4.4 Biodiversity

Infographic showing approach to achieving biodiversity net gain proposed by the Area Action Plan.

Figure 14: The principal elements of the biodiversity strategy for North East Cambridge

At a national and local level, biodiversity is a priority and recent national legislation has set out that new development must achieve a minimum 10% 'net gain'. While the Area Action Plan area has no nationally or internationally designated biodiversity sites, it is close to a number of designated areas and there is also a locally designated Wildlife Site on Cowley Road. Development at North East Cambridge should protect and substantially enhance the network of green and blue habitats across the site itself and the wider area, including Chesterton Fen and Milton Country Park.

This policy sets out how new development will achieve biodiversity net gain and measurably improve the biodiversity network across the wider area.

  • You told us that biodiversity and green infrastructure should be a key priority for the Area Action Plan. You commented there should be protection for the existing biodiversity assets within the site, such as the First Public Drain, mature trees and Cowley Road Hedgerow, which is a City Wildlife Site. You commented that new biodiversity measures should form part of a network which connects both across the site and into the wider area, including Milton Country Park and the River Cam corridor.
  • It was widely commented that biodiversity net gain should be achieved on the site, with some suggesting that the site should deliver in excess of the nationally recognised standard of 10% net gain. In terms of how this could be delivered, there were a range of views from bat and swift boxes to urban woodlands. You also told us that if biodiversity net gain could not be achieved on-site then off-site contributions should be sought in areas adjacent to North East Cambridge.
  • Several comments suggested that the site should include the River Cam corridor and Chesterton Fen to support links to the river and wildlife and ecological enhancement. This included the suggestion for a Riverside Country Park.
  • Broadly, there was support for a range of green spaces within the site as well as better connectivity to Milton Country Park for both biodiversity network enhancement and the well-being of people living and working in North East Cambridge.
  • You also told us that more information about the types of species and habitats currently on-site is needed to have a better understanding of the existing situation and best plan for biodiversity conservation and enhancement, at both a local and strategic level.

How your comments and options have been taken into account

  • The preferred approach sets out a site-specific biodiversity mitigation hierarchy and how the site should deliver a minimum of 10% net gain in biodiversity value. Whilst there were some comments stating that the Councils' should be seeking a greater biodiversity net gain percentage, the policy has been prepared to ensure that an appropriate balance can be achieved between meeting national biodiversity requirements, working towards the Councils' commitments in tackling biodiversity and ecological emergencies and the challenges of exceeding this within a higher density context.
  • The policy sets out the biodiversity assets of the area that should be protected as part of development proposals coming forward.
  • In line with comments received, the Councils are proposing a sequential approach to mitigating adverse impacts on biodiversity resources. This should be achieved on-site in the first instance and then in areas adjacent to North East Cambridge, such as Milton Country Park and Chesterton Fen, before considering wider mitigation measures across the city and further afield. This is a consistent approach with the existing local plan policy, but has been prepared to reflect the specific requirements related to the Area Action Plan.
  • Whilst the boundary of the Area Action Plan area has been amended to reflect some of the consultation responses on this issue, the Area Action Plan does not include the land between the railway line and the River Cam (Fen Road) or Milton Country Park. Instead the Area Action Plan seeks to improve pedestrian and cycling connectivity into this area via a new underpass to Milton Country Park and a bridge over the railway line. The new bridge into the area known as Chesterton Fen will provide off-site amenity and biodiversity improvements towards the north of Fen Road. Whilst much of the rest of the open land along Fen Road is in private ownership, the Councils would support the future use of these fields for off-site amenity and biodiversity improvements.
  • In response to the comments highlighting a lack of evidence on the existing biodiversity within the Area Action Plan area, the Councils have undertaken a site wide ecology study (2020), which has informed the preparation of this policy. In addition, this policy also sets out a requirement for future development proposals to be informed by an up to date ecological assessment of individual sites. This will identify the existing biodiversity assets within a specific site and any mitigation measures which will need to be introduced both during and post construction.

(16) Policy 5: Biodiversity and Net Gain

Development proposals will be required to deliver a minimum of 10% net gain in biodiversity value and shall follow the mitigation hierarchy. This will be achieved through:

  1. The provision of measurable improvements in the size, quality, diversity and relationship of the site's habitats, to deliver a coherent and high-quality ecological network as part of the wider green infrastructure network, landscape character and place making;
  2. The protection, enhancement and recovery of the most valuable existing habitats and species, and the creation of new complimentary habitats where possible;
  3. Increasing opportunities for the movement and dispersal of species across the city and into Milton Country Park and wider Fen landscape;
  4. Delivering coordinated habitat and water quality improvements to the First Public Drain, Milton Country Park and Chesterton Fen;
  5. Securing appropriate habitat management and monitoring plans are implemented to restore existing habitats and establish and retain new features, through a S106 agreement; and
  6. Providing accessible information for members of the public on the site's habitats, their management and species they support through a S106 agreement.

