| Tayside Biodiversity - Tayside
Biodiversity Action Plan - Coastal - Estuaries |
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NATURE CONSERVATION IMPORTANCE
Sub-tidal zone
Estuaries have extensive underwater habitats in the sediments supporting a variety
of algae (including seaweeds), plants, invertebrates and fish, which in turn
support species further up the food chain such as seals and birds. These areas
are also important nursery grounds for young fish.
Mudflats
Mudflats are highly productive areas which, together with other intertidal habitats,
support large numbers of predatory birds and fish. They provide feeding and resting
areas for internationally important populations of migrant and wintering waterfowl
and are also important nursery areas for flatfish. Mudflats are characterised
by high biological productivity and abundance of organisms, but low diversity
with few rare species. |
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Seagrass
Beds
Three species of Zostera occur in the UK and all are considered to be scarce:
Dwarf eelgrass Zostera noltii, Narrow-leaved Zostera angustifolia and Marine
eelgrass Zostera marina.
All three species are found in Tayside: the largest area being in Montrose
Basin. The
plants are an important source of organic matter and provide shelter and
a surface for
attachment by other species. Eelgrass is an important source of food for
wildfowl,
particularly Brent goose Branta bernicia and Wigeon Anas penelope which
feed on intertidal beds. The shelter provided by seagrass beds makes them
important nursery areas for fish, including Pollack Pollachius pollachius,
Twospotted goby Gobiusculus flavescens, Pipefish species and various Wrasse. |
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Swan Management Demonstration Project
- Montrose Basin
Mute swans Cygnus olor are present in nationally
important numbers on Montrose Basin; the
wintering flock consists of approximately 260 birds.
They feed mainly on the Zostera beds in the Basin
and move onto the adjacent arable land in
December when the density of the Zostera is
reduced. Attracted to fields of oilseed rape, cereals
and grass, they cause damage to these crops by
feeding and ‘puddling’ the fields with their feet.
To keep the swans off the arable land, a Swan
Management Demonstration Project was set up in
1998 to provide an area of arable crop adjacent to
Montrose Basin as a safe haven for them to feed in.
A Swan Scarer is employed for several weeks during
the winter to ensure the birds use the correct field.
The Project is a partnership between four of the
local farmers, Angus Council, Scottish Executive
Environment and Rural Affairs Department and
Scottish Natural Heritage, together with the British
Association for Shooting and Conservation, the
National Trust for Scotland, Scottish Agricultural
College and the Scottish Wildlife Trust. |
Saltmarsh
Saltmarshes form the upper vegetated parts of intertidal mudflats. They are built
up by a community of salt tolerant plants and are an important resource for
wading birds and wildfowl. They act as high tide refuges for birds feeding
on adjacent mudflats, as breeding sites for waders, gulls and terns and as
a source of food for passerine birds particularly in autumn and winter. In
winter, grazed saltmarshes are used as feeding grounds by large flocks of
wild ducks and geese. |
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Mammals
There is a population of approximately 650 Common seals
Phoca vitulina in the Tay Estuary which represents over 1% of
the total European population and is therefore of international
importance. Otters Lutra lutra are found in both the
Montrose Basin and Tay Estuary, but only anecdotal evidence is
available as regards their distribution and population numbers
as there is little existing data to call upon. |
Birds
The expansive mudflats and tidal nature of the Tay Estuary and
Montrose Basin are attractive as safe roost sites for geese.
Other bird species are attracted not only by the safety, but
also by the food supplies available. Waders feed on a range of
invertebrates whilst Wigeon and Mute swans at Montrose
feed primarily on Zostera. Montrose is a nationally important
moulting site for many of Tayside’s Mute swans.
Both Montrose Basin and the Tay Estuary support nationally
and internationally important populations of wildfowl and
waders. This is recognised by their designation as Special
Protection Areas (SPA) under the European Birds Directive
and as Ramsar Sites under the Ramsar Convention. |
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| Nationally
and Internationally important waterfowl populations wintering
on Tayside Estuaries |
| Species |
Estuary |
International Importance |
National Importance |
| Mute Swan |
Montrose Basin |
|
/ |
| Pink-footed Goose |
Montrose Basin
Tay |
/
/ |
|
| Greylag Goose |
Tay |
/ |
|
| Shelduck |
Montrose Basin |
|
/ |
| Widgeon |
Montrose Basin |
|
/ |
| Eider |
Montrose Basin
Tay |
|
/
/
|
| Goosander |
Montrose Basin
Tay |
|
/
/
|
| Knot |
Montrose Basin |
/ |
|
| Bar-tailed godwit |
Tay |
/ |
|
| Redshank |
Montrose Basin |
/ |
|
| Sandwich Tern |
Tay |
|
/ |
| Common Tern |
Tay |
|
/ |
| Arctic Tern |
Tay |
|
/ |
| Species
for which the two estuaries are locally important include Oystercatcher
Haematopus ostralegus, Golden plover Pluvialis apricaria, Sanderling
Calidris alba, and Black-tailed godwit Limosa limosa. Montrose
Basin holds a large latesummer tern roost which has numbered
in recent years over 2,000 mixed terns including Sandwich Sterna
sandvicensis, Common Sterna hirundo and Arctic Terns Sterna
paradisaea. |
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