Impacts of physiological characteristics and human activities on
the species distribution models of orchids taking the Hengduan Mountains
as a case
Xue-Man Wang1, Pei-Hao Peng1*,
Mao-Yang Bai1, Wen-Qian Bai1, Shi-Qi
Zhang1, Yu Feng1, Juan
Wang2, Ying Tang2
1 College of Earth Sciences, Chengdu University of Technology, Chengdu
610059, Sichuan, China
2 College of Tourism and Urban-rural Planning, Chengdu University of
Technology, Chengdu 610059, Sichuan, China
Corresponding author: Pei-Hao Peng (Email: peihaop@163.com)
Abstract: The biogeography research of orchids through species
distribution models (SDMs), a vital tool in the biogeography field, is
critical to understanding the fundamental geographic distribution
patterns and identifying conservation priorities. The correspondence
between species occurrence and environmental information is crucial to
the model’s performance. However, ecological preferences unique to
different orchid species, such as their life forms, are often overlooked
during the modeling process. This oversight can introduce bias and
increase model uncertainty. Additionally, human activities, as an
important potential predictor, have not been quantified in any orchid
SDMs. Taking the Hengduan Mountains as an example, we preprocessed all
orchid species’ occurrences based on physiological characteristics.
Choosing five spatial factors related to human activities to quantify
the interference and enter into models as HI factor. Using different
modeling methods (GLM, MaxEnt, and RF) and evaluation indices (AUC, TSS,
and Kappa), diverse modeling strategies have been constructed in the
study. A double-ranking method has been adopted to select the critical
orchid distribution regions. The results showed that classification
models based on physiological characteristics significantly improved the
model’s accuracy while adding the HI factor had the same effect but the
absence of enough significance. Suitability maps indicated that highly
heterogeneous mountainous areas were vital for the distribution of
orchids in the Hengduan Mountains. Different distribution patterns and
critical regions existed between various orchid life forms
geographically - terrestrial orchids were dominant in the mountain, and
mycoherterophical orchids were primarily located in the north, more
influenced by vegetation and temperature. Critical regions of epiphytic
orchids were in the south due to a greater dependence on precipitation
and temperature. These studies are informative for understanding the
orchids’ geographic distribution patterns in the Hengduan Mountains,
promoting conservation, and providing references for similar research
beyond orchids.
Keywords: orchids, species distribution models (SDMs),
physiological characteristics, human activities, biogeography,
conservation