A review of horseshoe bats flight lines and feeding areas.
G. Billington & M.D Rawlinson
CCW Science Report No. 755
© CCGC/CCW 2006 You may reproduce this document free of charge for non-commercial and internal business purposes in any format or medium, provided that you do so accurately, acknowledging both the source and Countryside Council for Wales's copyright, and do not use it in a misleading context. This is a report of research commissioned by the Countryside Council for Wales. However, the views and recommendations presented in this report are not necessarily those of the Council and should, therefore, not be attributed to the Countryside Council for Wales.
Report series: CCW Science Report Report number: No. 755 Publication date: September 2006 Contract number: FC 73-01-406 Contractor: Greena Ecological Consultancy Contract Manager: Liz Halliwell Title: A review of horseshoe bat flight lines and feeding areas Author(s): G. Billington, M.D Rawlinson Restrictions: None
Distribution list (core): CCW HQ Library, Bangor National Library of Wales CCW North Region Library, Mold British Library CCW North Region Library, Bangor Welsh Assembly Government Library CCW S&E Region Library, Cardiff Joint Nature Conservation Committee Library CCW S&E Region Library, Llandrindod Scottish Natural Heritage Library CCW West Region Library, Aberystwyth Natural England Library
Distribution list (others): Jane Garner, CCW South & East Wales Richard Dodd, Bat Conservation Trust Region Steve Lucas, West Wales Region Matthew Ellis, CCW North Wales Region Liz Halliwell/Jean Matthews – HQ Vincent Wildlife Trust Clive Hurford - HQ Peter Smith Peter Andrews Tony Mitchell-Jones, EN Geoff Billington Jessa Battersby, JNCC Bob Stebbings David Bullock - National Trust
Recommended citation for this volume: Billington, G., Rawlinson, M.D. 2006. A Review of horseshoe bat flight lines and foraging areas. CCW Science Report No: 755, 23pp, CCW, Bangor.
CCW Natural Science Report No. 755 CONTENTS CONTENTS ______i CRYNODEB GWEITHREDOL ______ii EXECUTIVE SUMMARY______iii 1 Introduction ______4 1.1 Evolution/ Ecology______4 1.1.1 Greater horseshoe bats ______4 1.1.2 Lesser horseshoe bats______5 1.1.3 Flight morphology ______5 1.2 Roosting Ecology ______6 1.3 Key threats to bats______8 1.4 Legislation ______8 1.4.1 The Bern Convention ______8 1.4.2 1981 Wildlife and Countryside Act ______8 1.4.3 The Habitats Directive ______8 1.5 Guidelines for the selection and notification of Bat SSSIs and SACs ______9 1.6 Relationship of SACs to SSSIs ______10 2 Aims ______10 3 Methods______10 4 Results______11 4.1 Habitat fragmentation ______11 4.2 Hedgerows ______12 4.3 Topography ______13 4.4 Foraging ______13 4.4.1 Lesser horseshoe bats______13 4.4.2 Greater horseshoe bats ______14 4.5 Artificial lighting ______16 4.6 Climate ______16 4.7 Insecticides and Pesticides ______16 5 Discussion______17 6 Acknowledgements ______19 7 References ______20 APPENDIX: Guidance for the identification/ management of horseshoe flight lines and foraging areas______23
i CCW Natural Science Report No. 755 CRYNODEB GWEITHREDOL Mae’r prosiect yma’n ymwneud â phennu canllawiau ar gyfer staff y Cyngor Cefn Gwlad o ran adnabod ffiniau llwybrau hedfan ystlumod a’r mannau a ddefnyddir gan ystlumod pedol mwyaf ac ystlumod pedol lleiaf (Rhinolophus ferrumequinum a Rhinolophus hipposideros) i chwilio am fwyd. Caiff yr wybodaeth yma ei defnyddio wrth ystyried hysbysu ac ymestyn Safleoedd o Ddiddordeb Gwyddonol Arbennig (SoDdGA) ac Ardaloedd Cadwraeth Arbennig (ACA) yn y dyfodol.
