Uncovering the Genetic Map and Spread of a Key Forest Oak

Jenn Hoskins
6th March, 2024

Uncovering the Genetic Map and Spread of a Key Forest Oak

Image Source: Natural Science News, 2024

Key Findings

  • In East Asia, the glaucous-leaf oak's habitat expanded post-ice age but is predicted to shrink with future warming
  • The oak has two genetic groups, with the western group being more diverse than the eastern
  • High genetic diversity in certain areas suggests they were refuges during past climate changes
Understanding how forests and their key species have responded to past climate events can provide valuable insights into how they might cope with future climate change. Researchers from the Central South University of Forestry and Technology have recently shed light on this topic by studying Quercus glauca Thunb, a cornerstone species of the East Asian subtropical evergreen broad-leaved forest[1]. Quercus glauca, or the glaucous-leaf oak, is widespread in East Asia and plays a critical role in forest ecosystems. The study aimed to unravel the genetic patterns across the species' range and predict how its distribution might shift with changing climate conditions. To achieve this, the team collected 781 samples from 77 different populations of Q. glauca and employed an ensemble species distribution model (eSDM). This model integrates various algorithms to predict where a species could potentially thrive, both in the past and the future. The eSDM revealed that Q. glauca's suitable habitat greatly expanded after the last glacial maximum (LGM), a period around 26,500 years ago when glaciers were at their peak. However, as the planet warms, these habitats are expected to shrink, with the distribution's center moving northeastward. The genetic analysis, which used nuclear SSR (simple sequence repeats) data, uncovered two distinct genetic lineages within Q. glauca, one in the east and one in the west. Interestingly, the western group showed higher genetic differentiation among its populations than the eastern group. Despite this, no clear phylogeographic structure was evident, meaning there wasn't a strong pattern of genetic variation correlating with geographic location. This finding contrasts with previous studies on other East Asian oaks, such as Quercus delavayi and Q. schottkyana, which exhibited significant phylogeographic structure, suggesting that different species within the same region can have varied genetic patterns[2]. Moreover, the study noted that areas like the Nanling Mountains possess high genetic diversity, hinting at their historical importance as refugia, where species could survive during harsh climatic conditions, and as corridors for species movement. The study also observed a negative correlation between habitat stability and genetic diversity (heterozygosity). This could be due to the mingling of different lineages as Q. glauca expanded after the LGM or possibly due to hybridization with closely related species. This idea of hybridization as a source of genetic variation and adaptation is supported by research on sympatric Asian oak species, where introgression—gene flow between species—has been shown to contribute to adaptation by introducing new genetic variations[3]. Furthermore, the findings echo the broader impacts of past climate events on biodiversity, as seen in the Lardizabalaceae family, where a significant diversification rate increase was associated with the rise of subtropical evergreen broad-leaved forests in East Asia during the late Miocene[4]. Similarly, the current study underscores the influence of paleogeographic and climatic changes on the genetic structure of forest keystone species. The study's predictions about the future distribution of Q. glauca also resonate with assessments of climate change impacts on U.S. biodiversity, where species are undergoing morphological, behavioral, and range shifts in response to climate change[5]. Such shifts can profoundly affect ecosystem productivity, species interactions, and the services ecosystems provide to society. In conclusion, the research from the Central South University of Forestry and Technology contributes to our understanding of how key forest species like Q. glauca have adapted to past climate changes and how they might respond to future global warming. This knowledge is crucial for informing conservation strategies and managing natural resources in the face of ongoing climate change.

GeneticsEcologyPlant Science

References

Main Study

1) Ensemble species distribution modeling and multilocus phylogeography provide insight into the spatial genetic patterns and distribution dynamics of a keystone forest species, Quercus glauca.

Published 4th March, 2024

https://doi.org/10.1186/s12870-024-04830-1

Related Studies

2) Seed germination schedule and environmental context shaped the population genetic structure of subtropical evergreen oaks on the Yun-Gui Plateau, Southwest China.

https://doi.org/10.1038/s41437-019-0283-2

3) Genome-wide analyses of introgression between two sympatric Asian oak species.

https://doi.org/10.1038/s41559-022-01754-7

4) A dated phylogeny of Lardizabalaceae reveals an unusual long-distance dispersal across the Pacific Ocean and the rapid rise of East Asian subtropical evergreen broadleaved forests in the late Miocene.

https://doi.org/10.1111/cla.12414

5) Climate change effects on biodiversity, ecosystems, ecosystem services, and natural resource management in the United States.

https://doi.org/10.1016/j.scitotenv.2020.137782


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