Libby Pool, MKA Ecology Graduate Ecologist

Image courtesy: Biomatrix Water

Due to its historic role, London Docklands has an extensive canal network. These canals provide a vital refuge for wildlife; their slow flow and managed water levels provide a unique habitat in an otherwise urban landscape. However in recent years, some sections of the canal network have become almost devoid of aquatic vegetation and marginal habitat.

New waterside developments provide an opportunity to restore these marginal habitats, however with space at a premium novel solutions are required. As part of a new office development, MKA Ecology has advised on the installation of innovative ‘floating ecosystems’ along a section of the canal. These floating ecosystems will create an attractive green edge for people to enjoy, whilst providing improved marginal habitat to support the wildlife.

To construct the floating ecosystems, rafts made of high-density polyethylene will be topped with pre-planted coir mats and anchored to the canal wall. The coir mats will be planted with a diverse mix of native wetland species including marsh marigold, purple loosestrife, yellow flag iris, water forget-me-not and several rushes and sedges. As the wetland vegetation establishes, the coir mats will biodegrade and the root systems will become submerged. This will improve water quality and reducing algal growth in the canal.

The floating ecosystems will benefit a range of species, including waterfowl, invertebrates, fish and mammals such as water vole and otter. The diverse marginal vegetation will provide nesting habitat for wildfowl and may reduce disturbance to nesting birds by absorbing waves created by passing boats, which can overturn or flood nests. In summer, many of the wetland plant species will produce nectar, providing foraging resources for pollinating insects. Wire mesh cages will be installed beneath the rafts, providing refuges for spawning fish. It is hoped that the floating ecosystems will attract new wildlife onto the canal, such as heron and kingfisher.

The project will contribute to a wider network of ‘aquatic green corridors’ emerging along the canal network. Floating ecosystems have already been established in other sections of the canal network. The benefits to wildlife have been clear with species such as moorhen, coot, Canada geese, Egyptian geese and tufted duck all taking refuge in the established vegetation.

In draft Local Biodiversity Action Plans, the use of ‘floating island technologies’ to enhance and restore marginal habitat along the canal network is advocated. It is hoped that future development on the canal network will be seen as an opportunity to add to this growing corridor of floating ecosystems.

For advice on how to establish floating ecosystems, please do get in contact.