FOSSIL FOOTPRINTS: LEFT BUT NOT FORGOTTEN: USING PHOTOGRAMMETRY FOR LONG-TERM PRESERVATION AND MANAGEMENT OF IN SITU PALEONTOLOGICAL RESOURCES: STORIES OF THE GOOD, THE BAD, AND THE UGLY

Fossil vertebrate tracksites provide a wealth of scientific information, not only about the characteristics of the trackmakers, but also insights into behavioral and community dynamics. Track-bearing surfaces are often stripped of their protective sedimentary covering to be mapped, studied, and hopefully photogrammetrically documented. In many cases, these surfaces are left exposed to natural weathering and human degradation (e.g., vandalism, carelessness). Because of the size and location of tracksites, the level of protection warranted by their scientific and educational values is often not feasible. Unlike most body fossils, vertebrate trace fossils are routinely left in place to preserve their context, frequently resulting in challenging management decisions. Fortunately, photogrammetry has increasingly been employed in the assessment, monitoring, and decision making of in situ paleontological resources. Although rarely used in paleontology prior to 1997, photogrammetry is currently considered state-of-the-art and best practice in the noninvasive, 3D digital data collection of vertebrate trace fossils. The discovery of the Red Gulch Dinosaur Tracksite 25 years ago in Wyoming heralded in a new era of ichnological documentation and tracksite management. Bureau of Land Management staff spearheaded the use of photogrammetry at this site and pioneered many techniques in photogrammetric ichnology. They remain on the forefront utilizing this technology for resource management with episodic photogrammetric documentation from various platforms (e.g., ground-based monopods and UAS) conducted at tracksites. High-quality data sets are coaligned into the same coordinate space supporting direct visual and quantitative analysis. These data have proven invaluable for understanding morphological degradation of the tracks themselves, as well as the condition of track-bearing surfaces due to erosion or wrongful impact, as was the case at the Mill Canyon Dinosaur Tracksite in Utah. Photogrammetry is a powerful tool which allows public land managers to inventory, monitor, manage, and protect in situ paleontological resources using scientific principles and expertise (à la PRPA), and make scientific-based management decisions to preserve these invaluable parts of America’s Natural Heritage.