Amphibian Habitat Management Handbook John Baker, Trevor Beebee, John Buckley, Tony Gent and David Orchard Acknowledgements Amphibian Habitat Management Handbook The authors are grateful to input from and discussion with Bob Bray, Chaela Carrell, Jim Foster (Natural England), Mark Jones, Peter Minting (Institute of Zoology), Pascale Nicolet (Pond Conservation), Bill Shaw (Amphibian and Reptile Conservation), Duncan Sweeting (Suffolk Amphibian and Reptile Group), Will Watson and Penny Williams (Pond Conservation). The authors are also grateful to colleagues who have contributed photographs to this handbook: Amber Teacher, Ash Bennett, Tim Bernhard, Lee Brady, David Coward, Ben Driver, Jim Foster, Chris Gleed-Owen, Jelger Herder, Fred Holmes, Phyl King, Anna McGrath, David Orchard, Angela Reynolds, Bill Shaw and David Woodhead. John Baker Species range maps are based on those kindly provided by Rob Still (WILDGuides). Trevor Beebee John Buckley Tony Gent David Orchard Published by Amphibian and Reptile Conservation, 655A Christchurch Road, Boscombe, Bournemouth, BH1 4AP Copyright © Amphibian and Reptile Conservation ISBN: 978-0-9566717-1-4 Designed by Bill Gerrish Printed by AC Print Solutions Ltd. www.acprintsolutions.com Cover images: This publication should be cited as: An amphibian pond (a pingo) in Norfolk (Amphibian and Reptile Conservation) Baker, J., Beebee T., Buckley, J., Gent, A. and Orchard, D. (2011). Amphibian Habitat Management Handbook. Smooth newt and natterjack toad (Fred Holmes) Amphibian and Reptile Conservation, Bournemouth. Amphibian Habitat Management Handbook Amphibian Habitat Management Handbook Contents Summary 1 7. Disease and Mortality 35 7.1. Disease 35 1. Introduction 3 7.2. Other diseases and causes of mortality 36 1.1. Background 3 7.3. Winterkill 36 1.2. Scope 3 7.4. Breeding associated mortality 37 1.3. Habitat requirements and principles 4 7.5. Predation 37 1.4. Global declines 4 7.6. Literature 37 1.5. Literature 5 8. Terrestrial Habitat 39 2. British Amphibians 7 8.1. Overview 39 2.1. Great Crested Newt Triturus cristatus 7 8.2. Terrestrial habitat requirements 40 2.2 Smooth newt Lissotriton vulgaris 9 8.3. Management of terrestrial vegetation 40 2.3. Palmate newt Lissotriton helveticus 10 8.4. Hibernation sites 41 2.4. Common toad Bufo bufo 10 8.5. Dispersal from ponds 42 2.5. Natterjack toad Bufo/Epidalea calamita 11 8.6. Literature 42 2.6. Common frog Rana temporaria 12 2.7. Northern pool frog Pelophylax lessonae 12 9. Landscape Ecology 43 2.9. Literature 13 9.1. Overview 43 9.2. Maintenance of genetic diversity 43 3. Legislation and Policy 15 9.3. Metapopulations 43 3.1. Legislation 15 9.4. Pond networks and clusters 43 3.2. Biodiversity Action Plan ‘priority species’ listing 15 9.5. Literature 44 3.3. Implications for site managers 16 3.4 Local authority sites 16 10. Specific Habitats 45 3.5. Development control and forward planning 17 10.1. Gardens 45 3.6 Agri-environment mechanisms 17 10.2. Sustainable Urban Drainage Systems 47 3.7 Literature 17 10.3. Ditches 48 10.4. Other land uses 48 10.5. Roads 48 4. Pond Creation 19 10.6. Literature 51 4.1. Benefits of pond creation 19 4.2. Pond location 19 11. Natterjack Toad 53 4.3. Water source 19 11.1. Background 53 4.4. Flooding 19 11.2. Habitat requirements 53 4.5. Warmth 20 11.3. Natterjack habitat 54 4.6. Public access 20 11.4. Habitat management 56 4.7. Will the new pond hold water? 20 11.5. Habitat restoration 58 4.8. Lined ponds 21 11.6. Natterjack pond creation 59 4.9. Pond design 22 11.7. Lined natterjack ponds 60 4.10. Excavation 23 11.8. Literature 60 4.11. Planning permission 23 4.12. Working with contractors 23 12. Translocation and Reintroduction 61 4.13. Stocking the pond 24 12.1. Translocations 61 4.14. Literature 24 12.2. Natterjack toad reintroduction 61 12.3. Site selection 61 5. Pond Restoration 25 12.4. Preparing a reintroduction site 62 5.1. Pond restoration 25 12.5. Translocating natterjacks 62 5.2. Find out about species present 25 12.6. Releasing natterjacks 63 5.3. Pond risk assessment 26 12.7. Head-starting natterjack tadpoles 63 5.4. Restoration of low risk ponds 26 12.8. Monitoring natterjacks 63 5.5. Precautionary principles 27 12.9. Literature 65 5.6. Restoring great crested newt ponds 27 5.7. Literature 29 13. Further Reading 67 6. Other Pond Species 31 6.1. Fish 31 6.2. Waterfowl 32 6.3. Non-native amphibians 32 6.4. Terrapins 33 6.5. Non-native invasive plants 33 6.6. Literature 34 i ii Amphibian Habitat Management Handbook Summary The Amphibian Habitat Management Handbook is approach is recommended, avoiding the transfer of a resource for a range of range of users including organisms and materials between ponds. There are