A comparison of camera trap and permanent recording video camera efficiency in wildlife underpasses

Abstract

In the current context of biodiversity loss through habitat fragmentation, the effectiveness of wildlife crossings, installed at great expense as compensatory measures, is of vital importance for ecological and socio‐economic actors. The evaluation of these structures is directly impacted by the efficiency of monitoring tools (camera traps…), which are used to assess the effectiveness of these crossings by observing the animals that use them. The aim of this study was to quantify the efficiency of camera traps in a wildlife crossing evaluation. Six permanent recording video systems sharing the same field of view as six Reconyx HC600 camera traps installed in three wildlife underpasses were used to assess the exact proportion of missed events (event being the presence of an animal within the field of view), and the error rate concerning underpass crossing behavior (defined as either Entry or Refusal). A sequence of photographs was triggered by either animals (true trigger) or artefacts (false trigger). We quantified the number of false triggers that had actually been caused by animals that were not visible on the images (“false” false triggers). Camera traps failed to record 43.6% of small mammal events (voles, mice, shrews, etc.) and 17% of medium‐sized mammal events. The type of crossing behavior (Entry or Refusal) was incorrectly assessed in 40.1% of events, with a higher error rate for entries than for refusals. Among the 3.8% of false triggers, 85% of them were “false” false triggers. This study indicates a global underestimation of the effectiveness of wildlife crossings for small mammals. Means to improve the efficiency are discussed.

Effectiveness of camera traps for quantifying daytime and nighttime visitation by vertebrate pollinators

“…While this would standardize all the cameras and could produce a more reliable data set, there is a cost involved in the screening of photos. Here, efficient tools to manage camera trap data, such automated image recognition software, are critical (e.g., Jumeau et al., ; Niedballa, Sollmann, Courtiol, & Wilting, ; Tack et al., ), and citizen science can assist (e.g., McShea, Forrester, Costello, He, & Kays, ; https://www.zooniverse.org/projects/birgus2/western-shield-camera-watch/classify). Increasingly sophisticated digital video recording devices (e.g., GoPro, https://gopro.com) offer another alternative and/or complementary option to still cameras that have enormous potential for, and are beginning to be applied to, pollination biology studies, even with invertebrates (e.g., Gilpin, Denham, & Ayre, ).…”

“…While the potential of camera trapping as a method for pollinator detection is clearly vast, there has been no rigorous evaluation of the sampling considerations needed for this type of study. Such an evaluation will be important for understanding potential issues such as the number of replicate camera traps needed, their effectiveness at detecting different groups of organism, the effect of camera setup (e.g., distance, angle), and ambient conditions (e.g., time of day, temperature), and the data they can reliably collect (Jumeau, Petrod, & Handrich, ). Here, we aimed to (a) measure the effectiveness of camera trapping as a method of identifying vertebrate visitors and (b) quantify visitation rates and timing of pollinator visits and (c) resolve which aspects of foraging behavior could be quantified.…”

AudioMoth: Evaluation of a smart open acoustic device for monitoring biodiversity and the environment

“…Such applications require numerous large and mains‐powered devices, positioned on the tops of buildings in strategic locations. These systems are impractical in the natural environment, away from a power source and in situations where large devices are prone to unwanted discovery and destruction, as commonly occurs with camera trapping (Jumeau, Petrod, & Handrich, ). Applications relating to resource exploitation require small‐sized, low‐energy and low‐cost devices, suitable for cryptic deployment of sufficient numbers for a grid that achieves full coverage of large tracts of exploitable habitat, often in remote terrain, over a continuous period of several months.…”

Distance and size matters: A comparison of six wildlife camera traps and their usefulness for wild birds

“…). However, one approach that is most similar to ours was done by Jumeau, Petrod, and Handrich (). These authors compared permanent recordings (video) with triggered pictures at two meters distance.…”