Green Infrastructure Strategy – Horsham District Council

Wilder Horsham District – August 2021

Horsham District Nature Recovery Network – Version 1 – August 2021


Nature is in dramatic decline, both nationally and within the Horsham District. To reverse this decline
better and more connected habitats are needed; which can be achieved by establishing a Nature
Recovery Network (NRN). This document sets out how a NRN could potentially be developed for
Horsham District, taking advantage of the existing areas with biodiversity value or high biodiversity
potential, and considering how they could be improved and linked together. Developing an NRN
underpins the Wilder Horsham District project, which is a partnership between the Sussex Wildlife Trust
and Horsham District Council.

The Network should incorporate rural and urban areas, to ensure that wildlife is not confined to
isolated protected sites and can move through the landscape. Built up areas, and infrastructure such
as roads, create a challenge for an NRN but wildlife corridors can be created around and even
through settlements. Corridors also minimise the habitat gaps to be crossed and, in some cases, can
even close them completely, for example crossing a road via a green bridge or underpass.

The Horsham NRN map work is aspirational, demonstrating what could be achieved and where
action could be targeted to reverse the biodiversity crisis. However, the Network and Nature
Recovery are reliant on the good-will and expertise of land-owners and land-managers for delivery.

The goal of the Wilder Horsham District project is to work with land-managers and communities at all
levels right across the district to help integrate nature recovery and connectivity into the many
different land-uses. This document is not intended to dictate how any land-manager should manage
their land but rather to highlight those areas that have particular features that give them high nature

The map is based on ecological data and principles and on the latest best practice and guidance,
including that from Natural England1
It may be updated to reflect further national guidance.

The map

1 Natural England Guidance (available at Nature Networks Evidence Handbook – NERR081 (
 Crick, H. Q. P., Crosher, I. E., Mainstone, C. P., Taylor S. D., Wharton, A., Langford, P., Larwood, J., Lusardi, J.,
Appleton, D., Brotherton, P. N. M., Duffield, S. J. & Macgregor N. A. (2020) Nature Networks Evidence Handbook.
Natural England Research Report NERR081. Natural England, York.
Wilder Horsham District – August 2021
is still in development and will be improved and refined as more data is added; although the core of
the NRN, such as the location of watercourses, will not change.

Undoubtedly there are areas that are rich in wildlife or have potential for nature recovery that do not
appear on this first version of the map. The document should be considered with this in mind.

Nature Recovery Networks

The idea of establishing NRNs was a significant commitment in the Government’s 25 Year Environment
Plan as a way to reverse the dramatic decline in wildlife that has occurred over the last 50 years.
NRNs are based on the Lawton principles of: Bigger, Better, More and Joined Up. The Government’s
Environment Bill is expected to introduce a statutory requirement to prepare local nature recovery
strategies, including NRNs, and effective measures at policy level will also be important for enabling
nature recovery.

The Wilder Horsham District Project has been established in response to the urgent pressures on
biodiversity with the aim of accelerating the delivery of measures for nature recovery. Consequently,
this first version of a map of a Horsham District NRN identifies where buffers could be added to existing
sites (bigger), areas which can be improved (better), areas with high potential for nature recovery
(more) and where there could be corridors or stepping stones between sites (joined up).

Part of the aim of the NRN is the restoration of natural processes2
, in particular: Natural Flood
Management (NFM)3
, Natural Grazing4 and Ecological Succession5
. This will bring benefits not only for
wildlife but also for the communities of The District, such as reduced flood risk and clean water.

The NRN can also make a significant contribution to tackling climate change by increasing carbon
storage. It will also bring health and wellbeing benefits by enabling people to increasingly enjoy and
connect with nature where they live, work and play.

The map contained in this document is at the District scale, but the principles can be applied at
different levels, from the entire country down to a single town or village. In towns and villages, for
example, open spaces, woodlands and water courses could also be managed to help wildlife thrive
and bring nature closer to people. NRN maps at Parish scale will help communities to take action that
will contribute to the District wide NRN. In its turn, the NRN for the District will need to be part of a
wider Network across the whole of Sussex and the South East. The current map is still evolving, for
example, it does not include species information (e.g. specific areas that have been identified for key
local species that are vulnerable to local extinction, or areas to bolster populations of species that
thrive in the District, but are vulnerable elsewhere). It also focuses specifically on biodiversity, as the

