Beijering et al. (in prep) eDNA and livetrap survey data for small mammal detection in the Netherlands

Research context This data was collected to map the distribution of the root vole (Alexandromys oeconomus ssp. Arenicola) in the Netherlands. This data was used to answer the research question: How does the eDNA method using scat samples compare to the traditional livetrap method in terms of accuracy, time-efficiency, and cost-effectiveness? Both survey methods target the root vole in the Netherlands. Study species The root vole (Alexandromys oeconomus arenicola) inhabits wet, densely vegetated areas such as reed beds, marshes, and damp grasslands. In the Netherlands occurs the critically endangered endemic subspecies, which is highly dependent on wet, non-wooded habitats. The species competes with other vole species, particularly with the field vole (Microtus agrestis). The field vole is displacing root vole in areas that are becoming drier, therefore suitable root vole habitat has a dynamic water regime with seasonal fluctuations which suppresses competing species (Witte van den Bosch & Bekker, 2009). Methodology eDNA Scat samples were collected following a standard protocol, with up to 5 latrines sampled per location within one hour. Pooled samples were preserved in ethanol and sent to Wageningen Environmental Research, where DNA was extracted and a cytochrome b barcode region was amplified to identify rodent and shrew species via metabarcoding on an Illumina MiSeq platform. Detections with low read abundance (<5%) were filtered out to minimize false positives. Livetraps Livetrapping was conducted using Longworth traps, with 20 traps per location set in pairs at 10-metre intervals. After 2–3 nights of pre-baiting, animals were trapped over two consecutive nights with checks every ~12 hours. Captured individuals were identified to species, recorded, and immediately released. Study area Study areas were located in Natura 2000 regions in the Netherlands with suitable root vole habitat – reed lands, marshes, extensively managed meadows, marshy hayfields, moist dune valleys and periodically flooded areas (La Haye & Schekkerman, 2017) and prior evidence of its presence from owl pellets or historical data. In the Netherlands the species only persists in five isolated regions: Texel, Frisia, North-Holland, Holland-Utrecht, and the Delta region. Study period The eDNA datasets were collected from 2015 to 2023 and the livetrap studies from 1991 to 2018. Data format Sheets 1-4 contain data of four parallel eDNA/livetrap surveys. Sheet 5 contains eDNA data collected by the Dutch Mammal Society and partners. Sheet 6 contains livetrap data retrieved from studies conducted by or available to the Dutch Mammal Society. Related publication This data is linked to an article; Beijering et al. (in prep) eDNA as a Tool for a reliable and efficient method of surveying small mammals: A Case Study on the Endangered Root Vole (Alexandromys oeconomus ssp. Arenicola) in the Netherlands. Contact For any questions, please contact the Dutch Mammal Society (corresponding author: Kim Beijering).