Hertfordshire wetlands: how Withey Beds in Rickmansworth is being revitalised
PUBLISHED: 15:11 11 November 2015
Withey Beds nature reserve in Rickmansworth is an ancient site of willow management - today important as one of the few remaining wetland sites in the county. Ellie Beach of the Countryside Management Service gives a guide to the work being done to enhance it
Withey Bed is an Old English term used to describe an area used to grow different species of willow trees for coppicing. This traditional management technique involves regularly cutting trees to ground level resulting in the regrowth of multiple stems which are subsequently harvested. Witheys once formed an important part of village economies supplying poles for basket work, thatching, firewood and many other uses.
Withey Beds in Rickmansworth was managed in this way and this has resulted in the varied wildlife habitats which exist today.
Withey Beds is still managed using traditional techniques. The rotational coppicing of willow preserves the character of the site and the future reintroduction of grazing with cattle will halt scrub from encroaching on to the flower rich meadow.
Why is Withey Beds important?
Throughout the 20th century wetlands greatly declined both in the county and on a national scale. Changes in land use, urban development and over-abstraction of water all contributed to this.
Withey Beds Local Nature Reserve is one of the few remaining wetlands in Hertfordshire. A Local Nature Reserve, it offers a variety of habitats such as wet woodland, swamp, grazing marsh and river (the Colne). These support a variety of wildlife, particularly insects including the rare oak jewel beetle and Roesel’s bush cricket (below) and birds including snipe and lapwing (above).
Countryside Management Service, working with the landowner Three Rivers District Council and the Environment Agency, has developed a range of plans to restore existing habitats and create new features. Gravel riffles have been constructed at a couple of locations along the Colne. Made from cobble-sized stone topped with finer gravels the riffles mimic what would form naturally if gravels were present. They help to restore the natural flow of the river and provide the perfect area for fish such as brown trout, chubb, barbel and dace to spawn by ‘cutting redds’ - creating shallow excavations in gravel in which to lay their eggs.
Once born, the fry need somewhere to mature protected from predators. A backwater (opposite page) has been created downstream for this purpose. Backwaters consist of a channel linked to the river with a deeper pool and marginal shelves. This provides a fry nursery and flood refuge area. The shallow margins ensure the water warms up quickly in the sun, creating productive conditions for the fish to grow quicker and with a better survival rate. It also provides an ideal nursery area for juvenile amphibians, invertebrates and other creatures.
Five small dragonfly ponds have been dug either side of the existing boardwalk to create new wetland features on the site. Dragonflies and damselflies spend the first stage of life in ponds, living under the water as nymphs and feeding veraciously on a range of aquatic invertebrates. After around five years these nymphs emerge from the water as adults - the beautiful insects we see on the wing in spring and summer.
A wetland scrape (a shallow depression with sloping edges that seasonally holds water) has also been created. This will provide an important resource for wading birds such as snipe and redshank that feed on aquatic invertebrates revealed on the muddy margins as the water retreats.
Grazing will also be introduced to the site to keep some areas free from scrub growth. Traditional conservation grazing is a more sensitive way of managing the grassland, producing more varied vegetation. This in turn is better for insects, birds and small mammals. It replaces the need for heavy machinery and protects the grassland habitat. w