Abstract:

Camera trap technology is increasingly used in wildlife research, and has become an important tool to assess biodiversity. Traditionally, biodiversity is monitored from the ground with limited visual access to the wildlife present in the canopy layers. The impact of this limitation on the results of biodiversity assessments is unclear. In this study, a region characterized by rich biodiversity - the southern section of Biluo Snow Mountain - was monitored using 20 camera-trappings from January 2016 to July 2017. We installed cameras in groups of two working synchronously: one in the understory (0.5-1.5 m) and one in the overstory (5-10 m). For 2,319 trapping days, the cumulative monitoring period averaged to 112.5 days. We photographed 44 species of wild animals (not including rodents such as rats), 20 of which were mammals and 24 were birds. The similarity index of canopy and ground species was 29.54%. Fifteen species appeared only in the canopy, 16 species appeared only on the ground, and 13 species were photographed in both forest strata. Obvious differences in the species composition present in different forest strata were observed, suggesting that monitoring two strata is necessary. Results show that the detection rate of species by camera traps can be improved by installing cameras in forest strata corresponding to the habitat of target species. Our method of camera trap monitoring in different forest strata can also be used to study the spatial selection and niche differentiation of wild animals. To fully assess the diversity of wild animals in forest ecosystems monitoring at different forest strata is essential; new monitoring standards must incorporate multi-strata monitoring.

Key words: camera-trapping, ground, canopy, wildlife surveillance, species differences, monitoring standards