Let’s consider a hypothetical development where BNG is a requirement of a planning submission. 

Remember that BNG requires a 10% increase in both habitat areas and 10% increase in linear features (swales / hedgerows etc) and possibly watercourse units too.

Whatever the development footprint, the remaining areas must be used to create a 10% BNG – effectively 110% of the whole initial site baseline value must be condensed into the remaining areas. The smaller the area, clearly the less feasible this becomes.

If we assume the total red line area to be 1 hectare (10,000m2), and the proposal is to develop area is 4,500m2 (45%) 

Assuming the initial Biodiversity Baseline Assessment records 10 Habitat Units and 5 Hedgerow Units, it will be necessary to have 11 Habitat Units and 5.5 Hedgerow Units post-development. 

Presuming that the Habitat Units are evenly spread throughout the site, 4.5 Habitat Units and 2.25 Hedgerow Units lost will be lost if 4,500m2 is built on. This means that the remaining undeveloped area (5,500m2) must achieve the BNG.

Consequently, the difficulty is obvious, in that the reduced area of 5,500m2 must generate 11 Habitat Units and 5.5 Hedgerow Units.

This may be achieved by creating, or enhancing habitats on site, so that the value of any given area (albeit it smaller than previously) is higher post development than it was pre-development. How many development sites work on a 45% footprint – remember this includes all hard surfacing: roads, paths, houses, parking, patios etc? In our experience 65% is far more often the intention.

Self-evidently, the larger the development area, the more difficult it becomes to achieve any gain, let alone a 10% BNG.

If you cannot provide 10% BNG on site then it may be provided offsite if you own adjoining land, or you will need to purchase Biodiversity Units from the Market or Defra Credits. The cost of this depends on your location, the availability of units and the type of habitat you need to create.

If you ae providing the BNG on site or adjoining, there will be a 30 years management requirement. Who will provide the BNG, manage it, maintain it and rectify if it fails to achieve the BNG Condition you have signed up to? Additionally, the LPA will require regular reports from an experienced and competent ecologist in years 2, 3, 5,10,15,20,25,30.

Consequently, developers are likely to need to pay far less for development land (or charge significantly more for property), when the financial implications are factored in.

Where developers are taking forward sites purchased in the past, the financial viability of these sites is now being questioned. This is especially true for social housing sites, which are borderline viable in many cases, even without BNG. 

It is also more difficult to create onsite habitats on smaller sites, as the human pressure is simply too great to enable biodiversity to exist alongside children playing football and dogs being exercised. 

The LPA know this and will reject unrealistic habitat creation in any BNG Plan.

Best Plan of Action

Careful consideration of site selection:

• Development sites which consist of existing hard surfacing: roads, car parks, factory units etc will invariably have a low BNG baseline value, making it possible to develop a larger area than a site which is rich in biodiversity. 
• It is also probable that some areas of a large site will be of greater BNG value than other areas, so selecting the best layout will be essential in minimising BNG losses on site.
• Every site will be different and it is strongly advised that you speak to us at the earliest opportunity to ensure your site can be assessed and evaluated before you commit to purchasing it, or if you already own it, before you pay for an Architect to design a layout.

Local authority ecologists are reporting a surge in under reporting the true BNG baseline and consequently rejecting planning applications.

There are some possible reasons for this:

• The ecologist undertaking the baseline assessment has inadvertently mistaken one habitat, or perhaps mis-calculated a habitats value. This results in the baseline metric score being lower than it should be.

This can be attributed to perhaps two genuine causations:

• There is often some professional judgement in assessing habitats and even two knowledgeable people might disagree, although the Metric is designed to prevent this happening.
• The ecologist making the assessment lacks experience, or sufficient knowledge to undertake the baseline assessment.
• The ecologist or company deliberately downgrades the existing habitats and deliberately inflates the post-development BNG to make a proposal appear better on paper, than in reality. 

The first category requires additional training and guidance, whilst the second are simply snake oil salespeople who unfortunately exist in every industry. 

Incidentally, if the thought crosses your mind that damaging the development site prior to instructing an ecologist might ‘de-value’ the biodiversity value, and make it easier to provide a paper BNG, be aware that Google Earth Pro offers the LPA the option of searching for site images over extended periods of time and will go back to January 2020 and they will assume a site value commensurate with the highest possible pre-development biodiversity value based on aerial images, which might well be higher than the actual value. Habitat degradation is likely to cost you more and or result in the LPA refusing your application. Don’t, do it..

We are known for our pragmatic (rather than obstructive approach), to development and will assist you in negotiating the increasingly more complex ecological and biodiversity requirements in bring your proposals forward, albeit on occasion there may not be a solution or at least one that accords with the financial considerations of any given site.

We strongly advise against pre-emptive site clearance and will not work with developers who engage in such practices. 

admin@ecological-surveys-ltd.co.uk

Telephone: 0800 888 6846 / 07736 458 609