生态学报2017，Vol.37Issue(20)：6836-6846,11.DOI:10.5846/stxb201607281547
荒漠河岸林胡杨群落特征对地下水位梯度的响应
Response of Populus euphratica communities in a desert riparian forest to the groundwater level gradient in the Tarim Basin
摘要
Abstract
The largest area of desert riparian forest is distributed in the Tarim Basin,northwest China.It controls the structure and function of the desert ecosystem;determines landscape patterns,vegetation processes,and land desertification;and changes the ecological environment of oases in southern Xinjiang.Populus euphratica Oliv.is the dominant species and is distributed widely across desert riparian forests.It protects biodiversity and desert ecosystem stability,and serves as a natural barrier to curb desertification and sandstorms.Since the 1950s,land has been reclaimed and the water resources have been utilized in the area.This has resulted in a reduction in the groundwater level,weak vegetation growth,and high desert plant mortality,which has affected the sustainable development of agriculture and the economies of the affected oases.The aim of this study was to understand the ecological responses of P.euphratica communities to changes in groundwater levels (GWL),to determine the rational GWL needed for the survival of desert riparian forest,and to provide a theoretical basis for population conservation and vegetation restoration in the Tarim Basin.Nine belt transects and 45 plots were established to monitor the GWL and vegetation in the upper reaches of the Tarim River and the ecological responses of the P.euphratica community to the GWL.The relationship between the vegetation and the GWL gradient were analyzed using multi-analysis methods,and Hill andβ-diversity index analyses.The Ward cluster analysis divided the 45 sampling plots into three types and the quantitative characteristics (density,DBH,canopy diameter,coverage,mortality) of the P.euphratica population and the GWL gradients were significantly correlated (P ＜ 0.01).The P.euphratica growth vigor decreased and the population structure transitioned from expanding to declining as the GWL decreased.Species diversity varied considerably in the three different plot types as the GWL decreased.In particular,when the GWL ranged from 4 to 6 m,the Hill-diversity index decreased sharply,and the diversity curve became a smooth line.Species diversity began to decline at GWL ＞ 4 m.Furthermore,the Cody (βc) and Whittaker (βw) values increased and the Sorensen (βs) value decreased as the GWL fell.Theβs,βc,andβw indexes,and the differences in groundwater levels were significantly correlated (P ＜ 0.01).At GWL ＞ 4 m,theβc andβw values increased,but theβs value decreased considerably.The above analyses suggested that the P.euphratica communities had similar structures and many common species,and that the P.euphratica population grew most efficiently at GWL ＜ 4 m,which was the most suitable ecological water table for P.euphratica population survival.At GWL ＞ 4 m,species diversity and the common species in the community decreased rapidly,differences in species components and environmental heterogeneity increased,the quantitative characteristics of the P.euphratica population varied significantly,and the community structure became simplified.When the GWL was about 6 m,vegetation became degraded and the dominant population declined considerably.Therefore,the rational ecological GWL for restoring degraded desert vegetation is about 4 m in extremely arid areas.关键词
荒漠河岸林/胡杨群落/Hill多样性/β多样性/地下水位梯度Key words
desert riparian forest/Populus euphratica community/Hill diversity/β-diversity/groundwater gradient引用本文复制引用
韩路,王海珍,牛建龙,王家强,柳维扬..荒漠河岸林胡杨群落特征对地下水位梯度的响应[J].生态学报,2017,37(20):6836-6846,11.基金项目
新疆生产建设兵团应用基础研究(2015AG006) （2015AG006）
国家自然科学基金项目(31560182,31060066) （31560182,31060066）
