全球气候变化背景下金川泥炭沼泽湿地水文动态及影响因素研究

发布时间：2018-01-01 07:11

本文关键词：全球气候变化背景下金川泥炭沼泽湿地水文动态及影响因素研究　出处：《东北师范大学》2016年硕士论文　论文类型：学位论文

【摘要】：水文是湿地的发生学要素,也是界定湿地生态系统的关键因素,水文过程通过改变物理化学环境,影响着土壤和生物。对湿地水文过程的研究,是湿地生态研究的重要基础,湿地水文也受到气候、地貌、地质、生物、人类干扰等因素的影响。全球气候变化导致气温升高,旱涝频发,将影响湿地脆弱的水文环境,进而对整个生态系统产生影响。本文选取金川泥炭沼泽湿地为研究对象,以2011年至2014年为研究时段,对全球气候变化下,湿地水位对降水的响应规律进行分析,并与影响因子——植被(生物多样性、生物量、盖度)、外界干扰(距河流远近)、地形(高程)、土壤性质(容重)进行相关分析,揭示水文情势的形成原因。分析水位与电导率的相关关系,推测水位对生态系统的影响机制,主要研究结果如下:(1)研究区域年降水量存在周期性丰枯变化,波动周期大致为3~5年。研究区域降水以小到中雨为主,发生频率在80%以上,对总降水量降水贡献率合计50%以上。而在全球气候变化影响下,强降水和干旱频率均呈现上升趋势,每年分别上升0.055%和0.005%。(2)金川湿地内水位因降水影响而上下波动,东部边缘区域水位最浅且波动剧烈;南部洼地水位最高且稳定;湿地核心地带水位较稳定,平均水位在地表附近。水位日增量与日降水量显著正相关。(3)不同频率降水影响下水位呈现不同的动态特征,密集的降水对湿地的扰动较小,维持着湿地水位稳定,而分散不均的降水对湿地扰动较大,湿地水位下降明显。由此推断,在全球气候变化,强降水和干旱同时增多的现状下,沼泽湿地水位稳定性将受到消极影响。(4)不同强度降水对湿地水位影响程度不同。强降水过程中湿地水位的波动幅度大于弱降水过程。强降水结束后,水位由峰值回落,下降速度由快(约2mm/h)减慢(0.3mm/h左右);而弱降水后,水位始终以缓慢的速度(0.3mm/h左右)下降,水位高度影响水流形式(表面流或表层流)而影响下降速度。强降水作用下,湿地水位波动剧烈,全球气候变化下,强降水增多,对湿地水文的扰动加剧。(5)水位动态变化受地形、外界干扰、植被群落特征、土壤渗透性等诸多因素的影响,水位随地表高程升高而降低,低洼区域易汇聚降水而表现为高水位;河流对湿地水位动态的影响显著,东部靠近河流的区域,水位波动最剧烈;植被丰富度越高、生物量越低,水位越稳定;土壤容重越低,渗透性越好,水位越稳定。金川湿地土壤容重随深度增加而增大,表层土壤是湿地水位波动的活跃层,估测0~20cm。(6)金川湿地中水体电导率与水位显著负相关,即随着湿地水位上升,电导率下降。水位的动态变化,影响土壤氧化还原环境,进而影响微生物生存和有机物分解释放无机盐,造成水化学的变化,表现为电导率的升降。水位波动剧烈的区域,电导率高,即盐分较高。全球气候变化下,湿地水位的稳定性差,将导致湿地土壤盐渍化,影响湿地植被生长和群落演替。
[Abstract]:Is the occurrence of wetland hydrological elements, but also defines the key factors of the wetland ecosystem, the hydrological process by changing the physical and chemical environment, affect the soil and biology. Research on wetland hydrological processes, is an important research of wetland ecosystem, wetland hydrology is also affected by climate, topography, geology, biology, human disturbances and other factors global climate change led to rising temperatures, frequent droughts and floods will affect the hydrological environment, fragile wetlands, and thus have an impact on the whole ecological system. This paper selects the Jinchuan peat swamp wetland as the research object, from 2011 to 2014 as the research period of global climate change, response of wetland water level on precipitation was analyzed, and influence factor (vegetation biodiversity, biomass, coverage), external disturbance (distance from river), topography (Gao Cheng), soil properties (bulk density) were analyzed to reveal the hydrological situation Causes of potential. Correlation analysis of water level and conductivity, the influence mechanism that level of ecosystem, the main results are as follows: (1) the presence of periodic change of annual precipitation runoff fluctuation cycle research area, roughly 3~5 years. Study on regional precipitation in small to moderate rain, the frequency of occurrence in more than 80% the total precipitation precipitation contribution rate of a total of more than 50%. While under the influence of global climate change, strong precipitation and drought frequency showed a rising trend, the annual increase of respectively 0.055% and 0.005%. (2) level in the Jinchuan wetland because of precipitation effects on wave, the eastern edge of the shallow water level fluctuation and southern depression; the highest level and stable; the core area of wetland water level is stable, the average water level near the surface. The water level was positively correlated with the daily increment of daily precipitation. (3) effects of precipitation under different frequency level showed different dynamic characteristics, intensive The precipitation less disturbance of wetlands, wetland to maintain a stable water level, and the uneven dispersion of precipitation on wetland large disturbance, wetland water level decreased significantly. Thus, in the current situation of global climate change, strong precipitation and drought also increased, wetland water level stability will be negatively affected. (4) effects of different intensity precipitation the wetland water level in different degree. The fluctuation of water level in the wetland strong precipitation process than weak rainfall. Rainfall after the water level by the peak, decline speed (about 2mm/h) decreased (about 0.3mm/h); and weak precipitation, water level is always at a slow speed (about 0.3mm/h) decreased, the water level effect the flow form (surface flow or surface flow) and influence the rate of decline. Heavy rainfall effect, wetland water level fluctuations, global climate change, precipitation increased, aggravating water disturbance on the wetland. The water level change (5) By outside interference, terrain, vegetation community characteristics, soil permeability, the influence of many factors, the water level decreased with the increase of surface elevation, low-lying areas to gather precipitation showed high water level; the influence of river on wetland water level dynamic significantly, near the river's eastern region, the most dramatic fluctuation of water level; the higher the abundance of vegetation. The biomass is low, the water level is more stable; the soil bulk density is low, permeability is better, more stable water level. Jinchuan wetland soil bulk density increased with the increase of depth, the surface soil is wetland water level fluctuation in active layer, 0~20cm. (6) to estimate the water conductivity and water level in Jinchuan Lake wetland is a significant negative correlation with wetland water level rise the electrical conductivity decreases. Dynamic changes of water level, the influence of soil redox environment, thereby affecting the microbial decomposition of organic matter and inorganic salt free survival, caused by changes in water chemistry, to lift water conductivity. The area with high fluctuating intensity has high electrical conductivity, that is, high salinity. Under the global climate change, the poor stability of wetland water level will lead to salinization of wetland soil, which will affect the growth and succession of wetland vegetation.

【学位授予单位】：东北师范大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X171

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