A Hidden View of Wildlife Conservation HOW CAMERA TRAPS AID SCIENCE, RESEARCH AND MANAGEMENT By Allan F. O’Connell
F
lorida panthers are among the world’s most endangered — and elusive — animals. For approximately four decades, scientists have been researching this small population of panthers that inhabit the dense forests and swamps of south Florida. Because of their wide habitat range along
with an absence of clear visual features, these animals are difficult to detect and identify. In 2013, however, researchers released a study that used camera trap images collected between 2005 and 2007 to generate the first statistically reliable density estimates for the remaining population of this subspecies (Sollmann et al. 2013). Camera traps — remotely activated cameras with infrared sensors — first gained measurable popularity in wildlife conservation in the early 1990s. Today, they’re used for a variety of activities, from species-specific research to broad-scale inventory or monitoring programs that, in some cases, attempt to detect biodiversity across vast landscapes. As this modern tool continues to evolve, it’s worth examining its uses and benefits for wildlife management and conservation.
A New Tool Emerges
Credit: David Shindle
Much like any new technology, the use of camera traps in wildlife research was initially slow to develop. Some of the early applications conducted in the late 1980s involved documenting avian nest depredation (Picman 1987, Savidge 1988). A decade later, researchers were using camera traps to identify unique striping patterns on tigers and developing mark-recapture models to estimate population size and density (Karanth 1995, Karanth and Nichols 1998). Early literature on the tool was similarly scarce. In the late 1990s, a lone review published in The Wildlife Society Bulletin served as the main guide for practitioners interested in using these devices (Cutler and Swann 1999).
An infrared-triggered camera captures a photo of an adult male Florida panther in Florida’s Fakahatchee Strand Preserve State Park. Elsewhere, a female panther leads her three kittens through the Picayune Strand Restoration Project Area in Southwest Florida. As part of this Comprehensive Everglades Restoration Project, the U.S. Fish and Wildlife Service, the U.S. Army Corps of Engineers, and the South Florida Water Management District reestablished hydrology and fish and wildlife habitat for listed species including the Florida panther. Credit: David Shindle
56
The Wildlife Professional, Fall 2015
© The Wildlife Society
However, all that has changed. Today a number of reviews are available on every imaginable feature related to camera traps and their use in sampling wildlife, along with camera trap specifications and technical capabilities (Meek and Pittet 2012, Rovero et al. 2013, Trolliet et al. 2014). In addition, a number of books that discuss related topics such as survey design and analytical options are now available (Kays, in press, Meek et al. 2014, O’Connell et al. 2011). Entire conferences and symposia are being devoted to the topic, and a torrent of information on camera trap technology and associated work including devices, survey design, sampling procedures, data storage and statistical analyses is springing up everywhere. The surge is unprecedented. A recent review shows that publications using camera traps were found in 95 different journals and, since 1994, the annual growth rate of camera trap publications appearing in the literature has held steady at 40 to 50 percent (Rowcliffe and Carbone 2008, Burton et al. 2015). In fact, the rapid increase in camera trap publications, in part, prompted speculation about uncoordinated growth of the use of camera traps in wildlife surveys and highlighted the need for greater coordination and consensus among practitioners (Rowcliffe and Carbone 2008).
Camera traps are cost effective — ranging from approximately $150 to $800. In addition, their wide availability has helped foster a burgeoning interest in the environment by both hunters and backyard nature enthusiasts.
The Ultimate Camera Trap
Camera traps are available from a number of manufacturers and with a wide variety of features. This table provides some of the more prominent design specifications that wildlife researchers should look for. More details can be found in Meek and Pittet 2012. Feature Camera functionality Trigger speed
Latency to first photo 0.5 seconds, two photos per second (near-video speed)
Photo speed
Up to two frames per second Infrared (IR) LEDs; LED flash one image per second
Image resolution
Programmable resolution 1.3–12 Megapixels (Mp) (12 Mp, 8 Mp, 5 Mp, 3 Mp, 1.3 Mp)
Frame-rate intervals
0–60 s between images
Photos per trigger
Programmable 1–100
Image settings
Choice of two aperture settings of f4 and f16
Image
Color day and color night (no filter), monochrome night (IR LED)
Flash range
0.5–50 feet, with manual dimming-control system for distance setting to enable close-up deployment, thereby avoiding white-out exposures, range 1.5–20 m
Video length
HD high definition video in MPEG4 format, duration adjustable between 10 and 60 s or can be programmed to continue until the motion stops.
