Effects of widespread fish introductions on paedomorphic newts in Europe

• Published in: Conservation Biology
• Main Authors: Denoël, Mathieu, Džukić, Georg, Kalezic, Milos L.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Blackwell Publishing Inc 2005
• Subjects: Extinction; Fish introduction; Introduced fish; Paedomorphosis; Polymorphism; Larzac; Balkan; Montenegro; Greece; Polyphenism; Global amphibian decline; Alpine lake; Mesotriton alpestris; Lissotriton helveticus; Triturus alpestris; Predation; Mesotriton alpestris lacustris; Mesotriton alpestris montenegrinus; Mesotriton alpestris piperianus; Mesotriton alpestris serdarus; Ichthyosaura alpestris; Dinaric Alps; Lac de la Cabane; Carassius auratus; Salmo trutta; Salvelinus fontinalis; Salvelinus alpinus; Onchorhyncus mykis; Ctenopharyngodon idella; Barbus peloponnesius; Italy; Alien species; Invasive species; Resilience; Alpine newt; Palmate newt; Apennines; France; Ichtyosaura alpestris apuana; Ichtyosaura alpestris reiseri; Ichtyosaura alpestris serdara; Ichtyosaura alpestris montenegrina; Ichtyosaura alpestris piperiana; Ichtyosaura alpestris lacustris; Cartography; Biodiversity loss; Alps; Life sciences; Aquatic sciences & oceanology; Zoology
• Online Access: https://orbi.uliege.be/handle/2268/3077; https://orbi.uliege.be/bitstream/2268/3077/1/Cons_Biol_2005-open-access.pdf; https://doi.org/10.1111/j.1523-1739.2005.00001.x

peer reviewed As a result of factors such as global warming, habitat destruction, and species introduction, amphibians are declining worldwide. No one, however, has analyzed the status of polymorphic amphibian species at a national or continental scale, although some local reports exist. Our aim was to report on the loss of intraspecific heterochrony as a loss to diversity in determining the consequences of fish stocking on European populations of paedomorphic newts. Paedomorphosis is a polymorphism in which larval traits are retained in the adult stage. We surveyed 39 paedomorphic populations of the alpine ( Triturus alpestris) and palmate ( T. helveticus) newts, all but one of which initially occupied fishless ponds and lakes in France, Italy, Slovenia, Bosnia, Montenegro, and Greece. Exotic fishes were found in 44% of the studied aquatic habitats, with a 100% presence in Montenegro. At all sites paedomorphs disappeared and metamorphs declined. Only fish explained these population changes because alternative factors such as drying were not significant. More catastrophically, fish introductions occurred in habitats known to support the largest populations of newts and even some endemic subspecies. If management and legislative measures are not taken to stop fish stocking, protect paedomorphs as conservation units at national and international levels, and restore natural habitats, all the largest paedomorphic populations may disappear in the near future. Their disappearance would represent a loss of one of the rare, fascinating examples of intraspecific heterochrony.