【摘要】：濕地退化將嚴重影響濕地生態(tài)功能的實現(xiàn),是目前人類面臨的重要生態(tài)環(huán)境問題之一,濕地生態(tài)恢復(fù)可以改善退化的濕地生態(tài)系統(tǒng),恢復(fù)生態(tài)系統(tǒng)功能。本文通過對七星湖近自然恢復(fù)濕地的長期野外監(jiān)測,研究了近自然恢復(fù)濕地植物群落演替特征,探討了濕地典型水生植物與淹沒水深、營養(yǎng)鹽水平時空變化的響應(yīng)特征,并研究了濕地植被演替過程中植物總生物量、植被面積、覆蓋率、植物群落多樣性指數(shù)變化對近自然恢復(fù)濕地營養(yǎng)鹽去除的影響。研究結(jié)果表明:(1)近自然恢復(fù)濕地多年運行以來,植物物種豐度以及群落多樣性在整體上有所下降,但在濕地出口區(qū)域均有所上升。近自然恢復(fù)濕地在高污染進水負荷的條件下植被群落有向簡單結(jié)構(gòu)發(fā)展的趨勢,當環(huán)境條件適宜時,濕地植被格局向多元化發(fā)展。(2)水深對近自然恢復(fù)濕地內(nèi)水生植物分布有重要影響,濕地典型水生植物通過自我調(diào)整,表現(xiàn)出了沿水深的不同分布特征。在恢復(fù)濕地建設(shè)完成后,濕地水生植被經(jīng)過6年的自然演替,植物適應(yīng)水深表現(xiàn)為:漂浮植物≈浮葉植物沉水植物挺水植物。近自然濕地各植物群落逐漸向自身適宜的水深區(qū)域發(fā)展,生長在同一水深區(qū)域的不同植物群落間產(chǎn)生了劇烈的競爭而導(dǎo)致群落演替。(3)近自然恢復(fù)濕地營養(yǎng)鹽水平對水生植物分布影響作用顯著,濕地水生植物對營養(yǎng)鹽水平有不同的響應(yīng)特征。蘆葦和香蒲群落對污染物耐受程度較高,蘆葦和香蒲能在濕地各單元內(nèi)均長勢良好,高濃度的氮磷不利于荷花、芡實和沉水植物的生長。近自然恢復(fù)濕地沉水植物對營養(yǎng)鹽的耐受能力表現(xiàn)為:菹草金魚藻=狐尾藻輪葉黑藻。菱角喜好生長在高營養(yǎng)鹽的區(qū)域,荇菜在水質(zhì)良好的濕地出口區(qū)域中長勢最好。(4)植物群落對水體溫度、pH和溶解氧有著顯著的影響。水體溫度在夏季與植被面積、覆蓋率和植被生物量顯著負相關(guān)。pH與植被面積、生物量和物種豐富度正相關(guān),與植被覆蓋率負相關(guān)。水體溶解氧在夏季和秋季與植被面積、覆蓋率和生物量負相關(guān),在春季和冬季正相關(guān),溶解氧含量隨著物種豐富度升高而上升。植物多樣性指數(shù)變化與水溫、pH和溶解氧無明顯趨勢。(5)近自然恢復(fù)濕地植被演替影響了濕地氮磷去除效率。濕地多年運行以來,整體氮磷去除率均保持較高水平,各濕地單元氮磷去除率隨著植被分布變化顯示了不同變化特征。在七星湖濕地植被演替過程中,濕地氮磷去除效果與濕地植物生物量和植被面積顯著正相關(guān);隨著植被覆蓋率的上升,濕地氮磷去除率先升高后下降,75%~80%的植被覆蓋率最有利于濕地氮磷去除;濕地植物物種豐富度與氮磷去除均呈現(xiàn)顯著正相關(guān)關(guān)系;濕地植物群落多樣性指數(shù)H和優(yōu)勢度指數(shù)D與氮去除率相關(guān)性較差,而與溶解態(tài)磷去除率呈現(xiàn)顯著正相關(guān);均勻度指數(shù)J與濕地磷去除率與相關(guān)性較差,與濕地氮去除率呈顯著負相關(guān)。近自然恢復(fù)濕地在長期運行過程中,濕地水生植物群落結(jié)構(gòu)和功能發(fā)生了巨大的變化。本文研究了近自然恢復(fù)濕地典型水生植物群落對營養(yǎng)鹽和水位的響應(yīng)機制,探討了近自然恢復(fù)濕地植被演替與營養(yǎng)鹽去除相互作用關(guān)系,為近自然恢復(fù)濕地植被適應(yīng)性格局構(gòu)建和濕地生態(tài)修復(fù)工程提供理論依據(jù)和技術(shù)支持。
[Abstract]:Wetland degradation will seriously affect the realization of wetland ecological function, which is one of the important ecological environment problems facing mankind. Wetland ecological restoration can improve degraded wetland ecosystem and restore ecosystem function. In this paper, the near-natural restoration wetland flora was studied by long-term field monitoring of Qixing Lake near-natural restoration wetland. The response characteristics of typical aquatic plants and submerged water depth and nutrient saline in wetland were discussed. The effects of total plant biomass, vegetation area, coverage and plant community diversity index on nutrient removal in near-natural restoration wetland during vegetation succession were studied. However, plant species richness and community diversity have declined on the whole since the restoration of wetlands operated for many years, but increased in the outlet area of wetlands. (2) Water depth has an important influence on the distribution of aquatic plants in near-natural restoration wetlands. Typical aquatic plants in wetlands show different distribution characteristics