Camera trapping videos and photos, including pre-processing
Initially the whole area was divided into a grid system of size 4×4
km2 (Figure 1) and between two and five camera-trap
locations in each grid cell were selected based on the presence of
carnivore sign and prey trails. Two infrared cameras (Eastern Red Hawk
E1B 6210M and LTL6210MM, Manufactured by Shenzhen Weikexin Science and
Technology Development Co. LTD Shenzhen, China) were set facing each
other at each trap station to increase capture probabilities and capture
the fur patterns on both sides of leopards, of which one was set to
record short videos (10 second length) and one to record photos (3
photos per trigger event). In order to capture quality images, cameras
were attached to trees 45–50 cm above the ground at a distance of
3.5–4 m from animal trails, and all vegetation or other obstacles in
front of the cameras were removed (Qi et al., 2015). All photographs
were automatically stamped with the time and date, moon phase and
respective location ID. A total of 102 camera locations operated between
March 2017 – June 2019, and among them, 78 cameras successfully
functioned to collect data over three sampling stages in two different
seasons (see below for details) with 131 (March–July 2017), 120
(September–December 2018), and 134 (March–June 2019) consecutive days
being sampled. Each camera was visited approximately every two months to
download image files and check/replace batteries. The remaining 24
cameras were stolen or damaged during the study period.
The 24-h activity patterns of all species were deduced from camera-trap
photo and video records (Qi et al., 2015, Yang et al., 2018b). We
analysed only photos taken at a minimum time interval of 30 minutes
(Santos et al., 2019) to avoid pseudoreplication. Based on local climate
characteristics, we defined two distinct periods: the winter period
(snow period: Nov– Apr) and the summer period (snow-free period: May –
Oct) (Table 1). The data processing was completed by specialists in
Prof. Jiang Guangshun’s research teams at the Feline Research Center of
National Forestry and Grassland and Administration (Northeast Forestry
University) who completed species identification and data arrangement.