Documenting den characteristics of bears and wolves in the Greater Yellowstone Ecosystem using LIDAR technology

Abstract In the Greater Yellowstone Ecosystem (GYE), American black bears ( Ursus americanus ) and grizzly bears ( Ursus arctos ) use dens to birth offspring and ensure a stable microclimate during hibernation over harsh winter months. Gray wolves ( Canis lupus ) do not hibernate but use dens to give birth to offspring and to provide offspring protection from predators. Previous studies acquired den site characteristics through physical measurements recorded by researchers in the field. Using the light detection and ranging (LIDAR) sensor onboard an Apple iPad Pro and iPhone, we scanned the interior of bear ( n = 9), and wolf ( n = 7) dens located in the GYE to generate point clouds of den structure. We then generated a 3‐dimensional (3D) digital model of each den by processing the point clouds using a combination of available software packages. Computer‐generated LIDAR dimensions from the 3D models were compared to physical den measurements recorded by field personnel. We found LIDAR dimensions were just as accurate as physical measurements, while offering less subjectivity. Using 3D LIDAR models, we also calculated the volume (range; 0.2 m 3 –24 m 3 ) of each den cavity and approximated the mass of substrate removed during den construction. Tablet and smartphone based LIDAR technology can be readily integrated into den site surveys with easy operability. The resulting 3D digital models can be cataloged for future studies and provide a more robust dataset compared to traditional physical measurements. Archived 3D LIDAR models provide infinite flexibility while allowing future scientists access to den sites they traditionally would be unable to visit and survey years later.