dune.
Once the marram grass has created a stable dune, other species can then grow between the marram plants, and the vegetation gradually becomes more varied on the fixed dune. Marram therefore plays an important role in stabilising coastlines of mobile sand, which occur in many parts of the inner Moray Firth.
Important sand dune sites include Loch Fleet(25) and Culbin Sands(64)
Shingle Beaches
Pebbles
carried to the coast from inland rivers like the Spey, Nairn and Findhorn have
built up over many centuries into ridges along the coast. Some of the stones
have been eroded from mountains far inland e.g. Cairngorms, by the ice sheet,
during the last ice age. Although the pebbles are too heavy to be carried out
to sea, the waves roll them along the coast and throw them up into storm beaches,
forming bars that may eventually cut off a large lagoon on the landward side.
During a particularly fierce storm, or series of storms, a new section of bar
may form rapidly, producing the 'curls' of shingle at the bar end, sometimes
trapping a small pool of seawater. Plants eventually grow on the older parts
of the bar and the bar becomes more stable.
The Shingle forelands at Spey Bay (24) and Culbin(64) are amongst the largest in Britain. Each ribbon of shingle marking the edge of a former coastline. This shingle now supports a distinctive community of lichens, flowering plants and insects.
Understanding the way these coastal features behave is important when planning housing or other building works, or developing coastal defences. Removing material from offshore, by dredging for sand and gravel, may also have unpredictable effects on these features.
Seabird breeding sites
Sand and shingle systems at Loch Fleet(25), Whiteness Head and Spey Bay(24) are used by breeding terns. Terns also use 'artificial' sites such as reclaimed land within McDermott's Fabricators Yard near Ardersier and at Nigg and RAF Kinloss.
Little Terns breed mainly in Caithness and Sutherland. The breeding success
is variable and human disturbance is implicated in many failures. Sandwich terns
have moved back into the Moray Firth since 1990, breeding near Ardersier; in
1992, 230 bred at McDermott's yard, Ardersier. There used to be major Sandwich
tern colonies at Culbin, the Morrich More and at Loch Fleet as well as at Whiteness
Head, where McDermott's yard now stands. Colonies of Common Terns range in size
and occur in the inner and outer Dornoch Firth, the Cromarty Firth, Whiteness
Head and Kinloss. Artic Terns breed in several colonies such as Kinloss.