洞庭湖区三个湖泊水生植物多样性的比较研究

比较研究了洞庭湖区华容县东湖、益阳市大通湖和岳阳市郊南湖水生植物多样性的现状，讨论了30年来3个湖泊水生植物多样性丧失的情况及与其所受人为干扰的关系，探讨了野菱、密齿苦草和菹草对人为干扰的适应机制、大通湖和南湖水生植物多样性及其退化水生态系统恢复的途径。主要结论如下：（1）199－2000年东湖、大通湖与南湖各分布有水生植物61种、56种和32种，其分别隶属于29科43属、26科39属和20科27属；各有水生植物群丛8个、6个和4个；水生植被覆盖率分别为26．17％、10．60％和9．99％。（2）30年来三个湖泊分别有3种、9种和13种水生植物消失，2个、5个和5个水生植物群丛类型消失。（3）水生植物多样性的现状是：东湖＞大通湖＞南湖，多样性下降的程度与其所受干扰强度成正相关。

A COMPARATIVE STUDY ON AQUATIC PLANT DIVERSITY AND ITS LONG-TERM CHANGES IN THE THREE LAKES OF DONGTINGHU DISTRICT IN CHINA

The aquatic plant diversity and its long term changes in the three lakes of Dongtinghu District in China were comparatively studied in this paper The adaptive mechanisms of Trapa incisa, Vallisneria denseserrulata and Potamogeton crispus to human disturbance were also investigated Besides, the approaches to restore the aquatic plant diversity and the degraded aquatic ecosystems of Lake Datonghu and Nanhu were suggested The main results are:(1) During 1999-2000,61,56 and 32 aquatic plant species were recorded in Lake Donghu,Datonghu and Nanhu,respectively.And 8 and 6 aquatic plant associations were identified in Lake Donghu and Datonghu, respectively, whereas only 4 associations were found in Lake Nanhu The respective aquatic vegetation coverage of the three lakes were 26 17%,10 60% and 9 99% (2) Comparaed with the studies in the early 1970s ,3,9 and 13 aquatic plant species,2,5 and 5 aquatic plant associations were found to have disappeared from Lake Donghu, Datonghu and Nanhu, respectively (3) The results indicated that the aquatic plant diversity in the three lakes is in the order of Lake Donghu>Datonghu>Nanhu at present, and the decrease of aquatic plant diversity in the three lakes were positively related to the intensity of human disturbance