Winter 2023

trading rules to ensure lost habitats
are replaced ‘like for like or like for
better’. Following confirmation that 10%
BNG is achievable, a detailed 30 year
landscape and habitat management
plan is produced. This states how the
post development habitats will be
enhanced, managed, and monitored;
demonstrating the best possible chance
of achieving the committed biodiversity
units.
What is the value of a Biodiversity
unit?
This would depend on what we mean by
‘value’. BNG units are assigned a value
weighting depending on the habitat’s
significance. For example; if the habitat
is a rare or nationally significant habitat
it will score a greater metric value, and
therefore will require a greater level of
mitigation or compensation if proposed
to be lost. Some habitats are considered
so valuable that they cannot be
measured using the standard format,
these are classed under National
Planning Policy as ‘irreplaceable
habitats’ i.e. Ancient Woodland. That
being said, if the development scheme
does include loss of irreplaceable
habitat, it could only be permitted
under very limited circumstances and a
bespoke compensation scheme will be
required.
A monetary value can also be assigned
to each biodiversity unit (BU). These
can be traded on the open market and
is relevant if the development cannot
achieve the minimum requirement
of 10% BNG within the development
red line boundary. There is no hard
and fast rule for the financial value
assigned to a BU, however, the industry
in general is beginning to set the rates.
For example; the typical cost for 1 BU
of other neutral grassland in moderate
condition is £30k. In addition to a
developer being able to purchase BU’s
on the open market, the government
has released statutory units. These
are more expensive to purchase and
require a 2 for 1 ratio, meaning they are
doubly expensive compared to the open
nature market. Prices for Statutory
BU’s range between £42k for low
distinctiveness habitat, up to £650k for
high distinctiveness habitats.
The demand for off-site biodiversity
units has established the creation
of ‘habitat banks’. This is where
landowners and/or developers set
aside areas and undertake habitat
enhancements for the purpose of
bringing the generated biodiversity
units to the market to trade, or to offset
local development that cannot meet
the required 10% BNG within the redline
boundary. It’s important to note that
a development should always seek to
achieve the required biodiversity within
its own redline. To further this the
metric includes a spatial risk multiplier,
reducing the value of habitats that
are used as offsite compensation
where these are located outside the
Local Planning Authority, or National
Character Area.
Delivering and achieving BNG
Mitigation hierarchy, establishment,
adaptive management, and a robust
monitoring strategy to identify potential
issues in good time are all essential
aspects of delivering BNG. Early
collaboration between the landowner,
design team, ecologists, landscape
architects and land managers is
essential in securing a positive outcome.
Establishing the premise that the
proposed development can deliver an
increase in biodiversity is one thing, but
this will need to be realised by skilled
landscape operatives and contracts
managers, who will be required to
establish and maintain a wide variety
of both broad and niche habitat types;
whilst working closely with ecologists
to monitor the success of the scheme
over time.
Some key points about BNG
• BNG is about measuring the quantity
and condition of habitats on site pre
and post development
• DEFRA metric uses Biodiversity units
as its main currency / units for some
habitats are valued higher than others
• BNG ensures an increase in habitat
units post development by either on site
or off site provision
• Developers should try to achieve BNG
within the development red line boundary
• Biodiversity units can be purchased,
and statutory units are available from
the government, but these typically cost
more than units bought on the open
nature market.
References available on request.
About the author:
Pond and heathland habitat.
Image credit: TEP
Richard Tomlinson is a Chartered
Landscape Architect and Associate
Landscape Manager at The
Environment Partnership (TEP) Ltd.
TEP have produced a number of helpful
guides for developers, landowners and
management companies wanting to
further understand BNG - follow @TEP_
Ltd on LinkedIn, Twitter (X), Instagram
and Facebook, and check for updates
on our website www.tep.uk.com.
www.greenscapemag.co.uk • GREENSCAPE WINTER 2023 19