Memorandum submitted by the Royal Horticultural
Society
SUMMARY
— The Royal Horticultural Society makes
this submission as the principal gardening charity in the UK which
has a significant leadership position on biodiversity in gardens.
— Urban land covers 11% of England
and gardens are the point where most of the population have close
contact and interaction with biodiversity.
— The inclusion of gardens in Biodiversity
Action Plans would begin to acknowledge the significant contribution
that gardens collectively make to biodiversity and would engage
the much more of the population in the biodiversity debate and
its conservation.
— The Invasive Non-native Species Framework
Strategy may not be sufficient to conserve biodiversity as it
does not embrace the considerable threat posed by the introduction
of as yet unidentified alien plant diseases and pests that could
devastate natural and cultivated habitats.
— The positive role that gardens and
associated green space in urban developments can make to limiting
biodiversity loss should be given greater attention
— Gardens are themselves collections
of considerable plant biodiversity that has been brought together
from around the world.
The following are the key points the Royal Horticultural
Society wishes to draw to the attention of the Environmental Audit
Committee:
1. The Royal Horticultural Society (RHS) is the
principal gardening charity in the UK with 370,000 members, with
the purpose of "the encouragement and improvement of the
science, art and practice of horticulture in all its branches".
The influence of the RHS extends far beyond its membership with
acknowledged leading and authoritative gardening publications,
including RHS Online; a range of national Flower Shows, including
Chelsea, that set the agenda for British horticulture, and four
gardens around the country that attract over one million visitors
per year.
2. The RHS has identified the biodiversity of
gardens and the urban managed environment to be of major significance.
The RHS is developing a leadership position on the role of gardens
in the delivery of UK biodiversity objectives. The RHS therefore
welcomes the opportunity to submit a memorandum to the Environmental
Audit Committee setting out its views on the loss of biodiversity.
3. The recent Natural England report "State
of the Natural Environment 2008" (Natural England, 2008)
acknowledged the significance of urban areas and gardens in particular
in maintaining biodiversity in urban spaces. Gardens and urban
spaces are particularly important as they are the place where
most people have close contact with biodiversity.
4. The UK is a densely populated and urbanised
country with approximately 11% of land cover in England being
urban. In urban areas, private gardens can represent 36-47% of
green space (Gaston et al. 2005), but are seldom considered fully
in strategies for urban biodiversity conservation. Beyond the
urban fringe, gardens can offer equally valuable habitat diversity
in a largely agricultural landscape. The Government's commitment
to halting biodiversity loss by 2010, and addressing biodiversity
concerns in an increasingly urbanised environment, should take
full account of the contribution that the country's 14 million
gardeners can make both individually and collectively.
5. Private gardens are characterised by a mixture
of native and non-native plants. Non-native garden plants make
an important contribution to biodiversity. Eighty seven percent
of non-native species in the average garden belong to native families
and 50% to native genera (Smith et al., 2006) and up to a third
of all UK invertebrate species visited a single garden in Leicester
over a 15 year period (Owen, 1991). The RHS conference, "Gardens—Heaven
or Hell for Wildlife?" in 2003, supported by the RSPB and
Wildlife Trusts, demonstrated the strength of consensus on the
important contribution gardens make to biodiversity. The results
of a major study of garden biodiversity, the BUGS project, done
by the University of Sheffield, funded by the Natural Environmental
Research Council (NERC) reinforced this view.
6. Gardeners can contribute significantly to
the conservation of biodiversity in their own gardens, and to
our understanding of biodiversity at a local level. The RHS has
an active partnership with the Wildlife Trusts in the joint website
(www.WildAboutGardens.org.uk) to engage gardeners and solicit
observations of their garden wildlife. The online project has
given rise to two successful books (Anon., 2006, 2007).
7. The RHS encourages gardening with wildlife
in mind, to develop an understanding and appreciation of biodiversity
in the garden, and to represent gardeners' interests in biodiversity.
8. The RHS team of scientists based at the RHS
Garden Wisley, maintain a diagnostic service to our members that
provides valuable information on plant and animal diversity in
UK gardens. Additionally, the advisory service to members identifies
pests and diseases from gardens and makes recommendations for
control. This service provides a national strategic function in
also monitoring the introduction and spread of alien and quarantine
plant pests and disease in the UK. The RHS works closely with
the Plant Health and Seeds Inspectorate and the Defra Central
Science Laboratory to deliver this function.
