Differing long term trends for two common amphibian species (Bufo bufo and Rana temporaria) in alpine landscapes of Salzburg, Austria.

Martin Kyek,Robert Lindner,Peter H Kaufmann,Stefan Lötters

doi:10.1371/journal.pone.0187148

Martin Kyek, Robert Lindner + Show 2 more

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https://doi.org/10.1371/journal.pone.0187148

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Journal: PloS one	Publication Date: Nov 9, 2017
Citations: 17	License type: CC BY 4.0

Affiliation: Haus der Natur - Museum für Natur und Technik

Abstract

This study focuses on the population trends of two widespread European anuran species: the common toad (Bufo bufo) and the common frog (Rana temporaria). The basis of this study is data gathered over two decades of amphibian fencing alongside roads in the Austrian state of Salzburg. Different statistical approaches were used to analyse the data. Overall average increase or decrease of each species was estimated by calculating a simple average locality index. In addition the statistical software TRIM was used to verify these trends as well as to categorize the data based on the geographic location of each migration site. The results show differing overall trends for the two species: the common toad being stable and the common frog showing a substantial decline over the last two decades. Further analyses based on geographic categorization reveal the strongest decrease in the alpine range of the species. Drainage and agricultural intensification are still ongoing problems within alpine areas, not only in Salzburg. Particularly in respect to micro-climate and the availability of spawning places these changes appear to have a greater impact on the habitats of the common frog than the common toad. Therefore we consider habitat destruction to be the main potential reason behind this dramatic decline. We also conclude that the substantial loss of biomass of a widespread species such as the common frog must have a severe, and often overlooked, ecological impact.

Highlights

Amphibian species are declining worldwide and in Europe, they are considered the most endangered class of vertebrates [1]
The basis of this study is data gathered over two decades of amphibian fencing alongside roads in the Austrian state of Salzburg, highlighting that these fences are not just an important instrument for applied nature conservation, and generate valuable long term data on population trends
Our study focuses on three synthesising aims: (1) to test whether this long-term data set gathered through volunteer amphibian fencing allow us to derive any significant population trends, (2) to compare the different statistical analysis methods used and (3) to discuss the potential ecological reasons for any ascertained trends

Summary

Introduction

Amphibian species are declining worldwide and in Europe, they are considered the most endangered class of vertebrates [1]. The reasons for this are various and often cumulative. Even though there are many studies dealing with amphibian conservation, the growing concern about declining amphibian populations was often based on either anecdotal evidence or derived from limited, often short-term data sets [5, 6]. In the last years though, increasing efforts were undertaken to generate new, or analyse existing, long-term data sets, often derived.

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