Comparing fine-scale temporal environmental DNA (eDNA) sampling to camera trapping for detecting mammalian carnivores

Bolton, P

Abstract

Anthropogenic pressures have caused global species declines, making accurate biodiversity monitoring essential in providing data to help avert extinctions. One-fifth of mammalian species globally are classed as under threat which means a rapid, reliable, and inexpensive monitoring method could help streamline conservation management decisions by following patterns or species dips/increases in the data. As many monitoring techniques are invasive or destructive, a non-invasive technique would reduce direct handling and stress to the animals. Environmental DNA (eDNA) has emerged as a cost-effective, non-invasive, and efficient biodiversity monitoring method which has been used for both aquatic and terrestrial species. Previous mammalian eDNA-based studies have effectively detected terrestrial and semi-aquatic mammals and compared favourably to camera trap results. However, carnivores are one of the more problematic groups regarding eDNA detections. In this study, the validity of semi-aquatic and terrestrial mammalian detection via eDNA was investigated within the north-eastern region of Spain by comparing eDNA metabarcoding to camera trap data at 25 sites along five rivers. Two eDNA sampling events were carried out 10 days apart to see if short term temporal sampling would validate results. 24 species were detected overall from the eDNA samples from five different orders, 22 species were detected in the second sampling period whereas only 18 were detected in the first sampling period. Camera traps were set to run for 10 days between the first eDNA sampling session till the second.
Species richness was noticeably higher when combining the samples. Six species of carnivores were detected with eDNA and seven by the camera traps, with five species overlapping. All six carnivores were detected in the second sampling period with only four detected in the first. Detection probabilities (using occupancy modelling) were largely similar for carnivores when using eDNA and camera traps. The successful detection of multiple carnivores within this study has shown how temporal eDNA sampling can provide rich and robust presence-absence data which aligns with traditional methods.

Citation

Bolton, P. Comparing fine-scale temporal environmental DNA (eDNA) sampling to camera trapping for detecting mammalian carnivores. (Dissertation). University of Salford

• Thesis Type: Dissertation
• Deposit Date: Feb 11, 2022
• Publicly Available Date: Feb 11, 2022
• Additional Information: Funders : Vincent Wildlife Trust;WildCRU
• Award Date: Feb 11, 2021