NBS topic areas

Keep up to date with industry developments

NBS solutions|

Products and services for all construction projects

NBS Building

NBS Building enables you to write concise, technically accurate and up to date specifications for building projects.

Building for biodiversity

What does the new generation of green buildings mean for bats and other building reliant species? Dr Carol Williams, author of Biodiversity for Low and Zero Carbon Buildings, gives her reflections.

It has become the ambition of new build to be truly sustainable and what an excellent goal that is. But to achieve that goal not only is it important to reach the highest standards for waste minimisation, use of sustainable materials and reducing energy use to achieve low or zero carbon buildings; it also needs to retain the value for biodiversity that our built environment has always provided.

All our British bat species will make use of buildings on occasion, but for some species, buildings are essential as roost sites. This situation has arisen over a long period of time as tree cover and availability of caves have become scarce and long ago some bat species adapted to share our built structures with us in order to survive. The common pipistrelle, soprano pipistrelle and brown long-eared bats are the species encountered most frequently in buildings but other species that may be present are Brandt's, whiskered, serotine, Leisler's and Natterer's bats. In the South West of England and Wales greater and lesser horseshoe bats may also be found. The older a building, the greater the likelihood of use by bats and the greater the diversity of species that may be present, including some our rarest bat species. However, newer buildings will commonly be used by some species such as pipistrelle.

In recent history, populations of some species of bat have fallen by 90% and even the most common are thought to have been reduced by approximately 60%. It is for this reason that all British bat species and their roosts are protected by law. It is illegal to: kill, injure or disturb bats, obstruct access to their roosts, or damage or destroy roosts. It is this fact that has resulted in me being asked whether it is a good idea to design in features for protected species that, if used by bats, would become protected by law. To that I would say that until now, with the standard type of building, bats have been able to find access and roosting sites in a whole range of parts of the building. Most of the time this has gone largely unnoticed by the human occupants or has been a mutually agreeable arrangement. However, occasionally the areas used by bats has led to some conflict which, whilst able to resolved to everyone's satisfaction in the vast majority of cases, can cause some angst. By designing in provision for bats this will enable the location of the roosting area within the building to be planned in advance to ensure future conflicts should be avoided.

It is not only bats that have come to rely on our built structures in this way. Those magnificent summer visitors, swifts, swallows and house martins all make use of built structures to nest and rear their young. So do our beleaguered house sparrows and starlings which, although once both common, are now in decline. Barn owls even take their name from their use of our farm-style buildings.

In recent times there have been an increasing number of developments that have given consideration for how wildlife moves from adjacent natural areas and through the development (connectivity) and where it is able to find food in a relatively undisturbed environment (unlit for nocturnal wildlife) - areas which make up the green infrastructure of a site. The use of Sustainable Urban Drainage and maintaining existing habitat features have also been paid attention. But the importance to wildlife of the actual built structures themselves is so often overlooked.

As to why do bats and biodiversity matter? Of course there is the already mentioned, wildlife legislation that gives protection to certain species and their places used for shelter or protection. And Section 40 of the Natural Environment and Rural Communities Act (NERC) 2006 that requires that all local authorities and other public authorities in England and Wales have a Duty to have regard to the conservation of biodiversity in exercising their functions; so it is something that should be expected to be demonstrated in any planning applications. The TCPA eco-towns biodiversity worksheet includes a table to indicate the expected levels of provision for building reliant species to be provided in any new development wishing to demonstrate good practice. But factual though this is, it is not the most positive view of the situation. Bats are recognised by the Government as indicators of biodiversity and so to support bats and enable them to thrive in the environment plays an important role in supporting a healthy balance in nature. Conserving and enhancing biodiversity makes economic sense too. People value living in an environment rich in wildlife. It is good for our physical and mental health. People are happier and they are willing to pay more.

So what about new buildings when we consider the requirement for low and zero-carbon homes? The need to reduce the carbon footprint of our future (and current) housing stock is without dispute. To enable this vital change to come about, new materials, designs and technologies have evolved rapidly. But it is likely that these changes to reduce our carbon footprint by making our buildings 'airtight' will lead to losses in biodiversity associated with our built environment unless this is considered early on in the process. It is so important that provision for all this biodiversity is accommodated. If we don't, there will be very few, if any, future roosting opportunities for bats or nesting opportunities for birds. And yet, with a little planning in advance, it should be possible to incorporate small changes to the design that would make new buildings a place where bats and birds can still find a home.

We know, and my recent work on writing a book on this subject has shown, that with the skills of the architects, even with low and zero-carbon designs it is possible to incorporate these potential roosting and nesting opportunities for the wildlife that have enriched our built environments for so long. We needn't banish our already declining wildlife neighbours. In fact the opportunity is there to be a part of aiding their recovery and enriching the lives of many at the same time.

Find out more

Biodiversity for Low and Zero Carbon Building: a Technical Guide for New Build, is published by RIBA Publishing and provides architects and construction professionals with guidance on how to incorporate provision for biodiversity in their new environmentally sustainable developments.