本文選題：土壤種子庫 + 高寒草地　； 參考：《蘭州大學》2015年碩士論文

【摘要】：土壤種子庫可以為群落提供繁殖體,在生態(tài)系統(tǒng)中有著重要作用。為了探究不同類型和季節(jié)的土壤種子庫特征,分析了三江源地區(qū)天然草地、黑土灘,退化人工草地三種草地類型不同時間的土壤種子庫。針對不同海拔和干擾,采用地面調(diào)查,室內(nèi)萌發(fā)等方法,分析了念青唐古拉山當雄地區(qū)陽坡圍欄內(nèi)外不同海拔梯度的地上群落多樣性和土壤種子庫特征。旨在為高寒草地管理和利用提供參考。結(jié)果如下：1)三江源地區(qū)三種草地土壤種子庫特征：①密度的范圍：2173.381-9452.362粒/m2,呈現(xiàn)出：黑土灘退化人工天然草地,在八月份種子庫依然較多,2386.351-6973.386粒/m2,約占四月份種子庫的64%-75%。②高寒草地土壤種子庫有明顯的垂直分布,大部分物種和種子分布于土壤上層。土壤上層適宜種子的萌發(fā),尤其退化人工草地。相對于天然草地的更新繁殖,黑土灘和退化人工草地的更新與土壤中種子關(guān)系更為密切。在不同類型的草地中,相同的物種也并不一定都選擇萌發(fā)。土壤種子庫對地上植被的貢獻可能受到環(huán)境的影響。相同的物種在不同的生境條件下,表現(xiàn)出來了不同的策略。③土壤種子庫物種組成與地上植被的物種組成相似度在不同的草地都較低(Cs0.33)。天然草地包含禾本科,莎草科,雜類草；而黑土灘和退化人工草地種子庫中除了禾本科,則以有異味的昆侖蒿(Artemisia nanschanica Krasch.),柔毛蓼(Polygonum sparsipilosum A.H.Li)以及碎米薺(Cardamine L.)為主；在退化人工草地中禾本科的比例更高。其中莎草科只在天然草地種子庫中出現(xiàn)。④在四月份,速效鉀與種子庫的種子數(shù)量和物種數(shù)量有顯著的相關(guān)關(guān)系。2)三江源地區(qū)三種草地在不同月份的土壤種子庫特征變化：①四月到八月再到十二月土壤種子庫密度的變化,天然草地沒有顯著變化；黑土灘先減少在增加；退化人工顯著減少。②土壤種子庫中物種數(shù)量,四月十二月八月；多樣性在黑土灘中,四月十二月八月,在天然草地中,四月八月十二月,在退化人工草地中,十二月四月八月；與地上植被的物種組成相似度,在八月份達到最低。3)當雄地區(qū)念青唐古拉山脈南坡海拔分布：①植物群落的多樣性隨海拔變化格局呈現(xiàn)單峰分布格局,即隨著海拔升高,群落多樣性指數(shù)、均勻度指數(shù)和物種豐富度都先增加后降低,主要為優(yōu)勢物種的變化,且為偏向高海拔的單峰格局。單峰式函數(shù)關(guān)系能較好地表達植物群落物種豐富度、多樣性和均勻度與海拔高度間的分布格局。海拔與Shannon-Wiener指數(shù)和物種數(shù)量有顯著的相關(guān)關(guān)系；與Simpson優(yōu)勢集中性指數(shù)和蓋度有極顯著的相關(guān)關(guān)系；而與Pielou均勻度指數(shù)則沒有顯著的相關(guān)關(guān)系。②當雄地區(qū)念青唐古拉山脈南坡土壤八月種子庫特征,范圍為0-1245.05粒/m2,土壤中有明顯的垂直分布。土壤種子庫物種組成與地上植被的物種組成相似度非常低(Cs0.2),最大值出現(xiàn)在中間海拔。隨著海拔的降低,土壤種子庫的種子密度和物種數(shù)量都表現(xiàn)出現(xiàn)增加后降低的規(guī)律。圍欄外種子密度的最大值出現(xiàn)在海拔4966m,而圍欄內(nèi)的最大值出現(xiàn)在海拔4809m。4)當雄地區(qū)念青唐古拉山脈南坡圍欄效果：①圍欄封育顯著改善了念青唐古拉山陽坡不同海拔樣地的蓋度,以及嵩草屬(Kobresia Willd.)的相對頻度(p0.05)。②圍欄外土壤中八月的種子庫海拔分布,體現(xiàn)這“單峰曲線”的變化規(guī)律。單峰曲線的變化規(guī)律在圍欄的干預后發(fā)生變化。
[Abstract]:The soil seed bank can provide a reproductive body for the community and play an important role in the ecosystem. In order to explore the characteristics of different types and seasons of the soil seed bank, the soil seed banks of three kinds of grassland types in natural grassland, black soil beach and degraded grassland in the source area of Sanjiang are analyzed. In order to provide reference for the management and utilization of alpine grassland, the results are as follows: 1) the characteristics of three kinds of grassland soil seed banks in Sanjiang source area: (1) the range of density: 2173.381-94 52.362 /m2, showing: the degraded artificial natural grassland in the black soil beach, in August, the seed bank is still more, the 2386.351-6973.386 grain /m2, which accounts for the vertical distribution of the soil seed bank of the 64%-75%. (2) alpine meadows of the seed bank, and most of the species and seeds are distributed in the upper layer of the soil. The upper layer of soil is suitable for the seed germination, especially the degradation. Artificial grassland. Relative to the regeneration of natural grassland, the renewal of the black soil and degraded artificial grassland is more closely related to the seed in the soil. In different types of grassland, the same species do not always choose to germinate. The contribution of the soil seed bank to the aboveground vegetation may be affected by the environment. The same species in different species are in different species. The species composition of the soil seed