Gathering Momentum: Building Urban Green Infrastructure Networks
Last month, the world celebrated the International Day for Biological Diversity (22nd May). Every year, environmentalists around the world use this UN-sanctioned day of recognition to promote issues surrounding biodiversity and the environment; drawing attention to global challenges, such as ecological collapse and the importance of healthy ecosystems, they seek to engage key stakeholders across the world to effect positive change.
Photographed by Connor Rusby
UN International Day for Biological Diversity 2024
This year, organisers have selected the theme “Be Part of the Plan”, whereby the UN is leading a call to action to halt and reverse the loss of biodiversity the world has seen in recent decades. This will be achieved through engaging stakeholders to support the implementation of the Kunming-Montreal Global Biodiversity Framework, also referred to as simply the ‘Biodiversity Plan’.
Put in place in December of 2022 during the Conference of Parties 15 (COP15), an international forum and annual meeting under the Convention on Biological Diversity, the Biodiversity Plan sets out an ambitious pathway for the world to live in harmony with nature by 2050. It consists of 4 overarching goals to be reached by 2050, as well as 23 smaller targets to implement by 2030. Key outcomes of this framework include a target to allocate 30% of the world’s terrestrial, coastal, and marine environments under protection by 2030, encouraging developed nations to finance conservation efforts in developing nations and foster the protection of indigenous land.
The crucial milestone of this year, specifically amongst governmental stakeholders, is to align national biodiversity strategies and action plans (NBSAPs) with the Biodiversity Plan. Specifically, these updated NBSAPs are obligated to describe how each country will implement the 23 targets.
UK Government plans
During COP15, a total of 188 nations (including the UK) signed up to the Biodiversity Plan. With British biodiversity in a sorry state, this could not have come sooner. According to the 2021 Joint Nature Conservation Committee (JNCC) UK biodiversity indicators report, 14 out of 24 biodiversity indicators are showing long-term decline in the UK[1]. Hence, the case for giving a much-needed boost to UK biodiversity is clear.
One key way that the UK is striving to meet its obligations under the Plan is through its Biodiversity Net Gain (BNG) legislation as part of the Environment Act 2021. Under this legislation, which came into full force in February 2024, it has now become a legal requirement in England (with adapted strategies amongst devolved governments) for developers to deliver at least a 10% increase in biodiversity, meaning the development will result in more or an improved quality of natural habitat than it’s existing state.[2]. The government has drafted step-by-step guidance for developers.
While it is too early to comment on the impact that the BNG legislation has had on urban biodiversity, we can point to similar, more local-level initiatives to understand how the collaboration of individual authorities and ecological experts can have a strong impact. For example, from 2002-2017 Hackney Local Council organised and implemented their Biodiversity Action Plan (BAP) in order to improve natural habitat across the borough. This work laid the foundation for future conservation efforts in the borough by “ensuring that biodiversity conservation was embedded into Hackney Council policy and the land-management practices of Hackney Council and other major landowners,” according to a recent report.
The result? Authors point to 4 key outcomes as evidence for the success of the locally led project:
An increase in habitat creation in Hackney parks, such as the establishment of wildflower meadows;
A major tree-planting programme in both streets and open spaces;
A significant increase in the installation of green roofs and other urban greening features in new developments;
The creation of a major new nature reserve at Woodberry Wetlands.
Enterprises such as these are essential in reversing the rampant loss in biodiversity we have seen since last century. Since 1970, the populations of 35% of wildlife species have decreased across the UK and 31% of species are found in fewer places than previously, with many of these exacerbated in urban areas. For instance, some bird species are thought to no longer breed within the Greater London region at all. With the increasing recognition of the benefits of healthy ecosystems, especially through the so-called ‘ecological services’, we are likely to see more similar initiatives arise.
Hackney Council is now moving forward with the next stage of their conservation plans for the borough, now taking shape as the ‘Local Nature Recovery Plan’. One factor that this updated plan focuses on is the interconnectivity of habitats across London, with greater importance given to identifying and restoring wildlife corridors and strengthening green networks.
Introducing green networks
Green networks, also referred to as green corridors or linkages, are defined as the multiple natural and semi-natural forms of green infrastructure, such as paths, woodland, and open areas, that link pockets of habitat. They are important in enhancing biodiversity, allowing the safe migration of species throughout urban environments and promoting pollinator populations. Aside from these clear benefits for wildlife, green networks are regarded as critical infrastructure in boosting public health, providing spaces for exercise, relaxation, and education, while delivering widespread benefits for physical and mental wellbeing, such as improved air quality and urban cooling.
Creating such networks also provide opportunities for developers to boost the level of biodiversity on their land whilst working within certain constraints. For instance, within the government’s plans themselves, they highlight what they describe as a ‘biodiversity gain hierarchy’, in which developers must follow a tiered approach to achieve BNG:
Create biodiversity on-site (within the red line boundary of a development site).
If developers cannot achieve all of their BNG on-site, they can deliver this through a mixture of on-site and off-site solutions. Developers can either make off-site biodiversity gains on their own land outside the development site, or buy off-site biodiversity units on the market.
If developers cannot achieve on-site or off-site BNG, they must buy statutory biodiversity credits from the government, which will be invested in habitat creation in England. However, this should be a last resort.
This is where green networks can really come into play. Owing to possible limitations within a given piece of land under planning, developers may be unable to boost on-site biodiversity, meaning they must explore alternative avenues to improve local habitats. One way in which they could achieve this, and do so to a maximal extent, would be to focus on the connectivity of existing habitats. As multiple research papers can attest, there is extensive value added to the ecological health of a region when existing habitats are linked, including within urban environments specifically [3][4].
