Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, School of Ecology and Environment, Inner Mongolia University, Hohhot, 010021, China.
Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, School of Ecology and Environment, Inner Mongolia University, Hohhot, 010021, China; Inner Mongolia Key Laboratory of Grassland Ecology, Hohhot, 010021, China.
Environ Res. 2024 Dec 15;263(Pt 2):120142. doi: 10.1016/j.envres.2024.120142. Epub 2024 Oct 12.
Phytoplankton are crucial primary producers in freshwater ecosystems, driving matter and energy flow across trophic levels, essential for biodiversity and ecological balance. Most research emphasizes environmental factors shaping their diversity, while the role of hydrological connectivity remains poorly understood. This study collected 81 phytoplankton samples from the Hetao Irrigation District along a gradient from upstream to downstream and utilized high-throughput sequencing to evaluate the spatial distribution patterns of phytoplankton diversity. The study analyzed the impacts of environmental factors, hydrological connectivity (water surface ratio, Wp), and human activities (land-use intensity, LUI) on phytoplankton diversity. The results revealed that the phytoplankton community comprised 9 phyla, 158 families, 378 genera, and 1189 species. There were significant differences in phytoplankton diversity among different water bodies, with a gradual increase in phytoplankton diversity from west to east across the five major irrigation areas. Lake Ulansuhai had relatively low phytoplankton diversity. The ASV number, Chao1 index, and ACE index showed significant positive correlations with dissolved oxygen (DO), pH, and water temperature (WT). The Shannon index and Pielou'e evenness (Pielou_e) index showed significant positive correlations with the water surface ratio (Wp). The partial least squares model indicated that environmental factors directly influenced phytoplankton diversity. Hydrological connectivity indirectly affected phytoplankton diversity by altering environmental factors. We emphasize that hydrological connectivity is as important as environmental factors in driving phytoplankton diversity in the Hetao Irrigation District. This study provides key insights for water quality assessment and biodiversity conservation in the region.
浮游植物是淡水生态系统中至关重要的初级生产者，驱动着物质和能量在营养级之间流动，对生物多样性和生态平衡至关重要。大多数研究强调了环境因素对其多样性的塑造作用，而水文连通性的作用仍知之甚少。本研究从上游到下游沿梯度采集了河套灌区的 81 个浮游植物样本，利用高通量测序评估了浮游植物多样性的空间分布模式。该研究分析了环境因素、水文连通性（水面比，Wp）和人类活动（土地利用强度，LUI）对浮游植物多样性的影响。结果表明，浮游植物群落由 9 个门、158 个科、378 个属和 1189 个种组成。不同水体的浮游植物多样性存在显著差异，五个主要灌区从西向东浮游植物多样性逐渐增加。乌梁素海的浮游植物多样性相对较低。ASV 数量、Chao1 指数和 ACE 指数与溶解氧（DO）、pH 值和水温（WT）呈显著正相关。Shannon 指数和 Pielou_e 均匀度（Pielou_e）指数与水面比（Wp）呈显著正相关。偏最小二乘模型表明，环境因素直接影响浮游植物多样性。水文连通性通过改变环境因素间接影响浮游植物多样性。我们强调，在驱动河套灌区浮游植物多样性方面，水文连通性与环境因素同样重要。本研究为该地区的水质评估和生物多样性保护提供了关键见解。