 Crick, H. Q. P., Crosher, I. E., Mainstone, C. P., Taylor S. D., Wharton, A., Langford, P., Larwood, J., Lusardi, J.,
Appleton, D., Brotherton, P. N. M., Duffield, S. J. & Macgregor N. A. (2020) Nature Networks: A Summary for
Practitioners. Natural England Research Report NERR082. Natural England, York
Wildlife Trust Guidance: Nature_Recovery_Network_Handbook_LO_SINGLES.pdf (
2 Natural Processes are the interactions that shape our planet and support life.
3 Natural flood management is when natural processes are used to reduce the risk of flooding and coastal erosion. Examples
include: restoring bends in rivers and changing the way land is managed so soil can absorb more water. Additional benefits
can include the creation of new wildlife habitats, the reduction of pollutants and increased carbon capture.
4 Grazing methods that mimic the natural grazing behaviour of wild herds. This can increase grass productivity by up to 300%
and significantly improve soil quality.
5 Ecological succession is the gradual process by which ecosystems change and develop over time. Nothing remains the
same and habitats are constantly changing.
Wilder Horsham District – August 2021
primary driver for this work is to reverse losses in wildlife. It does not incorporate information on other
aspects of interest or concern such as accessibility to nature6

The role of Wilder Horsham District

The main objective of the Wilder Horsham District project is to initiate the development and delivery
of the local NRN. The project brings together the Sussex Wildlife Trust and Horsham District Council. The
two organisations have distinct roles in the project, which are outlined in this paper. However, these
organisations will not be able to deliver the Network alone and partnership working will be vital. There
are two Project Officers, the Landowner Advisor and Community Support Officer. Together, they will
work with landowners, farmers, communities, Parish Councils and other organisations to promote
Nature Recovery and improve landscape connectivity for the benefit of wildlife.

The role of the Sussex Wildlife Trust

The Sussex Wildlife Trust employs the two project officers and supports them via the project team and
steering group. Sussex Wildlife Trust also provides technical and expert support for the project.
As a conservation organisation focused on protecting and enhancing the rich natural life of Sussex its
focus is on using Nature Recovery Networks to drive Nature’s Recovery across all of Sussex. As such
Sussex Wildlife Trust asserts its role in encouraging the District Council to make evidence based
decisions using the Nature Recovery Network information that the Wilder Horsham District Project has
produced and will continue to refine. The Sussex Wildlife Trust will promote Nature’s Recovery in
relation to the Council’s other roles and responsibilities, asserting the importance of the network for
the ongoing ecological integrity of the district, particularly where the Council’s other duties might
result in a competing priorities.

The role of Horsham District Council

The District Council supports the project officers based at the Sussex Wildlife Trust via the project team
and steering group. There is close working between both organisations, for example, encouraging
and supporting volunteers to undertake work that assists in the development of the network.
The District Council already manages many of its parks and countryside sites for the benefit of wildlife.
However, it will review its land management practices so that it contributes to the developing NRN.
Both organisations will work to inspire communities throughout the area to value wildlife and take
action, on land of all sizes, to help it thrive. This will be an essential part of delivering the NRN.
The District Council is also responsible for land use planning in the District (excluding the South Downs
National Park). The Government guidance on how Nature Recovery Networks should interact with
development is set out in the National Planning Policy Framework; the details of this are included at
the end of this document (see Appendix 1). In summary, planning should take account of the NRN
and use it to inform where development can be made sustainable by protecting and enhancing
nature. Adverse impacts should be avoided and opportunities to incorporate improvements for
wildlife in and around development should be encouraged. The upcoming mandatory requirement,
in the Environment Bill, for Biodiversity Net Gain reinforces that there must be wildlife gains as part of

6 These should be addressed in other strategies and programmes such as a Green Infrastructure strategy.
Wilder Horsham District – August 2021
development. The NRN map will help to identify the types of Biodiversity Net Gains that could be
Wilder Horsham District – August 2021
Construction of the Nature Recovery Network

The Basis of the Network

Water bodies, especially rivers, are extremely important in an NRN. The restoration of Natural Flood
Management is vital for holding water in the landscape both for improving habitat quality and for
preventing flooding of settlements. The District has the advantage of having two major river systems
that cover most of the area. The Adur and its tributaries form a network that covers the central and
South Eastern parts of the District. Tributaries of the Arun flow through the north of the district and the
main river runs down the western boundary. In connectivity terms, rivers are natural corridors, as well as
being valuable habitats in their own right, and so can form the basis of a NRN.
Figure 1. Watercourses in Horsham District (data provided by EA).

