About great crested newts
The great crested newt (Triturus cristatus) is the largest of the three British newt species with an adult length of 90 -170 mm. The adult male has a jagged crest along his back which decreases in size outside the breeding season. Both sexes are very dark in colour with a vivid orange belly patterned with irregular black spots. The skin is granular giving the species its alternative common name of warty newt.
The great crested newt spends the bulk of its life on land but is dependent on small to medium sized freshwater ponds to breed. Naturally a creature of rough grassland, scrub and woodland, the species has long been associated with lowland farmland but has also found a niche in former (and current) mineral workings and other 'brownfield' habitats. Terrestrial life is typically spent within 250 m of the breeding ponds but dispersal of up to 1000 m can occur. It is crucial that these habitat components are appropriately linked by areas conducive to newt movement to permit migration between key areas. Studies have shown that the density of ponds may be important to the long term survival of populations and that great crested newts prosper where several ponds within a given area are connected by suitable habitat so that if a pond becomes unsuitable then others are available.
The great crested newt is still quite widespread in Britain. The Scottish distribution is predominantly in Dumfries and Galloway, the Borders, across the central belt and around Inverness. A 1995-96 national survey located 85 ponds with great crested newt populations. Subsequent work from local surveys and environmental assessments linked to development proposals has brought this number up to around 100. The species may be numerous locally in parts of lowland England and Wales but is absent or rare in Cornwall and Devon. It is absent from Northern Ireland.
They are nocturnal predators on invertebrates, spending daytime in damp refuges, for example, under stones and logs. Breeding takes place in ponds in spring to early summer, governed by temperature. A female can lay around 300 eggs which are laid singly, attached to vegetation. Larvae usually develop through their aquatic stages over a three month period before adopting the terrestrial habit. However, metamorphosis is dependent on temperature and in cooler climates or nutrient poor (and hence invertebrate prey deficient) ponds, larvae can take much longer than three months to develop. Once on land they take around three years to reach breeding maturity.
The species has suffered a decline in recent years with studies in the 1980s indicating a rate of colony loss of approximately 2% over five years across Britain. It is estimated that there are about 18,000 occupied ponds within Britain, although only about 3,000 of these have been identified. The British population is amongst the largest in Europe, where it is threatened in several countries.
The great crested newt is threatened by loss of breeding ponds through destruction or degradation of water quality due to development or changes in agricultural practice, but also through natural succession, neglect and mismanagement. The introduction of fish to breeding ponds is almost always catastrophic. Of equal importance is the loss and fragmentation of terrestrial habitat.