Chatter about Natterjacks

The natterjack toad (Epidalea calamita) is an amphibian currently experiencing declines across Europe. This article aims to give a brief summary of the identification, location, degradation and conservation of the species, in the UK.

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 Identification

Adult natterjack toads usually grow to around 60-70mm in length. They are able to be distinguished from common toads (Bufo bufo) through their generally smaller size, because they have a distinctive yellow line visible down the middle of their backs and because they have fairly short legs, giving them an unusual walking style in contrast with the regular ‘hopping’ style of other toad species.

A natterjack toad may also be recognised through its distinctive call; natterjacks have a very loud, rasping mating call (made in the spring) due to the vocal sacs that they possess, found under the chin of male individuals. It is thought that this call can be heard up to a mile away from the individual.

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Natterjack toads breed around the edge of ponds during April-July. Spawn differs from that of the common toad in that it is laid in single string. Once the tadpoles have developed into toadlets, the yellow dorsal stripe is clearly visible making juvenile natterjack individuals easily recognisable.

Location

Natterjack toads are found in 17 countries across Europe, including the UK. However, declines in species numbers means that in Britain, they are usually confined to coastal sites. These may include sand dunes, coastal grazing marshes and sandy heaths. They require shallow and warm water facilities, thus natterjacks are often found in ponds amongst sand dune systems. This allows them to breed more effectively.

Across the UK, the toads are found on around 60 separate sites. Currently in the UK, the natterjack continues to notably reside in Suffolk, Norfolk, Lancashire, Lincolnshire, the Scottish Solway and the Cumbrian Coast, although several small populations are also found elsewhere as a result of successful reintroduction schemes, for example a single colony has been discovered on an upland fell site in Cumbria.

The first map below demonstrates historical records indicating the previous distribution of the species. The second map demonstrates the estimated distribution of the species in 2013, signifying natterjack toad declines.

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 Status

During the 20th century, the natterjack toad experienced significant declines across the UK, particularly in heathland areas in southern and eastern England. Today in the UK, the natterjack toad is currently listed under the national Biodiversity Action Plan, as a result of threats such as habitat loss due to human overpopulation, loss of coastal habitat sites due to sea defences and acidification of aquatic habitats.

Particular threats to the species also include the destruction of breeding ponds and terrestrial habitats, a degradation of habitat quality, issues stemming from climate change, threats from the chytrid fungal disease, currently threatening many amphibian species across Europe, fragmentation and isolation of natterjack toad populations, preventing dispersal and decreasing genetic viability, shading and silation of ponds and increased predation from other species, such as the common frog or great crested newt, which have been introduced into natterjack toad habitats.

Protection

In England, one of the main protection strategies includes the protection of sand dune habitats, essential for the survival of the natterjack toad, through inclusion in National Nature Reserves. Examples include Hoylake, Sanscale Haws and Ainsdale Sand Dunes. In Scotland the species is protected within Caerlaverock nature reserve and in Wales, although the species became extinct for a while, successful reintroduction plans have ensured that the natterjack once again resides in this area.

Strategies to help enable the protection of natterjack toads may include their translocation during major development projects on natterjack habitat sites, ensured connectivity between habitat sites and strict legislation; in the UK and in many places across Europe, it is an offence to kill, injure, capture or disturb natterjack individuals. Furthermore, it is also an offence to purposely damage or destroy known natterjack habitats and to try and keep, sell or trade individuals including eggs and those still within larval stages.

Recently, efforts are being made to construct a photographic database of natterjack toad individuals within Scotland, specifically along the Solway Firth. Each toad has a unique pattern of warts, allowing separate individuals to be identified. This information can then be used to help identify changes to populations in the future. There are currently thought to be around 200 breeding natterjack adults in Scotland currently, but all are exclusively found on the Solway Firth, meaning that effective conservation projects and monitoring in this area are a necessity.

James Silvey, left, and Pete Minting are two of the scientists involved in leading the study.

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James Silvey (RSPB Scotland) said:

 “The beautiful thing about natterjacks is they each come with their own individual fingerprint, and that’s in the form of the big warts and the yellow stripe on their backs.

“Each of the toads we photograph today could potentially live for 10 or 15 years and if we photograph it again we’ll know that individual was found here at Mersehead in 2014.

“We’re building up a database of natterjack mug shots for the future.”

 Another successful conservation project was also carried out at the RSPB Mersehead nature reserve, where a population of natterjacks was successfully established. Thus, with effective management schemes and new conservation initiatives, there could be some hope for the increase of natterjack toad populations across the UK.

 You can read more about the Scottish projects here: http://www.bbc.co.uk/news/uk-scotland-south-scotland-28703591

Photo credits:

Natterjack Toad by Matt Wilson

Natterjack toad by Dan Kane

Maps by Ordnance Survey (2013)

Male Natterjack Toad (Bufo calamita) by Simon Booth

Natterjack toad project by Dawn Nicoll

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