O fewn y DU, caiff ystlumod pedol mwyaf ac ystlumod pedol lleiaf eu gwarchod dan Gytundeb Bern, Deddf Bywyd Gwyllt a Chefn Gwlad 1981 a Rheoliadau Cadwraeth (Cynefinoedd Naturiol ac ati) 1994, sy’n rhoi Cyfarwyddeb 92/43/EEC ar waith er mwyn nodi nifer o fesurau ar gyfer diogelu’r rhywogaethau a restrir yn Atodiad II. Mae’r Atodiad yma’n cynnwys yr ystlum pedol mwyaf a’r ystlum pedol lleiaf, yn ogystal â’r ystlum du, y daethpwyd o hyd yn ddiweddar i’r gytref fagu gyntaf o’i bath y gwyddys amdani yng Nghymru (Billington 2001d). Mae gofynion y Rheoliadau’n cynnwys dewis, dynodi a gwarchod rhwydwaith o safleoedd a adnabyddir fel Ardaloedd Cadwraeth Arbennig (ACA). Mae’r rhan fwyaf o’r safleoedd yma wedi eu hysbysu eisoes fel Safleoedd o Ddiddordeb Gwyddonol Arbennig (SoDdGA). Sefydlwyd y rhain yn gyntaf yn 1947 (Anhysbys, 1992).
Er mwyn pennu’r meini prawf cefndir ar gyfer adnabod ffiniau safleoedd, fe gynhaliwyd adolygiad o’r llenyddiaeth gyhoeddedig ac anghyhoeddedig a geir, yn ogystal â’r canllawiau sy’n ymwneud â dewis a hysbysu SoDdGA ac ACA ystlumod. Rhoddwyd cryn bwyslais ar y mannau a ddefnyddir gan ystlumod ar gyfer chwilio am fwyd, yn ogystal â llwybrau hedfan.
Mae gwaith ymchwil wedi tanlinellu pwysigrwydd canopïau a mannau lle ceir llystyfiant o amgylch clwydi magu ystlumod pedol, yn enwedig llecynnau mawr sy’n cynnwys coetiroedd. Mae rhwydweithiau da sy’n cynnwys ffiniau caeau wedi hen ddatblygu, fel gwrychoedd, llinellau coed a llecynnau o brysgwydd, yn nodweddion cynefin pwysig sy’n cysylltu’r clwydi â’r mannau bwydo.
Nid ar hap a damwain y mae dwy rywogaethau y Rhinolophus yn dewis eu prae, os nad yw’r hinsawdd yn mynnu’n wahanol (Jones, 1990). Gwelir bod mannau bwydo sy’n cynnwys porfeydd wedi eu pori, sydd am y ffin â gwrychoedd aeddfed, yn bwysig i’r ddau fath o ystlum pedol.
Ar y dechrau, mae ystlumod pedol mwyaf ieuainc yn hela o fewn radiws o 1 cilomedr i’r glwyd fagu (Jones et al., 1995, Ransome, 1996) wrth i’w sgiliau hedfan a chwilio am fwyd ddatblygu. Fe ddangoswyd eu bod yn ddibynnol iawn ar borfeydd a gaiff eu pori gan wartheg (Randsome, 1996).
Darganfuwyd bod pryfed teiliwr yn brae pwysig i ystlumod pedol lleiaf sydd angen glaswellt byr ac amgylchiadau llaith. Mae larfa dyfrol rhai rhywogaethau’n awgrymu pwysigrwydd cyrsiau dŵr, corsydd a glannau afon yng ngoroesiad y rhywogaeth yma, ac felly yn y defnydd a wna’r ystlumod o gynefinoedd (McAney & Fairley 1988).
ii CCW Natural Science Report No. 755 EXECUTIVE SUMMARY This project is concerned with establishing guidelines for CCW staff in the identification of boundaries for bat flight lines and foraging areas of the greater and lesser horseshoe bats (Rhinolophus ferrumequinum and Rhinolophus hipposideros). This information will be used in the consideration of future notifications and extensions of Sites of Special Scientific Interest (SSSIs), and Special Areas of Conservation (SACs).
