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North Norfolk - Titchwell and Bitterns
The area of land which now comprises the Royal Society for the Protection of
Birds (RSPB) reserve at Titchwell was originally enclosed in 1786. Following
a breach in 1940 and further loss following the 1953 flood, the agricultural
land reverted to low level saltmarsh and reedbed. Regular inundation by the
tide was seen as a restriction on the ability of the site to support breeding
birds. The RSPB bought the marsh in the 1970's and embarked on the construction
of a series of embankments and sluices to regulate salinity levels creating
10ha of freshwater reedbed, 11ha freshwater marsh and 17ha brackish marsh. 58ha
of the original saltmarsh and 14ha of tidal reedbed were retained (Sills
& Becker 1988).
Through the normal process of succession the older reedbeds began to dry out
and in order to reverse the process a 1m high bank was built to retain water.
However, unforeseen by the managers, the bank blocked the path of young eels,
one of the principal food items of the bittern,
a rare and declining species in northwest Europe. One consequence appears to
have been a further decline in the breeding bittern population at the site between
1980 and 1991. This has been correlated with an increase in the average weight
of the eels crossing the dam to above 70gm, at which point they were too big
for the birds to feed upon (Sullivan 1991).
| Guidance: This case shows how important it is to understand quite
detailed components of the breeding and feeding strategies of some individual
species before embarking on habitat manipulation. |
Comment: This is an intensively managed site, which if it had been
left to develop following the 1953 inundation, would probably now exist as a
transitional saltmarsh to tidal reedbed.
References
Sills, N. & Becker, D.
1988.
Management Case Study: - the Conversion of Saltmarsh into Fresh and Brackish Water Habitats at Titchwell Marsh, Norfolk.
Royal Society for the Protection of Birds.
Sullivan, J.
1991.
Tiny eels are the best bait for bitterns.
New Scientist, 112., 9.
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