We support the proposal for 20% Biodiversity Net Gain (BNG, twice the national requirement of 10%), which recognises the poor starting point for biodiversity in the region, and support the policy that development should be required to achieve BNG. However:
● The outputs of the BNG calculation must always be ‘sense-checked’ by suitably qualified ecologists. Otherwise, we are concerned that over-reliance on the metric could lead to undesirable results. The metric has a number of flaws, a key one being that it favours habitats that are quick and easy to create, not necessarily those that have the greatest wildlife or climate benefit. Furthermore, it does not account for indirect impacts of development on habitats and species.
● The policy allows off-setting to take place off-site. Given that (as stated in the Council’s webinar) net gain is unlikely to be achievable “on-site” in most cases, the target itself starts to look meaningless. For example, quick gains in the Biodiversity Metric can be achieved by improving the measured condition of existing large biodiversity sites. While a desirable outcome in itself, this must not be used to compensate for the loss of a biodiversity site to development. It is important that the net result of this policy is not to ‘concentrate’ biodiversity in fewer sites. An increase in the total area of green space, with appropriate biodiversity, is necessary for improving ecological connectivity and climate resilience, and for balancing the objectives of nature recovery and improving people’s access to green space.
● New habitats created as part of the net gain approach need to be explicitly protected from development in future rounds of planning. In the government’s proposed implementation of BNG, new sites are only required to be protected for 30 years, but this time limit is inappropriate. It can take more than 30 years for a range of habitats to develop on a newly created site. For example, Trumpington’s two country parks, now almost 14 years old, are still developing to their full potential and already under threat from the Cambridge South station development. International guidance is that areas recognised as needing protection for their biodiversity should be accorded this “in perpetuity”.
● We are very concerned by the statement that “development proposals adversely affecting sites of
biodiversity or geological importance will not normally be permitted”. This policy should be much more strongly worded – it will be very difficult to assess/measure with
any certainty situations where “public benefits significantly outweigh any adverse impacts” – and we think that the proposed wording will provide a major loophole for developers to damage biodiversity. The flaws in the cost/benefit approach have been amply illustrated elsewhere in the country – for example by proposals to build a theme park on top of the Swanscombe Marshes SSSI, or to drain and build over an area of Portsmouth Harbour despite it holding every level of statutory wildlife protection. To address concern, we call for, at minimum, a strong policy statement that all existing designated sites
(with either national or local designation) remain protected and undeveloped. The development of such sites must not be considered under a cost/benefit analysis approach: it is not possible to weigh factors such as job creation against the irreversible loss of these special places. The consultation document itself makes it clear that, “National planning policy requires us to protect and enhance sites of biodiversity and geodiversity importance”, and this should be a fundamental policy within the Local Plan. The topic paper for biodiversity states “…we consider that additional clarity is required to set out how the principles [i.e. the requirement that sites of biodiversity importance are protected] set out in national policy should be applied at a local level” and this point needs to be addressed in the Local Plan.