Comparison of survey techniques on detection of northern flying squirrels

Abstract

The ability to detect a species is central to the success of monitoring for conservation and management purposes, especially if the species is rare or endangered. Traditional methods, such as live capture, can be labor-intensive, invasive, and produce low detection rates. Technological advances and new approaches provide opportunities to more effectively survey for species both in terms of accuracy and efficiency than previous methods. We conducted a pilot comparison study of a traditional technique (livetrapping) and 2 novel noninvasive techniques (camera-trapping and ultrasonic acoustic surveys) on detection rates of the federally endangered Carolina northern flying squirrel (Glaucomys sabrinus coloratus) in occupied habitat within the Roan Mountain Highlands of North Carolina, USA. In 2015, we established 3 5 Â 5 livetrapping grids (6.5 ha) with 4 camera traps and 4 acoustic detectors systematically embedded in each grid. All 3 techniques were used simultaneously during 2 4-day survey periods. We compared techniques by assessing probability of detection (POD), latency to detection (LTD; i.e., no. of survey nights until initial detection), and survey effort. Acoustics had the greatest POD (0.37 AE 0.06 SE), followed by camera traps (0.30 AE 0.06) and live traps (0.01 AE 0.005). Acoustics had a lower LTD than camera traps (P ¼ 0.017), where average LTD was 1.5 nights for acoustics and 3.25 nights for camera traps. Total field effort was greatest with live traps (111.9 hr) followed by acoustics (8.4 hr) and camera traps (9.6 hr), although processing and examination for data of noninvasive techniques made overall effort similar among the 3 methods. This pilot study demonstrated that both noninvasive methods were better rapid-assessment detection techniques for flying squirrels than live traps. However, determining seasonal effects between survey techniques and further development of protocols for both noninvasive techniques is necessary prior to widespread application in the region. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

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

“…The first monitoring studies of wildlife crossings in Europe, Australia, and North America used sand boxes to observe animal tracks, and particularly those of big game (Forman et al, 2002). More sophisticated methods are now employed, such as infrared or thermal video cameras (Serronha, Mateus, Eaton, Santos-Reis, & Grilo, 2013), genetic sampling (Corlatti, Hackländer & Frey-Roos, 2009;Sawaya, Kalinowski, & Clevenger, 2014), GPS collars (Dodd, Gagnon, Boe, & Schweinsburg, 2005;Olsson & Widen, 2008), radio telemetry (Baxter-Gilbert, Riley, Lesbarrères, & Litzgus, 2015;Dillon & Kelly, 2008), acoustic, infrared and microwave sensors (Diggins, Gilley, Kelly, & Ford, 2016;Glen, Cockburn, Nichols, Ekanayake, & Warburton, 2013;Gužvica et al, 2014), and automatically triggered cameras, also called camera traps (Šver, Bielen, Križan, & Gužvica, 2016). The choice of a monitoring technique depends on the targeted species, the goal of the study and the human and financial investment (Hardy, Clevenger, Huijser, & Neale, 2003).…”

“…The efficiency of a monitoring method can be defined as its ability to detect the greatest proportion of species in relation to its global cost, including the time invested in the installation, maintenance, and data analysis process (Mateus, Grilo, & Santos-Reis, 2011). In order to estimate the efficiency of camera traps, some studies compared this method to others (Diggins et al, 2016;Dillon & Kelly, 2008;Glen et al, 2013;Janečka et al, 2011;Li, McShea, Wang, Huang, & Shao, 2012;Lyra-Jorge, Ciocheti, Pivello, & Meirelles, 2008;Monterroso, Rich, Serronha, Ferreras, & Alves, 2013;Silveira, Jácomo, & Diniz-Filho, 2003;Villette, Krebs, Jung, & Boonstra, 2016). Other authors compared different models of camera traps (Hughson, Darby, & Dungan, 2010;Meek & Vernes, 2016;Rovero, Zimmermann, Berzi, & Meek, 2013;Swann, Hass, Dalton, & Wolf, 2004;Weingarth, Zimmermann, Knauer, & Heurich, 2013), their technical parameters (Kelly & Holub, 2008;Pease, Nielsen, & Holzmueller, 2016), and the different installation and placement methods (Foster & Harmsen, 2012;Guil et al, 2010;Smith & Coulson, 2012).…”

“…After a long period dedicated to the monitoring of big game, monitoring interest has now turned to small fauna and small mammals, which now represent a significant portion of the species studied with camera traps (Burton et al, 2015). Their detection is difficult due to their low body weight (Di Cerbo & Biancardi, 2012;Diete et al, 2016;Diggins et al, 2016;Glen et al, 2013;Ikeda et al, 2016;MCCleery et al, 2014;Meek, Ballard, Fleming, & Falzon, 2016;Meek & Vernes, 2016;Melidonis & Peter, 2015;Rendall, Sutherland, Cooke, & White, 2014). The effectiveness of wildlife crossings for these species, previously estimated by tracking beds and live trapping, is increasingly studied with technologically advanced camera traps (Bellis, Jackson, Griffin, Warren, & Thompson, 2013;Martinig & Bélanger-Smith, 2016).…”

Noninvasive and cost‐effective trapping method for monitoring sensitive mammal populations

“…An increase in door mass would have increased the likelihood of hair capture as squirrels pushed out of the door; however, this may have increased the likelihood of trap mortality from squirrels unable to escape. The human effort required to maintain live‐trapping grids for this species for demographic analysis, stable isotope studies of diet, or collect samples for DNA analysis would be time‐ and cost‐prohibitive and indeed, nearly all of the current monitoring efforts for this species and the endangered Carolina northern flying squirrel ( Glaucomys sabrinus coloratus ) use nest boxes for this reason (Stihler et al , Weigl et al , Ford et al ), whereas Boulerice and Van Fleet () and Diggins et al () recommend other noninvasive monitoring methods for this species. Similar methods using hair collection have been used to document presence–absence for other rare species of wildlife species including wolverines ( Gulo gulo ; Magoun et al ), Eurasian lynx ( Lynx lynx ; Schmidt and Kowalczyk ), and rare tropical carnivores (Castro‐Arellano et al ) because of the challenges related to studying species that occur at low density or in challenging terrain.…”

Determining the efficacy of camera traps, live capture traps, and detection dogs for locating cryptic small mammal species

“…Specifically, by effectively surveying species residence within a landscape, it permits better understanding of the species’ dynamics, movements, and status. How these factors are affected by other ecological variables can also be examined, and consequently, this enables development of strategic conservation and management programs, which augment efforts to conserve target species (Diggins, Gilley, Kelly, & Ford, ). Improving our capability to detect rare and elusive species is clearly fundamental to the success of such programs (Diggins et al, ).…”