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Monitoring at Orplands following sea wall breaching
Preliminary results some six months after breaching suggest that there had
been a 3mm gain in sediment height, widespread plant colonisation by halophytes,
use by invertebrates and crustaceans and extensive use by birds. Annual monitoring
reports have been produced by the Environment Agency since then. These show
the rate and extent of colonisation of the exposed tidal flats by plants and
invertebrate animals.
- At Orplands the poorer groundwater drainage of site A, which had not been
ploughed or drained since enclosure produced highly anoxic conditions. It
is thought these conditions prevented plant colonisation below 2.5m ODN. For
the same reason bivalve mollusc species, though present in substantial numbers
in the nearby mudflats, failed to colonise the same anoxic mudflats;
- To seaward of the realignment attempts at
saltmarsh restoration in the 1980s
were made. This site lends credence to the view that extending
saltmarshes (favoured in the 1980s) is probably not a viable means of habitat
restoration in this area at least.
| Guidance: Orplands (along with Tollesbury)
show that despite local factors, which can slow down the rate of plant colonisation,
successful re-creation of saltmarsh is possible when a managed
realignment takes. The site also provides examples of standardised
monitoring of bird populations following. Orplands differs from the other
Blackwater schemes in that no secondary defences were necessary. This means
that a full vegetation succession from lower to upper saltmarsh with transitions
to terrestrial vegetation has been able to develop. Information obtained
from here may be relevant to other sites where the re-creation of 'natural'
transitions are possible. |
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