【作者】 王兴菊；

【导师】 许士国；

【作者基本信息】 大连理工大学 ， 水文学及水资源， 2008， 博士

【摘要】 扎龙湿地地处寒温带,其独特的地理位置使流域水文过程和生态过程紧密地耦合在一起,在调蓄洪水、净化水体、保护生物多样性等方面具有重要的作用。然而,近年来,受区域气候变化及人类活动的影响,湿地生态水文情势变化显著,湿地退化严重。本文针对扎龙湿地生态环境演变的驱动因子及水文生态对主驱动因子变化的响应关系进行研究,揭示湿地生态环境的演变机理,完善我国寒区湿地的退化与修复理论。主要研究内容和成果如下:(1)分析研究降水、径流等气象水文要素的变化特性,以揭示寒区湿地气象水文变化的基本规律;采用时间序列周期方差分析外推法对降水和上游来水径流变化周期进行分析,提取湿地水文周期;采用叠加趋势预测模型预测湿地区域降水量与上游来水径流量的变化趋势。结果表明:扎龙湿地降水量总体上有减少趋势,并呈现以21年为周期的周期性波动特征;年均气温呈波动式上升趋势;蒸发量年际间波动较大,但无显著变化趋势;上游来水径流量呈现逐年减少的趋势,并存在周期性的波动特征,12年为一个周期。(2)基于扎龙湿地生态水文特征,分析了区域气候变化和人为因素对生态水文的影响,用灰色相关法分析计算了湿地面积变化与气候因子的相关关系:以月和年两种时间尺度研究了影响湿地典型景观(水面)面积变化的显著气候水文主因子及典型景观(水面)面积变化对环境因子的敏感性,从而分离出湿地生态环境演变的主驱动因子,为第四章、第五章和第六章进行主驱动因子变化及湿地水文生态对主驱动因子变化的响应研究奠定基础。结果表明:扎龙湿地具有时空分异特征和脆弱性特征,气候环境与人为因素是湿地动态变化的主要影响因素:湿地面积与气候因子之间有较好的相关关系:湿地面积与气温和降水量分别为负相关和正相关,狄色关联系数分别为-0.617和0.467;月最高气温与湿地上游来水量是影响湿地景观(水面)面积变化的显著气候与水文主因子。(3)用逐月蒸发量修正系数改进两参数月水量平衡模型,建立扎龙湿地上游来水(乌裕尔河)径流模型。采用水文模拟方法,定量研究气候变化和人类活动对湿地上游来水径流变化的影响。结果表明,改进的两参数月水量平衡模型能较好地模拟湿地上游来水径流,湿地上游来水径流序列显著变化的转折年份为1981年;各年代径流量呈现递减趋势,90年代径流量减少明显,约为背景值的85%;90年代期间,气候变化是乌裕尔河流域径流减少的主要原因,其影响量约占径流总减少量的60%;80年代期间,人类活动是乌裕尔河流域径流减少的主要原因,其影响量约占径流总减少量的80%。(4)利用湿地水循环模型模拟上游来水径流量与水面面积的变化,以水面面积为湿地典型水文状态指标,研究自然来水频率下水文状态指标对湿地上游来水径流量变化的定量响应关系;选取芦苇覆盖面积、鸟类多样性和水质为湿地的生态环境指标,基于水文与生态环境的指标指数,研究湿地生态环境对水文状态变化的响应关系。结果表明:湿地年平均水面面积与年上游来水量的变化趋势一致;不同来水频率下,水面面积对来水量变化的响应程度不同;湿地生态环境指标的指数与水面面积指数的变化趋势基本一致,但生态环境指标的变化相对于水面面积有不同程度的滞后响应,滞后先后顺序为水质、芦苇覆盖面积、鸟类多样性;生态环境指标随水面面积的变化呈现波动趋势,当水面面积处于775-880 km~2范围时,生态环境最好。(5)从大气-土壤的层面,研究了气候季节变化引起的湿地土壤环境变化及生态系统对土壤环境变化的响应,揭示了湿地水文生态对气候季节变化的响应关系:扎龙湿地芦苇沼泽的气温生长季节为3月29日～11月05日,约为248天,地温生长季节为5月29日～12月15日,约为200天;扎龙湿地季节性冻土广泛分布,土壤从每年的10月20日左右开始进入不稳定冻结期,第二年3月下旬达到冻结最大深度,3月5日左右开始消融到5月下旬全部消融;湿地的生态水文过程在很大程度上受季节性冻土及其水热状况的影响,季节性冻土的冻融过程有利于沼泽湿地的发育,同时对径流量和潜水位有重要影响,春末夏初增加径流量,秋冬季滞留降水,提高湿地的蓄水量。基于湿地气象水文要素的变化特性和生态水文特征分析,确定气候与水文因素中影响湿地生态环境演变的主驱动因子,从地表和土壤两个层面,研究湿地的水文生态对主驱动因子变化的响应关系,揭示湿地水文生态对气候变化与人类活动的响应以及湿地水文与生态系统之间相互影响、相互作用的关系,为正确修复与保护湿地提供理论依据和数据支持。更多还原

