How well do we really understand animal habitat use?: Coupling movement recording technologies provides improved insight

Background/Question/Methods

Understanding how species use and are constrained by their environments is central to ecology, and integral for effective conservation of biodiversity. However, collecting fine-scale information on how animals interact with their environment is challenging, especially on small or cryptic species. Here we describe new tracking collars that we built, comprised of a GPS data logger and 3-axis accelerometer, to enable better recording of animal movement and habitat use. Using either of these technologies alone is common in biological research, but, as we show, can lead to misleading or misinterpreted results. By using the GPS data logger for spatial reference and calculating distance travelled, and the accelerometer to measure activity, we can collect fine-scale information on how animals interact with their environment. We assessed the difference in the quality of information obtained from the two data sources using mountain brushtail possums (Trichosurus cunninghami) as a model species in an environment comprising of different habitat patch sizes and lengths. We tracked thirty-two possums for 3-7 nights at a time, totalling 137 nights of data across the eight consecutive seasons. A subset of 20 animals were injected with Doubly-Labelled-Water and tracked during a single season for ~6 days each to test whether the information from the data loggers could be used as a proxy for energetics.

Results/Conclusions

We found a significant but weak positive relationship between activity and distance travelled. Notably, by combining the two technologies, we show a significant difference in how animals interact with different habitat patch sizes, lengths, and level of disturbance. The combination of GPS technology with accelerometer data loggers provides detailed information on fine-scale spatial and temporal habitat use and a much more comprehensive understanding of how animals use specific areas within the environment. Relating this information back to energetics, we found no significant relationship between energy and distance travelled, but there was a significant positive relationship between energy and activity. By combining these technologies and techniques, we obtain new insights into how animals use specific environments, and a more comprehensive understanding of their ecology.