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

Abstract

The mechanism governing plant community assembly across large-scale Gobi deserts remains unclear. Here, we inferred the roles of different assembly processes in structuring plant communities in the Gobi deserts of the Qinghai–Tibet Plateau by using a phylogenetic tree, and leaf and root traits. The functional and phylogenetic structures of 183 plant communities were assessed, and their distributions were linked with environmental gradients. Our results demonstrated that functional convergence was prevalent in most functional traits (75% of the traits) and accentuated when all traits were combined. The phylogenetic structure exhibited significant divergence. We observed the contrasting response of functional and phylogenetic assembly structures to environmental gradients. More importantly, we found that the shifts in the functional assembly along environmental gradients were trait-specific, with dominant roles of local factors, such as gravel coverage and soil attributes, in determining the distribution patterns of most traits. However, the distribution patterns of leaf P concentration (LPC), root N concentration (RNC), and root P concentration (RPC) were mainly driven by climatic factors. These results reveal that niche-based processes, such as abiotic filtering and weaker competitive exclusion, are the major drivers of species co-occurrence, which results in the widespread coexistence of phylogenetically distinct but functionally similar species within the Gobi plant community. Our findings could improve the understanding of plant community assembly processes and biodiversity maintenance in extremely harsh drylands.

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

“…Precipitation is scarce, with an annual average of 85 mm. The vegetation in the study area is mainly composed of drought‐tolerant and ultradrought‐tolerant shrubs, semishrubs, and small trees, as well as drought‐tolerant herbs (Wang, Wang, et al., 2022b ). Dominant species in the shrub layer include Sympegma regelii , Salsola abrotanoides , Ceratoides compacta , Ceratoides latens , Reaumuria soongorica , Haloxylon ammodendron , and Ajania fruticulosa .…”

“…The harsh and unique environmental conditions of the QTP desert have led to the relatively recent evolution of lineages with adaptations to survive in this cold and arid environment and subsequent adaptive radiation of species in these lineages into different parts of the region's environmental space. Previous studies have demonstrated phylogenetic and functional convergence among species in the QTP (Wang, Wang, et al, 2022b;Yan et al, 2013). Therefore, we hypothesize that taxonomic beta diversity should be substantially higher than phylogenetic and functional beta diversity and contain a dominant turnover component (H1).…”

“…Although several studies have investigated beta diversity in arid or desert regions, the majority of these studies have focused on grasslands (Bergholz et al., 2017 ; Li et al., 2021 ; Tang et al., 2018 ) or wetlands (Hu et al., 2022 ; Jiang et al., 2021 , 2022 ). As a result, there is still a substantial research gap in our understanding of the diversity of desert ecosystems (Goettsch & Hernández, 2006 ; Wang, Qu, et al., 2022a ; Wang, Wang, et al., 2022b ).…”

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

“…The QTP is rich in plant and animal resources. To survive in this region, organisms have formed a unique adaptation mechanism in stressful environments, such as low temperatures and droughts, through natural selection for a long time, which provides good materials for the study of biological adaptability on the plateau [20]. Orinus belongs to the grass family (Poaceae) and is a genus found in alpine regions that is known for its significant economic value [21].…”