1). Here, co-occurrence of the two salamander species (S. s. terrestris and S. a. atra) has been documented across a wide altitudinal range (500 to 1000 m a.s.l.) in an area characterized by mixed forest, or grassland with small streams (Klewen, 1986; Werner et al., in press). We selected 23 and 19 watersheds of low-order streams, respectively, potentially suitable and accessible to both species (Fig. 1). Watersheds had an average surface area of 27 852 m2 (ranging 17 309–43 668 m2) and covered areas of deciduous to mixed forests at elevations of 450–900 m a.s.l. Though S. atra is water independent

with regard to its reproductive mode, Klewen (1986) observed highest species’ densities in the vicinities of streams. Thus,

we chose haphazardly an accessible 100 m section along a small fishless stream within each watershed for salamander surveys (hereafter ‘sampling site’). STAT inhibitor Because of the steep terrain of the watersheds, our surveys covered an area of up to 100 m width on both sides of the stream. We obtained detection/non-detection data for both salamander species at each sampling site by visiting the sites three to four times in a randomly chosen order between 9 May 2010 and 6 July 2010. A single observer conducted visual encounter surveys (Vonesh et al., 2010) of about an hour during daytime to search for salamander larvae in the stream and to search for juvenile and adult salamanders in the terrestrial habitat. Suitable shelter objects on the forest floor were turned Methocarbamol and inspected for salamanders. To analyze which factors affect selleck products the occupancy probabilities of the two salamander species, we measured habitat and climatic predictor variables (Table 1). Variables characterizing the stream and the surrounding terrestrial habitat

of each sampling site were estimated directly in the field. We measured two variables that describe stream features. For the variable ‘pools’, we estimated the area with a low stream current, which provide suitable microhabitats for the aquatic larvae of S. salamandra (Baumgartner, Waringer & Waringer, 1999) as proportion to the total area within the stream section. For three haphazardly chosen 1 m2 sample plots within each stream, we counted and classified the mean amount of hiding possibilities for salamander larvae (i.e. stones or dead wood with a surface of at least 100 cm2; Thiesmeier & Schuhmacher, 1990) by using a rank scale (1 = more than a mean of 25 hiding possibilities; 2 = mean of 15–24.9 hiding possibilities, 3 = mean of 5–14.9 hiding possibilities; 4 = less than a mean 4.9 hiding possibilities). To characterize the terrestrial habitat at each sampling site, we quantified the mean stream bank slope by measuring the distance (m) per metre height at three randomly chosen points at 1.5 m distance to the bank on both sides of a stream (indicating stream accessibility for deposition of salamander larvae; Manenti et al., 2011).