Nature is in trouble. A keynote research report, The State of Nature 2019 identified that 58 per cent of UK species have declined since 1970 (by which point nature had already been depleted).
Nearly one million species are at risk of extinction from human activities, says the IPBES’ Global Assessment Report on Biodiversity and Ecosystem Services.
Professor Partha Dasgupta in his critical report on the economics of climate change and nature called for “an integrated response to climate change and biodiversity loss.”
But there’s good news. The IPBES report also says that “if we take care of nature, nature takes care of us”.
Urbanisation is identified as one of the key pressures driving biodiversity loss. However, there is realistic potential for development to contribute to nature’s recovery.
In the latest report from the NHBC Foundation, Biodiversity in new housing developments: creating wildlife-friendly communities, design concepts, practical solutions and best practice case studies are laid out that place ecosystems at the centre of the house-building process.
The house-building industry is uniquely placed in having an opportunity to create not just houses, but sustainable communities, where people thrive alongside wildlife.
Following these guidelines would allow developers to pursue the vision stated by the President of the European Commission, Ursula von der Leyen last month of “cities of the future as urban forests”.
Working with nature to help resolve environmental challenges isn’t especially new but it is gaining more credence as evidence grows of the effectiveness of these nature-based solutions.
From wetlands absorbing and slowing run-off, to trees shading and storing carbon, and connecting greenspaces together to let animal populations retain genetic diversity, they all have multiple roles to play.
The ability for these solutions to solve many problems at once is the root to making them cost effective for developers as well, says the NHBC Foundation.
Besides giving improved climate resilience and adaptation, connecting people with nature improves well-being and reduces the risk of crime and poor health in the neighbourhoods served.
Adding nature is a recent addition to placemaking. It adds value, which is reflected in quick sales and either higher rents or fewer voids.
The report illustrates several ways to reduce costs:
- retaining soils and adapting planting / seed mixes to suit them rather than importing soil should cause fewer plant failures and reduce soil handling
- Sustainable Drainage Systems (SuDS) that use soft landscape features have lower installation and maintenance costs than hard engineered solutions
- locally adapted native species are more durable, so have lower long-term maintenance costs
The nature-based solutions evidence base
The UK Green Building Council (UKGBC) has also produced a report on nature-based solutions to the climate emergency.
This contains findings from the nature-based solutions evidence base, which is developing new financing solutions for investment in Greater Manchester’s natural environment.
It says: “Working with nature, solutions such as rain gardens, street trees, green roofs and walls and development of green spaces can help to tackle socio-environmental challenges including an increase in flooding events, water security, air quality, biodiversity and human health and wellbeing.”
The evidence base contains informative databases on green walls, green roofs, SuDS, green spaces, and street trees.
The use of brownfield sites
A new UK-wide survey of 2000 households has found that 59 per cent would like derelict land to be converted into modern, efficient housing and a place for cultural landmarks.
Over three quarters feel that when brownfield sites are regenerated, they bring a sense of freshness, art and culture to an area, improving the lives of everyone around it. However, as these sites stand, almost the same number believe that derelict sites are eyesores.
Brownfield sites often contain specialised habitats that emerge once they have been abandoned.
The NHBC Foundation’s report recommends that developments on brownfield land that incorporate these into their landscape designs have real potential to retain what are often now rare and specialised species characteristic of these sites.
The use of brownfield sites also prevents the urbanisation of greenfield sites, that reduce the space for nature even further.
“Area neutral” cities that develop by using only already pre-urbanised sites, without expanding, also become more interesting and diverse. “Area neutral” cities is a concept advocated by the young Norwegian eco-activist Gina Gylver.
Continual redevelopment and addition of this type gives rise to what David Green calls “the incremental city” and the type of neighbourhood that people seem to value the most.
In addition, having open green space close to home is important to 93 per cent of people, says the NHBC Foundation.
Community gardens or allotments are one such popular feature. There, residents can decide how they want it to be, which in turn gives them a sense of ownership and value that can extend to other areas of the greenspace.
Biodiversity Net Gain
This is a new concept that is already being applied in some areas and is expected to become mandatory for developers, at least in England and Wales.
At the outset of planning a development, developers will have to employ a qualified ecologist to undertake a desk study and a Preliminary Ecological Assessment which will identify whether there is a need for specialist surveys.
They will indicate how negative impacts can be avoided or minimised, and which features can be added to have the best impact for biodiversity.
The study must cover all key biodiversity features, providing a clear picture of the habitats present and their status, together with the priority species. It should go beyond species for which there is statutory protection.
SuDS
Sustainable Drainage Systems (SuDS) increase biodiversity and mimic natural processes in managing rainfall using landscape form and vegetation such as trees, shrubs, flowering plants and grassland.
They help with flow control and limit volumes of surface water to reduce risks of downstream flooding, and improve water quality by trapping silts and reducing pollution of water courses. They also help to recharge groundwater, which helps maintain river flows and support wetlands.
Bioretention beds, swales and filter strips manage run-off from paths and roads.
Omitting kerbs or leaving gaps between kerb stones allows water to enter these features. With good landscape design, these can be attractive amenity assets that require little maintenance.
Verge features that benefit wildlife include a varied and continued vegetation structure, including grasses, low herbaceous vegetation, shrubs and trees linking with other landscape features, and informal landscaping of grass and wildflower mixes appropriate to soil types and or conditions.
Where shrubs are used, plant mixtures of native and non-native shrubs of wildlife value in informal irregular shrub beds.
Creating biodiverse grasslands and tree cover
In just 50 years during the mid 20th century, 97 per cent of unimproved grasslands have been lost in England and Wales.
But by creating new native flower-rich grassland in landscaping, some degree of repair can be made.
All grasslands, other than sports pitches and amenity play areas, could and should, be flower-rich. This also reduces the maintenance needs of frequent mowing.
Flower-rich grasslands need low nutrient soils. The soil type present determines which seed mixes to use.
Tree planting and management styles must change to ensure climate resilience, the report says.
As well as providing direct shade, vegetation and tree canopy cover significantly reduces the effects of heat from hard surfaces. It recommends that canopy cover of more than 40 per cent has the greatest impact in reducing daytime temperatures.
Nature needs us and we need nature. Humans evolved in forests. Let cities become forests and mix the best civilisation can offer with satisying the real needs of human beings and the planet.
David Thorpe is the author of ‘‘One Planet’ Cities: Sustaining Humanity within Planetary Limits and Director of the One Planet Centre Community Interest Company in the UK.
We put in a Waterharvesting system into urban landscapes in Canberra Australia – artificial perched aquifers charging from grey or roof water – hugely successful in cooling and habitat support.