Climatic and Soil Factors Shape the Demographical History and Genetic Diversity of a Deciduous Oak (Quercus liaotungensis) in Northern China

Abstract

Past and current climatic changes have affected the demography, patterns of genetic diversity, and genetic structure of extant species. The study of these processes provides valuable information to forecast evolutionary changes and to identify conservation priorities. Here, we sequenced two functional nuclear genes and four chloroplast DNA regions for 105 samples from 21 populations of Quercus liaotungensis across its distribution range. Coalescent-based Bayesian analysis, approximate Bayesian computation (ABC), and ecological niche modeling (ENM) were integrated to investigate the genetic patterns and demographical history of this species. Association estimates including Mantel tests and multiple linear regressions were used to infer the effects of geographical and ecological factors on temporal genetic variation and diversity of this oak species. Based on multiple loci, Q. liaotungensis populations clustered into two phylogenetic groups; this grouping pattern could be the result of adaptation to habitats with different temperature and precipitation seasonality conditions. Demographical reconstructions and ENMs suggest an expansion decline trend of this species during the Quaternary climatic oscillations. Association analyses based on nuclear data indicated that intraspecific genetic differentiation of Q. liaotungensis was clearly correlated with ecological distance; specifically, the genetic diversity of this species was significantly correlated with temperature seasonality and soil pH, but negatively correlated with precipitation. Our study highlights the impact of Pleistocene climate oscillations on the demographic history of a tree species in Northern China, and suggests that climatic and soil conditions are the major factors shaping the genetic diversity and population structure of Q. liaotungensis.

Spatial patterns and interspecific associations among trees at different stand development stages in the natural secondary forests on the Loess Plateau, China

“…This may be due to the lack of airbags, wings, and other flight aids; it was difficult to spread the seeds over long distances with the help of wind, and the seeds were concentrated around the mother plants. The complex terrain in the mountains also concentrates seeds in low places (Yang et al, 2018). This result was the same as previous studies, particularly other coniferous species which were aggregated in small scales and a randomly distribution in large scales (Cain & Shelton, 1995;Koukoulas & Blackburn, 2005;Shibata, Kikuchi, Tanaka, Sueyoshi, & Yoshimaru, 2009).…”

“…Most importantly, the Loess Plateau contains some of the largest areas of soil erosion and possesses one of the most vulnerable ecosystems in the world (Sun et al, 2015). The high recruitment rates of P. tabulaeformis are due to the high light intensity and temperatures of the bare land, and the seedlings are competitive, especially on the burnt ground (Gomez, 2004;Yang et al, 2018). During reforestation or natural forest regeneration, internal competition among plants for limited resources has been proven to be the driving factor for forest succession.…”

“…Studies of vegetation variation and development have shown that, after herb and shrub communities, Pinus tabulaeformis, as a pioneer species, is generally the first established species and captures resources in disturbance openings (Fan, Guo, Wang, & Duan, 2014). The high recruitment rates of P. tabulaeformis are due to the high light intensity and temperatures of the bare land, and the seedlings are competitive, especially on the burnt ground (Gomez, 2004;Yang et al, 2018). Once P. tabulaeformis forests are formed, other, relatively shade-tolerant, species (i.e., Q. wutaishansea) are able to invade (Collins & Carson, 2004).…”

Localized environmental heterogeneity drives the population differentiation of two endangered and endemic Opisthopappus Shih species

“…Climate fluctuations would further promote differentiation between haplotypes or species.Additionally, the most recent diversification of haplotypes within species occurred primarily during the Quaternary glacial period (Fig. 4), which had a considerable impact on the distribution of modern animals and plants [16,[63][64][65]. Glacial and interglacial cycles played significant roles in the formation and differentiation of species.…”

Framework Phylogeny, Evolution and Complex Diversification of Chinese Oaks

“…A series of phylogeographic research on some widespread Chinese oak species suggest that geographical distribution and climate change during the past geological periods could have affected the intra-and interspecific genetic variation of these species [34][35][36][37][38][39][40][41]. Additionally, research on Chinese oak species seems to imply that adaptation to different environments may influence genetic diversity, species turnover, and thus be relevant for the implementation of conservation strategies [32,42]. Given that a well-resolved phylogeny could provide a framework to understand diversification patterns and the evolutionary history of plant species [16], it is imperative to generate a framework phylogeny of the Chinese oaks to understand the evolutionary process and diversification pattern of this species-rich group.…”