Sinnett, Danielle

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UWE Bristol Research Repository

MAXIMISINGBIODIVERSITYDanielle SinnettBPG NOTE 9Best Practice Guidancefor Land RegenerationIntroductionBiodiversity refers to the biological diversity of an area and can be defined as ‘thevariety of plants and animals found on earth, and the place in which they live’(www.sustainable-development.gov.uk). It reflects the variety of species that exist onglobal, national, regional and local scales.The significance of biodiversity is widely publicised, but is often thought of in termsof very specific and vulnerable areas at a global level. For example, the rain forestsof South America, as these affect our food, clothing, medicine, overall environmentand moral conscience, while the biodiversity of a reclaimed or urban area is oftenoverlooked as these sites appear to offer little habitat range or significance.However, brownfield sites often offer a vast resource of rare and protected species(Figure 1) and many have been designated as Sites of Special Scientific Interest(SSSIs) for their nature conservation value (DoE, 1996). Species diversity can also beenhanced by careful habitat placement, creation and management.Overall, recent research has shown that biodiversity is being lost. During the 20thcentury the United Kingdom lost over one hundred species of flora and fauna, andmany more have been significantly reduced in number or habitat range. Reduction inbiodiversity is often a result of a decrease in natural habitats, both in the land areathey occupy and their variety. Habitat loss and fragmentation impacts on the speciesdiversity in the following ways:n Populations are moved into smaller and smaller areas which, ultimately, areunable to support them.n Populations become fragmented so that they become isolated into populationsthat are too small to be self-sustaining.n Areas of habitats are so small that the ‘core area’ decreases to such an extentthat they are influenced by negative edge effects.n Intensive management and a decline in traditional management methods haveled to fewer older trees and less deadwood (www.woodlandtrust.org.uk).Reclaimed and brownfield land provides a valuable resource for counteracting someof these effects by creating new habitats that are sympathetic to surrounding areas,while recognising areas of existing wildlife interest. Woodland establishment is oftencrucial to the success of any attempt to increase biodiversity as a large proportion ofthe United Kingdom’s native wildlife lives in forests and woodlands. By increasing thebiodiversity value of a site, the area can become a valued recreational andeducational resource, in addition to improving the local environment and providing amore sustainable habitat for the future (www.sustainable-development.gov.uk).Figure 1 Common spotted orchids are amongthe plants often found growing on mine waste. BPG NOTE 9 PAGE 2Quantifying existing biodiversity resourcesIt should not always be assumed that because a site comprises brownfield orrestored land it has no ecological value. Many brownfield sites offer habitats that aresuited to species that are unusual in that region; for example, orchids are often foundthriving on the acidic soils produced by mine waste (Figure 1). Prior to any decisionsbeing made regarding the ecological enhancement of a site, the existing species andpotential for species need to be assessed. Initially, a desk-based survey can highlightinformation that may already be available locally, for example from the local recordscentre and local interest groups. Following this a habitat survey should be carriedout by an experienced ecologist. A number of methods exist for carrying outecological surveys, including an Extended Phase I Habitat Survey as set out inGuidelines for baseline ecological assessment (Institute for Environmental ImpactAssessment, 1995). This survey will characterise the site in terms of the habitats andvegetation, including their abundance, age and condition.  It will also provide anindication of the species that may inhabit or visit the site if no physical evidence isobserved (e.g. tracks). If the survey for determining the presence of protected orvaluable species is inconclusive or the presence of a particular species is suspecteda more detailed or targeted ecological survey may be recommended.During the assessment of the ecology present at a site, the following should beconsidered:n Are there any protected habitats or species present at the site or surrounding it?Statutory legislation exists to safeguard protected habitats and species whichneeds to be considered in the planning stages of woodland establishment.n Are there any rare species present at the site or surrounding it? This may includespecies that are not rare on a national scale, but might be locally.If the answer to either of these questions is yes:n What specific characteristics of the site must be retained/enhanced to maintainor encourage migration of populations?n What habitats and species are or were found in the areas surrounding the site?The proposed woodland establishment should complement the local environmentby appropriate landscape design and vegetation species selection.The current ecological value of the site and its surrounding area will be the primarydeciding factor on what actions need to be taken in increasing its biodiversity, inconjunction with the Local Biodiversity Action Plan (LBAP) for that area. If the habitatsurvey indicates that any areas currently support or have the potential to supportrare or unusual species then the site should be managed to ensure these species areencouraged. The following provide guidance on effective management of suchhabitats or species:n Broad Habitat Statements (Jackson, 2000): these give summary descriptions ofthe general habitats found in the UK as well as current issues affecting thesehabitat types and broad policies to counteract them.n Priority Habitat Action Plans: provide more detailed descriptions for specifichabitats; they also give current issues affecting these habitat types and broadpolicies to counteract them.n Action Plans for the specified ‘at risk’ species that have been identified within theUK, including any legislation relating to their protection.n LBAPs highlight the priorities for specific regions to ensure that the needs ofthese areas are met and that they contribute to national targets.All of these resources can be found on www.ukbap.org.ukBPG NOTE 9 PAGE 3Planning to maximise biodiversityThe following general rules, demonstrated in Figure 2, can be applied to increase theoverall biodiversity of an area. They may not all be suitable for every site, particularlyif the habitat survey has highlighted any protected or unusual habitats or species.Habitat location When establishing greenspace on contaminated and brownfield landthe primary objective should be to counteract habitat loss and fragmentation bycreating or enhancing habitats that are representative of semi-natural or naturalhabitats in the surrounding region. The biodiversity of an area will only besignificantly improved, and this improvement sustained, if habitats are created ormanaged to improve the ecological function of the wider landscape (Watts et al.,2005).Habitat shape The shape of habitat areas should be designed so that the size of thecore area is maximised, therefore reducing negative edge impacts. The moreexposed boundaries that exist increase the influence of surrounding areas; this couldinclude physical damage, air pollution or invasion by other species. However, longthin habitats may be suitable, for example along riparian zones or adjacent toestablished habitats that may enhance the site diversity.Figure 2 Habitat size and shape to promote biodiversity (after Diamond, 1975).