Sound
Sound is recorded during video.
Remote viewer
Remote wireless live viewer to aid camera setting, including detection-zone watermark. Viewer also allows programming and downloading to secure digital (SD) cards.
Battery type
Rechargeable lithium-ion battery: 45 days and/or 30 images and/or 15 flash
Battery charging
An induction charging system has been included to enable multiple charging capacities without the need for battery removal. Alternatively, a dockingstation recharger can be used.
Memory-card capacity
2–32 GB.
Door seal
The seal is water tight and insect proof, which prevents moisture, ants and small invertebrates from accessing the camera circuitry.
Weight
Light weight, only 400 g per unit (without battery).
Benefits and Uses In light of the need to further document the world’s biodiversity and collect information on rare and endangered species, the increasing interest in camera traps is not at all surprising. This emerging technology has revolutionized the noninvasive sampling of terrestrial animals (Long et al. 2008). Further, it allows for a hands-off approach, which has increased safety for both researchers and animals. An essential component of camera traps traces back to species identification, a fundamental element of nearly all biological and ecological research (Hoffman and Gaines 2008). Simply put, nothing samples an animal population better than a camera trap. Quality pictures can verify a particular species, provide evidence that can be validated by others and live on for decades (when properly cared for). Further, the popularity of camera traps and the information they generate stem from their broad applicability, ranging from a simple picture of a newly discovered or endangered species to estimation techniques that are then used to build complex models.
© The Wildlife Society
Specification
Credit: Adapted from Meek and Pittet 2012. Used with permission of CSIRO Publishing.
www.wildlife.org
57
Although camera trapping in wildlife began by largely focusing on mammals — particularly elusive carnivores — it has now branched out to every corner of the animal kingdom including forest birds, amphibians and even insects. The variety of applications inspired by camera traps continues as the devices are now being used in forest canopies, the marine environment, and for projects such as BeetleCam — a remote-controlled buggy with a camera mount developed in 2009 to take better pictures of lions (not beetles). Camera trap data is also being used to quantify activity levels for a variety of small- to medium-sized mammals (Rowcliffe et al. 2014) as well as to monitor migration phenology of caribou in the arctic (Tape and Gsustine 2014). Data collected from camera traps are widely available. For example, the Smithsonian Wild website, designed to showcase the organization’s research around the world, has compiled over 200,000 photos from professional camera trap surveys conducted in several different countries. Similarly, Wildlife Conservation Society has embarked on an effort to assemble and organize over 3 million camera trap images from programs that they run in 20 countries throughout the tropics (T. O’Brien, WCS, Pers. Commun.). EMammal — a website where citizen scientists deploy their own camera traps to gather photo data on mammal distribution throughout the mid-Atlantic region — and the Wildlife Picture Index — a biodiversity monitoring indicator that provides camera trapping information of terrestrial birds and mammals in select ecosystems (O’Brien et al. 2010) — also help raise awareness of wildlife conservation. More recently, researcher Alexandra Swanson placed more than 200 motion detector cameras throughout Tanzania’s Serengeti National Park in an effort to understand how the region’s predators interacted with other species. The result — hundreds of thousands of candid camera trap photos of giraffes, lions, warthogs, birds and countless other, often elusive, species — not only offers a unique view of wildlife in the Serengeti, but also helps inform science and research. These photos are now hosted on Snapshot Serengeti — a website that relies on citizen scientists to wade through the photos and help classify the animals. Today, even news sites like Mongabay have sections devoted solely to the topic of camera trapping, demonstrating that this technology is now firmly embedded in our environmental consciousness.
