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Journal of Applied Ecology 2003 40, 413 – 421

METHODOLOGICAL INSIGHTS

Blackwell Publishing Ltd.

Conservation strategy maps: a tool to facilitate biodiversity action planning illustrated using the heath fritillary butterfly G. J. HOLLOWAY*, G. H. GRIFFITHS† and P. RICHARDSON* Centre for Wildlife Assessment and Conservation, *School of Animal and Microbial Sciences and †The Department of Geography, The University of Reading, Whiteknights, PO Box 228, Reading RG6 6AJ, UK

Summary 1. The UK Biodiversity Action Plan (UKBAP) identifies invertebrate species in danger of national extinction. For many of these species, targets for recovery specify the number of populations that should exist by a specific future date but offer no procedure to plan strategically to achieve the target for any species. 2. Here we describe techniques based upon geographic information systems (GIS) that produce conservation strategy maps (CSM) to assist with achieving recovery targets based on all available and relevant information. 3. The heath fritillary Mellicta athalia is a UKBAP species used here to illustrate the use of CSM. A phase 1 habitat survey was used to identify habitat polygons across the county of Kent, UK. These were systematically filtered using relevant habitat, botanical and autecological data to identify seven types of polygon, including those with extant colonies or in the vicinity of extant colonies, areas managed for conservation but without colonies, and polygons that had the appropriate habitat structure and may therefore be suitable for reintroduction. 4. Five clusters of polygons of interest were found across the study area. The CSM of two of them are illustrated here: the Blean Wood complex, which contains the existing colonies of heath fritillary in Kent, and the Orlestone Forest complex, which offers opportunities for reintroduction. 5. Synthesis and applications. Although the CSM concept is illustrated here for the UK, we suggest that CSM could be part of species conservation programmes throughout the world. CSM are dynamic and should be stored in electronic format, preferably on the world-wide web, so that they can be easily viewed and updated. CSM can be used to illustrate opportunities and to develop strategies with scientists and non-scientists, enabling the engagement of all communities in a conservation programme. CSM for different years can be presented to illustrate the progress of a plan or to provide continuous feedback on how a field scenario develops. Key-words: GIS, invertebrate conservation, local community, Mellicta athalia, UKBAP. Journal of Applied Ecology (2003) 40, 413–421

Introduction Many species of plants and animals have declined across the world in recent years due to a variety of

© 2003 British Ecological Society

Correspondence: Dr G. J. Holloway, Centre for Wildlife Assessment and Conservation, School of Animal and Microbial Sciences, The University of Reading, Whiteknights, PO Box 228, Reading RG6 6AJ, UK (fax +118 9310180; e-mail [email protected]).

factors, including agricultural intensification, changes in land use, habitat loss and fragmentation (New 1997; Lande 1998). As a result and also as a response to their commitment to Article 6a of the Convention on Biological Diversity formulated at the 1992 Rio Earth Summit, the UK government published the UK Biodiversity Action Plan (UKBAP) (DOE 1995). The plan lists declining or scarce species, principally invertebrates, and for many a target for recovery is described. Currently, much invertebrate conservation is carried

