State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, Xinjiang, China.
College of Resources and Environmental Sciences, Xinjiang University, Urumqi, Xinjiang, China.
PLoS One. 2020 May 13;15(5):e0232907. doi: 10.1371/journal.pone.0232907. eCollection 2020.
Ecological restoration of degraded riparian Tugai forests is a key driver to combat desertification in arid regions. Previous studies have focused mainly on changes in groundwater as the underlying mechanisms of Tugai forest's decline. We evaluated species composition and diversity of Tugai forest and their relationship to groundwater, soil salinity, and soil nutrient. Using 73 quadrats (100 m × 100 m) from 13 transects located perpendicularly to river in the upper reaches of the Tarim River. Eighteen plant species belonging to sixteen genera and eight families were recorded, and the dominant species included Populus euphratica, Phragmites communis, and Tamarix ramosissima. Three P. euphratica stand ages were detected: young stand, mature stand, and old stand. There were significant differences in species diversity, groundwater depth, groundwater salinity, distance from the quadrat to the river channel, soil moisture content, pH, electrical conductivity, total salt, Cl-, SO42-, Ca2-, Mg2+, Na+, K+, soil organic carbon, and soil organic matter across the stand ages. Seven species were identified as indicators of the three stand ages. Redundancy analysis indicated that the Tugai forest diversity indices were negatively correlated with groundwater depth, groundwater salinity, and distance from the river, and positively associated with electrical conductivity, total salt, pH, Cl-, SO42-, CO32-, soil organic matter, soil organic carbon, and soil moisture content. Plant diversity was the highest at 3-6 m groundwater depth, followed by 0-3 m and then 6-9 m, with the lowest recorded at > 9 m. The appropriate groundwater depth for herbs was about 1-4 m, whereas the depth for trees and shrubs was about 3-6 m. The groundwater depth < 6 m was deemed suitable for the growth of desert riparian forests. This results provide a scientific reference for the ecological restoration and protection for Tugai forests in arid areas.
退化的河岸胡杨林的生态恢复是干旱地区防治荒漠化的关键驱动力。先前的研究主要集中在地下水变化作为胡杨林衰退的潜在机制上。我们评估了胡杨林的物种组成和多样性及其与地下水、土壤盐分和土壤养分的关系。在塔里木河上游，我们使用了 13 条垂直于河流的样带中的 73 个样方（100m×100m）。记录了 18 种植物，属于 16 属 8 科，优势种包括胡杨、芦苇和柽柳。检测到三个胡杨林龄：幼龄林、成熟林和老龄林。在样龄之间，物种多样性、地下水深度、地下水矿化度、样方到河道的距离、土壤含水量、pH 值、电导率、总盐、Cl-、SO42-、Ca2+、Mg2+、Na+、K+、土壤有机碳和土壤有机质均有显著差异。有 7 种物种被确定为三个林龄的指示物种。冗余分析表明，胡杨林多样性指数与地下水深度、地下水矿化度和距河道的距离呈负相关，与电导率、总盐、pH 值、Cl-、SO42-、CO32-、土壤有机质、土壤有机碳和土壤含水量呈正相关。在地下水深度为 3-6m 时，植物多样性最高，其次是 0-3m，然后是 6-9m，在>9m 时最低。草本植物适宜的地下水深度约为 1-4m，而树木和灌木的深度约为 3-6m。<6m 的地下水深度被认为适合沙漠河岸森林的生长。该研究结果为干旱地区胡杨林的生态恢复和保护提供了科学参考。
