Habitat improvement work across Nene Valley nature reserves is helping restore wetland habitats, including creating scrapes, building sand martin banks and re-profiling banks to create better wetlands for water birds. The works also improve floodplain capacity and carbon storage, during a four-year Network for Nature programme with £240,000 funding from Highways England, some of which started last year.
An additional £134,000 from Natural England will help complete island restoration at Summer Leys and Titchmarsh NR plus extend to two further Nene Valley reserves, Abington Meadows and Southfield Farm Marsh. The Environment Agency have contributed to extend the project also to Storton's Pits where reedbed and fen ditch restoration will take place. Work is planned for August and September to limit impact on wildlife; bird breeding will have mainly finished and many insects are on the wing; ground conditions are dry, so less damage to sensitive wetland vegetation.
Wooded islands and north reedbed Two wooded islands at the north end of Aldwincle lake are at the heart of primary habitat for waterbirds: the larger has a ring of willow around the perimeter, scrub in the interior, the other mainly scrub and bramble. This area is out of character with the core wetland habitat around it, and the presence of trees and scrub can deter waterbirds from nesting, feeding or roosting close to these islands. Work will clear these islands of trees to create bare habitat, suitable for a range of wintering, roosting and breeding waterbirds. We do not undertake any clearance of trees and scrub lightly, but we (and Natural England) believe this work will enhance the site for core designated waterbird species. A full ecological survey of both islands has been done to ensure that clearance work will not compromise any protected species so we are satisfied that the work will not cause significant issues. The loss of any trees from a reserve can elicit mixed views, but we are confident that the benefit to key designated waterbirds is significant - we continue to work to enhance the scrub sections to attract a wide range of bird species to the site.
North reedbed and scrape At the north end of Aldwincle lake a small section of reedbed is being colonised by willow trees; these will be cleared as part of the above work. Willow provides predator perches, decreasing the reedbed for breeding use. Main clearance work will take up to 6 weeks to complete. Contractor access to the islands will be by boat, with machine and operator: we hope not to cause high level disturbance, with work timed sensitively to avoid wet ground: most chicks will be mobile and any disturbance this year will be mitigated by increased breeding habitat in subsequent years.
Big Meadow A variety of wetland enhancement works finger scrape restoration; bank reprofiling; ring ditch restoration and scrape restoration. Scrape and ditch restoration will see some vegetation removal to provide open waters, increasing the variety of wetland habitats in this area. The bank will be reprofiled to gently slope into the lake, providing a constant muddy edge as the lake level changes - an excellent place for wading birds and ducks to feed on invertebrates.
Ford The base of the ford at the north end of the reserve, through the outflow of Aldwincle lake flowing into Brancey Brook, will be reinforced so that when flow from the lake is high, the stone doesn’t wash away, and allows access the whole site via vehicle for staff and graziers.
Hide replacement Thanks to a generous donor we are replacing both the North and Jack’s hide this year. North hide will be replaced like-for-like, while Jack’s hide is moving up onto the bund, giving better views for visitors over the scrape and onto Big Meadow. The new hides are due to be installed between mid-September and end of October: the existing hides will be taken down beforehand.
Sand martin bank A new sand martin bank will be installed to the left of Kirby hide in mid September a handful of willow trees on the edge of the lake will be removed to allow clear entry into the bank.
Marigold and small ponds Planned works will last approximately two weeks, focussing on the area around the ponds, as well as the eastern path leading toward the double-decker hide. Due to the SSSI and SPA protection on this site, these projects have been awarded prior approval by Natural England. The ponds are surrounded by a ring of overhanging willows, reaching over the water’s edge – predominantly on the south side. Leaf and branch fall makes its way into the water and slowly rots creating a large layer of rotting vegetation, increasing nutrient levels to the detriment of many species. Work will include dredging via long-reach diggers to remove this decomposing layer and expose the mud underneath, providing an improved habitat for invertebrates to thrive. The excavated material will then be piled with other vegetation to create several hibernaculae, a habitat for reptiles and small mammals to seek refuge.