conservation professionals and interested volunteers. no practical cures for amphibian diseases in the wild. Disease symptoms and other causes of amphibian There are seven amphibians native to Great Britain. mortality are described to assist field workers in Five of these are widespread; great crested newt, determining the likely causes of amphibian mortality. smooth newt, palmate newt, common toad and common frog. Of these, the great crested newt Amphibians spend a great deal of their time on land. and common toad are also Biodiversity Action Plan They inhabit a range of terrestrial habitat types, priorities. The great crested newt has breeding site requiring cover to retain moisture and provide habitat requirements that are also suitable for the other for their invertebrate prey. Management of terrestrial widespread amphibian species. On the other hand the habitat is usually required, especially to prevent the common toad can breed in relatively large water bodies shading of ponds by scrub and trees. Hibernation with fish, which tend to be less suitable for the other sites can be constructed, although amphibians should species. Hence, in many areas the great crested newt be able to find their own such sites within favourably is a useful target species for conservation management managed habitat. as an umbrella for the others. Movement of individuals between neighbouring There are two rare amphibians; the natterjack toad and breeding sites is important for long-term health of the northern pool frog. amphibian populations. Hence, landscape issues should be considered, especially the distance between The natterjack is a conservation priority and a habitat breeding ponds and the nature of intervening habitat. specialist with very different ecological requirements to the other native amphibians. Hence a section of the Opportunities for amphibians are also considered within handbook is dedicated to this species. specific habitats; gardens, Sustainable Urban Drainage Systems and drainage ditches. Measures to reduce the The pool frog is currently subject to a reintroduction impacts of roads are also reviewed. project and is not covered by the current handbook. The natterjack toad breeds in shallow, usually Ponds are not only amphibian breeding sites but are temporary ponds and requires sparsely vegetated also important habitat for many other species. A section terrestrial habitat. The natterjack can survive in habitat of the handbook describes planning and creating new that is too arid for other amphibians. In fact, if conditions ponds. Pond restoration can greatly improve ponds change so that sites become colonised by other in poor condition, yet the methods involved also have amphibians, the invading species become significant the potential to cause harm. Hence a section of the predators or competitors of natterjacks. handbook includes a risk assessment approach developed by Pond Conservation. The dispersed but limited range of the natterjack toad has meant that reintroduction is a significant element The relationships between amphibians and other of the conservation work for this species. A section species is considered. Amphibians vary in their ability examines translocations for conservation purposes, to withstand predation by fish. On the one hand focusing on the natterjack in particular. common toads successfully co-exist with fish. At the other extreme, fish can eradicate great crested newts. Given that toads can also survive without fish, the general principle is that fish should not be introduced to amphibian ponds. Waterfowl also have negative impacts on ponds and hence should not be encouraged. Disease is a significant issue in global declines of amphibians. Ranavirus and chytrid fungus are both present in Great Britain but the impacts of these pathogens is not yet understood. A precautionary Natterjack toad (Fred Holmes) 1 Amphibian Habitat Management Handbook 1. Introduction rural areas, benefiting from the creation of ponds for functional purposes as well as by-products of resource extraction from the ground. Rural pond numbers peaked early in the twentieth century, at roughly a 1.1. Background million. Since then ponds have been either lost or This handbook is intended to be a resource for a neglected as their functions have been replaced, range of people involved in amphibian conservation, or they have become degraded through lack of including site managers, community groups and management, lowered water tables and reduced volunteers. It is also hoped that it will be useful to local water quality. government staff and ecological consultants involved in development planning, to optimise conservation gain Amphibians spend part, in