Over the next month or so we’ll be undertaking some habitat management work out on the wetlands. So if you see people or machinery out on the brooks, this might explain what they’re up to….
Creation of ditch spurs
This is a continuation of the work done last summer/early autumn as part of the Back from the Brink project to benefit our rare Little Whirlpool Ramshorn Snails (Anisus vorticulus). To enable us to manage the water on site it is essential that the ditches are cleared periodically to allow water to flow along and between them. The ditches act as ‘wet fences’ allowing us to manage the grazing too.
To ensure that the snail population is not affected by this essential ditching management, one of the solutions is for us to create some ‘ditch spurs’ – short sections leading off the main ditches where the vegetation can grow relatively un-checked and provide a refuge for the snails when the main ditches are cleared.
Most of this work will be carried out on the far side of the North Brooks – the favoured spots for the special snail.
This tiny snail, who has a diameter less than 5 mm, is perhaps the rarest and most special creature on the reserve, and its presence is the reason that we have been designated as a Site of Special Scientific Interest (SSSI) and a Special Area for Conservation (SAC).
Photo from Toby Abrehart
The little whirlpool ramshorn snail is a small aquatic snail with a flattened spiral shell rarely more than 5 mm in diameter and is one of the rarest, most restricted and vulnerable freshwater molluscs in Britain. In the UK it is classed as Nationally Rare and Vulnerable (IUCN) and is a European Protected Species. Pulborough Brooks reserve holds what is considered to be the second largest population in England.
It has always been a very local species in Britain. It formerly occurred at around 15 sites in south-east England, but appears to have been lost from more than half of its pre-1965 known sites and is now restricted to three main population centres; the Arun Valley in West Sussex, the Norfolk Broads and the Pevensey Levels in East Sussex. It continues to decline in the face of water quality declines, inappropriate habitat management and direct loss through agricultural action.
It is generally considered to occur in unpolluted, calcareous waters in marsh drains with a dense aquatic flora, and to favour ditches with a diverse flora but little emergent vegetation. Ditches that are either completely cleared of vegetation or are choked with weed and silt are considered unsuitable. Winter flooding may be important in enabling young snails to colonise new ditches.
This project aims to create additional suitable habitat and test factors that may influence the snail’s ability to occupy ditches, such as method of ditch management, turbidity and the presence of carp. If deemed feasible, the snail may be translocated from ditches on the North Brooks to the southern and middle areas of the reserve in an attempt to increase its range.
Back from the brink
Thanks to National Lottery funding, leading conservation organisations including the RSPB will come together in one of the most ambitious conservation projects ever undertaken in the UK to bring some of England’s most threatened species ‘back from the brink’.
We'll work together to save 20 very rare and elusive species from extinction, including the shrill carder bee, chequered skipper butterfly, ladybird spider and northern dune tiger beetle.
The funding will also help a further 200 species that are under threat, including the grey long-eared bat, pine marten, willow tit, large garden bumblebee, lesser butterfly orchid and hedgehog.
Here at Pulborough Brooks we’re helping to bring two species back from the brink through habitat management work funded by this project – the little whirlpool ramshorn snail and the field cricket.
Back from the Brink is the first England-wide coordinated effort to bring a wide range of conservation bodies and charities together to save threatened species. The RSPB will be joining forces with Natural England, the Amphibian and Reptile Trust, Bat Conservation Trust, Buglife, Bumblebee Conservation Trust, Butterfly Conservation Trust and Plantlife to pool expertise and resources.
Drone flying
At the end of August you may see a drone flying above the wetlands at Pulborough. The drone will be capturing aerial photographs of the reserve, and in particular the ditches, as a way of monitoring the extent of emergent and floating vegetation. This is being done as part of the Back from the Brink project so we can monitor the suitability of ditches for the snail and assess the impact of our ditch management.
Surveying for snails
One of the very few people in the UK who can actually identify the Little Whirlpool Ramshorn Snail (and has a license to undertake survey work for them) will be performing survey work on some of the ditches at the end of August & into early September. His task will be to monitor the snail population and confirm which of the ditches the species is present in. Over time, we can then monitor the impact of the ditch management.
Playing with mud
We’ll need to time this one well – we need it to be dry enough to get machinery out onto the pool edges but wet enough that we can actually dig in the mud. We’ll be using a rotavator on the muddy edges of the pools which will break up the ground and help to create the bare patches of mud that allow our waders to feed on the aquatic invertebrates. This is particularly important to our breeding waders who bring their youngsters to the pool edges to feed.
Lapwing chick by Anne Harwood.
Island hopping
We’ll be doing some spraying on the islands out on the brooks and in front of the hides. A trained operative will be spraying an aquatic-approved herbicide to help control the coarser vegetation that has grown up and is largely ignored by the grazing cattle. The islands were created to provide places for waders to nest and also the muddy edges where they like to feed so clearing the islands so the vegetation is shorter and the edges bare & muddy will help our migrating and our breeding waders. This should also mean that the birds are easier for you and our visitors to see!
Green sandpiper by Gareth Hughes
Inevitably, the work may create some disturbance out on the brooks and in front of the viewpoints and hides. The team in the Visitor Centre will be able to tell you whereabouts we're working when you visit.