414 G. J. Holloway, G. H. Griffiths & P. Richardson

© 2003 British Ecological Society, Journal of Applied Ecology, 40, 413–421

out in an ad hoc and piecemeal manner in north-west Europe. On some other continents, for example Africa, South America and Asia, invertebrates are given low conservation status and invertebrate conservation is poorly resourced. Habitat management, where it occurs, may be carried out at a very local level in a manner determined by a single individual, often an ecologist with specialist knowledge. There is currently no system that facilitates dialogue between ecologists and nonecologists about the best procedure to follow to enhance the prospects of a species. The method described in this paper, using the example of the heath fritillary Mellicta athalia (Rott.) in Kent, UK, provides a spatial tool for identifying and mapping potential sites for the recolonization and reintroduction of the species. The heath fritillary M. athalia is listed as vulnerable in the UK Red Data Book (Wells, Pyle & Collins 1983) and is fully protected under Schedule 5 of the Wildlife and Countryside Act 1981. In the UK M. athalia is a butterfly species of open coppiced broadleaf woodland (Warren 1987a; Asher et al. 2001). However, with the decline of coppicing, the number of suitable patches has been reduced substantially. Before 1910 the butterfly was recorded in at least 58 10-km grid squares (Barnett & Warren 1995; Asher et al. 2001). By 1980 its distribution had reduced to just six 10-km squares containing 31 colonies in Kent, Essex and south-west England, colonies being defined as groups of probable breeding insects separated by more than 300 m (Asher et al. 2001). For many of the species listed in the UKBAP, individual species action plans have been devised outlining local or national targets. The heath fritillary action plan focuses on the Kent population, where there has been a reduction from 25 to 18 colonies over the last 20 years (Asher et al. 2001). The target is to return to 25 colonies of variable size in Kent by 2005. Furthermore, these colonies should be interconnected through natural dispersal because M. athalia is thought to exist in metapopulations (Hanski 1999; Baguette, Petit & Quéva 2000; Cowley et al. 2000; Bergman 2001) as a result of the ephemeral nature of its preferred habitat (Warren 1987b). However, no study has been carried out to investigate the feasibility of this target in the face of changes in landscape and ownership that might have occurred over the last few decades. The current study was carried out to determine the validity of this target and to identify possible sites for reintroduction using geographical information system (GIS) data from the Kent phase 1 habitat survey, distribution maps of plants of open woodland (including common cow wheat Melampyrum pratense L., the principal food plant of the Kent heath fritillary populations) and the known distribution of sites of breeding heath fritillaries. Although the study concentrated on the heath fritillary, a much more general goal was to develop a tool that could be used to plan strategically the implementation of species recovery programmes to achieve the targets specified. In particular, the procedure presented may have considerable value in countries

where species conservation is gaining in priority and where engagement of the local community in a conservation programme is a real possibility.

Materials and methods The Kent phase 1 habitat survey (Nature Conservancy Council 1990) contains 63 244 polygons of varying sizes corresponding to 137 habitat categories. The data were viewed using Arcview GIS, v. 3.1 (ESRI) and filtered to leave only those habitat types known to contain at least some elements required by M. athalia. For example, habitats such as saltmarsh or reedbeds were eliminated. The 38 remaining categories (essentially woodlands, grasslands and heathlands) were then assessed for their potential suitability based on published data on the ecology of M. athalia (see Appendix 1). Broadleaved woodland often containing areas of grassland, grassland sometimes with bracken, scrub or scattered trees, and heathlands are all types of habitats that M. athalia will use. All of these habitat types were ranked 1. Other types of habitats also included in these 38 categories were coniferous woodlands and dense continuous scrub. They were both considered to be barrier habitats (rank 0), as were unknown categories for example continuous bracken and recently felled woodland (rank 0). These latter categories were included in a category ‘unknown’ because information on their future use was not available and it was not possible to determine potential suitability for M. athalia. The number of polygons used in the study was further reduced by selecting a study area grid of 42 × 38 km (21 by 19 2 × 2-km tetrads) to include all large woodland complexes up to 35 km away from the Blean Wood complex, which is the focus of the heath fritillary population in Kent. The rationale was that the species action plan target is to produce 25 interconnected colonies. Because M. athalia individuals do not generally disperse more than 150 m (Warren 1987b) and all of the Kent populations are in or around Blean, the area covered by the grid would easily encompass the 25 habitat patches likely to contain the colonies to achieve this target (Fig. 1). The final study area contained 19 121 polygons of 38 categories. During July 1999, visits were made to Blean Wood to assess the current distribution of breeding M. athalia. In addition, it was established which of the relevant polygons (i.e. woodlands, grasslands and heathlands) were managed for wildlife (i.e. nature reserves). This information was entered for each polygon as binary data. The 1999 distribution of M. athalia was digitized onto the study area using binary (presence/absence) data entry into the grid database. From site visits and available literature the following 12 plant species were identified as being associated with the Kentish M. athalia colonies: pendunculate oak Quercus robur L., sweet chestnut Castanea sativa Mill., hornbeam Carpinus betulus L., bramble Rubus fructicosus L. agg., bracken Pteridium aquilinum (L.) Kuhn, heather Calluna vulgaris (L.) Hull, honeysuckle

415 Conservation strategy maps

Fig. 1. Study area and edited Kent phase 1 habitat survey data showing locations of the five areas identified as significant or potentially significant for the conservation of the heath fritillary Mellicta athalia. The orange tetrads refer to high priority (containing two to four indicator plant species) and the yellow low priority (containing one indicator plant species) tetrads (see text) containing cow wheat Melampyrum pratense. The coloured polygons are those falling into the categories defined in Table 1 and displayed in detail in Fig. 2. The grid contains squares measuring 2 × 2 km.


