Phylogenetic structure and formation mechanism of shrub communities in arid and semiarid areas of the Mongolian Plateau

Abstract

The mechanisms of species coexistence within a community have always been the focus in ecological research. Community phylogenetic structure reflects the relationship of historical processes, regional environments, and interactions between species, and studying it is imperative to understand the formation and maintenance mechanisms of community composition and biodiversity. We studied the phylogenetic structure of the shrub communities in arid and semiarid areas of the Mongolian Plateau. First, the phylogenetic signals of four plant traits (height, canopy, leaf length, and leaf width) of shrubs and subshrubs were measured to determine the phylogenetic conservation of these traits. Then, the net relatedness index (NRI) of shrub communities was calculated to characterize their phylogenetic structure. Finally, the relationship between the NRI and current climate and paleoclimate (since the Last Glacial Maximum, LGM) factors was analyzed to understand the formation and maintenance mechanisms of these plant communities. We found that desert shrub communities showed a trend toward phylogenetic overdispersion; that is, limiting similarity was predominant in arid and semiarid areas of the Mongolian Plateau despite the phylogenetic structure and formation mechanisms differing across habitats. The typical desert and sandy shrub communities showed a significant phylogenetic overdispersion, while the steppified desert shrub communities showed a weak phylogenetic clustering. It was found that mean winter temperature (i.e., in the driest quarter) was the major factor limiting steppified desert shrub phylogeny distribution. Both cold and drought (despite having opposite consequences) differentiated the typical desert to steppified desert shrub communities. The increase in temperature since the LGM is conducive to the invasion of shrub plants into steppe grassland, and this process may be intensified by global warming.

Modern Climate and Soil Properties Explain Functional Structure Better Than Phylogenetic Structure of Plant Communities in Northern China

“…This finding supports the idea that the functional structure should be better linked with local and contemporary drivers because the functional traits are more plastic compared with the phylogenetic relations, which are mainly shaped by historical and regional processes (Feng et al, 2014;Li et al, 2019). A recent study about shrub communities in this region also suggests that compared with the leaf width and leaf length, the height shows a low phylogenetic signal and high plasticity (Zheng et al, 2019).…”

Gluconeogenesis Alteration and p53-SIRT6-Fox01 Signaling Adaptive Regulation in Sheep from Different Grazing Periods

“…However, the decline in sheep health and meat quality caused by seasonal nutritional deficiencies has always been the main problem in the production of naturally grazing sheep [ 3 ]. Mongolian Plateau is a typical arid and semiarid region, with mean annual precipitation varying between 40-450 mm and 80-90% of the precipitation falling between June and September, decreasing from the southeast toward the northwest [ 4 ]. The mean annual temperature ranges between -2 and 6°C and has a frost-free season of 70-160 days [ 5 ].…”

Environmental Heterogeneity Affecting Community Assembly Patterns and Phylogenetic Diversity of Three Forest Communities at Mt. Huangshan, China

“…If competitive exclusion arises from competition among species, then the phylogenetic assembly of a community will be overdivergent [6]. In contrast to niche theory, Hubbell's neutral theory is based on a stochastic process; it holds that equal niches exist among different species, and the number of coexisting species is constrained by random processes and spatial distance [7,8]. Researchers have found that evergreen broad-leaved forests show phylogenetically random structures [9].…”

“…Many researchers have used a phylogenetic approach to investigate the predominant processes that underlie community structure [6,8,9,11]. Community phylogenetic structure is mainly reflected in two aspects: one is that measure the relatedness of species occurring together in a community or sample, and the other is that measure the concordance of phylogenetic and ecological dissimilarities among species [3].…”

“…Numerous studies have shown positive correlations between the spatial distribution of biodiversity and driving factors such as climate and topography [19,20]. For instance, mean winter temperature was the major factor that limited the phylogenetic distribution of shrubs in the Mongolian Plateau [8], and phylogenetic structure was related to precipitation in northwestern South America [21]. Lower precipitation may have caused the coexistence of closely related species.…”