Young willows on the edges will also be removed and used to bolster dead-hedging areas on the reserve. Removing these will provide a greater water edge, which will be re-profiled to create a shallow gradient leading towards the water – the muddy edge providing a ‘runway’ for various water-dwelling bird species, allowing them to feel secure. Additionally, exposing invertebrates to the surface provides a food source for birds. Several much larger willows towards the south of Marigold pond will be removed - a safety hazard at present: stems will be broken down and remain on-site as habitat piles, rotting down over time to provide nutrients and shelter for a host of invertebrate species.
Footpath repairs The footpath east of the car park towards the double-decker hide is being re-layed. During winter this path can become very wet and muddy, with lots of potholes and divots creating puddles. It will be scraped back to remove the degraded, upper surface and relayed to a width of 1.5 m - areas of path will also be re-profiled at a camber, facilitating water runoff into the hedge line, preventing puddles. During these works the footpath will be closed to the public.
Sand martin bank A new artificial sand martin bank will be installed to compliment the existing bank. This structure will provide 48 nesting chambers and will be ready for their return from migration in early spring, following overwintering in eastern and southern Africa. It will be installed by Green Future Building, a non-for-profit social enterprise who value conservation and sustainability. It will be constructed of sustainably sourced wood and recycled plastic: these banks can also be seen at our Nene Wetlands and Titchmarsh nature reserves.
Irthlingborough Lakes & Meadows cattle bridge Providing greater connectivity of Irthlingborough grasslands, a cattle bridge will be constructed within the Forgotten Meadow compartment of Nene Wetlands nature reserve. This will connect two areas of grassland currently separated by a narrow ditch, providing better access for graziers to manage conservation grazing, an important management process to improve diversity of grassland species, with prior approval from the Environment Agency, Natural England and North Northants Council. The steel framework will be constructed prior to installation and transported on site w/c 15 August.
Finger scrape restoration Wilson’s Pits Several existing finger scrapes will be dredged back to bare earth. During winter these shallow channels fill with water providing feeding ground for wetland bird species. They have filled with vegetation, reducing availability of an important food source – by scraping away the top layer of material, a wet, muddy under-layer is created for aquatic invertebrates restoring their conservation impact.
Higham lake fencing A stretch of fencing will be installed alongside the pathway around the eastern edge of the lake to reduce disturbance to overwintering birds.
A small area adjacent to urban Northampton, tucked between the Riverside shopping centre, the A45 and the river Nene rich in of biodiversity. Plenty of wintering birds on site, interesting plants and great for invertebrates – more than 400 species recorded. The meadow is grazed with cattle to maintain the structure of the grass, and scrub and willow regularly cut back. Willows have become dominant in some areas, leading to a loss of wet grassland and fen/swamp habitats and over-shading the ponds. Some will be removed from the edges of the two ponds on site and from the fen/swamp areas. Opening up the ponds will encourage growth of marginal vegetation whilst reducing leaf fall. The fenceline along the southern boundary will be replaced to ensure continued rotation of cattle grazing to maintain these newly restored features; work to commence early September for 3-4 weeks.
Over time remnants of 100-year-old fen ditches have become more vegetated and areas of open water have been lost. Work will focus on clearing sections of the ditches and reedbed to reinstate areas of open water and restart succession in others, creating a variety of sub-habitats within the features important to the lifecycle of invertebrates. Two ditches on the north side of the reserve will be cleared using an excavator to clear sections of two drains. The reedbed area has become more extensive over the past decade, and now only has a small area of open water; clearing an area of approximately 1 hectare of reed will create more open water and more ‘edge habitat’ ie, the interface between the open water and the older reed.
The reserve is a spring fed marsh within a mosaic of grassland and scrub beside the River Ise, with one area a Site of Special Scientific Interest (SSSI), the largest long-established washland area in the county home to a range of rare swamp habitats and associated vegetation, plus unusual aquatic invertebrates not widely found because of habitat requirements. The ditches and scrape features have become more vegetated and open water lost: work will clear sections of ditches to reinstate areas of open water and restart succession in others, creating a variety of sub-habitats within the features important to the lifecycle of invertebrates. Working on sections of the ditch and reedbed will allow insects to recolonize afterwards plus a water control feature which will bring greater hydrological control of the site to better manage the site with the impacts of climate change. Work to commence early August.
For further information about this work please email Northamptonshire@wildlifebcn.org