Lonicera periclymenum L., common cow wheat Melampyrum pratense L., tormentil Potentilla erecta (L.) Raeusch., wood sage Teucrium scorodonia L., foxglove Digitalis purpurea L. and black grass Alopercus myosuroides Huds. Distribution of these plant species was obtained from Philp (1982) and digitized using binary data entry (presence = 1, absence = 0) into the study area grid. The binary plant distribution data were subjected to cross-tabulated Fisher’s exact test (SPSS statistical software) with the M. athalia presence/absence binary data. Five plant species were found to correlate significantly (at least P < 0·005) with M. athalia distribution, one of which, Melampyrum pratense, is the primary food plant for Kent M. athalia (all tetrads containing M. athalia also contained Melampyrum pratense). All tetrads not scoring positively for Melampyrum pratense were ignored. The remaining four correlating species (Potentilla erecta, Calluna vulgaris, Teucrium scorodonia and Alopercus myosuroides) were considered to be indicator species. Tetrads containing Melampyrum pratense were then ranked according to the number of indicator species present. Those containing 0 or 1 indicator species were labelled ‘low priority tetrads’ for M. athalia habitat while those containing 2, 3 or 4 indicator species were labelled as ‘high priority tetrads’. The modified Melampyrum pratense distribution map was then overlaid onto the study grid. Polygons within high priority tetrads were selected and arranged into seven different categories of potentially suitable habitat for M. athalia for recolonization or reintroduction based on their attributes (Table 1). All polygons

falling within the seven categories were either broadleaved or mixed woodland, coppiced (although the rotation of coppice was unknown) and at least 5 ha in size. The smallest polygon containing an extant colony was 6·58 ha, although the butterflies may not have been utilizing all of this area. Polygons within high priority tetrads not conforming to these criteria were deemed unsuitable for heath fritillaries. An important factor was the distance separating colonies. Mellicta athalia is not a strong flyer and rarely moves more than 100 m (Warren 1987b) although sites 600 m removed from existing populations can be colonized over a long period of time (Warren 1987b). For this reason sites separated by 150 m or less were considered more likely to be colonized naturally than those separated by greater distances.

Results Of the 12 plant species investigated, the distributions of only five correlated with the distribution of M. athalia in Kent: Melampyrum pratense (P < 0·001), Potentilla erecta (P < 0·001), Calluna vulgaris (P < 0·001), Teucrium scorodonia (P = 0·001) and Alopercus myosuroides (P = 0·002). Of the 74 tetrads containing Melampyrum pratense, 52 were classified as high priority and 22 were classified as low priority. Within the 52 high priority tetrads, 110 polygons matched the criteria described in Table 1. The polygons were clustered around five sites (Fig. 1 and Table 2). All of the category 1, 2 and 3 polygons (31 in all) occurred in and around the Blean Wood complex (Fig. 1) because in Kent it is here that


Table 1. Polygon categories of suitability within high priority tetrads (see text) for the reintroduction or recolonization of the heath fritillary Mellicta athalia in Kent Category

Polygon criteria for selection

1. Occupied polygons

Containing extant M. athalia colonies (all category 1 polygons also exhibited the following criteria: broadleaved or mixed woodland, managed for conservation, coppiced, minimum area 6·58 ha)

2. Recolonization

Broadleaved or mixed woodland Coppiced < 150 m from at least one category 1 polygon Not separated from category 1 polygon by barrier Minimum area 5 ha unless part of larger complex

3. Recolonization

As for category 2 polygon except: < 150 m from at least one category 2 polygon Not separated from category 2 polygon by barrier

