Landscape features are effective geographical barriers resulting
inpopulation differentiation of plant species. Taihang Mountains in
China possess complexly geographical topology and specific landscape
characteristics. Two closely related syntopic Opisthopappus species,
mainly distribute in different areas of Taihang Mountains, respectively.
How the landscape of Taihang Mountains affects the gene exchange between
these two species still unclear. Combined SNP data from restriction-site
associated DNA sequencing (RAD-seq) and recently developed landscape
genetic methods (EEMS, Samβada, LFMM), we conducted a landscape genetic
analysis of these two species. It found that the diversity of O.
longilobus was higher than that of O. taihangensis, the gene flow was
mostly from north to south along Taihang Mountains. However, a general
north–south gene exchange barrier between O. longilobus and O.
taihangensis was detected. Among the landscape factors of Taihang
Mountains, eight was found to be the important ones, including average
precipitation in August, October, and November, solar radiation in
August, soil PH, built-up land, rain-fed cultivated land, and
workability. And these eight factors were closely related to the
occurred barriers, indicating that climatic conditions and human
activities rather than geographical environment resulted in these
barriers. Twenty-nine selected SNPs were identified to be significant
correlated with the eight factors, especially average precipitation in
November. Thus, the average precipitation in November could be regarded
as an ecological indicator for O. longilobus and O. taihangensis. The
results revealed the effect of landscape features on two species and the
adaption on the landscape environment of Taihang Mountains during the
long-term evolution.