58
The Wildlife Professional, Fall 2015
The Nitty Gritty of Camera Traps The camera trap has come a long way even since the ‘80s and ‘90s. Although film camera traps originally ruled the day, they were soon replaced by a digital version, further reducing the time and effort spent in the field. The majority of camera traps today use pyroelectric infrared detectors — otherwise known as passive infrared (PIR) — that trigger the camera when there is movement and a differential between background and animal body temperature (Meek and Pittet 2014). Further, a Freznel lens, which has a large aperture, short focal length and the ability to capture oblique light, is located in front of the PIR and allows greater detection of heat and motion (Meek and Pittet 2014). Experts have come up with specifications for an “ideal” camera (Meek and Pittet 2012; see table on page 57). While the list is long and needs vary by individual application, some of the more important functions are trigger latency, photo resolution and choice of artificial illumination — infrared versus white flash. In terms of manipulating camera trap data, a number of interfaces and photo management programs now exist such as Photospread and Picasa (Sundaresen et al. 2011), along with other protocols and approaches including Camera Base and DeskTEAM (Tobler 2007, Fegraus 2011). More recently, entire data management software systems including Aardwolf have been developed to handle and annotate more than 1 million photos as a stand-alone application on a personal computer. Aardwolf serves as an open-source, multi-platform solution to managing camera trap data from downloading the images to the final analyses (Krishnappa and Turner 2014). With respect to data analysis, camera traps have been at the heart of two estimation techniques — occupancy modeling (MacKenzie et al. 2006) and spatial capture-recapture (Royle et al. 2014) — that generate information about population abundance, density and distribution that helps incorporate data on movement and detectability in a probabilistic framework. Together, these advances have significantly improved our ability to make reliable inferences about the populations we study.
Future Needs As our knowledge of ecosystems increases, due in part to technologies such as camera traps, so too does the need to gather more accurate and precise information to inform that knowledge. Despite the
© The Wildlife Society
impressive array of camera trap features and abilities, practitioners would do well to maintain a level of transparency in their research while also carefully considering “methodological details and assumptions underlying camera trap work” (Burton et al. 2015). In addition, it’s important to remember that the data in these studies do not generate an end in and of themselves, but are best viewed either as gaining an understanding of how ecosystems and their component parts work or collecting data for decision making that helps improve those ecosystems (Nichols et al. 2011). And so, even amidst ongoing concerns regarding uncoordinated growth of camera trap surveys along with an absence of unified data collection methods, camera traps continue to serve as a critical and valuable tool that allows researchers to delve deeper into wildlife science and conservation.
Allan F. O’Connell, PhD, is branch chief of the Quantitative Methods and Monitoring Branch at the USGS Patuxent Wildlife Research Center. He is senior editor of the book, “Camera Traps in Animal Ecology: Methods and Analyses.”
A RESEARCHER’S DREAM WORLD AWAITS. Northern Manitoba... unstudied ecosystems, limited roads and development, unknown numbers of wolves, traditional native respect for wolves and wildlife... a region to study and better understand how the apex predator roams through Manitoba’s biomes and interacts with their prey - deer, moose, caribou, and even polar bears. It’s been called “a researcher’s dream world.”*
Spirit Way Inc. is a community based organization in Thompson, Manitoba that is working with many partners in developing a regional wolf economy and striving for best practices in all things wolf. Are there research, eco-tourism, and career opportunities for you? Talk to us at our presentations, work sessions, and display booth at the 2015 Wildlife Society Conference in Winnipeg, Manitoba.
THOMPSON SPIRIT WAY INC. www.thompsonspiritway.ca
[email protected] Facebook: WolfCapitalOfTheWorld Polar Bear Capital
MANITOBA
Wolf Capital
TWS Conference
*Erin McCloskey, author of “Wolves in Canada”
© The Wildlife Society
DESIGN NORTH • THOMPSON
www.wildlife.org
59