4. Reintroduction

Broadleaved or mixed woodland Managed for conservation Coppiced Minimum area 5 ha unless part of larger complex

5. Colonization from reintroduction

Broadleaved or mixed woodland Coppiced < 150 m from at least one category 4 polygon Not separated from category 4 polygon by barrier Minimum area 5 ha

6. Colonization from reintroduction

As for category 5 polygon except: < 150 m from at least one category 5 polygon Not separated from category 5 polygon by barrier

7. Reintroduction

Broadleaved or mixed woodland Coppiced Minimum area 5 ha unless part of larger complex

Table 2. The five areas in Kent containing polygons matching one of the seven categories listed in Table 1 and the distribution of numbers of categories in each area Category


Area

Grid reference

1

2

3

4

5

6

7

Total

Blean Wood complex Orlestone Forest complex Gribble and Wattle Woods complex Gorsley and Covert Woods complex Outlying, unconnected woodlands around Longbeech Wood

TR 11 60 TQ 99 37 TQ 86 35 TR 17 51 TQ 98 58

14

12

5

2 6 1

3 1

5

16 12

49 26 2 19 14

M. athalia breeds. Beyond Blean, 26 polygons of interest were located in the Orlestone Forest complex. The Gribble and Wattle Woods complex scored only two polygons, one each of category 4 and 5. Of the remaining 33 polygons located in the Gorsley and Covert Woods complex and around Longbeech, 32 of them fell into category 7, the one remaining being category 4 located at Longbeech. The polygons containing extant colonies of heath fritillary in the Blean Wood complex can be seen easily from the conservation strategy maps (CSM) (Fig. 2a) and the positions of these polygons relative to other high priority polygons as categorized in Table 1 are apparent. No colonies of heath fritillary are currently found in the Orlestone Forest, but with so many category 4, 5 and 6 polygons identified this complex has clear potential as a reintroduction site (Fig. 2b).

1

19 13

Discussion Many species action plans in the UK, in particular for invertebrates, lack ecological information, especially in relation to the distribution of former and current populations and suitable habitats. It is essential that where such information is available as much as possible is utilized during the development of species recovery programmes. The heath fritillary is a species for which we have a relatively large amount of ecological data so that the types of habitat management required by the species are reasonably well understood. What is lacking is the integration of such ecological data with landscape information and the distribution of other factors, such as food plants, to establish the opportunities that might be available, both now and in the future, to formulate feasible targets. The M. athalia species action plan aims


Fig. 2. Conservation strategy maps (CSM) for the heath fritillary Mellicta athalia in the (a) Blean Wood and (b) Orlestone Forest complexes, Kent, UK. The orange tetrads refer to high priority (containing two to four indicator plant species) and the yellow low priority (containing one indicator plant species) tetrads (see text) containing cow wheat Melampyrum pratense. White tetrads refer to those not containing cow wheat (category 2 in polygrid.shp legend). Grey polygons (category 0 in Kent.shp legend) identify habitat types not conforming to the ecological requirements of the heath fritillary or which fall wholly outside high priority tetrads. All seven polygon categories (Table 1) are illustrated in the CSM. The individual squares measure 2 × 2 km.


to establish 25 colonies in Kent by 2005. The rationale behind this target is that there were 25 colonies in Kent prior to 1980, but this approach to setting targets looks to the past rather than the future. It is likely that a variety of changes have occurred since 1980 that have contributed to the decline of M. athalia, so the aim to recreate a pre-1980 scenario may be inappropriate. The past distribution of colonies may nevertheless be useful.

In the present study, an attempt was made to integrate information from various sources using GIS to identify the potential number and distribution of suitable sites for M. athalia in Kent. The study demonstrated that the target of 25 colonies is feasible, possibly even conservative. For example, in the Blean Wood complex (Fig. 2a) 14 polygons currently contain colonies representing 775 ha while a further 17 polygons were placed into categories 2 or 3 (i.e. that could become



