Biodiverse Roofs deliver valuable environmental benefits by attracting desirable flora that provide habitat for wildlife and/or facilitate building designs that are sympathetic to the surrounding landscape - allowing BREEAM credits to be attained under the Land & Ecology category.
Similar in composition to Extensive Roofs, Biodiverse Roofs benefit from a growing medium that is a locally-relevant, engineered recycled mix of crushed brick and organic matter. Blackdown devises a bespoke growing medium mix specifically for each project's requirements, accounting for both the local environment and the planting strategy.
Additional features, such as timber, shelter, stones and other roofscape furniture can be incorporated into the roof design to achieve particular ecological objectives, such as attracting invertebrates.
Blackdown Biodiverse Schemes
Blackdown's unique service is ideal for bringing your Biodiverse Roof to life:
- Design advice: strategies to attract flora and fauna to the roof
- Supply of the appropriate plant species and biodiversity-enhancing features
- Installation of the biodiverse roof, appreciative of the importance of the inherent complexities
- Maintenance of the roof to provide optimum performance in fulfilling the biodiversity hypothesis
The design stage is critical to the success of biodiverse roofs in achieving objectives, with the system proposed on the basis of the biodiversity hypothesis. Blackdown has developed numerous biodiverse roof schemes to suit different environments and objectives, some of which are presented here:
Brown Roof Schemes
Constructed without vegetation, brown roofs self-colonise with native plants over time. Depending on the building's local environment, plant coverage may take 18 to 24 months to establish. Blackdown establish the most appropriate substrate to ensure that the roof delivers its long-term biodiverse objectives.
Customised Biodiverse Schemes
Native plant species such as wildflowers, grasses, hardy succulents, herbeaceous perennials and bulbs, are carefully selected to provide adequate feeding resources and habitat provision for maximum biodiversity potential.
Case-specific habitat templates can be designed to recreate native habitat and/or target specific wildlife, by incorporating purposely-selected roofscape furniture and substrate type and depth. Described below are examples of some of the planting strategy components that can be incorporated to achieve specific outcomes.
Dry Calcareous Grassland
The high diversity of grasses and wildflowers growing in chalk and limestone grasslands provides ideal habitat for numerous endangered wildlife species. Despite being one of the most important semi-natural habitats in Britain, they are increasingly threatened, with an estimated 80% reduction in the last 60 years.
A planting strategy, incorporating a range of location-specific native plant species, to replicate planting communities that naturally grow in exposed maritime areas. The inclusion of some of the most suitable native plants for roof greening applications, affords the Vegetated Sea-Cliffs system long flowering periods (early spring to late autumn). Vegetated Rocky Outcrops can be specified for inland applications.
Wildflower Habitat Meadow
A wildflower meadow setting, designed to provide food sources that will attract Lepidoptera (i.e. moths, butterflies etc). Through the identification of species present in the local area, as part of a biodiversity hypothesis, designs can be tailored specifically to attract the appropriate species through a balance of primary and secondary food resources and nectar plants. An alternative, Nocturnal Habitat Meadow strategy can be specified to provide invertebrate feeding resources to encourage habitation by bats.
An optimal flow of seasonal nectar plants is assured through a combination of native wildflower species and hardy succulent plants. An excellent vegetative coverage provides an abundant supply of nectar and pollen that attracts a variety of species (e.g. bumble bees, butterflies, hoverflies and day flying moths), some of which are identified to be at risk of extinction in certain Biodiversity Action Plans.