some cases most, of delivered through this process. Because of reference to their lives on land. The terrestrial habitat in the the underlying legislation and policy mechanisms, we countryside has also decreased in quality as improved have restricted coverage to Great Britain, namely the farming technology has reduced the number of countries of England, Scotland and Wales, However, invertebrates available as amphibian prey and as the the principles identified will be applicable more widely area of land given over to arable or improved grassland across northern Europe. has increased. There are seven amphibian species native to Great The direct loss of wildlife habitat to building Britain. Although a relatively small taxonomic grouping, development has also affected amphibians. For they present a range of conservation challenges and example, coastal sites favoured by the natterjack toad opportunities. Most of the species are widely have disappeared as they have been targeted by distributed (great crested newt, smooth newt, palmate humans as desirable areas for leisure developments. newt, common toad and common frog). Nevertheless two of these (great crested newt and common toad) Housing developments elsewhere have had mixed are listed as priorities under the UK Biodiversity Action impacts on amphibians. Whilst traditionally managed Plan (BAP). rural land has been lost, gardens, and in particular garden ponds, have provided a new habitat. These The remaining three widespread species, not ponds differ from their rural counterparts in several prioritised by the BAP (smooth newt, palmate newt ways; in particular, they are smaller. Nevertheless, and common frog), still merit attention. These species there are many more garden ponds, per comparable have undoubtedly experienced declines and require area of land, than there are ponds in the countryside. conservation measures to reverse these. For example, The varying abilities of amphibians to exploit garden the common frog is no longer a ‘common’ species in habitats have a significant bearing on their current great swathes of the the countryside. Hence, there is a conservation status. need for conservation information for the widespread amphibian species aimed at a broad array of user 1.2. Scope groups. Furthermore, amphibians make a good focus Conservation guidance for the two amphibians for education and local conservation action and can be originally prioritised by the BAP process has been umbrella species for habitat management. provided previously in the Natterjack Toad Conservation Handbook (Beebee and Denton, 1996) and The Great Two of our amphibians, the natterjack toad and Crested Newt Conservation Handbook (Langton, northern pool frog, are conservation priorities due to Beckett and Foster, 2001). Since their publication their rarity. The natterjack is confined to fewer than the UK BAP species list has been revised; common 60 locations. toad and pool frog were included in 2007. The current Amphibian Habitat Management Handbook provides The pool frog is even scarcer. It has only relatively information on not only the former two BAP species, but recently been recognised as a native species – a also generic advice covering the newly listed common discovery that coincided with its extinction in the wild. toad and the other widespread amphibian species. Pool frogs have been reintroduced, from Sweden, to a single site in England. The information given in the current handbook pertains Both the rare and the widespread amphibian species to habitat management and restoration. It also includes have suffered changes in conservation status during sections on translocation and reintroduction, which are the second half of the twentieth century. Prior to useful tools in the conservation of natterjacks. Advice is the intensification of agriculture associated with the also given regarding other pond organisims including 1939-45 World War, amphibians most likely thrived in fish, waterfowl, non-native herpetofauna and plants. Developing common toad spawn (ARC) 3 Amphibian Habitat Management Handbook Amphibian Habitat Management Handbook 1.4. Global declines Information on amphibian disease is also given, as this Amphibian Life Cycle is a high-profile, active research issue with implications for site managers and field workers. The relatively permeable skins of amphibians, eggs unprotected by shells, and their biphasic lifestyle, Amphibian survey methodology and standards are relying on terrestrial and aquatic habitats, have not covered in the handbook, as they constitute a contributed to the view that these animals are potential Adults shuttle between large subject that is covered thoroughly elsewhere, for