colonized naturally) accounting for a further 593 ha. In addition, a further 18 sites were identified as suitable for reintroduction. Within the Blean Wood complex alone, it would appear that there is more than enough potential to achieve the UKBAP target for the heath fritillary. By identifying potentially suitable sites, the procedure developed here provides an invaluable aid to establishing a priority list for allocating effort and funds. There is currently no system available that enables UKBAP target plans to be developed strategically and that can be used to demonstrate progress towards a recovery target. We propose that maps produced in this way should be called CSM. Having identified and categorized sites of potential importance, it would still be necessary to carry out field survey work to determine their value and to validate the information offered by the CSM. The study picked out the Orlestone Forest complex (Figs 1 and 2b) as an area that could be suitable to establish completely new colonies, particularly because some sites are already managed for wildlife. While the area cannot be considered a priority at present as it is approximately 27 km south of the nearest extant colony, this information indicates which sites might be targeted should future heath fritillary action plans include the establishment of completely new populations. Twenty-six polygons of potential value were noted in the Orlestone area. If one or more colonies could be established in the category 4 polygons, it is possible that some of the category 5 and 6 polygons could be colonized through natural expansion (note that a category 4 polygon once colonized becomes a category 1 polygon, and category 5 and 6 polygons then become category 2 and 3 polygons, respectively). CSM could be developed for a wide range of other species, in particular invertebrate species. However, the accuracy of a CSM is very dependent on the quality of the input data and the assumptions made. The more scientific information available on a species, the less subjective the decisions need to be about what the CSM should include. In this case the distribution of M. athalia is very well known and the Kent phase 1 habitat survey was completed only recently. However, the data on plant distributions were collected prior to 1980 and are coarse (presence or absence within each 2 × 2-km tetrad) compared with the other data sets. It is possible, therefore, that the distribution of one or more of the indicator plant species identified could have changed over the last two decades within Kent. The availability of up-to-date distribution maps may have produced different numbers of high priority tetrads and thus affected the conclusions. However, as it would be essential to carry out survey work to verify the conclusions of each species-specific map, most anomalies would be discovered at that stage. The production of CSM as a conservation tool has several advantages over ad hoc procedures. A CSM offers the opportunity to bundle together all information about a single species, irrespective of the source of

the data, and package it into a single, easily understood map. Once a CSM has been produced it can be used to identify shortcomings in one or more data sets and effort and resources can be targeted to improve the quality of the information. As new data become available they can be input to refine the CSM. For example, the quality of the heath fritillary CSM produced here could benefit from new surveys of Melampyrum pratense and the four indicator species. Resources could also be targeted towards the areas identified as most likely to be of current and future interest rather than spreading this effort too thinly across the county as a whole. Another important element is the distance that individual butterflies are able to move to recolonize suitable patches. A concerted effort could be made to gather data on dispersal rates and distances to add to that produced by Warren (1987b). Changing the threshold applied here from 150 m to say 300 m would change the appearance of the CSM considerably. Not all individuals influencing the conservation status of a particular species may have detailed knowledge of that species. A CSM provides a means of presenting all of the relevant information, no matter how complex or from which source, to a diverse audience as a single, easily visualized and understood map. A great deal of information may be known about a species but this is often only retained by the one person who has been working in the field on this species for many years. However, if this information is integrated into the CSM it can be made widely available and changed or upgraded as required. Two of the most important features of CSM are the ease with which the maps can be updated and the potential to engage stakeholders in a conservation programme. To illustrate this consider a hypothetical scenario focusing on the northern part of the heath fritillary CSM shown in Fig. 2a. Figure 3 shows the northern part of the CSM with the uncategorized (grey) polygons removed along with tetrad coloration to enable the changes to be seen more easily. Following open discussion it might be concluded that more information is needed on the distance that the butterflies disperse and the current cow wheat distribution for the CSM. The current CSM, including work to be carried out plus any other relevant information, for example the number of existing colonies, could be put onto a web site (Fig. 3a). Volunteers under the guidance of scientists could collect the data to update the CSM. The importance of involving the local community in conservation programmes cannot be overstated (Calheiros, Seidl & Ferreira 2000). A second meeting the following year would be required to assess how work had influenced the potential of the landscape for the heath fritillary (Fig. 3b). Polygons found not to contain cow wheat are now represented as grey polygons. Areas could be selected for management work (category 2 polygon labelled X) from the updated CSM along with a justification for this decision. Following



