3.7萬字              94頁           包括外文翻譯

摘  要

近年來由于頻繁的人類活動以及管理上的疏忽，湖泊富營養(yǎng)化的現(xiàn)象越來越嚴(yán)重，富營養(yǎng)化湖泊水環(huán)境對水生植物群落的影響已成為當(dāng)今重要的研究課題。本文以調(diào)研為基礎(chǔ)，對xx市三個典型富營養(yǎng)湖泊（玄武湖、莫愁湖、月牙湖）的水生植物群落特征進(jìn)行了分析。采用景觀生態(tài)學(xué)方法，對三個湖泊選取典型樣地，然后對樣地內(nèi)植物群落進(jìn)行分類與統(tǒng)計，分析水生植物的種類、應(yīng)用頻度及蓋度等數(shù)量特征，通過水生植物群落的豐富度、多樣性指數(shù)以及均勻性指數(shù)3個指標(biāo)來反應(yīng)水生植物的群落特征。

調(diào)查結(jié)果顯示，玄武湖水生植物的豐富度和多樣性指數(shù)以及均勻性指數(shù)分別為7.38，6.27和1.65，是三個湖中最高的，其景觀配置也較為豐富，常見植物主要為睡蓮、水花生和人工栽植的荷花。莫愁湖中應(yīng)用的水生植物共24種，其中荷花的應(yīng)用頻度最高，達(dá)90%，豐富度指數(shù)、多樣性指數(shù)和均勻性指數(shù)分別為5.48，3.92和1.23，稍低于玄武湖，可見莫愁湖水生植物種類與多樣性較好，但卻缺乏浮水植物與沉水植物。而月牙湖中物種的豐富度指數(shù)、多樣性指數(shù)和均勻度指數(shù)均為三個湖中最低，僅為3.91，3.36和1.17，可見其水生植物種類最為匱乏，植物配置也最為單調(diào)，岸邊主要生長著一些水花生和五節(jié)芒、早熟禾等植物，湖面上則覆蓋著大量的浮萍，浮萍使得水體透光度急劇下降，因此湖中沒有沉水植物生長?？傮w來看，3個湖大面積應(yīng)用的水生植物為水花生、黃菖蒲和早熟禾，應(yīng)用頻度都在30%以上，但3個湖泊的沉水植物卻較為稀少，目前調(diào)查的湖泊中只有玄武湖中有金魚藻、輪葉狐尾藻等兼具觀賞價值及生態(tài)功能的沉水植物。

本文還考察了水質(zhì)、水流條件、人為栽植和主導(dǎo)風(fēng)向幾個影響因素對水生植物的影響。調(diào)查結(jié)果表明，玄武湖近岸邊平均水深0.48m，半數(shù)以上水域的透明度只有0.2m左右，不符合水生植物生長的條件，因此只湖北面和湖心一個島周圍這類水深較淺的區(qū)域發(fā)現(xiàn)了沉水植物；同時人工栽植的荷花也使得一些水域的植物群落過于單一。莫愁湖的重金屬離子污染較嚴(yán)重，而氮、磷等營養(yǎng)鹽方面，因管理較好的緣故各項指標(biāo)均未超標(biāo)，莫愁湖的平均水深約1m，水體透明度在0.4m左右，因此難以生長沉水植物。主要植物為生長在岸邊的早熟禾、蛇莓等濕生植物以及人工栽植的海棠；此外，部分水面存在人工栽植的荷花與水杉，可見莫愁湖主要植物群落分布受人工栽植影響較大。月牙湖因污水的排放導(dǎo)致氮磷超標(biāo)，使得浮萍在湖面上瘋狂生長，同時因浮萍為無固定根的浮水植物，故受主導(dǎo)風(fēng)向影響較大，主要分布在湖面下風(fēng)向的一側(cè)。月牙湖的平均水深雖然只有0.35m，但水體透明度僅0.15m左右，加上湖面上浮萍的覆蓋，種種惡劣的條件使得沉水植物難以生長，因此在湖中沒有觀察到有沉水植物的存在。

關(guān)鍵詞：富營養(yǎng)化；水生植物；影響因素；群落特征

 

ABSTRACT

Lake ecosystem is an ubiquitous ecosystem in the city in recent years. Due to human’s activities and the negligence of management, lake-eutrophication becames more and more serious in recent years. Therefore, the influence of aquatic environment on plant community has been becoming an important topic. The characters of the aquatic plants communities of three typical eutrophic lakes (Xuanwu Lake, Mochou Lake, Yueya Lake) in Nanjing was analyzed based on the survey. Using landscape ecology method, the typical sample plots were selected, and then the plant communities were classified. In order to collect the statistic data of the plant communities, the species, frequency and coverage of aquatic plant communities were analyzed. With the richness, diversity and evenness indexes, the communities’ features were reflected. 

According to the surveying results, The richness and diversity and evenness indexes for aquatic plants in Xuanwu Lake of 7.38, 6.27 and 1.65 respectively, which were higher than other two lakes. Therefore, it can be concluded that there are abundant of aquatic plants in Xuanwu Lake and the common plants are mainly water lilies, alternanthera philoxeroides and lotus. There are 24 kinds of aquatic plants in Mochou Lake, and the application frequency of lotus is highest and up to 90%, and the richness, diversity and evenness indexes were 5.48, 3.92 and 1.23, slightly lower than that of Xuanwu Lake. There is a lack of floating plants and submerged plants in Mochou Lake. The species richness, diversity and evenness indexes for Yueya Lake are of 3.91, 3.36 and 1.17 respectively, which were the lowest among these three lakes. On the bank of Yueya lake, there are some alternanthera philoxeroides, miscanthus, and early ripe grasses, etc. The lake is covered with duckweed, leading to the transparency of water dropped sharply and hence depressed growth of submerged macrophytes. Generally speaking, the application frequency of alternanthera philoxeroides, iris pseudacorus and POA accounts more than 30%, but the application of submerged macrophytes is scarce. Only in Xuanwu Lake, there are verticillatum, myriophyllum and hornwort, which have ornamental value and ecological function. 

The effects of water quality, water flow condition, artificial planting and dominant wind direction on the character of aquatic plants were also investigated. Survey results indicate that the average depth of Xuanwu Lake is 0.48m, while the transparency was only about 0.2m, which does not meet the requiretment for the growth of aquatic plants. Therefore, only in the shallow water, like the north part of the lake and the region near the island, the submerged macrophytes were found. At the same time, the artificial planting lotus blooming also makes the plant communities dull. Mochou Lake of, Due to the good management, nitrogen, phosphorus and other nutrients are not out of limits, but the pollution caused by heavy metal is serious. It is difficult for the submersed macrophytes to grow in Mochou Lake for its average depth of ~1m and water transparency of 0.4m.

The main plants on the bank of Mochou Lake are kentucky bluegrass, duchesnea indica and hygrophytes and begonia. There are artificially planted lotus and metasequoia glyptostroboides on some part of the surface of Mochou Lake, therefore, the communities are highly affected by artificial planting. Due to the discharge of sewage, the concentration of nitrogen and phosphorus in Yueya Lake are out of limits and the duckweed blooms rapidly at the same time. Because the duckweed has no stable root, the distribution of duckweed is influenced by wind direction. The average depth of Yueya Lake is 0.35 m, while the transparency was only 0.15m. Due to the coverage of duckweed, the submerged plants were not observed.

Key words: eutrophication; aquatic plants; influence factors; community characters