(a) A small habitat with a small corearea can negatively impact onpopulation viability.(b) Long thin habitats reduce core areaand increase the negative edge effects.(c) Several small habitats withinteracting populations are preferableto one small habitat.(d) A large habitat is preferable to asmall or fragmented habitats.BPG NOTE 9 PAGE 4Habitat size Habitat areas should be large rather than small. The islandbiogeographical theories suggest that larger habitat islands can support a largernumber of species than smaller ones.Habitat linkages Habitat design should complement habitats surrounding the site toprovide linkages both within and off site. This is particularly important if thedeveloper wishes to encourage species to move into a new greenspace from existingwoodland or greenspace areas. For example, ancient woodland is often likely tocontain a rich variety of species that may be encouraged to move into a new area,reducing fragmentation and increasing the sustainability of the population(Spellerberg, 1995). However, landscape function is an important consideration andsites should be developed to ensure that the interactions within and between sitesare appropriate to encourage the desired habitat or species.Habitat types Vegetation species should be varied within an area. Monoculturevegetation provides little biodiversity. The selected species mix can be planted inclumps of single species types, or in mixed clumps; the size of clump and distancesbetween clumps can also be varied (Rodwell and Patterson, 1995). However, it maybe more beneficial to create or manage habitats that have less biodiversity if thosehabitats are rare or ecologically important to a region. Again, when choosing whichspecies to plant on a site the surrounding ecology should be taken into consideration.Information on species selection for specific site characteristics is available from theROOTS software package.Habitat management The encouragement of ground vegetation will also providehabitats for a wide range of species. This can be achieved by minimising herbicideapplications and, where possible, weeding by hand of undesirable species, andplanting a mix of coniferous and broadleaved species as conifers reduce the pH of thesoil. Any such encouragement of ground vegetation should be made withoutcompromising tree growth or establishment.  Species diversity is often considered tobe higher in areas where soils have a low nutrient status, so fertiliser applicationsshould be kept to a minimum. Further information on fertiliser use can be found inBPG Note 7: Fertiliser application in land regeneration.Forest Research is currently developing a suite of Biological and EnvironmentalEvaluation Tools for Landscape Ecology (BEETLE). These tools aim to provide ameans of assessing existing and predicting future landscape structure and functionwithin a region, enabling the user to ensure that any new habitat creation ormanagement will reduce fragmentation. Further information on the development andapplication of landscape ecology tools is available atwww.forestresearch.go.uk/landscapeecologyIn order to monitor the success of any management programme or vegetationestablishment on a site a Phase I Habitat Survey should be completed periodically.This will ensure that the site management is having the desired effect on habitatdevelopment and species enhancement. It will also highlight any changes that mayneed to be made to the existing management plan to enhance species response orencompass new priorities.Most brownfield and contaminated sites used for greenspace establishment will haveseveral end-users. These may include educational, community or local interestgroups and individual members of the public in addition to the wildlife inhabitants ofthe site. With careful consideration of each user’s requirements and appropriateplanning, these sites can offer a multifunctional resource encompassing ecological,social, archaeological and environmental benefits.The Land Regeneration and Urban Greening Research GroupForest Research, Alice Holt Lodge, Farnham, Surrey  GU10 4LHPhone: +44 (0) 1420 22255      Fax: +44 (0) 1420 520180      E-mail: landrec@forestry.gsi.gov.ukWebsite: www.forestresearch.gov.ukReferencesDepartment of the Environment (1996).Reclamation of damaged land for natureconservation. HMSO, London.Diamond, J.M. (1975). The island dilemma:lessons of modern biogeographic studies forthe design of nature reserves. BiologicalConservation 7, 129–146.Institute for Environmental ImpactAssessment (1995). Guidelines for baselineecological impact assessment. E. and F. Spon,London.Jackson, D.L. (2000). Guidance on theinterpretation of the Biodiversity Broad HabitatClassification (terrestrial and freshwater types):definitions and the relationship with otherhabitat classifications. JNCC Report No. 307.JNCC, Peterborough.Rodwell, J.S. and Patterson, G.S. (1995).Vegetation classification systems as an aid towoodland creation. In: The ecology ofwoodland creation, ed. R. Ferris-Khan. Wiley,Chichester, 63–74.Spellerberg, I.F. (1995). Biogeography andwoodland design. In: The ecology of woodlandcreation, ed. R. Ferris-Khan. Wiley,Chichester, 49–62.Watts, K., Humphrey, J.W., Griffiths, M.,Quine, C. and Ray, D. 2005. Evaluatingbiodiversity in fragmented landscapes:Principles. Forestry Commission InformationNote. Forestry Commission, Edinburgh.Useful linkswww.forestresearch.go.uk/landscapeecologywww.roots-software.co.ukwww.sustainable-development.gov.ukwww.ukbap.org.ukwww.woodlandtrust.org.uk© Crown copyright 2006

Best Practice Guidance for Land Regeneration Note 9: Maximising biodiversity

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Best Practice Guidance for Land Regeneration Note 9: Maximising biodiversity

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