along the water depth through self-adjustment. After six years of natural succession of aquatic vegetation in the restoration wetlands, plants adapt to the water depth as follows: floating plants floating leaf plants submerged in water The plant communities in the near-natural wetland gradually develop to their own suitable water depth region, and there is fierce competition among different plant communities growing in the same water depth region, resulting in community succession. (3) The level of nutrient saline in the near-natural restoration wetland has a significant effect on the distribution of aquatic plants, and the aquatic plants in the wetland have a significant effect on nutrient saline water. Phragmites australis and cattail communities have higher tolerance to pollutants. Phragmites australis and cattail can grow well in each unit of the wetland. High concentration of nitrogen and phosphorus is not conducive to the growth of lotus, seed and submerged plants. Leaf black algae. Water chestnut prefers to grow in areas with high nutrients. The growth of sauerkraut is best in areas with good water quality. 4. Plant communities have significant effects on water temperature, pH and dissolved oxygen. Water temperature is negatively correlated with vegetation area, coverage and biomass in summer. pH is negatively correlated with vegetation area, biomass and species abundance. Dissolved oxygen in water was negatively correlated with vegetation area, coverage and biomass in summer and autumn, positively correlated with spring and winter, and dissolved oxygen content increased with the increase of species richness. Nitrogen and phosphorus removal efficiency of wetland is affected by succession. Overall nitrogen and phosphorus removal rate of wetland has maintained a high level since years of operation. The nitrogen and phosphorus removal rate of each wetland unit shows different characteristics with the change of vegetation distribution. With the increase of vegetation coverage, the removal rate of nitrogen and phosphorus in wetland increased first and then decreased, and 75%~80% vegetation coverage was the most favorable for nitrogen and phosphorus removal in wetland. There was a significant positive correlation with the removal rate of dissolved phosphorus, a poor correlation between the evenness index J and the removal rate of wetland phosphorus, and a significant negative correlation with the removal rate of wetland nitrogen. The response mechanism of aquatic plant community to nutrients and water level was discussed, and the interaction between vegetation succession and nutrient removal in near-natural restoration wetlands was discussed.
【學(xué)位授予單位】：華北電力大學(xué)(北京)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：X171.4

【參考文獻】

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本文編號：2181855