Development of a Low Cost Remote Sensing and Geospatial Technique for Primate Census and Surveys


Species: Long-tailed macaque (Macaca fascicularis) & Proboscis monkey (Nasalis larvatus)
IUCN Status: Long-tailed macaque = Least concern, Proboscis monkey = Endangered
MSc researcher: Amaziasizamoria Jumail
Supervisors: Liew Thor Seng, Danica Stark, Kimberly Fornace, Milena Salgado-Lynn
Institution: Universiti Malaysia Sabah
Duration: 2016-2018

Accurately estimating the number of individuals in a primate group is important for primate ecology, population density and abundance studies. These data are critical for understanding how disease impacts primate populations, the conservation of primate species, and understanding the cause of variation in primate behaviour, specifically in terms of rates of competition. Therefore, this study optimised thermal camera technology and assessed the usefulness of a thermal camera used as a handheld tool as a means of estimating primate populations within Sabah by comparing two survey techniques which consisted of thermal surveys used as a handheld tool and the visual survey.

  1. To develop a workflow for experimental design, image acquisition, and data processing and analytical procedure for the proposed remote sensing census technique.
  2. To evaluate this census technique’s efficiency, sensitivity and specificity at different conditions and habitats.
  3. To demonstrate the capability and potential of this technique for population size estimation and sleeping site identification studies. 

Thermal survey optimisation

Prior to the primate survey data collection period, trials were conducted along the Kinabatangan River to determine the optimal conditions to enhance the image quality during the surveys. The variables tested and recorded were: 1) distance from the observer (on the boat) to the riverbank, 2) boat speed, 3) time of day, and 4) weather conditions. For each transect, the number of groups and individuals in each group were obtained using both handheld thermal imaging and visual (non-thermal) observations. In addition, the position of the primate groups detected on the screen monitor was marked with a handheld GPS. The transect surveyed each day was selected based on where we found the primates settling in a particular section of the study site the evening before.

Long-tailed macaque (Macaca fascicularis) ©Rudi Delvaux
Proboscis monkey ©Rudi Delvaux