Fig. 3. Hypothetical scenario illustrating how the northern part of the heath fritillary Mellicta athalia CSM shown in Fig. 2a might change from (a) the present day situation, which highlights scientific work that needs to be carried out, to (b) the following year after the work has been completed and the CSM updated, highlighting where the management work is to be carried out during the next winter period, and (c) the CSM updated following establishment of a new colony, highlighting where management work is to be carried out during the next winter period. The uncategorized polygons (grey) in Fig. 2a along with the tetrad colours have been omitted to enhance clarity. The polygon colours refer to their category (Table 1): brown = category 1, red = category 2, pink = category 3, green = category 7.



habitat management, the CSM may change (Fig. 3c) and another meeting would be required to discuss management options for the third year, and so on. The system would allow continual feedback highlighting how the efforts of volunteers have altered the potential of the landscape for the species in question, thus maintaining motivation. The whole process becomes very transparent and accessible. A CSM consists of a series of layers of information. In some cases more than one species of interest might occupy the same area. If CSM have been produced for each species it would be possible to overlay the two (or more) CSM. This approach could be used to highlight ‘hotspots’ for the species that require special attention. On the other hand, the species may have contrasting requirements and what is good management for one species may be less beneficial for another species. A multiple CSM could identify areas that should be managed sensitively (or not at all) to avoid harming one or other of the species. In principle, a CSM could be produced for every UKBAP species and many similarly threatened species beyond the UK. A large number of appropriate data sets are already available, for example on soil type, drainage characteristics, waterways, roads and habitat characteristics. To illustrate the procedure, the Kent phase 1 habitat survey was used here. Phase 1 is not available for all counties, but other sources of data could be used, including the new Satellite Land Cover Map 2000 available from the Centre for Ecology and Hydrology, UK. As new information becomes available it should be easy to modify an existing CSM by adding a new layer of information or by modifying a threshold value (e.g. maximum dispersal distance). For many invertebrate species very little is known and the CSM may consist of little more than one or two layers of information, but these CSM provide important baseline information to upgrade when new data become available. Reasonable amounts of ecological information are already available for other invertebrate species. These are mainly butterfly species, such as the adonis blue Lysandra bellargus (Thomas 1989; Rusterholz & Erhardt 2000; Asher et al. 2001) and the silver-spotted skipper Hesperia comma (Thomas & Jones 1993; Hill, Thomas & Lewis 1996; Asher et al. 2001; Thomas et al. 2001), for which autecological information and distribution data are available (Asher et al. 2001). To utilize fully the dynamic capacity of CSM, it will be necessary to make them available in electronic format. For each UKBAP species there could be a link from the web page to CSM, which could take the reader to local, regional or national CSM. Each CSM could be updated every few years so that progress towards meeting targets could be seen easily and changing opportunities for conservation in the field could be assessed.

