Arboreal camera trapping: taking a proven method to new heights

Abstract

Summary1. Although camera trapping has been shown to be a highly effective non-invasive tool for wildlife monitoring, the technique has not yet been widely applied to studies of arboreal species. Despite the unique challenges that camera trapping in the canopy poses, its versatility and relatively non-invasive nature, combined with recent technological improvements on the cameras themselves, make camera trapping a highly useful tool for arboreal research.2. We present data on the methodology and effectiveness of arboreal camera trapping during the first 6 months of a year-long study in the Lower Urubamba Region of Peru investigating animal use of natural crossing points (i.e. branches) over a natural gas pipeline clearing. We placed Reconyx PC800 Hyperfire cameras in 25 crossing points of 13 distinct natural canopy 'bridges' at a mean height of 26Á8 m. 3. After 6 months of data collection, we logged 1522 photoevents, recording 20 mammal, 23 bird and four reptile species. An analysis of animal passing events in front of the cameras over time did not suggest any negative response to camera presence. While we found that cameras in the canopy are triggered more frequently by nontarget stimuli (e.g. leaves) than cameras on the ground, we demonstrated significantly reduced false triggering following leaf removal within 1Á5 m of the camera. 4. Our results suggest that arboreal camera trapping can provide robust documentation of a diversity of vertebrate species engaged in a variety of activities, and we provide recommendations for other researchers interested in using in this method. This is the most extensive arboreal camera trapping study to date in terms of the length of the study period, the number of cameras being used and the height of the cameras in the trees. Therefore, lessons provided from this experience can be used to improve the design of future arboreal camera trap studies.

Out on a Limb: Arboreal Camera Traps as an Emerging Methodology for Inventorying Elusive Rainforest Mammals

“…Understanding the effects of anthropogenic disturbance to canopy environments is particularly important given that a number of different taxonomic assessments have suggested that biodiversity within canopy strata is under greatest threat due to habitat modification [4,[7][8][9][10][11]59]. Here we suggest that the arboreal camera trapping method can be both useful and cost-effective in the long term for conservation assessments and can provide opportunities to learn more about some of the most charismatic [12] and threatened species in the world [38,39,54] which may otherwise remain largely unknown and could quietly disappear from our planet. …”

Comparing spatial capture–recapture modeling and nest count methods to estimate orangutan densities in the Wehea Forest, East Kalimantan, Indonesia

“…Camera trapping also provides additional data beyond population abundance or density that can allow researchers to develop a more well-rounded understanding of elusive and difficult-to-study populations. This includes information about population structure, demography, activity and ranging patterns, social interactions, and body condition (Head et al, 2012;Nakashima et al, 2013;Galvis et al, 2014;Gregory et al, 2014). For example, once encounter history data is obtained using camera trapping, more general SCR models for open populations or accommodating non-IDed detections can be developed, allowing researchers to obtain a more detailed understanding of population demographics.…”

“…Setting cameras in the trees is one possibility. Recent studies demonstrate that it is possible to obtain captures of primates with arboreal camera traps (Gregory et al, 2014) and cameras placed in carefully selected arboreal locations could supplement records on the ground. This might be especially useful in areas where there is a sex difference in use of the ground, as may be the case at certain locations in Wehea (e.g., sepans) and has been found at other orangutan study sites (e.g., Manduell et al, 2011).…”

“…Despite its promise and wide application in wildlife studies, camera trapping has only recently been embraced by primatologists (Head et al, 2012;Olson et al, 2012;Tan et al, 2013;Loken et al, 2013Loken et al, , 2015Galvis et al, 2014;Gregory et al, 2014). Most notably, a recent study simultaneously used nest surveys and camera trapping to estimate the relative abundance and distribution of chimpanzees (Pan troglodytes troglodytes) and gorillas (Gorilla gorilla gorilla) across different habitat types in West Africa, and found that the two methods produced roughly comparable results (Nakashima et al, 2013).…”

Scene‐specific convolutional neural networks for video‐based biodiversity detection

“…Without sufficient observations, it is difficult to make conservation decisions regarding animal presence, population size or habitat preferences. As an alternative to direct observation, many researchers are adopting passive monitoring systems using image capture (Anderson et al., ; Gregory, Carrasco Rueda, Deichmann, Kolowski, & Alonso, ; Schmid, Reis‐Filho, Harvey, & Giarrizzo, ). While image‐based monitoring reduces the effort and invasiveness of documenting animal presence, it generates a large number of extraneous images without animals (Swanson et al., ).…”