indicators of environmental health. The discovery that land and water to breed. example: amphibians were in decline, in some cases to the point of extinction, in disparate areas of the world where • Surveying for (Great Crested Newt) Conservation habitat was presumed to be protected from human (Froglife, 2003). activity, created fears of a decline in amphibians driven • Great Crested Newt Mitigation Guidelines (English by previously unrecognised factors perhaps acting at a Nature, 2001). global level. • Protocols for the National Amphibian and Reptile Recording Scheme. Juveniles may spend the Surveying for natterjacks is an exception. Although greater part of two or three guidance is provided in Natterjack Toad. Survey years on land. During this Guidelines (The Herpetological Conservation Trust), it phase they may wander far is repeated here as survey is essential to monitor the from water. success of introductions. The pool frog is subject to a reintroduction programme, which is guided by a published strategy (Buckley and Eggs and larvae Foster, 2005). Hence, further habitat management develop in water. At metamorphosis advice for this species is currently unnecessary and is juveniles move from not provided in the current handbook. water to land. 1.3. Habitat requirements and principles The western toad Anaxyrus boreas was one of the Amphibians have complex life cycles. This refers to the amphibian species declining in apparently pristine fact that the life cycle includes a larval (tadpole) stage habitat, sparking fears of ‘global decline’ (ARC) which is terminated by metamorphosis into a juvenile which has a completely different morphology and Arguably, the global decline phenomenon has been lifestyle. The pre-metamorphic stage is dependent on of little relevance to amphibian conservation in Great an aquatic environment; the post-metamorphic stages Britain. There is little mystery about declines in our (juvenile and adult) include long periods living on land. native species. Habitat loss, fragmentation and 1.5. Literature Even in the terrestrial habitat, amphibians are heavily degradation are readily apparent causal factors. National Amphibian and Reptile Recording Scheme dependent on water. They have permeable skins which Beebee, T. and Denton, J. (1996). Natterjack Toad www.narrs.org.uk/ make them prone to desiccation, although tolerance of Since the initial fears surrounding the global decline Conservation Handbook. English Nature, Peterborough. arid conditions varies between species. phenomenon it has become clear that amphibians, as Pond Conservation. Pond Creation Toolkit. a class, are neither particularly good indicator species Buckley, J. and Foster, J. (2005). Reintroduction www.pondconservation.org.uk/millionponds/ The best amphibian breeding sites also tend to be nor more threatened than some other groups of strategy for the pool frog Rana lessonae in England. pondcreationtoolkit ‘good wildlife ponds’. Much of the advice given in this animals. Also, subsequent research has blurred English Nature Research Report 642. English Nature, handbook mirrors that provided by Pond Conservation the boundaries between the mysterious declines in Peterborough. The Herpetological Conservation Trust (undated). regarding high quality pond habitats (Williams et al., apparently pristine habitats and those in obviously Natterjack Toad. Survey Guidelines. Booklet available 2010 and the Pond Creation Toolkit). human-modified landscapes. Amphibian disease English Nature (2001). Great Crested Newt Mitigation from Amphibian and Reptile Conservation. illustrates this point. Disease is emerging as a key Guidelines. English Nature, Peterborough. Terrestrial habitat requirements for most native species driver behind many of the previously inexplicable global UK Biodiversity Action Plan. are fairly generic, as amphibians can occupy a variety declines. The same diseases have been identified Froglife (2003). Surveying for (great crested) newt www.ukbap.org.uk of different habitat types. The natterjack toad is an in native amphibian populations. Although habitats conservation. Froglife Advice Sheet 11. Froglife, exception, requiring sparsely vegetated sites that are in Great Britain cannot be regarded as pristine, and Peterborough. Williams, P., Biggs, J., Whitfield, M., Thorne, A., Bryant, inhospitable to the other species. hence differ from classic ‘global decline’ sites, the long- S., Fox, G. and Nicolet, P. (2010). The Pond Book: A term impacts of disease are still a matter of interest to Langton, T., Beckett, C. and Foster, J. (2001). Great Guide to the Management and Creation of Ponds. Pond amphibian conservation here. Crested Newt Conservation Handbook. Froglife, Conservation, 2nd edition. Pond Conservation, Oxford. Halesworth. 