新疆塔里木河下游植物群落逆向演替分析

ANALYSIS ON CONVERSE SUCCESSION OF PLANT COMMUNITIES AT THE LOWER REACHES OF TARIM RIVER

通过对塔里木河中下游沿河植物群落的调查分析及地下水位下降对地表植被生态过程影响的研究 ,探讨塔里木河下游近几十年来植被的逆向演替过程 ,并划分出不同的演替阶段。根据草、灌、乔植被对地下水位具有不同的适应能力 ,塔里木河下游植物群落退化顺序也不相同 ,首先是草本退化 ,其次是灌木退化 ,再者是乔木退化。经调查分析表明 ,塔里木河下游植物群落的逆向演替顺序为 :乔灌草群落阶段→乔灌群落阶段→乔木或灌木群落阶段。在逆向演替过程中 ,各阶段有规律地进行 ,群落结构特征。

Tarim River is the longest continental river in China, its watershed is the important base of grain and famous quality fruit in Xinjiang. There are the natural vegetation belts composed of arbors, shrubbery and grass along either banks of Tarim River. There are many problems of damaged ecosystem in the lower reaches of Tarim River in long time as a result of excessive fell, excessive herd and irrational exploitation and utilization of water resources in the middle reaches of Tarim River. The dominant factor is water to lead vegetation to damage. In this paper, by analysis on conditions of plant growth along the river and research on ecological response process of vegetable to change of groundwater in the middle and lower reaches of Tarim River, the converse succession of plant communities in the lower reaches of Tarim river is preaumed during recent 50 years and divide the different succession stages are divided. At first, the plant species, conditions of plant distribution, conditions of soil water and soil organic matter are investigated, then a lot of historical data about the lower reaches of Tarim River are collected and some work in succession of plant communities have been completed. By research and analysis, the succession series of plant communities in the lower reaches of Tarim river are: comm. Arbor + shrub + herbage→comm. Arbor + shrub→comm. Arbor(or comm. shrub). On the basis of the response of the different plant communities to decline of groundwater, the sequence of degraded plants is: the stage of degraded herbage→the stage of degraded shrub→the stage of degraded arbor. The structure and composing of plant community change obviously during the converse succession. At different sections in the lower reaches of Tarim River, the actualities of degraded plant are unlike. There are different status of plant growth to decline of groundwater at different sections in the lower reaches of Tarim river such as Yinsu, Abidali, Alagan and Kaogan section etc.