2 MATERIAL AND METHODS
2.1 Occurrence data of Francois’ langur
A total of 171 occurrence records of Francois’ langur were obtained from
our survey data. From 2017 to 2020, we conducted field surveys in all
known distribution areas of the species in Guangxi, Guizhou, and
Chongqing provinces, which are located in the southwest China with
special ecological environment of karst ecosystem (Figure 1). We
recorded the occurrence of species based on direct observations, fecal
remains and infrared cameras. To avoid overfitting in the models (Li et
al., 2022) and to prevent spatial auto-correlation of raster data, we
used the SDM Toolbox v2.4 (spatially rarefy occurrence data) of ArcGIS
10.2 to ensure that there was only one occurrence record for the species
in each 1 × 1 km resolution grid cell (Tu et al., 2021). After
selection, 82 occurrence records of Francois’ langur were identified for
modelling analysis.