Morphological and Genetic Variation along a North-to-South Transect in Stipa purpurea, a Dominant Grass on the Qinghai-Tibetan Plateau: Implications for Response to Climate Change

Abstract

Estimating the potential of species to cope with rapid environmental climatic modifications is of vital importance for determining their future viability and conservation. The variation between existing populations along a climatic gradient may predict how a species will respond to future climate change. Stipa purpurea is a dominant grass species in the alpine steppe and meadow of the Qinghai-Tibetan Plateau (QTP). Ecological niche modelling was applied to S. purpurea, and its distribution was found to be most strongly correlated with the annual precipitation and the mean temperature of the warmest quarter. We established a north-to-south transect over 2000 km long on the QTP reflecting the gradients of temperature and precipitation, and then we estimated the morphological by sampling fruited tussocks and genetic divergence by using 11 microsatellite markers between 20 populations along the transect. Reproductive traits (the number of seeds and reproductive shoots), the reproductive-vegetative growth ratio and the length of roots in the S. purpurea populations varied significantly with climate variables. S. purpurea has high genetic diversity (He = 0.585), a large effective population size (Ne >1,000), and a considerable level of gene flow between populations. The S. purpurea populations have a mosaic genetic structure: some distant populations (over 1000 km apart) clustered genetically, whereas closer populations (< 100 km apart) had diverged significantly, suggesting local adaptation. Asymmetrical long-distance inter-population gene flow occurs along the sampling transect and might be mediated by seed dispersal via migratory herbivores, such as the chiru (Pantholops hodgsonii). These findings suggest that population performance variation and gene flow both facilitate the response of S. purpurea to climate change.

The Tanggula Mountains enhance population divergence in Carex moorcroftii: a dominant sedge on the Qinghai-Tibetan Plateau

“…We illustrated that C. moorcroftii held rich genetic variation ( H e = 0.58). The high level of genetic variability within populations of C. moorcroftii is similar to other outcrossing perennial grasses (e.g., Stipa purpurea , H e = 0.585 25 ) and comparable to those of the perennial and woody species that range across most areas of QTP (e.g., Populus szechuanica , H e = 0.488 26 ; Prunus sibirica , H e = 0.774 27 ). The high genetic diversity of C. moorcroftii may be due to its biological characteristics such as perenniality, wind-pollination, and generalist characteristics, allowing it to persist in a range of environmental conditions on the QTP.…”

“…The high genetic diversity of C. moorcroftii may be due to its biological characteristics such as perenniality, wind-pollination, and generalist characteristics, allowing it to persist in a range of environmental conditions on the QTP. The relativly large effective population size ( N e > 800, Table 3 ) and frequent gene flow between populations (mean N m > 1.0, Table S 5 ) might also contribute to the observed high level of genetic diversity 25 . In addition, the F index data (Table 3 ) suggests that it has a high degree of outcrossing, hinting that sexual reproduction plays an important role in contributing to high genetic variability.…”

“…Significant heterozygote excess occurred in most C. moorcroftii populations (Table 3 ), suggesting a heterozygote advantage 25 , 28 . This may be attributed to faster growth and lower mortality of heterozygous genotypes compared to homozygous types, resulting in higher heterozygosity in populations 28 .…”

“…The reason for TM interrupted gene flow across north and south C. moorcroftii populations may be related to the snow–cover on the TM ridge and the dispersal modes of this species. The high elevation snow–covered ridge of the TM can directly impede air-mediated pollen flow in C. moorcroftii as a physical barrier, decreasing dispersal distance 25 . In addition, the seeds of C. moorcroftii have smooth surfaces, which mainly disperse by gravity to locations near mother plants.…”

Morphology and Genetic Diversity of Jabon Putih Seedling from 4 Populations in Sumatra, Nusa Kambangan, Kalimantan, and Sulawesi

“…Jenis ini mempunyai sebaran tumbuh yang luas dan diduga mempunyai plastisitas dan adaptasi tinggi terhadap lingkungan alaminya. Plastisitas memberi implikasi bahwa suatu kelompok gen yang terbagi di antara populasi mampu beraklimatisasi dan menghasilkan morfologi/ fenotipe berbeda pada setiap lingkungannya (Lind & Johansson, 2011;Liu et al, 2016). Karakterisasi pola perbedaan morfologi pada populasi di hutan alam tersebut merupakan informasi awal yang sangat penting untuk menyatakan hipotesis tentang kemungkinan pola keragaman genetik, karakter-karakter khusus yang secara nyata beradaptasi dan respon plastis terhadap lingkungannya (Ohsawa & Ide, 2008).…”