高寒草地退化与围栏封育对土壤种子库及其与地上植被关系的影响

发布时间：2018-06-17 23:52

本文选题：土壤种子库 + 高寒草地　；参考：《兰州大学》2015年硕士论文

【摘要】：土壤种子库可以为群落提供繁殖体,在生态系统中有着重要作用。为了探究不同类型和季节的土壤种子库特征,分析了三江源地区天然草地、黑土滩,退化人工草地三种草地类型不同时间的土壤种子库。针对不同海拔和干扰,采用地面调查,室内萌发等方法,分析了念青唐古拉山当雄地区阳坡围栏内外不同海拔梯度的地上群落多样性和土壤种子库特征。旨在为高寒草地管理和利用提供参考。结果如下：1)三江源地区三种草地土壤种子库特征：①密度的范围：2173.381-9452.362粒/m2,呈现出：黑土滩退化人工天然草地,在八月份种子库依然较多,2386.351-6973.386粒/m2,约占四月份种子库的64%-75%。②高寒草地土壤种子库有明显的垂直分布,大部分物种和种子分布于土壤上层。土壤上层适宜种子的萌发,尤其退化人工草地。相对于天然草地的更新繁殖,黑土滩和退化人工草地的更新与土壤中种子关系更为密切。在不同类型的草地中,相同的物种也并不一定都选择萌发。土壤种子库对地上植被的贡献可能受到环境的影响。相同的物种在不同的生境条件下,表现出来了不同的策略。③土壤种子库物种组成与地上植被的物种组成相似度在不同的草地都较低(Cs0.33)。天然草地包含禾本科,莎草科,杂类草；而黑土滩和退化人工草地种子库中除了禾本科,则以有异味的昆仑蒿(Artemisia nanschanica Krasch.),柔毛蓼(Polygonum sparsipilosum A.H.Li)以及碎米荠(Cardamine L.)为主；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种子库中出现。④在四月份,速效钾与种子库的种子数量和物种数量有显著的相关关系。2)三江源地区三种草地在不同月份的土壤种子库特征变化：①四月到八月再到十二月土壤种子库密度的变化,天然草地没有显著变化；黑土滩先减少在增加；退化人工显著减少。②土壤种子库中物种数量,四月十二月八月；多样性在黑土滩中,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；与地上植被的物种组成相似度,在八月份达到最低。3)当雄地区念青唐古拉山脉南坡海拔分布：①植物群落的多样性随海拔变化格局呈现单峰分布格局,即随着海拔升高,群落多样性指数、均匀度指数和物种丰富度都先增加后降低,主要为优势物种的变化,且为偏向高海拔的单峰格局。单峰式函数关系能较好地表达植物群落物种丰富度、多样性和均匀度与海拔高度间的分布格局。海拔与Shannon-Wiener指数和物种数量有显著的相关关系；与Simpson优势集中性指数和盖度有极显著的相关关系；而与Pielou均匀度指数则没有显著的相关关系。②当雄地区念青唐古拉山脉南坡土壤八月种子库特征,范围为0-1245.05粒/m2,土壤中有明显的垂直分布。土壤种子库物种组成与地上植被的物种组成相似度非常低(Cs0.2),最大值出现在中间海拔。随着海拔的降低,土壤种子库的种子密度和物种数量都表现出现增加后降低的规律。围栏外种子密度的最大值出现在海拔4966m,而围栏内的最大值出现在海拔4809m。4)当雄地区念青唐古拉山脉南坡围栏效果：①围栏封育显著改善了念青唐古拉山阳坡不同海拔样地的盖度,以及嵩草属(Kobresia Willd.)的相对频度(p0.05)。②围栏外土壤中八月的种子库海拔分布,体现这“单峰曲线”的变化规律。单峰曲线的变化规律在围栏的干预后发生变化。
[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.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S812

【参考文献】