Have great crested newts Triturus cristatus translocated to a pond in mid-Wales been detrimental to existing amphibian populations?

https//doi.org/10.33256/hb175.2427
AUTHOR FRED SLATER
ABSTRACT In the period 1981–1985; our amphibian research was focused on a large pond in mid-Wales where on average 1,400 common toads Bufo bufo; a combined population of some 3,000 smooth newts Lissotriton vulgaris; palmate newts Lissotriton helveticus; and some 200 female common frogs Rana temporaria bred regularly. In the mid-1990s an unintentional release of some great crested newt eggs; larvae or efts took place; by 2008 fifty great crested newts were trapped entering the pond. By 2022; only one clump of frog spawn; two strings of toad spawn were found together with noticeably fewer Lissotriton spp.; particularly smooth newts; with great crested newts becoming the dominant amphibian species. From 2023 to 2025 no anuran spawn was found in the pond; by 2024 it became difficult to find Lissotriton newts; but torchlight surveys of great crested newts in early April gave an estimated population of 500. A similar survey in April 2025 gave similar results. Visits from anuran predators; otter Lutra lutra; buzzard Buteo buteo; grey heron Ardea cinerea have also declined suggesting a food chain effect related to increasing great crested newt numbers.

The Herpetological Bulletin is a quarterly publication in English. It includes full-length papers, natural history notes, book reviews, and other items of general herpetological interest. Emphasis is placed on natural history and conservation as well as captive care that includes breeding, husbandry, veterinary, and behavioural aspects.

pdf 05. Have great crested newts Triturus cristatus translocated to a pond in mid-Wales been detrimental to existing amphibian populations?

16 downloads

Open Access

Download (pdf, 406 KB)

https://doi.org/10.33256/hb175.2427

AUTHOR: FRED SLATER

ABSTRACT: In the period 1981–1985, our amphibian research was focused on a large pond in mid-Wales where on average 1,400 common toads Bufo bufo, a combined population of some 3,000 smooth newts Lissotriton vulgaris and palmate newts Lissotriton helveticus, and some 200 female common frogs Rana temporaria bred regularly. In the mid-1990s an unintentional release of some great crested newt eggs, larvae or efts took place and by 2008 fifty great crested newts were trapped entering the pond. By 2022, only one clump of frog spawn and two strings of toad spawn were found together with noticeably fewer Lissotriton spp., particularly smooth newts, with great crested newts becoming the dominant amphibian species. From 2023 to 2025 no anuran spawn was found in the pond and by 2024 it became difficult to find Lissotriton newts, but torchlight surveys of great crested newts in early April gave an estimated population of 500. A similar survey in April 2025 gave similar results. Visits from anuran predators, otter Lutra lutra, buzzard Buteo buteo and grey heron Ardea cinerea have also declined suggesting a food chain effect related to increasing great crested newt numbers.