Four years monitoring of the endangered European plethodontid salamanders.

The ongoing biodiversity crisis is strongly threatening amphibians, mostly because of their peculiar physiology, their sensitivity to climate change and the spread of diseases. Effective monitoring involving assessments of pressure effects across time and estimation of population trends play a key role in mitigating amphibian decline. To improve implementation of standardized protocols and conservation efforts, we present here a dataset related to one of the amphibian genera whose onservation status is considered the most declining according to the IUCN. We report information on 66 populations of the endangered European cave salamanders, genus Speleomantes, that was collected through a standardized monitoring along a four-year period (2021-2024). Demographics data of the populations and fitness-related data of single individuals are reported. Furthermore, we include 3,836 high quality images of individuals that can allow to perform studies aiming to assess the phenotypic variability within the genus, and to perform long-term capture-mark-recaptured studies.

Capture-mark-recapture data on the strictly protected Speleomantes italicus.

This data set collects capture-mark-recapture data, biometric data, and stomach contents of seven populations of the Italian cave salamander (Speleomantes italicus), one of the strictly protected European plethodontid species endemic to mainland Italy. We monitored six subterranean populations inside caves, and one fully epigean population living in a forest, surveying a total area of >5200 m2 . Data collection was performed 24 times throughout a year for each of the subterranean populations, and seven times in late winter-early spring for the epigean population. Salamanders were individually identified using two different marking methods: subcutaneous injection of visual implant elastomers (VIE) and photographic recognition of the dorsal pattern. Overall, the data set contains information on 1283 captured salamanders, corresponding to 783 different individuals and 500 recapture events. This type of data can be used to assess the species detection probability and to estimate the size of the populations, which are fundamental parameters for the assessment of its conservation status. Captured salamanders were weighed using a digital scale and photographed next to a reference ruler to perform post hoc measurements. This allows to assess the potential variation of the body condition of individuals through the time, and the potential divergences between conspecific populations. Furthermore, repeated measurements of recaptured individuals can allow to evaluate the seasonal growth rates of Speleomantes. Before their release, the salamanders underwent stomach flushing, a non-invasive technique that allows us to investigate the food residues in the salamanders' stomach. In 951 salamanders, we were able to recognize a total of 7077 consumed prey items belonging to 37 different prey categories (i.e., order level or lower), completing the information on the consumed prey for the entire Speleomantes genus. Data on consumed prey can be used to assess potential divergences between populations or between individuals of different ages/sexes, but also to assess the potential trophic specialization of individuals. The distinctiveness of this data set is that, by combining the capture-mark-recapture data with those on the diet of individuals, it allows to perform detailed studies on the consistency of individuals' food preference over time, an analysis that has never been performed on these salamanders. We release the data set into the public domain under Creative Commons Attribution 4.0 International license (CC-BY). When you use this data in your publication, we request that you cite this data paper; if you are using the whole data set related to the entire project, please cite all the related papers. If this data set will be an important part of the data analyzed in your study, you should consider discussing a collaboration with the data set contact person. If you plan to use data from the European plethodontid salamanders trophic niche project, please contact the contact person to find out if similar analyses are already underway or if unpublished updates are available.