My name is Rebecca Berzins, and I am a senior Marine and Environmental Biology and Policy (MEBP) major at Monmouth University. In the MEBP program, we study a variety of New Jersey native species. I have been working with my mentor, Dr. Sean Sterrett, on a project involving a particularly sensitive species of turtle. The diamond-backed terrapin (Malaclemys terrapin) is the only brackish water turtle species in North America. Sandy Hook Bay is one of their main habitats in New Jersey. Diamond-backed terrapins are a Species of Greatest Conservation Need throughout most of its range, including New Jersey. They are a vulnerable species globally because their populations are declining. Terrapins congregate in saltwater marshes during the breeding season, which presents an exciting opportunity for revolutionizing wildlife population monitoring.
Traditional wildlife monitoring for turtles involves trapping the turtles, weighing and measuring them, marking their shells, and then releasing them, with the hope of catching them again in the future. This process is not very effective and can be detrimental. Diamond-backed terrapins are not currently an endangered species, but they may be in the future if we do not find a more effective and less invasive monitoring method.
The goal of our research project is to develop a non-invasive sampling method that also digitizes the data. Wildlife researchers are increasingly using drone technology to gather information without directly interacting with animals. Drones allow us to measure, identify and count animals remotely. However, we know little about how drones detect terrapins or influence their behavior. Our research attempts to determine the maximum height a drone can fly while still being able to detect terrapins. The drone should be low enough to detect terrapins but high enough not to disturb them. Dr. Sterrett and I created an experiment to find this height using 3D printed terrapins, or decoys. The decoys were made in three sizes, large to represent adult females, medium to represent adult males and small to represent juveniles. We selected random numbers of each sized decoy to put in the water and then flew the drone over, taking pictures from 60 feet up to 200 feet. We gave these pictures to independent observers, other Monmouth students with no knowledge of the experiment. The observers used a program called iTag to mark the decoys they saw and label them by size. Our research is not complete yet, so we cannot make recommendations on what height drones should fly at, but we have other results. Unsurprisingly, we found that drone height and decoy size were important factors for accurately counting terrapins. Observers counted decoys more accurately when the drone was closer to the water, and they had an easier time counting large decoys than small ones. When we finish our research, we will have created a standardized model for other wildlife researchers to use.
Rebecca Berzins is a part-time employee of Garden State Veterinary Specialists.