4 5 Amphibian Habitat Management Handbook 2. British Amphibians Native amphibians of Great Britain Great crested newt Triturus cristatus England, Scotland and Wales Smooth newt Lissotriton (Triturus) vulgaris England, Scotland and Wales Palmate newt Lissotriton (Triturus) helveticus England, Scotland and Wales Common frog Rana temporaria England, Scotland and Wales Common toad Bufo bufo England, Scotland and Wales Natterjack toad Epidalea (Bufo) calamita England, Scotland, and Wales Northern pool frog Pelophylax (Rana) lessonae England There are seven species of amphibian native to Great reproductive failure. For example, if a pond dries before Britain. The distribution maps included here also include larvae can complete their development the population Northern Ireland, the Republic of Ireland and Isle of may be relatively unaffected because a large proportion Man. The common frog, natterjack toad and smooth of the adults is likely to survive to reproduce the newt are native to the Republic of Ireland, the smooth following year. newt and common frog are found in Northern Ireland while the common frog is the only amphibian native to The great crested newt prefers to breed in relatively the Isle of Man. Other species of amphibian have been large ponds not supporting fish, such as were introduced to these areas from outside their natural traditionally found in the rural landscape. Typically, ranges. breeding ponds are also well insolated, supporting abundant submerged vegetation and with a pH >5.5. British amphibians breed primarily in standing water, Nevertheless, great crested newts can be found especially ponds. Ponds are naturally relatively dynamic in a range of pond types. They fare well in water environments. Vegetation and water levels can vary storage tanks and disused swimming pools and large substantially over the course of a year as well as more populations have become established in flooded former gradually over the long term. Pond-dwelling species quarry sites. tend to be adapted to this changeable environment. Similarly, amphibians are flexible in their ecology. The following species accounts, therefore, should be read as guides recognising that exceptions and variations may arise according to local conditions. 2.1. Great Crested Newt Triturus cristatus Ecology The great crested newt is the most aquatic of the three British newt species. In the terrestrial stages it does not venture far from breeding sites. Although individual newts may move more than a kilometre from a pond, most remain within 250 m and a great deal of terrestrial activity is likely to take place closer to the pond than this. The great crested newt is relatively long-lived; in undisturbed habitat individuals can survive into their teens. In most populations life expectancy is shorter than this but nevertheless, females usually survive to breed over several years. This longevity can allow A typical great crested newt breeding site – a sunny, populations to persist despite occasional years of well-vegetated pond on low intensity farmed land (ARC) Natterjack toadlet (Ash Bennett) 7 Amphibian Habitat Management Handbook Amphibian Habitat Management Handbook The great crested newt is believed to have declined the gills. This neotenous, or paedomorphic, condition is more rapidly than other widespread amphibian species most likely to occur in cool ponds. and has particularly suffered from the degradation of rural ponds due to agricultural intensification. It has not adapted to alternative habitat provided by garden ponds as well as have the smooth newt and common frog. Although in rural areas, where garden ponds tend to be larger anyway, gardens and their ponds may provide critically important habitat within an otherwise inhospitable landscape. Although very different from typical breeding ponds, Flooded brick pits at Hampton Reserve, south of great crested newts can thrive in water storage tanks Peterborough support the largest known population of and disused swimming pools (ARC) great crested newts (ARC) 2.2 Smooth newt Lissotriton vulgaris Reproduction The female produces several hundred Sexually mature smooth newt retaining gills (ARC) eggs in a breeding season. Each is produced individually and wrapped in a folded leaf, using her Distribution and status The smooth newt is hind feet. The egg-laying period extends over several widespread and common but prefers hard water months. ponds with a neutral pH, rarely being found in ponds lower than pH 6. Its tolerance of a wide range of Larvae are present in breeding ponds over the habitats ensures that it is probably the most abundant summer, feeding