【Abstract】 Zhalong wetland locates in cool temperate zone, its unique geographic location makes the basin’s hydrological and ecological processes couple closely, plays various eco-hydrological functions, such as flood storage against drought, soil erosion control, water purification, biodiversity maintenance, etc. However, in recently years, due to the regional climate change and effect of human activity, the situation of eco-hydrology change particularly, the wetland has degraded seriously. The paper picks up the eco-environmental evolution driving factors of zhalong wetland and eco-hydrological response relation to study, reveal the eco-environmental evolution mechanism of wetland objectively, perfect humble region wetland degeneration and restoration theory of our country. The main research contents as follows:(1)Analyze precipitation, runoff and other climatic and hydrological factors’ variation characteristics; reveal humble region wetland climate hydrology variation rule; adopt time series extrapolation to analyze the change period of precipitation and inflow runoff, abstract the wetland hydroperiod; adopt superimposition tendency forecast model to forecast the change tendency of precipitation and inflow runoff within the wetland. The precipitation presents a decrease trend and fluctuates with the period of 21 years, the annual average air temperature shows significant increasing trend, although the annual average evaporation fluctuates significantly, as a whole, it has no evident change trend, and the inflow shows a significant degressive trend and fluctuates with the period of 12 years.(2)Analyze the eco-hydrologic impact of regional climatic changes and human factors based on zhalong wetland eco-hydrological characteristics, calculate the correlation between wetland area and climatic factors with grey correlation method; examine the evident climate and hydrology main factors affecting wetland landscape (surface)area with two kind scales of month and year and its sensibility to environmental factor, separate wetland eco-environment evolution main driving factors. This can get ready for the next research on chapters 4,5 and 6, which aima at the main driving factors’ change and wetland eco-hydrologic response to the main driving factor’ variation. Zhalong wetland possess spatio-temporal difference and frangibility characteristic, climatic environment and human factor is the wetland dynamic variation’s primary effect factor; it has better correlativity between wetland area and climatic factor: it has positive correlation between wetland area and air temperature, and negative correlation with precipitation, grey association coefficient is respectively -0.617,0.467; the monthy maximum air temperature and inflow are the critical factors influencing water surface area of the wetland.(3) Modify the monthy water balance model with two parameters by using correction coefficients of evaporation month by month, establish the inflow simulation model for Zhalong wetland, and study the change of upstream runoff due to climatic change and human activities quantitatively adopted hydrological simulation method. it is shown that the model modified can simulate the wetland inflow very well, that the critical year for inflow series change is 1981, that inflow runoff shows a significant degressive trend, especially in the 1990’s, it accounts for 85 per cent of the background value, and that in the 1990’s, climate change is the main factors influencing the inflow and the decrement occupies 60% of the total decrement, but in the 1980’s, human activity is the main factors influencing the inflow and the decrement occupies 80% of the total decrement.(4)Simulate the inflow runoff and water surface area by using a water cycle system simulation model of the wetland, take water surface area as the typical hydrology state index, discuss the quantitative response of hydrology index to inflow runoff with natural inflow frequency, take reed area, avifauna variety and water quality as ecological environment indexes, discuss the response of ecological environment to hydrology state. the results show that both of the change trends of annual average water surface area and inflow runoff are consistent, that the response of water surface area to inflow runoff is different with different frequency, and that both of the change trends of ecological environment index and water surface area are almost consistent, but the change of ecological environment index lags behind the change of water surface area with different degrees, i.e., water quality, reed area and avifauna variety in order of priority. It is important to note that it is not better for ecological environment when water surface area is bigger, only when water surface area is in the range of 775-880 sq.km, ecological environment is better.(5) From atmosphere-earth lay, discuss the wetland soil circumstance change and its ecological response caused by climate change with seasonal variation; research wetland seasonal frozen ground’s distribution characteristic, freeze-thaw rule and eco-hydrologic function; reveal the eco-hydrologic response to climatic change: it has perfect corresponding relation between the wetland soil temperature and vegetation season, in zhalong wetland, moss land’s air temperature growing season is from 29, march to 5, November, about 248 days, ground temperature growing season is from 29, may to 15, December, about 200days; zhalong wetland seasonal frozen ground range widely, the soil comes into instable freezing period around 20, October every year, and reach frozen extreme depth until the last ten days of march next year. And finishes melting around 20 may next year; wetland eco-hydrologic process is influenced by seasonal frozen ground and hydrothermal condition to a great extent; the amount of frozen backwater increase by 20-40% is beneficial for plant hibernation and springtime multiply, also is the key factor to promote salinization, swamping and keep ecological equilibrium. Frozen soil prevent seeping, thia can promote wetland’s development, seasonal freeze-thaw course has important impact on runoff and groundwater table, the pondage of wetland can be increased by increasing runoff in late spring and early summer, staying precipitation in autumn and winter.更多还原