Development shall avoid having any adverse impact on the nature conservation value of:

  • The First Public Drain and other watercourses and bodies within the site;
  • Local Nature Reserves including Bramblefields;
  • City Wildlife Sites and Country Parks including Cowley Road Hedgerow;
  • The River Cam County Wildlife Site; and
  • Any other areas of natural or semi-natural sites within or adjacent to North East Cambridge.

Within North East Cambridge, development proposals shall take all practicable opportunities to enhance the area's nature conservation value and ensure that site users have access to healthy, biodiverse green spaces.

Where an adverse impact on biodiversity is unavoidable, this shall be minimised as far as possible and appropriate measurable mitigation provided.

Mitigation of adverse impacts on biodiversity resources

Where mitigation is required to compensate for the reduction or loss of existing biodiversity resources, this shall be provided in liaison with the Councils with the following principles ensuring the objective of contributing to the creation of a coherent on-site and off-site, high quality ecological network is met:

  1. Identified projects to be agreed with the Councils for on-site habitat provision/enhancement and management wherever practicable. Where this is not practicable to be delivered on-site, this should be followed by identified improvement projects to be agreed with the Councils to Milton Country Park and/or Chesterton Fen, followed by sites within the wider local area, and then other sites elsewhere within Greater Cambridge;
  2. The maintenance, and where possible, enhancement of the ability of plants and animals including pollinating insects to move, migrate and genetically disperse across the city; and
  3. The provision/enhancement of priority habitats identified at the national, Greater Cambridge or local level, having regard to the scarcity of that habitat within North East Cambridge.

Where mitigation is needed, an offsetting mechanism based on the Natural England biodiversity offsetting metric version 2.0 will be used to calculate requirements. Temporary impacts to habitats which can occur during ground works and construction should seek to be mitigated through interim measures to promote biodiversity.

The amount of mitigation required will be determined having regard to:

  1. The importance of the biodiversity resources that will be adversely affected, particularly in terms of whether they:
    1. Include priority habitats identified at the national, Greater Cambridge or local levels; and/or
    2. Are able to support protected species and priority species;
  2. The range of biodiversity resources that will be adversely affected, with greater mitigation being required where a mosaic of habitats will be lost, or a large number of species affected;
  3. The size and quality of biodiversity resources that will be adversely affected, and their function within wider ecological networks;
  4. The impact of the development on the role and resilience of remaining biodiversity resources, for example in terms of the ability of individual species to maintain self-sustaining population levels and/or to adapt to climate change; and
  5. Any other issues identified through ecological assessment of the site.

The biodiversity net gain metric will be identified once the mitigation measure is implemented and fully established. The creation of any new habitats should take into account the likely impact of climate change and be resilient to these effects.

Planning applications will need to be supported by a 'Biodiversity Checklist' that considers the impact of the proposals against a set of constraints including designated sites/priority habitats and protected species.

Relevant objectives: 1, 4

If development is to be genuinely sustainable then it will need to play a key role in protecting and enhancing Greater Cambridge's biodiversity resources. On-site biodiversity improvements will also be vital to enhancing the liveability and well-being of urban areas, and improving the connection of people to nature, particularly in higher density urban areas such as North East Cambridge.

Biodiversity net gain is an approach which aims to leave the natural environment in a measurably better condition than beforehand. The Environment Bill (2020) sets out how the environment will need to be at the centre of policy making. In particular, it introduces a minimum 10% biodiversity net gain requirement for new development to ensure new developments enhance biodiversity and create new green spaces for local communities to enjoy. The National Planning Policy Framework encourages net gains for biodiversity to be sought through the plan making process and the Councils will support a biodiversity net gain of more than 10% where this can be achieved.

In May 2019 Cambridge City Council declared a Biodiversity Emergency. South Cambridgeshire District Council has also set out a commitment to double the existing area of rich wildlife habitats, tree cover and accessible green space within the District in order for nature and people to thrive, and businesses to prosper, recognising the current ecological emergency.

The message at a national and local level is therefore clear that biodiversity issues need to be taken seriously and are a key component of sustainable development. The Area Action Plan seeks to respond to this by ensuring that the existing biodiversity resources in North East Cambridge are protected and enhanced. This will be a significant challenge given the scale of development proposed. Therefore, all development in the Area Action Plan area will have a significant role to play in this, and the cumulative benefit of small-scale improvements in biodiversity resources should be maximised.

Existing habitats in and around North East Cambridge

There are a number of existing habitats across North East Cambridge, including woodland, scrub, hedgerows, ephemeral perennial vegetation, watercourses and ponds. These habitats support a number of species such as Common Frog, Smooth Newt, Viviparous Lizard, House Sparrow, Common Swift, Soprano Pipistrelle bat and Water Vole.