on small pond organisms, especially amphibian in Britain, although it is less abundant in zooplankton. Great crested newt larvae tend to live soft water areas such as in western Britain and upland in the water column rather than on the pond bottom. areas. Populations in rural areas have presumably This habit is thought to explain this species’ particular declined with the intensification of farming, but the vulnerability to fish predation. ability to thrive in garden ponds means that the smooth newt is common in this habitat. Larvae metamorphose from late August to mid-October. Male smooth newt in terrestrial phase (ARC) At this point metamorphs (or efts) generally move into Ecology The smooth newt is not as aquatic as the terrestrial habitat. The great crested newt, however, is great crested newt. Adults spend the breeding period more variable in this respect than other amphibians as in the water but return to land soon afterwards. The sometimes metamorphs either remain in the pond or skin of the smooth newt changes texture between return to the pond during the juvenile stage. It takes two aquatic and terrestrial stages, which tend to be discrete or three years to attain sexual maturity during which phases. Occasionally adult smooth newts spend the time the newts live mostly on land. Distribution of great crested newt (based on a map winter in ponds but this is unusual. In most cases they provided by Rob Still/WILDGuides) remain terrestrial until early spring when they migrate to breeding ponds. The great crested newt has colonised several former quarry sites with great success and several of The smooth newt is not as long-lived as the great these sites have been designated Special Areas of crested newt, reaching six or seven years at most. Conservation for the species. Reproduction Breeding behaviour is similar to that of the great crested newt, although adult smooth newts tend to leave the water sooner than the great crested newt and smooth newt larvae tend to complete the larval stage earlier in the year, from July to September. The young newts then live on land until becoming Juvenile great crested newts may stay in the water mature two or three years later. (ARC) Occasionally, smooth (and palmate) newt larvae spend Distribution and status The great crested newt is longer in the larval stage than is normal, in some cases widespread throughout lowland England and Wales, overwintering as large larvae and completing development although scarce or absent from southwest England to efts the following year. In more extreme cases smooth and much of western Wales. It has a limited range in Large garden ponds in rural areas can be important (and palmate) newts may continue to grow to sexual Distribution of smooth newt (based on a map provided Scotland. by Rob Still/WILDGuides) breeding sites for the great crested newt (ARC) maturity while retaining some larval features, usually just 8 9 Amphibian Habitat Management Handbook Amphibian Habitat Management Handbook 2.3. Palmate newt Lissotriton helveticus Where the species’ ranges overlap, the palmate newt Mortality of toads crossing roads during annual Ecology The natterjack toad is at the northwestern can often be found in the same breeding ponds as springtime migrations to breeding sites is readily edge of its global range in Great Britain where it can smooth newts. It is less likely to be found with the great apparent and has been the focus of public attention. survive in only a few early successional stage habitats. crested newt. Although roads can adversely affect amphibian Most of these are coastal (dune and upper salt marsh/ populations through direct mortalities other less readily merse); together with heathland, all are lowland. The apparent factors may also be at work, such as the natterjack forages in areas of open ground or very 2.4. Common toad Bufo bufo fragmentation of habitat and toad populations. The short vegetation where it can see, pursue and catch Ecology The common toad is the most terrestrial of the common toad is also likely to have been negatively its invertebrate prey. It can survive in hot, dry habitats widespread amphibians. Outside of its breeding season affected by a general decline in habitat quality by burrowing. It readily digs into a suitable substrate, it may move up to several kilometres from water. It is associated with the intensification of farming. usually sand, to avoid the extremes of temperature and not very fussy in its choice of terrestrial habitat. Rough dryness that would be lethal to other amphibians. grassland and woodland are particularly favoured. The common toad is more tolerant of dry conditions than Reproduction For breeding the natterjack