塔里木河下游荒漠植物多样性、地上生物量与地下水埋深的关系

样带是研究植物群落沿环境因子梯度变化的重要方法。用样带法研究了塔里木河下游荒漠植被群落物种多样性和地上生物量在垂直河道方向随地下水埋深梯度变化的关系。结果表明：（1）样带植物群落物种多样性与地下水埋深极显著负线性相关（P〈0.01），Margalaf指数、Pielou指数、Shannon-Wiener指数和Simpson指数均随地下水埋深增大而减小，地下水埋深是影响群落组成和物种多样性的重要因素。（2）单一乔木层、灌木层、草本层地上生物量和乔灌草地上总生物量与地下水埋深均极显著负相关（P〈0.01），地下水埋深从3 m增大到7 m时，地上总生物量由912.2 g·m^-2减少到不足30 g·m^-2，地下水埋深是制约荒漠植被地上生物量和分布的主要因素。（3）群落多样性与地上生物量之间显著正线性相关（P〈0.05），即随多样性增加，地上生物量呈增加趋势。

Relation of Desert Vegetation Species Diversity and Aboveground Biomass to Groundwater Depth in the Lower Reaches of Tarim River

Transect is an efficient way to make a study about plant communities changes alone the gradients of environmental factors,this paper makes a transect study on desert vegetation species diversity and aboveground biomass alone gradients of groundwater depth in the lower reaches of Tarim River.The results showed that (1) Regression analysis of diversity indices (including Margalaf index,Pielou index,Shannon-Wiener index and Simpson index) and groundwater depth showed an extremely significant negative correlation (P<0.01),diversity indices decreased with the increase of groundwater depth,groundwater depth is one of the important factors that affecting the species diversity.(2) Regression analysis of total aboveground biomass of desert vegetation and groundwater depth also shows an extremely significant negative correlation (P<0.01),aboveground biomass decreased from 912.21 g·m^-2 to less than 30 g·m^-2 when groundwater depth changed from 3 to 7 meter,groundwater depth is the main factors that affecting the aboveground biomass and its distribution.(3) Regression analysis of diversity indices and aboveground biomass showed an significant positive correlation (P<0.05),that is,aboveground biomass increased with the increase of diversity indices.The research is helpful to ecological restoration of the lower reaches of the Tarim River and to provide theoretical basis and reference for the environmental protection.