There are no nationally or internationally designated biodiversity sites within the Area Action Plan area, but a City Wildlife Site is located on Cowley Road and Bramblefields Local Nature Reserve borders the south of the area. The North East Cambridge Habitats Regulation Assessment has identified that impacts from air pollution, recreation and water quantity and quality could result in 'likely significant effects' on Devil's Dyke Special Area of Conservation (SAC), Wicken Fen Ramsar and Fenland SAC and further engagement will be required with the Environment Agency and Natural England.

Land to the east of North East Cambridge, known as Chesterton Fen, is an area of species poor, open grassland situated between North East Cambridge and the River Cam. Through the provision of improved access over the railway line into Chesterton Fen, there is an opportunity to create a new Local Nature Reserve in this area containing wetland characteristics and fenland habitats such as open water, wet grasslands, reedbeds and the restoration of drainage ditches. This would need to be carefully considered alongside the need to provide public amenity space. A habitat creation project at Chesterton Fen should be developed to provide significant opportunities for biodiversity and people and funded by development within North East Cambridge through a Section 106 agreement.

North East Cambridge lies at the gateway to the wider Fen landscape, which is under increasing challenges and threats due to changes associated with climate change, food production and population growth. The interrelationship between North East Cambridge and the Fens provides the opportunity for biodiversity enhancements and future development to have a strong identity, excellent resources management as well as a link into innovation and learning. This reflects the work being undertaken through the Fen Biosphere Project by Cambridgeshire ACRE.

Adverse environmental effects predicted prior to construction should be mitigated or prevented through a construction environmental management plan (CEMP) based on the latest British Standards.

Achieving biodiversity net gain

Development within North East Cambridge will be required to deliver a minimum 10% net biodiversity gain (using The Biodiversity Metric 2.0, as published by Natural England (2019) or any future equivalent). Biodiversity net gain in development is defined as "development that leaves biodiversity in a better state than before".

Planning Policy Guidance sets out the long-established mitigation hierarchy to avoid, protect and mitigate loss of habitats. In addition, a measurable biodiversity net gain is now required through increased area and or quality of habitats on site. Such provision can be multi-functional, including the provision of green roofs and walls, street trees and sustainable drainage systems. It also notes that relatively small features such as swift bricks and bat boxes can achieve important benefits for specific species.

The spatial framework for North East Cambridge offers the most significant opportunity to enhance the city district's biodiversity resources and provide a network of habitats, with a significant linear park which connects with existing green assets, as well as the potential to secure off-site biodiversity improvements at Chesterton Fen. There are also numerous opportunities elsewhere within North East Cambridge to secure significant biodiversity enhancements, ranging from strategic water habitats such as the First Public Drain to individual development sites.

To achieve the required minimum 10% net gain, biodiversity should be considered and designed into proposals from inception. Where on-site provision is not feasible, greenspace and biodiversity enhancement will need to be provided in alternative ways and/or accommodated off-site. The provision of extensive areas of biodiverse living roofs are necessary to replace the existing open mosaic habitats which are of significant value within the North East Cambridge area, particularly around the railway sidings and at the Waste Water Treatment Plant. These roofs can also provide vital greening in dense urban areas such as North East Cambridge.

It will be important to ensure that habitats and species both on and off-site are resilient to disturbance from human activity, including recreation, predation by pets, noise and light pollution.

Due to the presence of bats within North East Cambridge and the migration routes of foraging bats along the greenspaces and First Public Drain, there is a requirement for integrated bat features within new buildings, which is in addition to the requirements set out in Appendix J of the Cambridge Local Plan. It is recommended that integrated bat features for crevice dwelling bats should be installed at a density of at least one for every two buildings. Features for bats which roost in roof voids, or require internal flight areas, should be installed at one for every 25 buildings. Development proposals should also improve hedgehog permeability across development parcels.

Due to its location and the scale of change set out in this Area Action Plan, from an early stage, development proposals are encouraged to consider using the Natural Cambridgeshire Local Nature Partnership Developing with Nature Toolkit to demonstrate how development will achieve a net biodiversity gain in an area which is recognised as a gateway to The Fens.

  • Site wide and landowner parcel Biodiversity Net Gain from the 2020 baseline
  • Biodiversity Net Gain and habitat improvements to Chesterton Fen from the 2020 baseline
  • Biodiversity enhancements to City and County Wildlife Sites

Cambridge Local Plan 2018

  • Policy 59: Designing landscape and the public realm
  • Policy 69: Protection of sites of biodiversity and geodiversity importance
  • Policy 70: Protection of priority species and habitats

South Cambridgeshire Local Plan 2018

  • Policy NH/4: Biodiversity
  • Policy NH/6: Green Infrastructure
  • Biodiversity SPD (2009)
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