Testing the Functional and Phylogenetic Assembly of Plant Communities in Gobi Deserts of Northern Qinghai-Tibet Plateau

Linkage between community assemblage of floral traits and pollinator fauna: a comparison among six geographical regions

The persistence of angiosperm communities largely depends on pollinator-mediated interactions. However, the importance of plant-pollinator interactions has often been overlooked in studies of plant community assembly. This study aims to assess the influence of plant-pollinator interactions on the assembly of plant communities. We compared the distribution of three floral traits (colour, symmetry, and tube length) across approximately 650 animal-pollinated plant species in six plant communities located in distinct geographical regions: Mongolian grassland, Japanese grassland, Japanese alpine zone, Swedish subalpine zone, Swedish alpine zone, and New Zealand alpine zone. Additionally, we examined the pollinator fauna in each community, focusing on the taxon-specific usage of floral traits by pollinators. The composition of all floral traits was predictably linked to taxonomic composition of the pollinator fauna and taxon-specific preferences of pollinators for certain floral traits. Furthermore, the dispersion of floral morphology depends on composition of pollinator fauna, rather than phylogenetic dispersion of plant communities. Interestingly, while composition of flower symmetry was largely linked to plant family composition, compositions of flower colour and tube length were almost independent of plant family composition. Our study suggests that pollinator fauna influences the assembly of floral traits. Analysis considering plant family composition suggests that the assembly process could be either ecological, where plant-pollinator interactions select for specific functional traits from a pre-existing pool, or evolutionary, where traits evolve in response to the pollinator environment within a community. This highlights the dual pathways through which pollinator fauna influences plant community assemblages.

A Study of the Diversity Patterns of Desert Vegetation Communities in an Arid Zone of China

The Gobi Desert ecosystem is currently experiencing the impacts of persistent climate warming and extreme weather. However, the relative influences of factors such as soil, climate, and spatial variables on the β-diversity of desert plants and their key components have not been systematically studied. In this research, the Dunhuang North Mountain and Mazong Mountain areas were selected as study areas, with a total of 79 plant community plots systematically established. The aim was to explore intercommunity β-diversity and its components and to analyze the interrelationships with climate factors, soil factors, and geographic distance. The results indicate that (1) there is a geographic decay pattern and significant differences among plant communities in the Dunhuang North Mountain and Mazong Mountain areas, with β-diversity primarily driven by replacement components. (2) Climate, soil, and geographic distance significantly influence β-diversity and its replacement components, with climate factors exerting the greatest influence and geographic distance the least. (3) Multiple regression analysis (MRM) reveals differential effects of climate factors, soil factors, and geographic distance on β-diversity and its replacement components, with climate and soil factors exerting a much greater influence than geographic distance. In summary, the β-diversity of plant communities and their replacement components in the Dunhuang North Mountain and Mazong Mountain areas result from the combined effects of habitat filtering and dispersal limitation, with habitat filtering having a greater impact, while environmental heterogeneity is an important factor influencing species differences in this region.

Transcriptomic Profiles of Long Noncoding RNAs and Their Target Protein-Coding Genes Reveals Speciation Adaptation on the Qinghai-Xizang (Tibet) Plateau in Orinus

Long noncoding RNAs (lncRNAs) are RNA molecules longer than 200 nt, which lack the ability to encode proteins and are involved in multifarious growth, development, and regulatory processes in plants and mammals. However, the environmental-regulated expression profiles of lncRNAs in Orinus that may associated with their adaptation on the Qinghai-Xizang (Tibet) Plateau (QTP) have never been characterized. Here, we utilized transcriptomic sequencing data of two Orinus species (O. thoroldii and O. kokonoricus) to identify 1624 lncRNAs, including 1119 intergenic lncRNAs, 200 antisense lncRNAs, five intronic lncRNAs, and 300 sense lncRNAs. In addition, the evolutionary relationships of Orinus lncRNAs showed limited sequence conservation among 39 species, which implied that Orinus-specific lncRNAs contribute to speciation adaptation evolution. Furthermore, considering the cis-regulation mechanism, from 286 differentially expressed lncRNAs (DElncRNAs) and their nearby protein coding genes (PCGs) between O. thoroldii and O. kokonoricus, 128 lncRNA-PCG pairs were obtained in O. thoroldii, whereas 92 lncRNA-PCG pairs were obtained in O. kokonoricus. In addition, a total of 19 lncRNA-PCG pairs in O. thoroldii and 14 lncRNA-PCG pairs in O. kokonoricus were found to participate in different biological processes, indicating that the different expression profiles of DElncRNAs between O. thoroldii and O. kokonoricus were associated with their adaptation at different elevations on the QTP. We also found several pairs of DElncRNA nearby transcription factors (TFs), indicating that these DElncRNAs regulate the expression of TFs to aid O. thoroldii in adapting to the environment. Therefore, this work systematically identified a series of lncRNAs in Orinus, laying the groundwork for further exploration into the biological function of Orinus in environmental adaptation.

Drivers of desert plant beta diversity on the Qinghai-Tibet plateau

The desert ecosystem of the Qinghai-Tibet Plateau (QTP) is an important component of China's desert ecosystem. Studying the mechanisms shaping the taxonomic, phylogenetic, and functional beta diversity of plant communities in the QTP desert will help us to promote scientific conservation and management of the region's biodiversity. This study investigated the effects of environmental (including altitude, climate factors, and soil factors) and geographic distances on three facets of beta diversity as well as their turnover and nestedness components based on field survey data. The results showed that turnover components dominate the three facets of beta diversity. However, the turnover contributions to phylogenetic and functional beta diversity were lower than for taxonomic beta diversity. Environmental distance had a greater influence than geographic distance, with the former uniquely explaining 15.2%-22.8% of beta diversity and the latter explaining only 1.7%-2.4%. Additionally, the explanatory power of different factors for beta diversity differed between herbs and shrubs, with environmental distance being more important for the latter. Distance-based redundancy analysis suggested that soil total potassium content had a substantial impact on the beta diversity of three dimensions, with mean temperature of the coldest month and soil total phosphorus content having a substantial impact on taxonomic and functional beta diversity as well. Our results support that environmental sorting plays a predominant role in shaping plant community composition across QTP desert ecosystems. To maintain the plant diversity of this region, it is crucial to prioritize the conservation of its diverse environmental conditions and actively mitigate its degradation by anthropogenic pressures.

Ecological Niche and Interspecific Association of Plant Communities in Alpine Desertification Grasslands: A Case Study of Qinghai Lake Basin

The study of niche and interspecific relationships is one of the classical ecological theories. We set up four desertification gradients. The "Levins" and "Pianka" method were used to calculate the species' niche breadth and niche overlap. Interspecies associations were analyzed by the ratio of variance (VR), Chi-square test, association coefficient (AC) and Ochiai index (OI). The results showed that in grasslands with different degrees of desertification, Stellera chromosome (3.90), Thermopsis lanceolate (3.52) and Aster almanacs (3.99) had larger niche widths, which were wide-area species of plant communities in the desertification area. The ecological niches of the same species in different habitats or different species in the same habitat were multi-dimensional. Niche differentiation measured by niche overlap can occur at any community succession stage. Niche width and niche overlap were not always consistent with environmental changes. Moreover, there was no linear relationship between them. The interspecific connection coefficient fluctuated greatly with the environment. The results can provide a reference for the study of plant community competition mechanism and desertification control in desertification land of the study area. We still do not know the mechanism of how the plants were preserved and how the retained plants adapted to the new environment during the desertification process. We can further study these questions in the next step.