| Abstrakt: |
Raffles' banded langur (Presbytis femoralis) is one of three species of non-human primates in Singapore. With only 67 individuals left, it is listed as locally Critically Endangered. Due to its elusive nature, arboreality, and small population size, public awareness of its presence in Singapore is low, and this hampers conservation efforts. We thus initiated a citizen science project on Raffles' banded langurs in Singapore. Citizen scientists carried out field observations during weekends (08:00--11:00 and 15:30--18:30, with 96 survey assignments per survey cycle of 24 weeks). Overall 143 people were recruited to take part in the surveys. They completed 631 survey assignments from August 2016 to October 2019 (3.5 years), with an average volunteer retention rate of 38%, i.e., 38% volunteers continued to the next cycle while 62% were new volunteers. A total of 157 sightings of Raffles' banded langurs were recorded, amounting to a 24.9% encounter rate, i.e., one sighting for every four survey assignments. On average, 65.8% volunteers saw the langurs at least once. Using sighting locations, group demographics, high-resolution photographs from citizen scientists, and data collected by researchers, we confirmed five groups of langurs comprising 34 individuals along the survey route--over half of the langur population in Singapore. With data from observations of the langurs' use of roads to travel between forest fragments, the authorities were able to plan and construct a rope bridge to facilitate their safe crossing. We consider this citizen science project a success because of the high rate of observations made of these critically endangered and infrequently seen wild primates. Most importantly, this project demonstrates a successful partnership between the public, a government agency, non-governmental organizations, and educational and private institutions. [ABSTRACT FROM AUTHOR] |
