1 Introduction of eDNA
method
Due to the intensification of human activities and increased
interference with the natural environment, the continuous decline of
global biodiversity has become one of the major challenges in the 21st
century (Butchart et al., 2010). Rapid, sensitive and accurate
biodiversity survey tools are required to measure fluctuations in
species diversity and abundance to inform conservation and management
strategies (Kelly et al., 2014). Environmental DNA is DNA that can be
extracted from environmental samples (such as soil, water or air)
without prior isolation of any target organisms (Lodge et al., 2012;
Taberlet et al., 2012). Environmental DNA analysis is divided into two
main categories: single species identification and eDNA metabarcoding.
Single species identification is mainly used for sensitive detection of
rare and endangered animals and invasive non-native species in the
context of environmental and species richness surveys (Wilcox et al.,
2013). eDNA metabarcoding refers to analysis of eDNA with
high-throughput sequencing technology, processing eDNA from water, soil
and air by PCR amplification to determine the presence of species and
perform biodiversity assessment (Ruppert et al., 2019). Compared with
traditional survey methods, the eDNA metabarcoding technique provides
outstanding species recognition. It can be used even if the
investigators lack extensive abilities to classify species. Further, the
use of eDNA does not require sampling approaches that are destructive or
invasive to the environment or the biological community, nor does it
require special equipment or particular observation times to detect
those species that are difficult to observe due to small size or numbers
(Deiner et al., 2017). Therefore, this technology has been widely used
in the field of ecology.