Within the UK both greater and lesser horseshoe bats are protected under: The Bern Convention, the Wildlife and Countryside Act (1981) and the Conservation (Natural Habitats, &c.) Regulations 1994, which implement the Council Directive 92/43/EEC specifies a range of measures for the protection of species listed on Annex II. This includes not only the greater and lesser horseshoe bats, but also the barbastelle bat for which the first known maternity colony has recently been found in Wales (Billington 2001d). The requirements of the Regulations include the selection, designation and protection of a network of sites known as Special Areas of Conservation (SACs). The majority of these areas have already notified as Sites of Special Scientific Interest (SSSIs), these were first established in 1947 (Anon, 1992).
To establish the background criteria for the identification of site boundaries, a review has been carried out of the literature currently published and unpublished and the guidelines for selection and notification of bat SSSIs and SACs. Particular emphasis has been placed on bat foraging areas and flight lines.
Research has highlighted the importance of canopy and vegetation cover area around horseshoe maternity roosts particularly large areas of woodland. Good networks of well-developed field boundaries such as hedgerows, tree lines and areas of scrub are important habitat features linking the roosts to feeding areas.
The choice of prey items is non random for both Rhinolophus species, unless climatic conditions dictate otherwise (Jones, 1990). Feeding areas containing grazed pasture bounded by mature hedgerows are important for both the horseshoe species.
Greater horseshoe juvenile bats initially hunt within a 1km radius of the maternity roost (Jones et al., 1995, Ransome, 1996) as they develop there foraging and flight skills, they have been shown to be highly dependent on cattle-grazed pasture (Ransome, 1996).
Tipulids have been found to be an important prey item for lesser horseshoe bats and require short grass and damp conditions. The aquatic larvae of some species indicate the importance of water courses, marshes and river banks in the survival of this species, and therefore in the habitat usage of the bats (McAney & Fairley 1988).
On emergence bats utilise regular flight paths, which can extend over considerable distances. Movement along these flight paths show individuals flying close to the ground, and wherever possible under or close to vegetation cover. Whenever they come across the presence of gaps within vegetation both species actively reduce the flight height, particularly the lesser horseshoe bat.
Horseshoe bats actively avoid foraging in, or crossing, illuminated areas and the provision of culverts can assist them in crossing roads more safely (Cresswell 2001).
A series of guidelines to evaluate important features around horseshoe roosts has been included in the Appendix.
iii CCW Natural Science Report No. 755 1 INTRODUCTION The government, and hence CCW is required to notify a series of SSSIs and SACs for the protection of certain species. In Wales this includes greater and lesser horseshoe bats and also barbastelle bat, for which the first known breeding colony has recently been located (Billington 2001). Historically, the approach has been to notify maternity roosts meeting the appropriate criteria, sometimes including a small foraging area or flight lines immediately around the roost. However, the Habitats Regulations (and the Directive from which they are taken) require the protection of all the features essential for the species’ survival and thus it is important to include not only roosts but also flight lines and foraging areas. In doing so it is necessary to identify site boundaries. This report will review published and unpublished literature to provide guidelines on the identification of site boundaries for both SSSIs and SACs for greater and lesser horseshoe bats.
