Non-Trapping, Non-Invasive, Rapid Surveillance Sampling Using Tracking Tunnels, Trail Cameras, and eDNA to Determine Presence of Pest Predator Species

Abstract

A common challenge for land managers is knowing which vertebrate pest species are present in areas they manage, especially if such areas are remote like isolated habitats, rugged terrain, or infrequently traveled islands. Most invasive predator species, such as feral dogs, cats, mongoose, and commensal rodents pose great threat to human health and key resources such as native species. Animal trapping to determine the presence of a pest species can be expensive and dangerous, requiring permits, experienced personnel, multiple days, and multiple trapping methods. Furthermore, many invasive pest species may go unnoticed because they are nocturnal, secretive, or leave little evidence of their presence. Tracking tunnels, trail cameras, and environmental DNA (eDNA) are non-trapping methods that can be used to rapidly assess if vertebrate pest species are present in a given habitat or ecosystem, including before, during, and after pest suppression techniques are implemented. We share tracking tunnel dimensions and specifications so readers can make their own tracking tunnels for rodent and other small mammal sampling, and we provide some common distributers where tracking tunnels can be purchased. A brief overview of trail camera technology and eDNA forensic uses are described, as well as their applications for vertebrate pest identification, surveillance, and damage management. To demonstrate these methods, we share example case studies from the Caribbean, including first time records of house mouse presence at Sandy Point National Wildlife Refuge in St. Croix (US Virgin Islands) and along a rainforest elevation gradient in the Luquillo National Forest, Puerto Rico. Additionally, we describe case studies of trail camera use on Desecheo Island (Puerto Rico) to determine brodifacoum bait consumption, and eDNA use in Wyoming to determine native bird depredation events. Tracking tunnels and trail cameras are recommended as quick and inexpensive ways to reveal the vertebrate pest species that are present at a site or habitat. These non-trapping, non-invasive techniques can provide quick and efficient methods of surveillance, detection, and monitoring of vertebrate pests, and otherwise may be used as effective tools to aid in wildlife damage management.

Monitoring for the presence of invasive arboreal rodents: an assessment of monitoring tools across forest strata

“…The e cacy of rodent monitoring methods in different management scenarios therefore warrants careful assessment. Some of the most commonly used devices to monitor the presence of rodents include motion-triggered camera traps, chew cards, and tracking tunnels (Shiels et al 2018;Nottingham et al 2021). There are distinct bene ts and challenges with the use of each of these devices as rodent monitoring tools.…”

“…Differences in chew marks can yield species-speci c data, though excessive chewing by some species can mask the presence of others (Burge et al 2017). Tracking tunnels can similarly yield speciesspeci c data for small mammals through the analysis of inked footprints (Shiels et al 2018). Due to 'shyness' or neophobia of some animals however, the use of tracking tunnels may under-estimate presence and subsequent density estimates (Cooper et al 2018).…”