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Newt in progress: Status for Triturus alpestris in Denmark
Abstract
Following the extensive habitat management of T. alpestris carried out since 1988 in Southeast Jutland, South Denmark, there has been an impressive increase in the number of breeding habitats. From 1988 to 1997 the number has increased by more than 6 times, from 32 to 201. That is a yearly growth of 22.7%. In the future more emphasis will be put on restoring the existing breeding ponds.
... The wide range of habitats also includes drainage and roadside ditches (Babik & Rafiński 2001, Arntzen et al. 2009, Pabijan 2018) and artificial reservoirs created by damming watercourses (Kolenda et al. 2019). In addition, Alpine newts often use amphibian conservation ponds (Bringsøe & Mikkelsen 1997). The ecological plasticity of this species is further emphasized by the fact that its habitat preferences may show regional differentiation. ...
In Central Europe, watercourses are not considered important breeding habitats for most amphibians, including the Alpine newt Ichthyosaura alpestris, for which the reproduction in a lotic habitat has rarely been documented. However, two breeding sites of this species were found during a herpetological survey conducted in the Western Carpathian foothills. Thirty-nine kilometers of small streams were visually searched between 2015 and 2020, and two occupied stream sections were sampled 27 and 20 times, respectively. The Alpine newt adults (mostly in May) and then the larvae (from the end of July to October) were observed in stream pools, which are slower-flowing and deeper than the surrounding parts of the stream channels. One site was occupied in each of the six years, while the other in three (2016-2017 and 2019) out of five, which indicates that the choice of these stream stretches as breeding sites was not a single-year, peculiar case. Nevertheless, reproduction of the Alpine newt in a lotic habitat remains a rare phenomenon, making it difficult to investigate the reasons for choosing this type of breeding habitat.
... Fra 1987 og fremefter er der i bjergsalamanderens naturlige sønderjyske udbredelse systematisk blevet nyetableret og oprenset vandhuller, hvortil salamandrene selv er vandret. Eksempelvis skete der på den måde mere end en seksdobling af bekraeftede ynglevandhuller (fra 32 til 201) for arten fra 1988 til 1997 (Bringsøe & Mikkelsen 1997). Herefter har vi i Bjergsalamandergruppen prioriteret at fastholde den gode taethed af ynglevandhuller ved primaert at oprense vandhuller, når nogle af dem med tiden på forskellige måder er blevet forringede. ...
Alpine Newt (Ichthyosaura alpestris) established after unauthorised introduction in Gentofte, north of Copenhagen, far from its natural Danish distribution. Is translocation of the Alpine Newt acceptable?
In August 2017, a hitherto unknown population of the Alpine Newt, Ichthyosaura alpestris, was recorded in the northern outskirts of Copenhagen on the island of Zealand, eastern Denmark. During August, October and November, a total of 14 or 15 individuals (adults and juveniles) were found under dead wood on the forest floor. The locality, named Bernstorffsparken or Bernstorff Slotshave (situated in Gentofte), is an urban park of 61 hectares and less than half consists of deciduous forest. There is one pond free of fish and most newts have been found near that pond. Yet another water body with at least some breeding success probably exists further south because juveniles were recorded in that area. The risk for this newt’s ability to disperse to a major forested habitat named Jægersborg Dyrehave to the north is judged. The locality is separated from this habitat by roads with heavy traffic. It is an open question whether I. alpestris will be able to cross the roads during rainy nights. But to the south it may be able to colonise nearby garden ponds if any should exist there though there are also roads with much traffic a bit further south.
On this new finding site, I. alpestris has certainly been introduced illegally by humans. In 1987 or 1988 a local amateur herpetologist informed the author of recent and unauthorised collection of some individuals of this species in Harzen, Germany, and subsequent release in Gentofte 2 km from Bernstorffsparken. Now the population seems well-established. It probably originates from Harzen.
The author considers it unfortunate that I. alpestris has been introduced to Zealand though it will most probably not cause any harm to the indigenous fauna and flora.
Another and very recent case of translocation of I. alpestris in Denmark – within its natural range in southeastern Jutland – is also mentioned and commented upon. It is argued that numerous cases of state-authorised translocation of various animal species in Denmark may well have led to a general misunderstanding in the public that moving animals will be beneficial to the fauna and biodiversity. Apart from the two cases mentioned in this report translocation of I. alpestris has never been carried out in Denmark. The national Danish conservation authorities are encouraged to be more cautious about allowing translocation.
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