Project Name: Acoustic Monitoring with Black-and-White Ruffed Lemurs
Grantee: Carly Batist
Discipline: Biological Anthropology
Funding Cycle: 2019-2020
About the Project:
This project will continue work started during my PDIG-funded field season in Summer 2019, in which I used acoustic monitoring with black-and-white ruffed lemurs (Varecia variegata) in Ranomafana National Park, Madagascar. Varecia have a vocal repertoire with 12 different call types, the most iconic of which being their contagious, raucous roar-shriek choruses. Passive acoustic monitoring (PAM) is a non-invasive, cost-effective method that uses remotely-activated sound recorders to monitor wildlife populations, detect illegal activity, and identify effects of human disturbance on animals. Only four studies have ever assessed Varecia vocalizations, the majority of which were conducted in captivity in the 1980’s. This is the first study to examine the acoustic structure and function of wild Varecia vocalizations and is also the first to use PAM with a wild lemur community; it therefore serves as a proof-of-concept. These data (8000+ hours of recordings) now need to be processed and analyzed to determine the effectiveness of PAM in detecting ruffed lemurs. I, along with undergraduate research assistants, will use novel machine-learning methods to create a training dataset and detection algorithm for the black-and-white ruffed lemur roar-shriek chorus. This will then be used to estimate the number of callers in each chorus, which can be used in site-occupancy models to determine the abundance of V. variegata in a given area. This low-cost, low-labor monitoring method is spatially and temporally scalable; with the validation of this analysis workflow, PAM can then be expanded throughout the fragmented Varecia home range to conduct updated censuses (the last being >20 years old). PAM has been widely adopted as a conservation tool for bats and marine mammals, but has not yet been effectively integrated into primatology. This project will repackage methods used with other species in an innovative way, specific to primate behavior and conservation.