PCR-based amplification of a cox1 mini-DNA barcode gene from feces: A non-invasive molecular technique to identify environmental DNA samples of maritime shrew (Sorex maritimensis)

The Maritime Shrew (Sorex maritimensis) is endemic to Canada and found only in Nova Scotia and New Brunswick. The Maritime Shrew has been identified as one of the vertebrate species in Nova Scotia that is most susceptible to the effects of climate change and global warming, and it is listed by NatureServe as Vulnerable (category G3). While generally regarded as a wetland specialist, relatively little is known about their specific habitat preferences. Non-invasive methods of sampling have proven valuable in identifying and monitoring such rare species. The objective of this study was to optimize a non-invasive method to document presence of Maritime Shrews using non-invasively collected fecal DNA and to develop a PCR-based protocol to amplify a short, [~]120 base pair section of the cox1 gene using shrew-specific primers. We used baited feeding tubes to collect shrew feces. Cox1 PCR primers were designed to preferentially amplify this mini-DNA barcode for shrews in samples that may contain feces from rodents as well. The primers were designed to amplify a small amplicon to increase the likelihood of successful amplification from degraded DNA. This technique is likely to be effective for documenting the distribution and habitat preferences of this relatively rare shrew in Nova Scotia and New Brunswick.