Green infrastructure and biodiversity: How real estate can contribute to biodiversity gain and resilient ecosystems in the built environment

By Flaminia Borelli, EPRA ESG Associate

The state of things
About 15 years ago, the UN’s Millennium Ecosystem Assessment concluded that over the previous 50 years, humans had changed ecosystems “more rapidly and extensively than in any comparable period of time in human history”, which has resulted “in a substantial and largely irreversible loss in the diversity of life on Earth”[1]. Today, the UN is once again warning on the risks of the substantial biodiversity loss. During its yearly plenary in Paris, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) has presented a landmark report[2] on the state of biodiversity and ecosystem services, assessing the impacts of human activity and the deterioration of nature due to economic development.
The picture is not the most reassuring for not only the current state but also future projections on biodiversity. The IPBES report states that up to one million species are threatened with extinction in the next decades, and 23% of land areas have experienced a decrease in productivity due to degrading land usage. Urban areas have more than doubled since 1992, states the IPBES, with a 25 million km of new paved roads foreseen by 2050.
A progressing enlargement in the size of the urban areas puts the natural environment at risk, but it is also an incredible opportunity for commercial real estate to contribute to preserving and enhancing biodiversity. If adequately designed and implemented through an integrated approach, also known as ecosystem approach[3], that takes into account urban design and land management along with specific climate and economic factors, green infrastructure and landscaping can be a successful means for nature integration in the built environment, restoring and enhancing the biodiversity and ecosystem, ensuring the delivery of healthy ecosystem services.
The benefits of biodiversity-enhancing tools in the built environment
From an ecological perspective, the gains of green infrastructure are multiple, acting on the conservation of resources in the case of bioswales and permeable pavements, better air quality, cooling temperature and restoring habitats for green roofs and wild corridors. First, bioswales and permeable pavements, by treating water as a resource to be reintroduced to the system, can provide a risk-free solution with resource savings, also benefitting to the complex urban system by reducing the risk of flooding. Then, a building’s green roof can sustain a great variety of plants and function as permanent or steppingstone habitat for different animal species, positively impacting the surrounding ecosystem. Furthermore, proximity to nature is related to substantial improvements in occupiers’ wellbeing and health.
At the same time, we must not forget the economics of green infrastructure. Research tells us that implementing green infrastructure leads to an increase in property value of between 2% and 5% and an increased average rental rates for office buildings by 7%. From an operational perspective, by controlling for climate-specific characteristics, green infrastructure can help to reduce the energy demand of a building in both winter and summer.
For instance, green roofs help buildings being more energy-efficient. Indeed, the reduced heat loss in winter and hot conservation during summer helps to reduce energy consumption per m2. Through a field experiment, Liu et al. 2003[4] found out that, under Canadian climate conditions, comparing bituminous and green roofs, the latter was able to moderate the heat flow through the roofing system and reduce the energy demand for conditioning by more than 75%.
The contribution of listed real estate sector: EPRA members
As an industry association, EPRA is in the right position to monitor the efforts that the listed real estate sector is undertaking regarding preserving biodiversity in the built environment. In the most recent years, EPRA members, being aware of their pivotal position to contribute to biodiversity gains, have planned and implemented projects in order to restore the ecosystem in different geographical areas.
The French company Covivio, operating in France, Italy, and Germany, has developed ‘The Sign’ building in Milan, a complex of office buildings covering 40,000 m2 including green areas and a landscaped terrace garden. While green pathways welcome the entrance to the building, the green area makes it to the rooftop where landscape gardens will be dedicated to tenants’ social gatherings. Here the landscape garden includes plants and recycling rainwater management systems as well as photovoltaic panels. Together with a positive impact on the energy efficiency of the building and the urban heat island effect, the complex has a substantial effect on the tenants’ wellbeing.
As part of a long-term project aiming to achieve 25% of biodiversity net gain (BNG) for five sites among both operational and development sites, Landsec, a British diversified property company operating in the UK,  set the goal to maximise biodiversity potential of its assets located both in urban areas as well as extra-urban ones. On the operational sites in the extra-urban areas, the company is developing 220 m2 of wildflower garden at Hatfield Galleria and has planted aquatic plants species in order to restore and improve the biodiversity balance of the natural sites within the area at White Rose lakes in Leeds. Differently within the development sites, other development projects in London will host 1700 m2 of new green walls, trees and plants of around 76 different species.
How do you measure a net gain?
Once adequate infrastructures are implemented, measuring the actual impact on biodiversity represents one big challenge. Impact evaluation strategies and the development of suitable indicators are considered, in general, the most effective instruments to assess the results of a project implementation.
The BNG, which is one of the most widely used indicators, assesses whether a net improvement with respect to pre-existing biodiversity condition has been achieved following the intervention of a development project on a certain site. The assessment is based on a structured set of steps comparing pre-development and post-development habitat data that are converted into key metrics called ‘biodiversity units’. In the case of a net improvement to the biodiversity of a site subject to development, BNG is achieved.
A working group led by CDC Biodiversité – and to which EPRA member Icade is part of called the Club of Positive Biodiversity Businesses (B4B+ Club) – has recently developed the Global Biodiversity Score (GBS), which aims to measure the biodiversity footprint of companies. The GBS is a quantitative measure assessing the impact on biodiversity operated by end-user companies and their value chain. Compatible with already existing indicators, the GBS has broad coverage in terms of industries and sectors, which makes it appealing for becoming a pillar in biodiversity and ecosystems’ change assessment.
The benefit of system-thinking approach to biodiversity gain
As a matter of fact, best practices in the sector, as well as peer-reviewed literature, provide us with evidence on green infrastructure being an effective mean for enhancing biodiversity and creating a resilient ecosystem. To achieve that, an integrated approach where human activities depend on nature’s ability to support them is what we need for creating a more sustainable system.
Commercial real estate plays a major role in pursuing such an approach, contributing to integrating the built environment into the natural one within the urban context to create a more balanced system and benefit from it at the same time.
[1] Millennium Ecosystem Assessment, “Current States and Trends Assessment”, 2005
[3] Ecosystem approach is defined by CBD as the “integrated management of land, water and living resources that promotes conservation and sustainable use in an equitable way.”