9. The RHS is doubtful whether the Invasive Non-native
Species Framework Strategy will prove fully effective in conserving
biodiversity in part due to its limited focus on invasive plants
and larger animals. It excludes plant pests and diseases as these
are addressed in Plant Health regulations. A report commissioned
by the RHS has identified a serious threat to biodiversity at
the confluence of these strategies and regulations. Plant health
regulations only cover known threats ie named species of invertebrate
or pathogen. The ever increasing international trade in garden
plants is introducing new, previously unidentified pests and diseases
into the UK. Should these alien species "escape" onto
our native flora considerable damage could result as demonstrated
by the epidemic of Dutch elm disease in the 1970s.
10. In the view of the RHS the UK Biodiversity
Action Plan fails to represent gardens adequately as private and
public gardens are not identified clearly as part of the "UK's
biological resources" and therefore not highlighted for protection.
We believe that gardens need recognition for the important contribution
they make to biodiversity and require nationwide protection.
11. Current threats to gardens and their associated
biodiversity are numerous and significant. These all have the
effect of reducing garden size which in turn reduces the diversity
of habitats that can be found in gardens. Diversity of habitats
in the garden is central to an overall higher biodiversity. The
key planning policies leading to reduced garden size include the
new housing targets, existing gardens categorised as brown-field
sites and therefore a priority for building development, trends
in hard-landscaping (especially for purposes of parking cars)
and the loss of trees due to house insurance company stipulations.
12. The RHS considers guidelines encouraging
development on brownfield sites risk damaging biodiversity. This
is for two reasons. Firstly, brownfield sites can be of biodiversity
import in their own right—eg the case of the Black Redstart
(bird) in London wasteland. Secondly, if gardens continue to have
brownfield designation then their loss and fragmentation is very
detrimental to biodiversity. The diversity of habitats within
an average garden is not sufficiently compensated for by the replacement
with smaller gardens or communal open space.
13. Where climate change impacts on habitat loss
(eg coastal erosion, pond and wetland loss, decline in beech woodland
in the south) and where flora or fauna are not able to migrate
to more suitable habitats, gardens will become increasingly important
in providing habitat refuges. Local initiatives may be taken by
gardeners to help support threatened species. Garden habitats
that are particularly useful in this regard include trees, ponds
and the inclusion of vegetation with a diversity of structure.
There are indications that non-native plants are of significant
benefit to wildlife and a joint research project into the effect
of natives and non-natives on biodiversity is being initiated
by the RHS and other members of the Wildlife Gardening Forum.
14. Current legislative measures affecting gardens
are largely due to drivers such as flood reduction rather than
biodiversity and are insufficient.
15. Planning policy does not adequately protect
biodiversity in gardens. Trees may receive some protection if
they meet Tree Protection Order requirements but by and large
garden trees, ponds and other vegetation have little protection.
16. Government plans for housing growth need
to take more account of the collective contribution the associated
gardens and green space could make to biodiversity. The appropriate
structuring and management of these spaces could do much to limit
the loss of biodiversity. As currently constituted, new gardens
are not a replacement for greenbelt.
17. Local Biodiversity Action Plans rarely identify
gardens as areas of importance or action. This omission needs
redressing and organisations such as the RHS are ideally positioned
to co-ordinate and educate gardeners on the importance of managing
gardens for biodiversity.
18. Gardens are themselves collections of considerable
plant biodiversity. Historically plant collectors have brought
plants from all corners of the world to the UK where they have
been propagated and cultivated. Some garden collections preserve
biodiversity that is under threat elsewhere in the world.
REFERENCES
Anon. (2006) Wildlife Gardening for Everyone,
Think Books, ISBN 1845250168
Anon (2007) Birds in your Garden, Think Books,
ISBN 9781845250447
Gaston, K J, Warren, P H, Thompson, K and Smith,
R M. (2005) Urban domestic gardens (IV): the extent of the resource
and its associated features. Biological Conservation 14,
3327-3349.
Natural England 2008 State of the Natural Environment
2008.
Owen, J. (1991) The ecology of a garden: the first
fifteen years. Cambridge University Press, pp 403.
Smith, R M, Thompson, K, Hodgson, J G, Warren, P
H and Gaston, K J. (2006) Urban domestic gardens IX: Composition
and richness of the vascular plant flora, and implications for
native biodiversity. Biological Conservation 129, 312-322.
2 June 2008
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