Geographically driven shifts in land use influence phytoplankton community patterns in the Inner Mongolian Plateau lakes

地域驱动的土地利用格局对内蒙古高原湖泊浮游植物群落的影响

Phytoplankton play an irreplaceable role as producers in maintaining lake ecosystems.Nevertheless,scant attention has been given to investigating the dispersion of phytoplankton communities and the factors influencing them across expansive areas.In this study,we present the results of a survey on the distribution of phytoplankton community and the effects of different driving factors in 11 lakes along Inner Mongolia in July–August 2020.Non-metric multidimensional scaling analysis and variance decomposition(VPA)were used to elucidate the distribution of phytoplankton communities and the response of drivers.A total of 169 species of phytoplankton from 8 phyla were detected.Both the abundance and diversity of phytoplankton in the Inner Mongolia lakes showed a trend of high in the east and low in the west(with Daihai Lake as the boundary).The Margalef index of phytoplankton significantly negatively correlated with salinity(r=−0.707,P<0.05)and total dissolved solids(r=−0.720,P<0.05),and both density and biomass highly significantly positively correlated with the suspended solids,Chlorophyll a and trophic level index.The VPA explained 38.9%of the changes in the phytoplankton community with the highest rate of explanation of land use.Therefore,preventing anthropogenic impacts,as well as reducing nutrient loads,can effectively ensure the ecological diversity of lake phytoplankton in lake populations with large geographical spans and varying levels of nutrients.

浮游植物作为生产者在维持湖泊生态系统方面发挥着不可替代的作用。然而,对横跨区域尺度的浮游植物群落分布及其影响因素却很少受到关注。本文介绍了2020年7–8月内蒙古11个湖泊中浮游植物群落分布的情况及其驱动因素。采用非度量多维尺度分析和方差分解等方法,阐明了浮游植物群落分布模式及其对驱动因素的响应。研究结果显示,共检测到8门169种浮游植物。内蒙古湖泊浮游植物的丰度和多样性均呈东部高、西部低的趋势(以岱海湖为界)。浮游植物Margalef指数与盐度(r=−0.707,P<0.05)和总溶解固体(r=−0.720,P<0.05)呈显著负相关,密度和生物量均与悬浮固体、叶绿素a和营养级指数呈显著正相关。方差分解解释了浮游植物群落中38.9%的变化,其中土地利用的贡献度最高。最后,本文提出减少人为影响和养分负荷可以有效保证地理跨度大、养分水平差异明显的湖泊群浮游植物的生态多样性。