References Asher, J., Warren, M., Fox, R., Harding, P., Jeffcoate, G. & Jeffcoate, S. (2001) The Millennium Atlas of Butterflies in Britain and Ireland. Oxford University Press, Oxford, UK. Baguette, M., Petit, S. & Quéva, F. (2000) Population structure and migration of three butterfly species within the same habitat network: consequences for conservation. Journal of Applied Ecology, 37, 100 –108. Barnett, L.K. & Warren, M.S. (1995) Species Action Plan: Heath Fritillary Mellicta athalia. Butterfly Conservation, Wareham, UK. Bergman, K.-O. (2001) Population dynamics and the importance of habitat management for conservation of the butterfly Lopinga achine. Journal of Applied Ecology, 38, 1303–1313. Calheiros, D.E., Seidl, A.F. & Ferreira, C.J.A. (2000) Participatory research methods in environmental science: local and scientific knowledge of a limnological phenomenon in the Pantanal wetland of Brazil. Journal of Applied Ecology, 37, 684 – 696. Cowley, M.J.R., Wilson, R.J., Léon-Cortés, J.L., Guitiérrez, D., Bulman, C.R. & Thomas, C.D. (2000) Habitat-based statistical models for predicting the spatial distribution of butterflies and day-flying moths in a fragmented landscape. Journal of Applied Ecology, 37, 60 –72. DOE (1995) Biodiversity: the Steering Group Report. HMSO, London, UK. Hanski, I. (1999) Metapopulation Ecology. Oxford University Press, Oxford, UK. Hill, J.K., Thomas, C.D. & Lewis, O.T. (1996) Effects of patch size and isolation on dispersal by Hesperia comma butterflies: implications for metapopulation structure. Journal of Animal Ecology, 65, 725 –735. Lande, R. (1998) Anthropogenic, ecological and genetic factors in extinction. Conservation in a Changing World (eds G.M. Mace, A. Balmford & J.R. Ginsberg), pp. 29–52. Cambridge University Press, Cambridge, UK. Nature Conservancy Council (1990) Handbook for Phase 1 Habitat Survey – A Technique for Environmental Audit. NCC, Peterborough, UK. New, T.R. (1997) Butterfly Conservation, 2nd edn. Oxford University Press, Oxford, UK. Philp, E.G. (1982) Atlas of the Kent Flora. The Kent Field Club, Canterbury, UK. Rusterholz, H.-P. & Erhardt, A. (2000) Can nectar properties explain sex-specific flower differences in the Adonis Blue butterfly Lysandra bellargus ? Ecological Entomology, 25, 81–90. Thomas, J.A. (1989) Ecological lessons from the reintroduction of Lepidoptera. Entomologist, 108, 56 – 68. Thomas, C.D. & Jones, T.M. (1993) Partial recovery of a skipper butterfly (Hesperia comma) from population refuges: lessons for conservation in a fragmented landscape. Journal of Animal Ecology, 62, 472– 481. Thomas, C.D., Bodsworth, E.J., Wilson, R.J., Simmons, A.D., Davies, Z.G., Musche, M. & Conradt, L. (2001) Ecological and evolutionary processes at expanding range margins. Nature London, 411, 577–581. Warren, M.S. (1987a) The ecology and conservation of the heath fritillary, Mellicta athalia. I. Host selection and phenology. Journal of Applied Ecology, 24, 467– 482. Warren, M.S. (1987b) The ecology and conservation of the heath fritillary, Mellicta athalia. II. Adult population structure and mobility. Journal of Applied Ecology, 24, 483–498. Wells, S.M., Pyle, R.M. & Collins, N.M. (1983) The IUCN Invertebrate Red Data Book. IUCN, Gland, Switzerland. Received 24 April 2002; final copy received 30 October 2002


Appendix 1 The 38 phase 1 habitat survey categories remaining after filtering out those habitats known to be of no significance to heath fritillary Mellicta athalia, and the associated rank of the categories Broadleaved woodlands (rank 1) Semi-natural broadleaved woodlands Mixed semi-natural woodland Plantation broadleaved woodland Semi-improved acid grassland with mixed plantation woodland Plantation broadleaved woodland with unimproved neutral grassland Semi-improved neutral grassland with plantation broadleaved woodland Plantation broadleaved woodland with tall ruderal Mixed plantation woodland Plantation broadleaved woodland with semi-improved acid grassland Semi-improved neutral grassland with mixed plantation woodland Mixed parkland and scattered trees Broadleaved parkland and scattered trees Broadleaved parkland and scattered trees with semi-improved neutral grassland Grasslands (rank 1) Unimproved acid grassland Unimproved acid grassland with scattered bracken Unimproved neutral grassland Unimproved neutral grassland with scattered scrub Unimproved acid grassland with dense scrub Unimproved neutral grassland with dense scrub Semi-improved grassland with dense scrub Semi-improved acid grassland Semi-improved neutral grassland Semi-improved neutral grassland with mixed plantation woodland Semi-improved acid grassland with scattered scrub Scattered scrub with semi-improved neutral grassland Heathland (rank 1) Acid dry shrub heath Dry heath /acid grassland mosaic Scattered bracken Wet dwarf shrub heath Unknown categories (rank 0) Continuous bracken Recently felled coniferous woodland Recently felled mixed woodland Recently felled broadleaved woodland Scattered scrub Barrier habitats (rank 0) Coniferous parkland and scattered trees Semi-natural coniferous woodland Dense continuous scrub Plantation coniferous woodland
