河西走廊水生植物多样性格局、群落特征及影响因素

水生植物是湿地生态系统重要组成部分,研究水生植物多样性分布格局及其影响因素对地区水生植物资源保护具有重要意义。通过野外调查并结合气候等环境因素,研究了河西走廊主要水生植物群落类型、数量特征、水生植物多样性分布格局及影响因素,并对中域效应假说进行了验证。研究结果表明:(1)河西走廊地区共有水生植物29科42属84种,群落的聚类分析可将河西走廊水生植物群落划分为15个主要群落类型;(2)河西走廊水生植物群落类型主要受到水温、海拔、经纬度等环境因子影响,群落物种多样性指数与盐度以及溶解性固体总量呈显著性相关;(3)河西走廊水生植物多样性空间格局呈现出"∩"型的单峰格局,中域效应模型能较好地解释该地区水生植物多样性水平的纬度格局及海拔垂直分布格局,对该区域水生植物物种丰富度在纬度和海拔梯度上的变异解释率分别为57.56%、63.5%。分析表明,河西走廊水生植物物种丰富度格局由几何(边界)限制和随机过程及其他未知因素共同控制,且几何(边界)限制和随机过程贡献率较大;同时本研究中未考虑的环境异质性、气候、人为干扰等因素也对河西走廊水生植物多样性空间分布产生重要影响。

Biogeographic pattern, main community types, and the influencing factors of aquatic macrophytes in the Hexi Corridor of Northwest China

Aquatic plants are an important part of wetland ecosystems. Studies about the distribution pattern of aquatic plants and its influencing factors can provide important background for the regional protection of aquatic plant resources. In this study, the main aquatic plant community types, quantitative characteristics, species richness patterns, and influencing factors of aquatic plants in the Hexi Corridor were studied using field investigation data. The mid-domain effect hypothesis was used to explain geographical diversity patterns of aquatic macrophytes in the region. The main results are as follows:(1) there were 84 species belonging to 42 genera of 29 families of aquatic plants in the Hexi Corridor. Cluster analysis of the community showed that there were 15 main aquatic plant community types in this region; (2) the aquatic plant community types in the Hexi Corridor were mainly affected by environmental factors such as water temperature, elevation, latitude, and longitude. The community species diversity index was significantly correlated with salinity and total dissolved solids; (3) the spatial pattern of aquatic plant diversity in the Hexi Corridor exhibited a unimodal pattern. The mid-domain effect model better explained the latitudinal pattern and the vertical distribution pattern of aquatic plant diversity in the region, with explanation rates reaching 57.56% and 63.5%, respectively. These results indicate that the patterns of aquatic macrophyte species richness in the Hexi Corridor were determined by geometric (boundary) constraints, random processes, and other unknown processes. Geometric (boundary) constraints and random process showed a higher contribution rate on geographic richness gradients. Also, we highlight that unmeasured factors including environmental heterogeneity, climate, and human disturbance may greatly affect aquatic plant species richness in the Hexi Corridor of Northwest China.