Application of real-time PCR for the identification of the endangered species Galemys pyrenaicus through faecal samples

Background Currently, many micromammals are important targets for study. The endangered Galemys pyrenaicus is an outstanding example. Globally, their populations have suffered a substantial decline in last 20 years. In the surveyed area, the capture of desman is legally forbidden due to the high conservation concerns. Reason by non-invasive sampling through faeces is proposed for its monitoring. Furthermore, the confusion between faeces from desman and Mediterranean water shrews must be considered. Thus, the aim of this study was focused on developing RT-PCR assays to determine the presence of Galemys pyrenaicus and N. a. anomalus from non-invasive samples. Methods and results The study was conducted in the mountains of the System Central of Extremadura (Spain). A total of 186 samples were collected from 2018 to 2021 by experts where historically reported and/or our previous studies confirmed their presence. RT-PCR assays using hydrolysis probes were designed to detect genetic material from both desman and Mediterranean water shrews and its specificity was confirmed. The reliability of the method was further assessed by PCR sequencing of mitochondrial Cyb and d-loop, resulting fully compatible with the RT-PCR approach. Intraspecific phylogenetic relationship was reported to improve knowledge about mtDNA variability in the desman from the Central System. Conclusions We demonstrated that RT-PCR gives a gold opportunity to further map the species using faeces which minimizes disturbance and reports both population status and individual presence. Cost-effective RT-PCR combined with field-collected faeces allows us to better investigate the full range of occurrence of the species.