Meeting Abstract
Knowledge of an animal’s home range is a crucial component of informed management decisions. Yet, many home range studies are limited by study area size, and thus may underestimate the size of the home range. Here, data collected by multiple research groups studying dolphins on the east coast of Florida were combined to determine how home range estimates change with increasing study area size. Analyses used photo-identification data collected in the St. Johns River (SJR; Jacksonville, FL) and adjacent waterways, extending a total of 253 km south to Mosquito Lagoon in the Indian River Lagoon estuarine system. Univariate kernel density estimates (KDE) were computed for individuals with 10 or more sightings (n=20) by projecting coordinates onto a midline through all study areas with distances from the origin measured for each point. Sightings were weighted by survey effort in each area. Kernels were calculated for the primary study area (SJR) first, then additional kernels were calculated by combining the SJR and the next adjacent waterway; this continued in additive fashion until all study areas were included. The 95% and 50% KDEs calculated for the SJR study area alone ranged from 21-35 km and 4-19 km, respectively. The 95% and 50% KDEs calculated for all combined study areas ranged from 116-217 km and 9-70 km, respectively. This study illustrates the degree to which home range may be underestimated by the use of limited study areas and demonstrates the benefits of conducting collaborative science.