requires other amphibians excepting the natterjack. shallow, ephemeral pools that warm up quickly to speed Male palmate newt (David Orchard) the tadpoles’ development. Natterjacks breed later Reproduction Adults are present in breeding ponds in the year than common frogs and common toads. Ecology The palmate newt leads a very similar life to for only about two weeks. Males greatly outnumber Spawning begins in April or May depending on weather the smooth newt, occupying a similar ecological niche. females. After breeding they move back into terrestrial conditions. Later spawn may be laid in June, July and It does, however, prefer soft water or slightly acidic habitat. Common toads tend to breed in larger water even the first week of August depending upon rainfall ponds, notably in upland areas and on lowland heaths. bodies than do other amphibians although drainage and the availability of ephemeral pools. In Kent and Norfolk it is also associated with ancient ditches are also used. This species seems to need woodland. relatively open water. The eggs and larvae are Spawning takes place in shallow water, usually 5-10 cm distasteful to fish, so common toads can thrive in fish deep. The female produces several thousand eggs as Reproduction Breeding ecology is very similar to that ponds. Common toads may migrate considerable a single row in spawn strings. The eggs and tadpoles of the smooth newt. distances to specific, traditional breeding ponds. develop rapidly so that newly metamorphosed toadlets leave the water from mid-May to July, peaking in June Distribution and status Due to its preference for at most sites. Natterjack tadpoles do not compete well soft water the palmate newt tends to be abundant in with those of the common toad or frog and natterjacks northern and western Britain. In southwest England it is need ponds that are not used by other anurans, or more common than the smooth newt. great crested newts which eat their eggs and tadpoles. Distribution and status The natterjack’s distribution has always been restricted in Britain due to its specific habitat requirements. Over the last 100 years or so, it has disappeared from more than 75% of its former haunts with losses from heathlands in southern and eastern England being particularly severe. It is now Distribution of common toad (based on a map provided found in only about 60, mostly coastal, sites throughout by Rob Still/WILDGuides) England, southwest Scotland and north Wales. The stronghold for the species is on the northwest coast, north of Liverpool to the Solway Estuary. Nearly all 2.5. Natterjack toad Bufo/Epidalea breeding sites in the UK are protected, having SSSI calamita status, and at most sites populations are monitored Common toad mating ball (David Orchard) annually by site managers or volunteers. Distribution and status The common toad was added The natterjack is a European Protected Species and a to the list of priority species during the revision of the priority species in the UK’s Biodiversity Action Plan. The national Biodiversity Action Plan in 2007. Prioritisation plan highlights both the threats to the species and the was not due to scarcity of this species, rather to conservation measures needed to address them. declines. The common toad is widely distributed throughout a large range and is probably present in every 10-km square of lowland, mainland Britain. Nevertheless, declining status has been found in southern and eastern England (Carrier and Beebee, 2003). Reasons for decline have not been firmly identified. Distribution of palmate newt ((based on a map provided by Rob Still/WILDGuides) Male natterjack in breeding pond (Fred Holmes) 10 11 Amphibian Habitat Management Handbook Amphibian Habitat Management Handbook on farm land have declined due to agricultural site for the northern pool frog in England although the intensification but the common frog is sufficiently reintroduction programme plans secondary releases adaptable to readily exploit garden ponds, which in to additional sites. All other pool frog populations in some areas may provide more significant habitat than Britain are believed to have originated from importations agricultural land. from more southerly populations in Europe and are genetically dissimilar to northern pool frogs. 