The extent and design detail of all the habitat enhancements will be developed and mapped during an 18 month Development Phase, based on detailed survey work and consultation.
Much of the biodiversity interest in the site focuses on its aquatic birdlife.
The ecological analysis carried out as part of the Walthamstow Reservoir Feasibility Study recommended that the site is also likely to contain interesting and diverse terrestrial habitats, which could be further enhanced.
These proposed habitat enhancements include:
- Where operational functionality will allow, the reservoir margins that are not already vegetated, will be planted and floating reed-beds and islands will be added at appropriate locations. Vegetated margins and reedbeds are of particular interest for gadwell, shoveler and bittern. The increase of this habitat has the potential to attract a more regular presence of this iconic bird;
- Additional islands to help increase habitats for duck species and support an increase in their number;
- The creation of new fish swims;
- Tree planting and meadow/grassland creation, and the control of invasive species – particularly Japanese knotweed and giant hogweed;
- Artificial sand/earth banks in order to attract nesting sand martins and kingfishers and a number of bird roosting poles and nesting platforms will be erected as well as bat roosting boxes, bird nest boxes and bird feeding stations.
Walthamstow Reservoirs flora: Nearly 300 species of plant have been recorded across the wooded areas, grass banks, fen and open water habitats of the Reservoirs.
Some these species are rare in the Greater London area, and their presence supports the Reservoirs’ SSSI and Metropolitan nature conservation interest status.
These include marsh-marigold, the hybrid ‘graceful’ sedge, common club-rush and a sizeable stand of lesser bulrush found within the fringes of fenland vegetation by the banks of the Coppermill Stream.
In addition, the open waters also support the nationally scarce whorled water-milfoil which supports the Ramsar status of the site.
The two Warwick Reservoirs support the most substantial areas of marginal vegetation, with great hairy willowherb, reed, reed-grass, and great pond sedge being present.
Most of the reservoirs are otherwise surrounded by mown grassland which in parts is often diverse, with red campion, bladder campion, common mallow, hawk’s-beard, hardheads, burnet saxifrage and meadow buttercup.
Elsewhere, varying densities of scrub and bramble thickets tend to add diversity to the banks, affording nesting and foraging opportunities for birds, small mammals (including bats) and invertebrates.
These support a diverse mixture of trees and shrubs, including crack and goat willows, sycamore, elder, poplar and hawthorn.
Walthamstow Reservoirs invertebrates: The grasslands, scrub, trees and marginal vegetation support a diversity of invertebrates; insects, spiders and molluscs.
Beetles, butterflies, bees, wasps, grasshoppers, hoverflies and plant bugs benefit from the diversity of vegetation, and the flowery grasslands.
Many species will be typical for the area, and include those found across much of London such as green-veined white, orange tip and speckled wood butterflies, marmalade fly, bumblebees, and thick-kneed beetles.
Within the water bodies a range of aquatic invertebrates are present, providing food for birds and fish. These include leeches, hoglouse, water beetles, pond-skaters, midge larvae and aquatic worms, and water snails.
Importantly a rare water-boatman – Micronecta minutissima – is found here, helping to support the Reservoirs’ Ramsar status.