1.1 Evolution/ Ecology British bats belong to two families, the Vespertilionidae (of which 16 species occur within the UK), and Rhinolophidae. The two families can be readily distinguished from one another in almost all features of their anatomy, but especially by their noses. Vespertilionids have simple muzzles, whereas Rhinolophus have a complex series of skin flaps, including a horseshoe-shaped piece, around the nose (Yalden, 1993). The nose leaf is very variable in form and complexity. It is believed to serve as an acoustic lens, focusing the nasally emitted echolocation calls. The genus Rhinolophus includes about 69 species and is found through out most of the Old World, including temperate regions (Yalden, 1993, Altringham, 2001). Five species of Rhinolophus are found in Europe, and only two, greater horseshoe bat Rhinolophus ferrumequinum and lesser horseshoe bat Rhinolophus hipposideros occur within the UK. Both greater and lesser horseshoe bats are rare species that display restricted distribution patterns throughout the UK.
1.1.1 Greater horseshoe bats On mainland Europe the greater horseshoe bat is found in Belgium, Luxemburg and the south of Germany, Poland, Ukraine and Russian Federation. It is also found on many of the larger Mediterranean islands belonging to mainland European states and on Cyprus and Malta. Within the UK, the greater horseshoe bat is one of the rarest species in the UK Entwistle et al. (2001) with the distribution restricted to southwest England and South Wales. Originally a cave roosting bat, they have adapted and utilised many man made structures, with many maternity colonies in Europe now found in buildings particularly older larger houses and farm buildings.
Dietary studies have found that they are selective feeders preferring larger insect prey such as moths and beetles with crane flies (Tipulidae), caddis flies (Trochoptera) and parasitic wasps (Ichneumonoid) being secondary and tertiary items of choice. Beetles constitute the greatest proportion of the bats’ dietary intake are mainly from the family of largest insects Scarabaeidae, cock chafer (Melolontha melolontha), small dung beetle (Aphodius sp.) and various types of large dung beetles (Geotrupes sp.) (Duvergé 1996, Ransome 1996, 1997 & 1997b).
Radio-tracking studies for many colonies over several years show a consistent specialised hunting technique for greater horseshoe bats (Ransome 1996 Duvergé 1996) and the use of foraging areas with a similar structure. Observations have shown foraging greater horseshoes bats fly close to and within physical clutter, where they were observed hawking, perch-feeding, flying close to hedges, landing on the ground and/ or gleaning to catch prey (Jones and Rayner
4 CCW Natural Science Report No. 755 1989, Duvergé, 1996). This is supported by theoretical predictions, based on their wing morphology and echolocation techniques (Altringham 2001).
Some findings of studies of lesser horseshoe bat have shown they travel quickly from the roost to a foraging area at approximately 1 - 2m above grassland, alongside linear features such as tall hedgerows and woodland edge (Bontadina, Schofield, Naef-Daenzer 2002). Research by Billington has shown this to only be the case in completely open areas, in several studies bats have been recorded and observed flying 2-5m above ground level (beside vegetation) and in some cases several metres up at canopy level (Billington 1999, 2000 & 2001c).
It appears that ancient woodland (Bontadina et. al. 2002) and permanent pasture are two key habitats for this species (Ransome 1996). These habitats provide the bats with insect food and linear features such as woodland edges and hedges, which they use as flight paths. Studies in the southwest of England showed that greater horseshoe bats generally preferred ancient semi- natural woodlands and cattle grazed pastures as foraging sites and that juveniles needed foraging sites within a much smaller radius of the roost than adults (Duvergé 1996).
1.1.2 Lesser horseshoe bats In central and southern Europe lesser horseshoe bats are widespread extending as far eastwards as the Middle East but its status is rare. Distribution of the lesser horseshoe within the UK is restricted. Populations are centred in Western Ireland, Wales, and southwest England.
Lesser horseshoe bats are one of the smallest bats in the UK, displaying slow highly manoeuvrable flight patterns and echolocation adapted for detecting insect wing beats in cluttered environments. These behaviours, together with, together with dietary studies, support the importance of woodland and canopies in its foraging activity.