2.8. Literature Beebee, T. and Denton, J. (1996). Natterjack Toad Conservation Handbook. English Nature, Peterborough. Buckley, J. and Foster, J. (2005). Reintroduction strategy for the pool frog Rana lessonae in England. Female northern pool frog basking in open area of English Nature Research Report 642. English Nature, pond bank (ARC) Peterborough. Northern pool frogs prefer relatively open ponds where Carrier, J. and Beebee, T.J.C. (2003). Recent, emergent vegetation growth does not overly shade substantial and unexplained declines of the common the water. Within the pond pool frogs occupy warm toad Bufo bufo in lowland England. Biological microhabitats and bask in the sun especially on floating Conservation 111, 395-399. mats of vegetation and around pond margins. Carroll, E.A., Sparks, T.H., Collinson, N. and Beebee, Reproduction Pool frogs breed from late May to T.J.C. (2009). Influence of temperature on the spatial early June. Each female produces a few small spawn distribution of first spawning dates of the common frog Distribution of natterjack toad (based on map clumps, usually deposited on top of vegetation mats, (Rana temporaria) in the UK. Global Change Biology produced by Rob Still/WildGuides) presumably benefiting from the warmth at the water’s 15, 467-473. surface. Under these conditions the eggs hatch relatively rapidly, within approximately five days. The Jehle, R., Thiesmeier, B. and Foster, J. (2011). The 2.6. Common frog Rana temporaria tadpoles are unpalatable to fish and pool frogs thrive in Crested Newt. A Dwindling Pond-Dweller. Laurenti- Ecology The common frog can be found in a wide ponds supporting large numbers of sticklebacks. Verlag, Bielefeld. range of habitats, although it is less tolerant of dry Distribution of common frog (based on map produced conditions in the terrestrial habitat than are toads. It by Rob Still/WildGuides) Although pool frog tadpoles are very small on hatching, JNCC (website). Great crested newt Triturus cristatus – breeds in a wide variety of water bodies, which means they grow rapidly, metamorphosing from late July until SAC selection species account. that in any particular area a frog population tends to be late September with numbers of froglets peaking in www.jncc.defra.gov.uk/ProtectedSites/ 2.7. Northern pool frog Pelophylax spread over many local water bodies. August. It is unclear whether late developing tadpoles SACselection/species.asp?FeatureIntCode=S1166 lessonae can survive over winter. Reproduction The common frog breeds early in the Ecology The northern pool frog is a warmth-loving Langton, T., Beckett, C. and Foster, J. (2001). Great spring. The exact timing of spawning is related to species, emerging from hibernation a little later than Distribution and status Until the 1990s it was Crested Newt Conservation Handbook. Froglife, temperature and hence varies geographically. Common the common frog and common toad and remaining generally believed that the pool frog was not native to Halesworth. frogs spawn earliest in the southwest, with spawn active until late August or September. Adult frogs spend Britain. All populations of pool frogs present in England appearing in December on the Lizard peninsula, for much of the active season in ponds rather than on land. were believed to have originated from deliberate Oldham R.S., Keeble J, Swan M.J.S. and Jeffcote example. Spawning is approximately one week later Numbers in the pond peak in May and June and then introduction from continental Europe. Pool frog status M. (2000). Evaluating the suitability of habitat for the for every 100 km further east and five days later for decline over the summer, presumably as frogs move was reviewed in the light of several lines of research Great Crested Newt (Triturus cristatus). Herpetological every 100 km north (Carroll et al. 2009). The pattern of into terrestrial habitat. It seems likely that some frogs that concluded that the species had, in fact, been Journal 10(4), 143-155. spawning activity within a season can also be affected hibernate in ponds but mostly this occurs in terrestrial present prior to the documented dates of introduction. by temperature, with cold snaps breaking spawning habitat. In particular a population from Thompson Common activity into several peaks. in Norfolk was more closely related to pool frogs from Scandinavia rather than to populations further south in Each female produces a single clump of spawn, usually Europe which were the sources of introduced frogs. in the warm shallows at the edge of water bodies. Spawning usually takes place in standing water, but Re-evaluation of pool frog status came just as the sole sometimes ditches and streams are used. known native Norfolk population dwindled to extinction. Since then a reintroduction programme has been Distribution and status The common frog is present devised for the northern pool frog (Buckley and Foster, throughout most of mainland Britain, from lowland 2005), importing frogs from Sweden and releasing habitat to approximately 1,000 m altitude. Populations them at a site in Norfolk. This is the currently the sole 12 13