First evidence of predation on the native endangered Iberian desman (Galemys pyrenaicus) and Iberian water shrews (Neomys anomalus) by the invasive species American mink using eDNA tools in Extremadura (Spain)

Abstract

Background: Wildlife conservation and management aims to restore population declines, it is the vulnerable or endangered populations who require the greatest conservation efforts. In this context, non-invasive sampling has been evaluated as an option for reporting prey/predator impact. Galemys pyrenaicus is currently threatened throughout its range, and cohabits with Nemys anomalus, in Extremadura (Spain). Predation by American mink and otter has been suggested, but the first one is considered a serious conservation problem. This study has focused on the use of molecular methods based on RT-PCR and DNA sequencing, as it can inform on how invasive predators are harming the desman or the Iberian water shrew, and how these genetic tools can be used to detect predation.

Methods and results: Five samples (faecal and stomach contents) were received and RT-PCR assays were performed using TaqMan probes simultaneously targeting the cytochrome b (cytb) genes of G. pyrenaicus and N. anomalus, and the presence of both micromammals as prey was assessed. The predator was identified by Sanger sequencing using the nuclear IRBP gene. The assays provide a powerful tool for identification of invasive species, as in this case, but further confirmation by comparative sequence alignment by BLAST search was also necessary.

Conclusions: This study contributes to highlight simultaneously monitor and discriminate predation on specific micromammals with faecal samples of predators. Also supports the use of highly sensitive DNA analysis from samples obtained from predators as an additional methodology to monitor their effects on prey populations.

Keywords: Galemys pyrenaicus; Neomys anomalus; Neovison vison; Faeces; Identification; Invasive species; Predation.

Fig. 1

Map showing the three sampling areas with water course, and the location of the samples analyzed: Ambroz (A), Jerte (J), and La Vera (Tietar) (V)

Fig. 2

Fast Minimum evolution tree of the sampled IRBP sequence (labeled unknown, indicated with a yellow arrow) and its most similar sequences identified in a BLAST search (identity ≥ 88% molecular weight)