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Pressures on tidal sand and mud flats
Pressures on intertidal sand and mud flats include some or all of the following:
- Habitat
loss;
- Reduced sediment supply;
- Changes in sediment patterns;
- Changes in wave patterns;
- Pollution;
- Increased nutrient loads;
- Sea level change;
- Harvesting animals (e.g. lugworms for fishing).
Enclosure of tidal land (including 'warping'
to recreate saltmarsh) causes loss of habitat. Where port and other industrial
related development is involved large expanses of tidal flats can be lost.
Dams, offshore sand extraction, maintenance dredging (estuaries) and protection
of eroding cliffs reduce sediment supply to the coast and resulting erosion.
Offshore structures including breakwaters can also restrict long-shore drift,
change sediment and wave patterns. Pollution and nutrients can cause indirect
effects on other habitats such as 'rotting' of surface vegetation and further
erosion. All of these activities have a special significance for the conservation
of wintering
waterfowl populations.
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General guidance: It is important to look at the wider picture
when assessing whether a mudflat is eroding or not. It is possible and
in some cases likely that the erosion could be part of the natural cycle
of erosion and accretion, which is a feature of this habitat.
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