Lesser horseshoe bats feed mainly in dense broadleaved woodland and areas of wet woodland, bank side vegetation and parkland. They actively avoid open areas and instead use tree lines, woodland edges over grown hedges and vegetated banks of streams to move between roosts and woodland feeding areas (Schofield & Bontadina 1999).
The high importance of semi or unimproved wet pasture bounded by hedgerows has been found in the main foraging areas of one of the largest European colonies at Glynllifon in Gwynedd (Billington 2001a & 2002a).
1.1.3 Flight morphology Bats of the Rhinolophus family are specialised having broad wings with narrow tips with low wing loading resulting in a generally slow but highly manoeuvrable flight they also have high and constant frequency echolocation calls with a high duty cycle (Altringham, 2001, Bontadina et al. 2002). They detect and take insects at close range, using constant frequency calls (CF) to detect fluttering insects. Greater horseshoe bats produce an echolocation call that is dominated by a CF component of 50ms, preceded and followed by short frequency modulated pulses (FM) (<5ms). The use of CF calls starting and terminating in FM pulses is typical of bats flying close to and within foliage.
5 CCW Natural Science Report No. 755 Comparison of feeding behaviour of the lesser and greater horseshoe bats shows although both have flexible foraging styles, the lesser horseshoe bat is predominately an aerial hawker, whereas the greater horseshoe can spend much of its time fly catching (Duvergé & Jones 1994).
Perch hunting, or fly catching, is where the bat feed by hanging from a perch, intercepting passing prey. They use echolocation techniques like those feeding in vegetation but have variable aspect ratio and wing loading, since flight performance may be dictated by factors other than foraging.
1.2 Roosting Ecology
Bats spend a large period of their life within the roost. Their roosting habits influence local and global distribution, densities, foraging and mating strategy, social structure and seasonal movements and even the morphology and physiology of bats. By choosing a suitable roost, bats can gain many advantages:
• Protection from the weather. • Protection from predators – ‘The selfish herd’. (Hamilton, 1971) • Cheaper thermoregulation – energetic savings during roosting. • Reduced commuting to foraging sites. • Improved mating opportunities. • Information transfer – knowledge of foraging and roosting sites • Competition avoidance – few other vertebrates can make use of most bat roosts.
Similarly foraging behaviour can also be divided into a number of different aspects:
• Selection of foraging areas • Prey selection • Competition for resources • Predator avoidance
However, the processes involved in roost selection and foraging behaviour are complex, with many mutually dependent interactions (Altringham, 2001). The availability of suitable roosts will influence foraging behaviour, but roosting behaviour itself may be influenced by the abundance and dispersal of food, which in turn are influenced by the habitat types present and habitat management.
Existing maternity roosts are of the utmost importance, where the reproductively active female bats for the colony gather to rear their young, often sharing these roosts with non-breeding females and males. The bats are strongly attached to these traditional maternity sites, and the loss of them through either roost disturbance; removal of animals for research purpose; exclusion; remedial timber treatment; vandalism and habitat change (Stebbings and Griffith, 1986) could be detrimental to the population.
Both Rhinolophus sp. use night roosts usually located on the boundaries of foraging sites (Duvergé 1996, Schofield 1996, Jones et al. 1995, Billington 1999, 2000, 2001a, 2001c & 2002a). These are important in a number of ways, they reduce intra-specific competition as they enable individuals to diverge and forage further afield and occasionally it may be advantageous for bats to remain in these satellite roosts during the day to conserve energy levels rather than return to the maternity roost that same night.
6 CCW Natural Science Report No. 755 When pronounced changes of weather occur reduction in temperature, heavy rainfall or gales may cause bats to remain at these roosts instead of returning to the main roost. For females, as pregnancy progresses, satellite roosts become more important and their value cannot be overestimated as they enable heavily pregnant females to forage in areas that would otherwise be denied (Schofield, 1996).
The loss of satellite roosts can result in increased competition for suitable foraging sites close to the maternity roost and this may reduce the productivity of the colony. Furthermore, the regular usage of satellite roosts over a number of years could promote the establishment of new maternity roosts as more individuals use them (Schofield, 1996).
