MOVEMENT CHARACTERISTICS EXPLAIN ENERGETIC EXPENDITURES OF A CRYPTIC CARNIVORE, THE PACIFIC MARTEN.
Marie E. Martin; University of Wisconsin-Madison; 1630 Linden Drive, Madison, WI, 53706; (630) 340-2910; memartin5@wisc.edu; Katie M. Moriarty, Jonathan N. Pauli
Energetic balance is critical to the survival and persistence of free-ranging species. Quantifying energetic requirements can inform our understanding of species' ecology, including their vulnerability and response to shifting biotic and abiotic conditions. While techniques exist to derive expenditures and activity patterns of wildlife, there is limited research linking field metabolic rate (FMR) with behavior of free-ranging terrestrial species. We tested the efficacy of movement characteristics (e.g., velocity, distance, motion variance) in predicting expenditures of a small forest carnivore, the Pacific marten (Martes caurina) in northern California. We paired the doubly-labeled water technique to measure CO2 production with movement data derived from GPS collars to quantify relationships between movement and expenditure. Average FMR (+/- SD) for female and male martens (n=8, 3F:5M) was 627 kJ (+/- 142.0 kJ) and 913 kJ (+/- 61.88 kJ), respectively. Body-weight and movement velocity accounted for the majority of variation in FMR (R2=0.93 and p=0.0203); mass-specific FMR was positively related to velocity (R2=0.69 and p=0.0419). Our results suggest changes in behavior, such as increased movement velocity, are important and influential factors in energetic expenditures of forest carnivores. In the future, we will estimate FMR of additional GPS-collared animals to further disentangle the relationships between landscape composition and energetic budgets.
Ecology and Conservation of Martens and Fishers   Student Paper