Widespread species of Phragmites australis has a high degree of intraspecific variation in functional traits along external climatic and environmental gradients. However, the underlying mechanisms of the environmental gradient at regional scale on intraspecific variation and adaptation strategies of species functional traits are still not well understood. The leaf, stem and root traits of P. australis in lakeshore wetlands of semi-arid and arid regions in the Inner Mongolia Plateau were measured to reveal the variability of functional traits at regional scales and the influencing factors, and to reveal the ecological adaptation strategies of P. australis in different regions through plant economic spectrum. The results showed that variation of functional traits of P. australis had a significant latitudinal pattern. Temperature determined the intraspecific variation of the functional traits of P. australis, and the influence of soil properties was small. Plant economic spectrum theory was also applicable to the functional traits of various organs and whole plants of P. australis, and different ecological adaptation strategies were confirmed across arid and semi-arid regions. This study provides a new understanding of intraspecific variation of functional traits of P. australis originates from temperature-mediated climatic differences brought about by sampling geographic locations, rather than the soil properties of the sampling locations and the joint of climate and soil. The utilization and assimilation of resources of P. australis were conservative in arid regions, while in semi-arid regions it was an acquisition strategy.

Studies on water origin and transformation relationship between groundwater and surface water is important for understanding on hydrological processes and water resources management. In this study surface water and groundwater samples from Xiliugou and Wulagai River basin were collected and analyzed for stable hydrogen and oxygen isotopes and hydrochemistry data. The results show that the pH of all water samples ranged from 6.81 to 8.91, blongs to weak alkaline water; the average value of TDS in surface water and groundwater is less than 1000mg/l, which is low mineralization water. Na•Ca-SO 4•HCO 3 type and Ca•Na-HCO 3 type was the dominatnt hydrochemical types for surface water in Xiliugou and Wulagai River basin, respectively; Na•Ca-HCO 3 type and Ca•Mg-HCO 3 type for groundwater in Xiliugou and Wulagai River basin respectively. The End-Members Mixing Analysis (EMMA) used for hydrograph separation indicated that in the growing season, the groundwater was recharged by precipitation (76.87 %), and surface water (23.13 %) in Xiliugou; the groundwater in Wulagai was mainly recharged by precipitation (65%) and surface water (35 %).

Soil microbes are key players in wetland ecosystems. The biogeography of bacterial and fungal communities and their underlying mechanisms for generating and maintaining lakeshore wetlands are important in microbial ecology but remain unclear. Here we investigated the biogeographical patterns and the factors shaping bacterial and fungal communities in lakeshore wetland soils at a regional scale in northern China. Our results revealed that the diversity of soil bacterial and fungal communities in lakeshore wetlands had significant geographical distribution patterns in both longitude and latitude gradients; and notably the geographical distribution pattern of α-diversity is mainly manifested in species richness. Climate, edaphic properties, and plant diversity together determined the geographical distribution patterns of bacterial and fungal community diversity, contributing 66.05% and 49.66% of the diversity variation, respectively. As droughts intensify, the assembly of bacterial communities is gradually dominated by deterministic processes dominated of habitat filtration, while fungal communities are dominated by random processes of species dispersal. Structural equation modelling revealed that the differences in temperature and precipitation originating from geographical distances directly modulated the geographical distribution of fungal community diversity, while bacteria were indirectly regulated by influences of local soils and plants. Our findings highlight that different sensitivity of soil bacteria and fungi to climate change and different responses to soil communities in lakeshore wetlands may have profound implications for the stability and functioning of wetland ecosystems.