If the number of adults in the maternity roost increases to the point at which the surrounding habitat is close to its capacity, then it may be more beneficial and energetically advantageous for some of the colony to remain permanently in the satellite roost (Schofield, 1996). Over a period of years the female young of the bats roosting in the satellite roost would remain and a new maternity colony would become established.
So, not only is the identification and conservation of maternity roosts important, but also that of satellite roosts (Schofield, 1996, Billington 1999, 2000, 2000a, 2001c & 2002a). Since night roosts are mainly used at night, they can be any structure that provides fairly waterproof shelter, including open structures that are brightly lit in the daytime, but so long as they provide a safe sanctuary to consume and digest food at night, bats will use them. In general, lesser horseshoe bats tend to use more sheltered enclosed buildings than do greater horseshoes.
Open sided farm buildings, barns, chimneys of derelict buildings, stables, garages, eaves of houses, branches of large trees, even climbing ivy can be used as night roosting places (Billington 1999, 2000, 2001a, 2001c & 2002a, Ransome and Hutson 2000, Schofield et al., unpub 2003). The more sheltered and dimly illuminated night roosts are also used during the day.
Research has also highlighted the importance of canopy and vegetation cover area around the roost (Schofield, 1996, Ransome, 1996, Schofield, et al., unpub 2003.). Vegetation at winter roosts may encourage winter foraging to be more successful in mild winter spells when windy and wet conditions often occur.
Emergence times have been linked to ambient light levels (Ransome, 1996, Racey et al., 1987) At higher latitudes the duration of darkness is reduced, which will limit the foraging time available, however with the presence of vegetation around the roost exit, individuals will exit at a time closer to dusk as they provide shelter and protection from flying predators (Ransome 1996, Racey et al. 1987, Schofield 1996, Jones et al. 1995).
Schofield (1996) found that the clearing of a line of trees used as a commuting route from a church to woodland had a marked effect; it was shown that emergence times were delayed by 30-40 minutes.
The main maternity roost, satellite roosts and suitable foraging habitat tend to be all linked by linear structures such as hedgerows, tree-lines and riparian vegetation.
7 CCW Natural Science Report No. 755
1.3 Key threats to bats
The main threats to bats today consist of:
• Loss or degradation of habitat. • Habitat isolation through fragmentation, including access denied to key foraging areas due to the construction of new road systems (Lode, 2000), or urban areas. • Decline in insect diversity and abundance. • Loss or damage to roosts. • Loss of linear linkage from roosts to foraging sites. • Changes in stock management. • Increase usages of insecticides/pesticides can build up through the food chain, one effect is to sterilise dung through the use of worming compounds, preventing dung beetles from breeding.
1.4 Legislation
Under British and European legislation it is an offence to deliberately capture or kill any bat species, to deliberately, or recklessly disturb the animal, or to damage or destroy a breeding site or resting place used by these animals. There is an equivalent legislation in Northern Ireland under The Wildlife (Northern Ireland) Order 1985.
Bats are protected under: 1.4.1 The Bern Convention Bats receive protected status by their listing on Appendix II of the Council of Europe Bern Convention. This listing and the UK’s Accession to the convention resulted in the Wildlife and Countryside Act being passed into the UK law.
1.4.2 1981 Wildlife and Countryside Act Protects bats and their roosts in England, Scotland and Wales.
1.4.3 The Habitats Directive All European bat species are protected under The Council Directive 92/43/EEC of May 1992 on the conservation of natural habitats and of wild fauna and flora (the Habitats Directive). This Directive became effective in June 1994 and serves to ensure that rare species and their habitats receive strict protection and that appropriate monitoring of populations will be undertaken.