bank and the species composition of the aboveground vegetation were lower in different meadows (Cs0.33). The natural grassland consisted of Gramineae, sedge, and hetero grass, while the black soil beach and the degraded artificial grassland were divided into Gramineae, and the Kunlun Artemisia (Artemisia n) with odors. Anschanica Krasch.), Polygonum Polygonum (Polygonum sparsipilosum A.H.Li) and chestnut (Cardamine L.) mainly; the proportion of Gramineae in degraded grassland is higher. Among them, the family of sedge is only in the natural grassland seed bank. (4) in April, there was a significant correlation between the number of seeds and the number of seeds of the seed bank,.2) three. The characteristics of the soil seed bank of three kinds of meadows in different months in Jiangyuan region: (1) the change of soil seed bank density in April to August and December, there was no significant change in the natural grassland; the black soil beach was reduced first and the degradation artificially decreased. (2) the number of species in the soil seed bank, August December in December, and the diversity in black. In the soil beach, in August of December April, in the natural grassland, December August in August, April August, in the degraded artificial grassland, the similarity between the species composition of the vegetation and the lowest.3) in the southern slope of the Tangqing Tanggula Mountain Range: (1) the diversity of the plant community is presented with the change of altitude. The single peak distribution pattern, that is, the diversity index, evenness index and species richness of the community first increase and then decrease with the elevation, mainly the change of dominant species and the single peak pattern to high altitude. The single peak function relationship can better express the species richness, diversity and evenness of the plant community. There is a significant correlation between altitude and the Shannon-Wiener index and the number of species; there is a significant correlation with the concentration index and coverage of Simpson dominance; but there is no significant correlation with the Pielou evenness index. (2) the characteristics of the August Seed Bank of the southern slope of the Tangqing Tanggula Mountain Range in the county of the male region are 0-1245.05 In the soil, there is a clear vertical distribution in the soil. The species composition of the soil seed bank is very low (Cs0.2) and the maximum value appears at the middle altitude. The seed density and the number of species in the soil seed bank are increased and then decreased with the decrease of the altitude. The maximum value of the seed density outside the enclosure is out. At the altitude of 4966m, the maximum value in the fence is at the altitude of 4809m.4) in the south slope of the south slope of the Tanggula mountains, the south slope of the mountain area: (1) the enclosure seal greatly improved the coverage of different elevation like land in the sunny slope of the Tang Gula mountain, and the relative frequency of the Kobresia Willd. (P0.05). The distribution pattern of the single peak curve reflects the change rule of the unimodal curve.
【學位授予單位】：蘭州大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：S812

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