Abstract:
Intra-specifi genetic diversity is a fundamental component of biodiversity, and is key to
species adaptation and persistence. However, signifiant knowledge gaps still exist in
our understanding of the patterns of genetic diversity and their key determinants. Most
previous investigations mainly utilized single-species and/or a limited number of explanatory
variables; so here we mapped the patterns of plastid genetic diversity within 15 plant
species, and explored the key determinants shaping these patterns using a wide range
of variables. Population-level cpDNA sequence data for 15 plant species from the
Longitudinal Range Gorge Region (LRGR), southwest China, were retrieved from literature
and used to estimate haplotype diversity (HD) and population pairwise genetic differentiation
(FST) indices. Genetic diversity and divergence landscape surfaces were then generated
based on the HD and FST, respectively, to clarify the patterns of genetic structure in the
region. Subsequently, we analyzed the relationships between plastid genetic diversity and
16 explanatory variables (classifid as anthropogenic, climatic, and topographic). We found
that the highest genetic diversity occurred in the Yulong Mountain region, with a signifiant
proportion (~74.81%) of the high diversity land area being located outside of protected
areas. The highest genetic divergence was observed approximately along the 25 °N
latitudinal line, with notable peaks in the western and eastern edges of the LRGR. Genetic
diversity (HD) was weakly but signifiantly positively correlated with both Latitude (lat) and
Annual Mean Wet Day Frequency (wet), yet signifiantly negatively correlated with all of
Longitude (long), Annual Mean Cloud Cover Percent (cld), Annual Mean Anthropogenic
Flux (ahf), and Human Footprint Index (hfp). A combination of climatic, topographic, and
anthropogenic factors explained a signifiant proportion (78%) of genetic variation, with
topographic factors (lat and long) being the best predictors. Our analysis identifid areas of high genetic diversity (genetic diversity “hotspots”) and divergence in the region, and
these should be prioritized for conservation. This study contributes to a better understanding
of the features that shape the distribution of plastid genetic diversity in the LRGR and
thus would inform conservation management efforts in this species-rich, but
vulnerable region.