【摘要】：濕地是地球上重要的生態(tài)系統(tǒng)之一,具有很高的生態(tài)價(jià)值。在干旱半干旱地區(qū)濕地研究中,草甸被視為陸域過(guò)濕土壤上的濕地類(lèi)型。本研究中的草甸屬于低地草甸,主要分布在低濕區(qū)域,像河濱、河漫灘、溝谷、洼地等,其植被類(lèi)型具有隱域性,不呈地帶性分布。本文采用野外調(diào)查、室內(nèi)分析的方法,研究了銀川平原草甸濕地植被的分布特征,草甸濕地土壤鹽化等級(jí)的劃分,鹽分累積狀況,主要鹽分組成成分以及影響銀川平原草甸植被分布及生長(zhǎng)特征的主要因子,研究過(guò)程和主要結(jié)論如下：(1)本研究共設(shè)置樣地57個(gè),樣方123個(gè),根據(jù)傳統(tǒng)的分類(lèi)方法將研究區(qū)植物群落劃分為3個(gè)植被型,8個(gè)植被亞型,27個(gè)群系。根據(jù)土壤表層全鹽含量(0-20)cm,把研究區(qū)土壤劃分為5個(gè)等級(jí)：Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ,它們對(duì)應(yīng)的含鹽量分別為≥10g/kg、4～10g/kg、2～ 4g/kg、1～2g/kg和1g/kg。(2)植物多樣性指數(shù)均表現(xiàn)為ⅤⅢⅣⅡⅠ,其中Pielou均勻度指數(shù)表現(xiàn)為ⅠⅢⅤⅣⅡ,說(shuō)明隨著土壤鹽分對(duì)植物多樣性指數(shù)影響較大。(3)研究區(qū)草甸土壤全鹽含量在垂直方向上表現(xiàn)出明顯的表聚現(xiàn)象,在0-30cm土層,隨著土壤深度的增加,土壤全鹽含量急劇下降,在30～70cm土壤全鹽含量的下降則較為平緩；各鹽分離子除了HCO3-、CO32-均表現(xiàn)出明顯的表聚現(xiàn)象,但在不同的土壤等級(jí)中,只有Na+、K+、Cl.和土壤全鹽的表現(xiàn)一致,均為ⅠⅡⅣⅣⅤ。(4)草甸濕地植物體中也有一定的鹽分累積,在植物體中,主要鹽分為NaCl、 NaHCO3;在土壤中主要鹽分為NaCl、NaHCO3、Na2CO3。(5)草甸濕地各土壤鹽分因子的相關(guān)性分析結(jié)果表明,土壤全鹽、pH與大部分鹽分離子都呈顯著或極顯著正相關(guān)或負(fù)相關(guān),Na+、Cl-與大部分離子之間都呈顯著或極顯著相關(guān)關(guān)系。所有鹽分離子的主成分分析表明：在0～30cmNa+、Cl-是研究區(qū)的主要鹽分離子,在30～100cmNa+、Ca2+、Cl-是研究區(qū)鹽分累積的主要鹽分離子。(6)對(duì)研究區(qū)草甸濕地植物群落特征和經(jīng)過(guò)變異膨脹因子篩選后的9個(gè)土壤環(huán)境因子進(jìn)行RDA分析,植物群落特征在第1軸、第Ⅵ軸上所占的解釋量較大,分別為31.5%和67.9%,累積解釋群落特征的信息量為99.5%,Na+、Cl-、TS對(duì)植物群落特征的變異起到了很好的解釋。Na+與植物群落的生物量呈顯著負(fù)相關(guān)關(guān)系；Na+含量與蓋度、物種數(shù)呈負(fù)相關(guān)；Cl-含量與生物量、蓋度、物種數(shù)呈負(fù)相關(guān),但相關(guān)性并不顯著。(7)銀川平原草甸濕地土壤鹽分呈自南向北逐漸增加的空間變化；不同草甸植被類(lèi)型的含鹽量大小為鹽生草甸典型草甸濕生草甸；不同地形部位草甸的鹽分含量表現(xiàn)為干湖灘洪泛平原堤外湖灘濕湖灘渠邊沙灘,地下水埋深和水鹽循環(huán)過(guò)程是鹽分分布特征的決定性因素。
[Abstract]:Wetland is one of the important ecosystems on the earth and has high ecological value. In the study of wetlands in arid and semi-arid areas, meadow is regarded as the wetland type in overwet soil. The meadow in this study belongs to lowland meadow and mainly distributes in low-wet areas such as riverside, floodplain, gully, depression and so on. The vegetation type of meadow in this study is regional and not zonal. In this paper, the distribution characteristics of meadow wetland vegetation in Yinchuan Plain, the classification of salinization grade of meadow wetland soil, and the salt accumulation in meadow wetland were studied by field investigation and indoor analysis. The main salt components and the main factors affecting the vegetation distribution and growth characteristics of meadow in Yinchuan Plain were studied. The main conclusions were as follows: (1) there were 57 plots and 123 sample plots in this study. According to the traditional classification method, the plant communities in the study area were divided into 3 vegetation types, 8 vegetation subtypes and 27 formations. According to soil total salt content (0-20) cm, the soil in the study area was divided into five grades: 鈪，

本文編號(hào)：2428852