Evolutionary legacy of a keystone tibetan conifer tree
The leading plant journal New Phytologist has selected a study led by Umeå University researcher Xiao-Ru Wang as its cover story in the October issue. The paper is about effects of landscapes and range expansion on population structure and local adaptation.
Text: Ingrid Söderbergh
P. densata is the dominant forest-forming species in the southeastern Qinghai-Tibetan Plateau.
“Understanding the origin and distribution of genetic diversity across landscapes is critical for predicting the future of organisms in changing climates”, says Xiao-Ru Wang, professor at the Department of Ecology and Environmental sciences at Umeå University.
The study addresses a fundamental question in landscape genetics: the relative roles of population history, geography and natural selection in shaping genetic diversity in wild populations.
In the study, Xiao-Ru and a Chinese research group analyzed diversity and population structure in the pine tree Pinus densata, a keystone species on the Qinghai-Tibetan Plateau. They mapped the genetic variation to geographical and climate variables across the distribution range to establish the contribution of geo- and eco-factors to the observed spatial genetic pattern. Based on this information, the study further simulated how its genetic legacy may limit the persistence of P. densata in future climates.
The results illustrate that significant adaptation to extreme environment, when coupled with reduced diversity as a result of past demographic history, constrains potential evolutionary response to climate change.
As the dominant forest-forming species in the southeastern Qinghai-Tibetan Plateau, the resilience of P. densata underlies regional ecosystem function. Qinghai-Tibetan Plateau is the largest plateau on earth and also the most vulnerable ecosystem. While the deep valleys and high mountain ridges of the Qinghai-Tibetan Plateau have helped to create a global biodiversity hotspot, these same features can constrain adaptive responses to climate change. This is a particular concern for organisms with limited dispersal ability.
“The strong signal of genomic vulnerability in P. densata may be representative for other plateau endemics. As we accumulate further examples, it will become possible to gain a more general understanding of how demography and landscape factors constrain or promote adaptation to novel and changing environments,” Prof. Xiao-Ru Wang explains.
The study was performed in close collaboration with Beijing Forestry University; the joint team has been working together on this study system for more than 20 years.
professor at the Department of Ecology and Environmental sciences at Umeå University.
Zhao, W., et al: Effects of landscapes and range expansion on population structure and local adaptation. New Phytologist Volume228, Issue1 October 2020. Pages 330-3432020. https://doi.org/10.1111/nph.16619