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Introduction to Amphibians

Great Crested Newt by Terry Coult

There are five native amphibian species in the region; Common Frog Rana temporaria, Common Toad Bufo bufo, and the three newt species, Palmate Lissotriton helveticus, Smooth Lissotriton vulgaris and Great Crested Triturus cristatus. All are quite widespread, the most frequent being the Common Frog, and the least frequent the legally protected Great Crested Newt. All five species are declining in numbers.

Their habitat requirements are fairly similar, with some species slightly more restricted than others. All five species use mainly natural or semi-natural terrestrial habitats and breed in still, fairly neutral pH waters. Frog and toad tadpoles can survive on plant material such as algae, though they will also eat animals. Newt efts will only eat invertebrate animal material. Consequently, frogs and toads can more readily colonise new ponds at an earlier stage of succession than newts can.

In the species accounts, the descriptions of the newts, in particular, often include the words ”usually”, “mostly”, “generally”. There is quite a lot of variation in both appearance and behaviour, some of which is unexplained, and this should be borne in mind with these species. The terms used to describe juvenile newts vary between publications. Here, they are called aquatic efts and terrestrial efts. Elsewhere, terrestrial efts may be called “efts” and aquatic efts may be called “larvae”. In this account, “larvae” is considered to be more appropriately used only for invertebrates.

Amphibians are regularly surveyed for, so there are many reliable records for these species. The protected status of Great Crested Newts ensures that developments requiring planning permission often have to have amphibian surveys of nearby ponds. The main survey method for newts is the use of “bottle traps” placed in the water and left overnight. These work like lobster pots, trapping the newts when they enter the bottles. Water Shrews Neomys fodiens are sometimes accidentally caught, with fatal results. Other amphibian survey methods are “torching” the pond after dark, netting, and looking for eggs and for terrestrial animals. A protected species survey licence is needed when surveying for Great Crested Newts.

The high level of public interest in amphibians has enabled the Wildlife Trusts to carry out public surveys of garden ponds in South Tyneside, Tees Valley and elsewhere. These have highlighted the importance of these ponds to amphibians and added to the picture of the distribution of the amphibian species, particularly for the introduced Alpine Newt Ichthyosaura alpestris.

The basic information on amphibians in our region came from H. G. Bolam (Bolam, 1915; 1917). Since 1998, regional maps of the distribution of the records of our amphibians have been periodically published (Durkin, 2010A). Natural England has a set of criteria for the designation of Sites of Special Scientific Interest (SSSI), on the basis of the numbers of species present and the breeding population size of each of the species. The criteria are discussed under each of the native species.

Non-native species are occasionally found. Alpine Newts have been well established at several ponds for many years, and can spread to other ponds, so they have their own account here. Pool Frogs Pelophylax lessonae and Natterjack Toads Epidalea calamita were reported in coastal North Northumberland in the 19th century, almost certainly as short lived introductions. Great Crested Newts have been available from pet shops, sometimes from continental species and some of these may have been released into the wild. These may account for some of the variation found in some of our Great Crested Newt populations.

The small, fragile bones of amphibians are rarely retained in the fossil record. All five of our native species have probably been present since post-glacial times and probably no other species have been present and then become extinct. Except for Palmate Newts, the native species have all been recorded since the 19th century. Palmate Newts were only considered to be a separate species from Smooth Newts in Britain in the 19th century.

Frogs are celebrated in place names at Frog Hall in Teesdale and at Frog Wood Bog SSSI in Hamsterley Forest. Toads and newts have been less popular, unless we can count Newton Aycliffe!

All of our native amphibians have some legal protection under the Wildlife and Countryside Act, and Natterjack Toad and Great Crested Newt have fuller protection under the European Species and Habitats Directives (English Nature, 2004).

by John Durkin