There are twenty-four articles in the Council Directive. Article III, Conservation of natural habitats and habitat species, deals with Special Areas of Conservation (SACs). “Member States shall endeavour to improve the ecological coherence of Natura 2000 (sites) by maintaining and where appropriate, developing, features of the landscape which are of major importance for wild flora and fauna as referred to in Article 10. “…..to encourage the management of feature of the landscape which are of major importance for wild flora and fauna. Such features are those which by virtue of their linear and continuous
8 CCW Natural Science Report No. 755 structure (such as rivers with their banks or the traditional systems for marking field boundaries) ……are essential for the migration dispersal and genetic exchange of wild species” (Article 10).
The main objectives of the habitats directive are to contribute towards ensuring biodiversity through the conservation of natural habitats and of wild fauna and flora in the European territory of the member states to which the treaty applies (Article 2.1)
The Greater horseshoe bat Rhinolophus ferrumequinum is listed on Schedule 5 of the Wildlife and Countryside Act (1981), Annexes IIa and IVa of the European Habitats and Species Directive, and Appendix II of the Bern Convention.
The Lesser horseshoe bat Rhinolophus hipposideros is also listed on Schedules 5 and 6 of the Wildlife and Countryside Act (1981), Annexes IIa and IVa of the European Habitats and Species Directive, and Appendix II of the Bern Convention.
1.5 Guidelines for the selection and notification of Bat SSSIs and SACs
The 24 articles of the Habitats Directive “specify a range of measures, including conservation of features in the landscape that are important for wildlife, the protection of species listed in the annexes from damage, destruction or over exploitation, the surveillance of natural habitats and species, and ensuring that introductions of non-native species are not detrimental to naturally occurring habitats and species. The most stringent obligations relate to the selection, designation and protection of a network of sites – Special Areas of Conservation (SACs).”
Article 4.1 of the Habitats Directive requires stages of approach, on the basis of the criteria stated in Annex III (stage 1), that each Member state shall propose a list of species indicating which species in Annex II that are native to its territory the sites host. For animal species that have large distribution ranges these sites shall correspond to the places within the natural range of such species, which present the physical or biological factors essential to the life and reproduction. The criteria to be employed in stage one can be summarised for both the habitat and species present
For the habitat as: 1. Degree of representativity. 2. Area. 3. Degree of conservation of habitat structure and functions and restoration possibilities. 4. Global assessment of conservation value, (an overall assessment based on the three above). For the species as: 1. Population size and density. 2. Degree of conservation of the features of the habitat that are important for the species, and restoration possibilities. 3. Degree of isolation of the population in relation to the species natural range. 4. Global assessment of conservation value.
Annex III (stage two), requires the assessment of the overall importance of the sites in the biogeographical regions and the EU as a whole.
9 CCW Natural Science Report No. 755 Criteria for stage two assessments may be summarised as:
1. Relative value of the site at national level. 2. Relationship of the site to migration routes, or its role as part of an ecosystem on both sides of one or more community frontiers. 3. Total area of the site. 4. Number of Annex II species present. 5. Global ecological value of the site at the level of the biogeographical region, and or EU as a whole.
Annex III of the Habitats Directive is concerned with criteria for selecting sites eligible for identification as sites of community importance and designation as special areas of conservation.
In 1915 the UK produced a provisional list of 273 areas, worthy of protection as nature reserves. This work helped to prepare the ground for the first official strategy for nature conservation, set out in 1947 and led to a selection of national series of sites notified as site of Sites of Special Scientific Interest (SSSIs) (Anon, 1992).
1.6 Relationship of SACs to SSSIs
It is not appropriate to assume, that all of the UK’s SSSIs should be put forward as candidate Special Areas of Conservation (cSACs). Many SSSIs have no Annex II species present or any significant numbers, and so cannot be regarded as of Community importance within the meaning of Directive. Even where sites do have habitat types and species listed in a Directive they may not qualify for selection when assessed against the criteria set out in Annex III of the Directive and other principals established (Anon, 1992).
2 AIMS