Hence, if developers are unable to boost biodiversity by an estimated 10% on the land under development, then a very impactful means of improving this off site could be through focusing on habitat connectivity.
Green networks as part of your development plans
The advantages of making space for nature are varied and meaningful, though implementing green infrastructure in areas where space is already at a premium can be difficult. Creating greenery that adds ecological value to an area can be achieved with careful planning and cross-sector collaboration.
Developers and built environment professionals can help to improve green networks in several ways:
Assessing the local state of biodiversity / ecology;
Using lateral thinking;
Considering the surroundings.
Assess local biodiversity and ecology
One of the first steps in any development project, owing to the environmental regulations that surround it, is defining the ecological assets within the vicinity. This means that developers must record the different habitats on the land under consideration to determine where green infrastructure improvements and investments would be best targeted.
There are a number of means by which developers can generate an overview of these ecological assets and we recommend speaking to professional consultants on how to do so. However, one available tool is the Green Infrastructure Focus Map, which is an online map of London that provides a composite green infrastructure ‘score’ for different regions based on several metrics. Despite being a relatively quick way of assessing each region, the depth of information it provides on air quality, public space, deprivation, space dedicated to conservation, and urban heat island effects is impressive.
For example, one of the areas it focuses on is access to green space in the local area. In areas that are particularly lacking in this regard, it would make sense to incorporate a greater level of public green space, such as by providing communal gardens in a residential project. Conversely, where green spaces are more abundant, it is likely more valuable to invest resources in protecting biodiversity and keystone species within the area.
Think laterally (or perhaps vertically)
When considering urban greening and the provision of green infrastructure, parks, urban gardens, and allotments are the main features that one thinks of. However, these are usually not included within the scope of most development projects. Particularly in our dense cities, the premium on space is so great that the aim of the game is to maximise the extent of land that is built on, meaning that many can see these large green areas as very high investments. However, by thinking more broadly about how to meet your BNG requirements, developers can maximise both the land under consideration and biodiversity gains.
For example, in areas where space is intrinsically limited, one possible alternative to expansive green areas is through the installation of ‘green’ or ‘living’ walls. They have become a growing trend within the industry as both land prices and environmental obligations rise. Green walls consist of vertical structures that have different types of plants and greenery planted within them and can be freestanding or affixed to an existing structure, meaning they offer strong potential in terms of BNG in areas where space is limited.
There are also a number of ways to maximise the environmental benefits derived from these structures. For instance, with regards to the choice of plants, developers should take care to select species that are native to the region and play positive roles in the lifecycle of other species, strengthening trophic interactions and building stronger local ecosystems. This could mean ensuring plants that are appealing to a number of different pollinators, such as bees and butterflies, are included in the proposals.
However, the position of structures like green walls and roofs need to be considered in the overall calculus of the development, especially with projects that likely face competing priorities. Consider, for example, a conflict of interest between providing green infrastructure and boosting the provision of renewables. Here, arguments could be made to allocate roof space for the former (e.g. biodiverse green roofs) or the latter (e.g. solar panels). Therefore, only through considering green infrastructure needs within the wider context of the development can appropriate solutions be determined.
Consider the surrounding area
It is important to consider the specific needs of the surrounding area when planning any development project. Namely, developers need to consider whether their proposed green infrastructure is suitable, given the context the area. For example, there have been instances of developers placing bat boxes in areas of high traffic, noise pollution, and densely packed buildings. Here, it is unlikely that roosting bats will be attracted to these boxes, thereby having no overall impact on the local environment or biodiversity.
However, installing green roofs or green walls within these areas could be far more appropriate. In many of these urban housing developments, roofs are often under-utilised spaces that could be easily adapted into thriving habitats for insects. Furthermore, it has been demonstrated that these nature-based solutions can serve as relatively inexpensive ways to reduce both air and noise pollution in busy urban areas, by absorbing carbon dioxide and dampening sound, whilst also contributing to the green networks.
Therefore, when developers are working on individual projects, they need to consider the unique local environment and what measures can truly augment biodiversity in the area. If not, these green measures may just result in a waste of both time and investment.
Conclusion
The International Day for Biological Diversity is an important day as it allows us to reflect on the obligations of developers and design teams to ensure we can create lived environments that can contribute as positively to their non-human residents as to the people who live there.
In the UK, working under the framework of regulations such as the BNG, developers need to exercise their creative muscles as measures such as these, of necessity, provide a greater level of constraint regarding what they can achieve. One of the most exciting and innovative approaches to doing so is through the installation of green infrastructure that links habitats in the local area, boosting the strength and size of green networks. These measures can improve the biodiversity gains within an area, whilst also acting within the constraints placed on developments in terms of land area.
A list of some useful resources include:
For guidance on green design solutions: The Urban Greening for Biodiversity Net Gain Design Guide
For guidance on BNG: Guidance for BNG: Steps for Developers
For assessing local statutory (legally protected) greenspaces: MAGIC database
For information on how your project can benefit from providing green infrastructure: Guidance from the Global Designing Cities Initiative or a research paper The Multifunctional Benefits of Green Infrastructure in Community Development for a detailed assessment of various green infrastructure types and outcomes.
To learn more about these nature-based solutions and how Love Design Studio can support the biodiversity of your project, get in touch today.