The Importance of Water
Wet habitats, especially wet
woodlands, are some of the
most biodiverse habitats in the
UK and the drying up of the
landscape has been a
significant factor in the recent
biodiversity loss, especially in
declines of invertebrates.
Habitat restoration along
watercourses has huge
potential for driving species

Water quality is also extremely
important for both people
and wildlife and vegetated
buffer zones along
watercourses are effective in
removing pollutants from
surface run-off.
Returning sections of our
waterways to a more natural
state would slow down the
flow and create a more
balanced system of water
In particular the proposed
licenced reintroduction of
beaver to the District would
restore a keystone species
that would have far-reaching
ecological benefits.

Wilder Horsham District – August 2021
Core Sites (better)

These sites are the core of the network. They are already existing sites that have already been
identified as being crucial to wildlife in the district because of either their intrinsic quality, that they are
managed with wildlife and nature as the key drivers or both. The Network should aim to improve the
quality of these sites, many of which already have statutory obligations for management or
protection through local provisions.

These include the Sites of Special Scientific Interest (SSSI), Local Wildlife Sites (LWS), Nature Reserves
(SWT, NT and RSPB) and sites managed by Forestry England. Also included are the Natural Capital
Assets in the district; these are habitats of particular value in terms of biodiversity and ecosystem
services. The habitats concerned are: Ghyll Woodland, Floodplain Woodland, Lowland Fen,
Reedbed, Lowland Heath, Acid Grassland, Intertidal Mudflat, Lowland Meadow and Lowland
Calcareous Grassland.

Wilder Horsham District – August 2021
Figure 2. Core sites in Horsham District

The rewilding project at Knepp is also included in these core sites. This site is important for two reasons.
As a rewilding project it has shown what can be achieved for Nature Recovery. Additionally, in terms
of the NRN it occupies a strategic position almost exactly in the centre of the district. It is therefore
ideally placed to serve as a hub for the Nature Recovery Network.

New Sites (more)

There are areas within the district that have been identified as having very high potential for Nature
Recovery. The location of these sites is fixed by their geography and/or underlying geology. The main
areas are those where heathland or acid grassland restoration is possible (mainly on the greensand),
where lowland calcareous grassland restoration is possible (on the chalk of the South Downs) or
References for the core sites
SPA: Land notified under the
Wildlife & Countryside Act 1981
(as amended) and the
Conservation (Natural Habitats,
& c.) Regulations 2010 (as
amended); SAC: Land notified
under the Conservation of
Habitats and Species
Regulations 2017 (as
amended); Ramsar sites:
Wetlands of international
importance designated under
the Ramsar Convention; SSSI:
Land notified under the Wildlife
and Countryside Act 1981 (as
Site Search
LWS: Non-statutory sites that
contain features of substantive
nature conservation value.
Administered by the Sussex
Local Wildlife Sites Initiative
Sussex Local Wildlife Site
Initiative (
Natural Capital Assets: Sussex
Local Nature Partnership: Sussex
Natural Capital Investment
Strategy – Sussex Local Nature
Partnership (
Wilder Horsham District – August 2021
where restoration of wet habitats are possible (mainly along the river valleys and tributaries of the
Adur and the Arun).

Figure 3. Sites with Very High habitat potential in Horsham District

These sites are high priority to target with management advice because of the significant contribution
they could make to Nature Recovery but also because of the connectivity they provide between
other sites. Ideally as much of this area as possible would become part of the core of the Nature
Recovery Network with management to benefit nature.

Other new sites and buffered sites (more and bigger)

Another targeted landscape-scale approach to conserving biodiversity and the basis for an
ecological network are the Biodiversity Opportunity Areas (BOAs). Each area has a set of
conservation priorities for biodiversity so that habitat enhancement, restoration and recreation
References for very high habitat
potential Sites
Tink, M. and Baker, R. (Jan 2012)
Adur & Ouse Catchment
Habitat Potential Model, A
Sussex Biodiversity Record
Centre report supported by
Sussex Wildlife Trust and funded
by the Environment Agency
Tink, M., Baker, R. and
Southgate, F. (July 2011) Arun &
Rother Catchment Habitat
Potential Model, A Sussex
Biodiversity Record Centre
report funded by Natural
England and the South Downs
National Park Authority.
Tink, M. and Baker, R. (Nov
2011) South Downs Wooded
Heath Habitat Potential Model,
A Sussex Biodiversity Record
Centre report funded by the
South Downs Heathland
Tink, M. and Baker, R. (June
2012) South Downs National
Park Lowland Calcareous
Grassland Habitat Potential
Model, A Sussex Biodiversity
Record Centre (SxBRC) report
funded by the South Downs
National Park Authority.
Wilder Horsham District – August 2021
projects can make the most of opportunities to establish large areas of habitat and connections
between them. They are included in the map below (Figure 4.)

