Select Committee on Environmental Audit Written Evidence


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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