Habitat use during the aquatic phase of the newts Triturus vulgaris (L.) and T. cristatus (Laurenti) in central Norway: proposition for a conservation and monitoring area

Abstract

Amphibian populations are declining at an alarming pace in many parts of the world. Consequently, as part of the strategy for establishing a 360 km 2 conservation and reference area for amphibians in central Norway, 341 lentic water bodies were surveyed to investigate and briefly describe their hydrography and the occurrence of the newts Triturus vulgaris (L.) and T. cristatus (Laurenti) in the area. In particular we investigated the factors that could explain the presence of the respective newt species, including biotic and abiotic factors. The multiple logistic regression analyses suggested that the presence of T. cristatus was best explained by altitude and ion concentration, both in a nonlinear fashion, whereas fish had a negative effect on T. cristatus, which was never found coexisting with fish. The presence of T. vulgaris was best explained by altitude (linear relationship) and ion concentration (convex relationship), besides the occurrence of T. cristatus. Triturus vulgaris was occasionally found to occur at low densities in ponds having fish. For both species the probability of presence was higher when the opposite newt species was present. pH influenced both species in a convex nonlinear fashion with highest probability of presence around pH 6.5. This area is valuable for conservation, monitoring and reference for marginal amphibian populations. Any decline in their abundance would be discovered relatively quickly, and likely causes could be inferred. It can also serve as a reference area for future comparative studies of amphibians elsewhere.

Distribution patterns and environmental determinants of European newts in the Montenegrin karst area

“…As far as breeding sites are concerned, the Montenegrin karst newts' aquatic preferences overall appear to fit into the general picture of the "preferable" newt breeding site (a water body with a relatively stable hydroperiod, with dense aquatic vegetation, intermediate pH, and ionic concentration, and without fish) (e.g., Arntzen & Teunis 1993;Ildos & Ancona 1994;Marnell 1998;Oldham et al 2000;Babik & Rafinski 2001;Joly et al 2001;Denoël et al 2005;Skei et al 2006;Denoël & Lehmann 2006). However, regarding the aquatic preferences of new species in the Montenegrin karst area, none of the breeding site characteristics could discriminate newt species, both in syntopy and allotopy.…”

“…Landscape characteristics, such as the density of nearby water bodies and the possible network of migration corridors (e.g., Joly 2001;Van Buskirk 2005), are very important because newts exhibit limited dispersal abilities, spawning-site fidelity and structuring as demes (Arntzen & Wallis 1991;Ficetola & Bernardi 2004;Smith & Green 2005;Jehle & Sinsch 2007). However, understanding of the newt-speciesdistribution causalities has been largely improved using spatial-environmental modeling of environmental characteristics in studies aimed at elucidating problems such as the determination of a species' range limits, the definition of the biogeographical history of species, and the impact of climate warming (e.g., Teixeira et al 2001;Teixeira & Arntzen 2002;Arntzen 2006;Skei et al 2006;Arntzen & Themudo 2008). …”

Pond‐based survey of amphibians in a Saxon cultural landscape from Transylvania (Romania)

“…Such variables are, for example, the reed cover of the ponds and the presence of predatory fish (Hartel et al 2007a), but in the case of H. arborea it may also be the light conditions (and implicit the temperature) of the ponds (Pellet & Hoehn 2004). The lack of pond occupancy-altitude relationship for other amphibian species that prefer permanent ponds such as T. cristatus (Gustafson et al 2006;Skei et al 2006) and B. bufo (Scribner ) may be explained by the larger ecological plasticity of these species in the altitudinal range and environmental conditions of this area. These species were found to be influenced by reed cover and predatory fish (Hartel et al 2007a), and in the case of B. bufo by landscape composition and configuration (Hartel et al 2008).…”

“…Amphibian species that are documented to prefer permanent, vegetated ponds for reproduction, such as T. cristatus, B. bufo, R. dalmatina, H. arborea, R. esculenta complex (Vos & Stumpel 1995;Scribner et al 2001;Nyströ m et al 2002Nyströ m et al , 2007Gustafson et al 2006;Skei et al 2006), have a large permanent pond occupancy (Figure 3). The area studied by us allows proper conditions for these species and a large species richness since the permanent ponds are well represented and well vegetated [the mean amount of macrophyte vegetation cover of the ponds being up to 30% ], the ponds without predatory fish are still in high number [41% (Hartel et al 2007a)], the permanent ponds are closely situated to the forests [average distance is 232 m ], the forest coverage is large (Table I), and the land use is, in large part, traditional (Mountford & Akeroyd 2005).…”

Amphibian recovery after a decrease in acidic precipitation

“…This is also the general impression of T. cristatus . It prefers ponds and lakelets with a higher pH and is also the most vulnerable of the species dealt with here (Strand 2002;Skei et al 2006;Dolmen 2010). Most of the minimum pH values seen for species in the present study are supported by Strand's (2002) investigations of close to 1300 ponds and lakes in various parts of Norway.…”