Cave salamanders (Speleomantes spp.) in Germany: tentative species identification, estimation of population size and first insights into an introduced salamander

The pathways of introduction of non-native amphibians are diverse, as historically amphibians were used as pest control agents, food stock, or were introduced to perform research. Today, the pet trade is the main source for amphibian introductions into novel ranges. However, these introductions mainly concern anurans, whereas cases involving urodeles are less common. Since 2013, a population of European cave salamanders, Speleomantes spp. Dubois, 1984, is known to be present in Germany. However, knowledge on the size of this population is missing, and it is unknown to which of the similar-looking species of Speleomantes it belongs. Here, we applied loglinear capture-recapture models to estimate population size, and used a recently published photographic database, including more than 1000 images of all eight Speleomantes species, to determine the species identity of the German population. According to our estimates, the population consists of 170 to 485 individuals (± 134 to 320). Based on colour pattern the population most likely belongs to S. italicus (Dunn, 1923). We additionally provide the first evidence for reproduction and give further insights into this non-native salamander population.