Searching for rare and secretive snakes: are camera-trap and box-trap methods interchangeable?

Abstract

ContextAdvancements in camera-trap technology have provided wildlife researchers with a new technique to better understand their study species. This improved method may be especially useful for many conservation-reliant snake species that can be difficult to detect because of rarity and life histories with secretive behaviours. AimsHere, we report the results of a 6-month camera-trapping study using time lapse-triggered camera traps to detect snakes, in particular the federally listed Louisiana pinesnake (Pituophis ruthveni) in eastern Texas upland forests in the USA. MethodsSo as to evaluate the efficacy of this method of snake detection, we compared camera-trap data with traditional box-trapping data collected over the same time period across a similar habitat type, and with the same goal of detecting P. ruthveni. Key resultsNo differences in focal snake species richness were detected across the trap methods, although the snake-detection rate was nearly three times higher with camera traps than with the box traps. Detection rates of individual snake species varied with the trapping method for all but two species, but temporal trends in detection rates were similar across the trap methods for all but two species. Neither trap method detected P. ruthveni in the present study, but the species has been detected with both trap methods at other sites. ConclusionsThe higher snake-detection rate of the camera-trap method suggests that pairing this method with traditional box traps could increase the detection of P. ruthveni where it occurs. For future monitoring and research on P. ruthveni, and other similarly rare and secretive species of conservation concern, we believe these methods could be used interchangeably by saturating potentially occupied habitats with camera traps initially and then replacing cameras with box traps when the target species is detected. ImplicationsThere are financial and logistical limits to monitoring and researching rare and secretive species with box traps, and those limits are far less restrictive with camera traps. The ability to use camera-trap technologies interchangeably with box-trap methods to collect similar data more efficiently and effectively will have a significant impact on snake conservation.

Safe from sunburn: The divergent diel pattern of a Hydrophis sea snake

“…Tag studies are also expensive and sample sizes tend to be small (Lashley et al, 2018), plus resulting changes in behavior can bias results (Fitch & Shirer, 1971). Camera trapping is slowly gaining ground as a method for detecting terrestrial snakes, but diel patterns have yet to be published, and the potential for use in the marine environment is yet undetermined (Neuharth et al, 2020;Welbourne et al, 2017).…”

“…For land‐based studies, the development of tracking collars and then camera traps that could autonomously detect and capture animals in action without the disturbance of human presence (Bridges & Noss, 2011) provided new opportunities for the statistical modeling of animal activity patterns and increased contributions to this growing field of study (Distiller et al, 2020; Lashley et al, 2018; Rowcliffe et al, 2014; Zhang et al, 2017). Camera trap studies with terrestrial snakes suggest adequate performance for faunal detection (Neuharth et al, 2020) but may be less effective for specific ethological investigations (Welbourne et al, 2017). Camera traps in marine environments are even more problematic.…”

Comparing camera traps and visual encounter surveys for monitoring small animals

“…Camera trapping efforts targeting reptiles and amphibians frequently employ timelapse methodology (Gibson et al 2015), which can demand an intensive data processing component, as it often produces a very high proportion of non-target images (Hobbs and Brehme 2017). For example, Neuharth et al (2020) used time-lapse methods to survey snakes and reported an average of 1 target species detection per 16,038 images. Furthermore, our ratio of target to nontarget images exceeds that reported in similar studies employing the AHDriFT method (Amber et al 2021).…”

Novel Technologies and Their Application for Protected Area Management: A Supporting Approach in Biodiversity Monitoring

“…Use of remote photography has become standard for documenting species distributions over broad spatio-temporal scales [59]. Photographic approaches are suitable for examination of species occupancy or abundance in aquatic and terrestrial biomes [34] and are suitable for targeting a range of animal species [60][61][62][63][64][65]. Robust statistical methodologies are available for data analysis, including spatially explicit capture-recapture techniques (SECR), multi-layered robust principal component analysis, occupancy modeling, and predator-prey co-occurrence analysis [66][67][68][69].…”

“…One advancement to PIR sensors, the so-called HALT trigger, utilizes a near-infrared beam to increase camera trapping performance on arthropods and small vertebrates [63]. As an alternative to sensorbased CT activation, automated TL photography has application to document arthropods, squamates, and avian roosting sites [62,65,[77][78][79]. In addition to PIR and HALT, infrared technology has been used to create a less invasive flash mechanism for night photography compared to use of xenon or LED flash [55].…”