Figure 4. Other sites with high restoration potential and buffering of core sites.

There are twelve BOAs that are wholly or partly within the District, these are: Adur to Newtimber;
Woods Mill Steam to Adur; North Bramber Floodplain; Central Downs Arun to Adur; Lower Adur Arun
Watershed; Knepp Estate with Fluvial extensions; The Mens and Associated Barbastelle Flightlines;
Parham to Fittleworth;

Ifield Brook;

The St.Leonard’s Watershed; Rusper Ridge and Houghton to

Also included here are the two designated landscapes that overlap with the District. These are the
South Downs National Park (SDNP), in the South of the District, and the High Weald Area of
Outstanding Natural Beauty (HWAONB). These areas are not selected solely on the basis of
Biodiversity Opportunity Areas
The Biodiversity Opportunity
Areas (BOAs) are priority areas
of opportunity for restoration
and creation of Biodiversity
Action Plan (BAP) habitats.
They are a spatial
representation of the BAP
targets and the BOAs are
areas of opportunity, not
constraint. The BOAs included
in the map do not include all
the BAP habitat in the region,
nor do they include all the
areas where BAP habitat
could exist. In particular, more
work is needed to develop
approaches in urban and in
marine environments.

The Biodiversity Opportunity
Areas Map is the property of
the members of the South East
England Biodiversity Forum ©
South East England Biodiversity
Forum 2009. Reproduction of
the BOA Map is subject to
conditions © Crown
Copyright. All rights reserved
Sussex Local Nature Partnership
Wilder Horsham District – August 2021
biodiversity but both have biodiversity interest and potential for habitat improvement or restoration,
particularly where linking sites is concerned. Additionally some known sites where wilding or
regenerative agriculture is planned have been included here.

Existing or proposed core sites could be made bigger with buffering, that is, providing a transitional
habitat that protects the main habitat. Buffers vary in size and composition depending on the size
and type of area they are protecting. Any size of buffer is generally an improvement but, of course,
the bigger the better. The Sussex Wildlife Trust has often used twenty metres as a “rule of thumb”
buffer width, with thirty metres for more sensitive sites such as ancient woodlands. However, the most
effective buffers are those tailored to the specific site and a number of methodologies have been
devised to calculate appropriate buffer sizes7
. Typically wet features need the biggest buffers and if
all large water courses in the district could have a 30m buffer with 12m buffer for the smaller water
courses then that would be hugely beneficial. Buffers that are intended to provide wildlife habitat
and woody debris or maintain water temperatures need to be at least 30m8
. Some of the potentially
very highly biodiverse wet habitats such as riparian woodland benefit from a much wider buffer to
hold the moisture and maintain habitat quality. Research suggests that some species groups, such as
birds, may require wider buffers of up to 144m9
. Obviously buffers will be very site specific and will
need to take into account current land uses but the NRN should aim for a high standard supported
by ecological principles10
Corridors and stepping stones (joined up)

The core sites combined with what might be termed the ‘fixed’ areas for improvement provide a very
solid foundation for a Nature Recovery Network. However there are still gaps and this is where there is
an exciting opportunity to engage with landowners in the rest of the district, which is most of it. Knepp
has shown what can be achieved on farmland through wilding techniques and more such areas
would certainly be beneficial. However, wilding is by no means the only way to improve biodiversity
and regenerative agriculture and stewardship options can also greatly increase the value and
permeability of the landscape for wildlife.
Figure 5 (below) shows some potential links to join up the network more fully. These could be corridors
with a nearly complete habitat connection or more like stepping stones with a series of habitat
patches facilitating movement. Indeed because of the built infrastructure in the district, especially the
road network, only the shortest links will be continuous corridors and most will contain stepping stone
elements. In the longer term the NRN would really benefit from infrastructure, such as green bridges,
that allows the habitats to cross the major roadways in the district.
The links shown here are based partly on what seem logical routes to take based on the known
habitats but at the moment they are indicative. These links are potentially much more fluid than other
parts of the network and the final form will depend on engagement by landowners and communities.

