Offwell Wetland Survey
1. An area of wetland, showing
transitions between open water, swamp, marsh and dry land has been successfully restored.
This is particularly important because wetlands throughout Europe have been lost. In
Britain little remains of the many wetland areas which were once part of the landscape.
2. Plant biodiversity in the
region has increased eight to nine-fold compared to the area before restoration. The
clearance of rhododendron was commenced in 1988. The Wetland
was flooded in March 1989. In comparison with the area when it was covered rhododendron
there has been a complete transformation. (To access a survey of woodland before
and after it was cleared of rhododendron click here.)
3. Animal biodiversity has
increased by a much greater order of magnitude. The Wetland is now very important for
dragonflies, damselflies and amphibians. The swamp and marsh areas are particularly
important for young amphibians, grass snakes and voles. In winter, woodcock and snipe feed
in the wetland. In early spring, large numbers of toads and frogs spawn. They in turn
provide food for predatory aquatic invertebrates, fish and grass snakes. From late
spring onwards, the Wetland supports high invertebrate numbers because of plants such as
willow sp. Willows will support over 400 species of insects and mite. In turn, these high
invertebrate numbers provide food for a range of bird species. These include Spotted
flycatcher, Pied flycatcher, Black Cap, Chiff Chaff, Willow Warbler, Garden Warbler,
Dunnock, Marsh Tit, Willow Tit, Blue Tit, Great Tit, Long Tailed Tit as well as common
birds such as Wren, Blackbird and Robin. The Wetland is ideal for aquatic birds such as
Water Rail, Moorhens and Mallard ducks. Kingfishers are frequent visitors and have
been filmed feeding their young in the Wetland (video).
Even Otters now visit. The benefit to wetland wildlife of the restoration has been
4. Plant species in the wetland are
dominated by those characteristic of wetlands in England.
5. The plant species show different
zonation patterns in the wetland with relation to water depth.
6. The different zones within
the wetland are distinct, but also overlap. The boundaries between them are not sharp, but
7. The Rhododendron which dominated
the area prior to restoration is still present and dominates the dry land zones of the
wetland. Without continuous maintenance of the wetland and the prevention of silt build-up
in the area, the Rhododendron will rapidly encroach again.
A kingfisher in the Wetland
To find out how rhododendron has affected a woodland
Find out more about wildlife here.