The great crested newt (Triturus cristatus) is Britain’s largest and most threatened newt (5). The body is generally dark brown to black in colour with a warty appearance, which gives the species its other common name, the warty newt (1). The underside is bright orange with black markings that are unique to each individual. Females tend to be slightly longer than males, and in the breeding season the latter develop an obvious crest between the head and the tail, and a silver streak along the middle of the tail. The specific name cristatus derives from the Latin word meaning crested (6). Outside the breeding season, the male and female great crested newt is fairly similar in appearance, but the females always have an orange line on the tail (1). Juveniles generally look like females but may have a yellow stripe along the back (1).
Great crested newts feed on a range of aquatic invertebrates, but occasionally tackle large prey items such as adult smooth newts and large dragonflies (1). They are mainly active at night, spending the day at the bottom of ponds or hidden in vegetation (1). Males have an extravagant display used in courtship, which involves a male standing on his front legs in front of a female with an arched back while he waves his tail around. If the female is receptive the male transfers a spermatophore. Eggs are laid in February or March and are protected from predation by having the leaves of water plants folded over them. The appearance of vegetation showing a characteristic ‘concertina’ effect is a good indication of the presence of this species (1). Great crested newts leave the water in August and September; their behaviour during their period on land is poorly understood (1).
The great crested newt is widespread throughout northern and central Europe extending east to the Ural Mountains in Russia (1). The species has a wide distribution in Britain, but is absent from Cornwall, Devon, and parts of Wales and Scotland (1) and is generally uncommon (5). The British great crested newt population has undergone a very severe decline in the last 50 years (1).
Inhabiting a wide range of habitats, including farmland, woods, grasslands, dunes, quarries, industrial and ‘brown-field’ sites (9), the great crested newt favours large ponds with abundant weeds and no fish (1). The habitat structure within the site such as hedgerows, varied topography and the availability of refuges in which the individuals can hide is very important and can determine whether the species can occupy a site or not (9). Occasionally the great crested newt also uses garden ponds (1) and natural springs (9). The condition of land between occupied sites is also an important factor, as many newt populations persist as metapopulations, a series of local populations between which individuals migrate (9). If there is little connectivity between patches of suitable habitat, migration will be unlikely (9).
The great crested newt is classified as Least Concern (LC) on the IUCN Red List (1). Listed in Appendix II of the Bern Convention (2), Annexes II and IV of the EC Habitats Directive (3), the Wildlife and Countryside Act 1981 (2) and Schedule 2 of the Conservation Regulations 1994 (4).
The decline of the great crested newt population is due to a number of factors, including a large-scale loss of breeding ponds (7). Intensification of agriculture has resulted in many farm ponds becoming redundant, leading to neglect (9), and a decline in the suitability of the surrounding habitat (9). Many new ponds that would otherwise be suitable for the great crested newt are stocked with fish, which predate on both eggs and larvae(9). Ponds that survive in agricultural land often become polluted with pesticides and fertilisers (7).
The great crested newt is a priority species under the UK Biodiversity Action Plan (BAP). The species action plan aims to maintain and enhance current populations (2) with a target of the restoration of populations to at least 100 sites (7). A number of publications on this species have been produced; English Nature has published 'Great crested newt mitigation guidelines' targeted at developers and others involved in land-use changes, which could cause conflict with conservation of this species (8). Froglife has published 'The Great Crested Newt Conservation Handbook'.
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