7 See for example: LBS brochure FINAL ( & Introducing the “Derived Root-system Radius” –
An attempt at an evidence-supported-calculation for calculation of buffer zone size in respect of Ancient Semi-natural
Woodland, Ancient Trees & Veteran Trees: Arboricultural Journal: Vol 41, No 3 (
8 Given as a distance of 100 feet in this guidance: bufferguide (
See also: Broadmeadow&Nisbet_1.pmd (
9 See:
10 The standing advice from NE for ancient woodland states “a minimum buffer of 15 metres” with the caveat that “larger
buffers may be required” (Ancient woodland, ancient trees and veteran trees: protecting them from development –
GOV.UK ( However the NRN is based on ecological evidence rather than planning requirements.
Wilder Horsham District – August 2021

Next Steps

As mentioned above this is only the first iteration of the NRN map. It is based on the available
evidence but as the project progresses and more data is added or becomes available the map will
be further refined. In particular we will consider the following areas:
Refining the habitat and habitat potential data
Some of the data on the map is already very accurate, such as the designated sites and Habitat
Potential models, but some is more broad brush. As more accurate data becomes available, either
through work by the Project or via other means it will be added to the map.
Adding species data
Many species groups are well recorded in the District and where data exists it can be used to refine
the NRN and inform the types of habitat improvements required to make the network effective. For
example the “B-Lines” work of Buglife can be used to target areas for wildflower meadow creation11
Caution must be used with some data however because survey effort for many species is not even
across the District. Lack of records does not necessarily mean that a species is absent.
Mapping at more refined scales
This first version of the NRN map has been produced at the District scale which is a fairly coarse
resolution. More detailed mapping at a finer scale for example at a catchment scale, a Parish scale
or a settlement scale will help inform how the pieces of the network can actually be put together. For
example we will consider how a NRN could be built through Horsham Town itself.

Linking with habitats beyond the District

At the moment the mapping stops at the District boundary. This makes sense in terms of the Project
but it is, obviously, not a boundary that is recognised by Nature. A future iteration of the map will look
at a buffer around the District and consider how the network could link up beyond the boundary12
Changes in the District

The most important aspect of the map is to act as a guide to effect Nature Recovery. The Wilder
Horsham District Project will be working with landowners, communities and partners to try and create
more, bigger and better habitats and more links between them. As these emerge they will also be
mapped showing the progression towards a wilder Horsham District.
Dr Richard Black
Wilder Horsham District
August 2021

11 The B-lines project notes the national importance for bees and other pollinating insects of habitats such as chalk
downland and lowland heath that are found in Horsham District: B-Lines South of England | Buglife
12 Working with neighbouring Councils, organisations and communities will be vital to achieve this.
Wilder Horsham District – August 2021
Figure 5. The first version of Nature recovery network for Horsham.
Wilder Horsham District – August 2021

Appendix 1

References in the National Planning Policy Framework to Nature Recovery Networks

The National Planning Policy Framework contains several paragraphs relating to NRN’s and the
planning system. The key paragraphs are set out below for information. It should be noted that the
government periodically update the NPPF, supporting planning guidance and publish ministerial
statements. The most up to date information will always be available on the government’s website.–2
“Planning policies and decisions should contribute to and enhance the natural and local
environment by:
(d) minimising impacts on and providing net gains for biodiversity, including by establishing
coherent ecological networks that are more resilient to current and future pressures”
Paragraph 174
“Plans should: distinguish between the hierarchy of international, national and locally designated
sites; allocate land with the least environmental or amenity value, where consistent with other policies
in the Framework, take a strategic approach to maintaining and enhancing networks of habitats and
green infrastructure; and plan for the enhancement of natural capital at a catchment or landscape
scale across local authority boundaries.”
Paragraph 175
“To protect and enhance biodiversity and geodiversity, plans should:
(a) Identify, map and safeguard components of local wildlife-rich habitats and wider
ecological networks, in the hierarchy of international, national and locally designated sites
of importance for biodiversity, wildlife corridors and stepping stones that connect them;
and areas identified by national and local partnerships for habitat management,
enhancement, restoration or creation”
Paragraph 179.
The above paragraph includes the following footnote:
“Where areas that are part of the Nature Recovery Network are identified in plans, it may be
appropriate to specify the types of development that may be suitable within them”.


The Wildlife Trusts logo

Great news for nature!

Hi Richard W.,

Yesterday, you may have seen us celebrating a major win for nature!

The Government has listened to you, and the 208,000+ other people, who signed our ‘State of Nature’ petition by promising to make England the first country EVER to put a deadline for nature’s recovery in law.

I wanted to let you know personally about this great news. This promised investment and action could help turn the tide for wildlife after decades of decline. Yesterday’s amendment to the State of Nature Bill should result in more wildlife, and help improve our climate, air, water and wellbeing. 🌳

We would like to say a huge thank you for supporting this campaign and helping ensure nature’s recovery. 


Nikki Williams
Director: Campaigning and Communities
The Wildlife Trusts