London: Insects up high

Over the next three years, the Living Roofs for Wildlife project will install a total of six living roofs in central London. The roofs will eventually be part of a vegetation network that will ensure the survival of the city's bumblebees, butterflies, insects and birds. The project is focusing on the brown-banded carder bee (Bombus humilis) and the black redstart (Phoenicurus ochruros). Both species are threatened and their habitats are rapidly being disrupted with the expansion of urban areas and the intensification of farming. In order to recreate lifelike habitats for these threatened endemic creatures, the living roofs will be covered in wild flower meadows, sandy areas and shingle.

Two of the roofs have already been installed, designed to comply with recommendations based on previous research in the area. The roof of Lewisham Town Hall has been planted since April 2009 and has attracted a lot of wildlife. With the help of the plant toadflax (Linaria vulgaris) and other vegetation it has been possible to attract honey bees (Apis mellifera). The project thus fulfils the objectives of the UK biodiversity action plan. The project has also installed electricity-generating solar panels on part of the living roof on the headquarters of Transport for London, which was ready for planting in November 2009.

In order to reverse the reduction in urban wildlife it is necessary to establish how green living roofs can be best adapted to the needs of urban wildlife. Experiences with the six roofs involved in the project will therefore help to clarify what positive effect the living roofs have on London's wildlife. The project will, among other things, map which animals inhabit the living , which type of plants/flowers are needed to attract them and which substrata is the most viable.

The Living Roofs for Wildlife project builds on 10 years of previous experience and work on living rooms. The project's backers, wildlife charity Buglife and leading experts in the green roof business, LivingRoofs, have been working determinedly for several years to get more living green roofs installed in London. Work with living green roofs initially focused on the black redstart, rare as a breeding bird in the UK which is entirely dependent on green urban breathing spaces. Their efforts have resulted in the establishment of 400,000 m² of living roofs in London between 2004 and 2009. Against this background, an important study of biodiversity on living roofs was carried out in 2007.

In addition to the roofs' function as a habitat for wildlife they also serve, like all other green roofs as efficient insulation. Living roofs do not require much drainage, since the roof holds onto and helps evaporate 70-100% of rainwater. In London and other cities, living roofs - in addition to providing necessary habitats for the city's insects - can also help to reduce energy consumption and prevent the flooding of the sewage system. However, Dusty Gedge of LivingRoofs believes it is important to maintain the focus on living conditions for biodiversity in the planning and installation of green roofs. The climatic and insulation-related advantages of living roofs follow as a matter of course when optimum living conditions are created for insects and small birds.