【作者】 沃晓棠；

【导师】 孙彦坤；

【作者基本信息】 东北农业大学 ， 作物生态学， 2010， 博士

【摘要】 随着全球环境变化研究的深入,已经有越来越多的证据表明全球气候正逐步变暖,那么湿地作为地球重要的生态系统对气候变化的敏感将如何做出响应?目前关于气候变暖对湿地生态系统影响的研究在国内外都很广泛,可以肯定气候变暖必将对湿地生态系统造成一定影响,那么对于扎龙湿地而言,变化情况又将怎样?本研究以扎龙湿地1960-2006年逐日气象数据和1979-2006年影像数据(Landsat TM)作为气候变化与土地利用变化的主要信息来源,运用目前较先进的地球空间技术(3S技术)和景观生态学及气候统计学理论与方法,分析扎龙湿地近46a气候变化趋势及土地利用与土地覆盖空间格局、组合特征与动态变化情况,并借助典型相关分析方法与周期方差外推法进一步探寻扎龙湿地土地利用与土地覆盖动态对气候变化的响应与影响,从而在时空尺度上揭示其土地覆盖景观格局变化情况及其气候变化主要驱动因子,并以此为基础,进行扎龙湿地的可持续发展评价研究,为实现扎龙湿地土地资源的可持续利用和社会经济的可持续发展提供理论参考。主要结论如下:(1)扎龙湿地土地利用与土地覆盖动态变化研究结果显示,沼泽地与草地为扎龙湿地基质景观类型。不同研究时段(1979-1989年、1989-1999年和1999-2006年)耕地均增加;本世纪初期沼泽地面积大幅萎缩;裸地在整个研究时段(1979-2006年)下降趋势显著。1979-2006年扎龙湿地土地利用类型间转变突出表现为:沼泽地向草地和耕地转变、草地向耕地以及裸地向草地和耕地转变,沼泽地向草地转变区域在湿地核心区边缘已有明显分布,表明湿地退化已经深化到核心区。扎龙湿地土地利用类型重心迁移分析显示,近30年沼泽地、耕地、草地和裸地的迁移方向为东北,沼泽地与草地作为湿地的基质景观类型,其迁移方向表明扎龙湿地核心区在向北漂移,可以推测湿地核心区的迁移趋势是区域气候变暖趋势的可能响应。随着土地的不断开发,20世纪70年代至本世纪初扎龙湿地土地利用程度综合指数日益加大,本世纪初土地资源的利用进入高速阶段。扎龙湿地境内各县的土地利用程度均逐渐提高,除泰来县外,土地利用程度最高水平均出现在本世纪初。总体而言,扎龙湿地各县耕地面积均增加,变化幅度最大为富裕县,裸地面积均减少,变化幅度最大为杜蒙县,耕地和裸地相反的变化趋势可以认为耕地对裸地的占用已经成为不可忽视的事实。(2)扎龙湿地土地利用景观格局动态分析显示,20世纪80-90年代扎龙湿地各类景观斑块数量均大幅度增加,景观破碎化程度达到最高水平,斑块趋于分散和零碎,连接程度较低。进入21世纪,各类景观的斑块数与斑块面积比值呈现下降趋势,景观格局尺度聚合度小幅提高。自20世纪80年代开始耕地景观优势度持续上升,草地和裸地逐渐削弱,斑块趋于均衡化。20世纪90年代末沼泽地破碎化程度及优势度均达最高水平。由于湿地边缘地带较分散的沼泽地斑块面积大幅度减少,湿地核心区连接程度较高的斑块保留下来。自2001年起政府多次向扎龙湿地补水,并且加大宣传和监管力度,以上事实可能是最大斑块指数上升和景观形状指数下降的主要原因,并在一定程度上缓解了沼泽地破碎化趋势,但湿地退化的现实依然严峻。20世纪70年代至本世纪初扎龙湿地景观多样性、景观均匀度、景观形状指数与面积周长分维数变化趋势均为上升,表明扎龙湿地景观形状趋于不规则,边界破碎复杂,土地利用趋于多样化和均匀化,完整性较差,景观格局趋向复杂化。(3)1960-2006年扎龙湿地气候变化分析显示,近46a以来扎龙湿地年平均气温,年最低气温、最高气温和年≥10℃积温上升趋势显著,表现出很强的变暖趋势。年平均气温在1988年发生的突变达统计显著。年平均气温,年最低、最高气温和年≥10℃积温2-6a左右尺度的周期振荡显著。近46年来扎龙湿地年降水、年中雨及年大雨降水总趋势减少,降水偏少期均出现在60-70年代与本世纪初期,且突变趋势较弱,无显著突变过程发生。扎龙湿地年降水、年中雨及年大雨降水2-4a时间尺度偏干与偏湿期转换频繁。近46a扎龙湿地年相对湿度呈波动下降趋势,1995年的突变过程达显著水平。年相对湿度2a的时间尺度周期振动信号最强,整个时间域内年相对湿度的偏干期占据优势地位。扎龙湿地年均气温空间格局为准西南-东北向差异,即西南部气温偏高,东北部气温偏低,降水、相对湿度与其空间格局恰好相反。突变界年(1988年)后,扎龙湿地暖冬与热夏事件发生频率与强度均显著增加,20世纪80年代中期以来,扎龙湿地大气湿润度在减少,未来几年将持续偏暖和少雨的气候变化趋势,气候在向暖干方向发展。(4)扎龙湿地土地利用景观动态变化与气候变化的典型相关分析结果显示,景观斑块面积在耕地、沼泽地、湖泊与裸地中具有显著代表性,不同土地利用类型对应的气候显著性代表因子均为年最低气温、年最高气温、年≥10℃积温和年相对湿度。草地复杂的景观格局变化趋势是年气温、年降水与年相对湿度共同作用的结果。各地类均有典型因子的趋势分量与年最低气温趋势分量存在统计显著相关关系。扎龙湿地耕地、沼泽地、草地和景观级别土地利用变化与气候典型因子间周期性特征无显著关系;湖泊与裸地面积的10年周期波动是年最低气温9年周期波动的可能响应。近30年扎龙湿地沼泽地与湖泊土地利用景观格局变化与气候变化相关关系最强,其次为耕地与草地,裸地表现最弱。可以认为沼泽地与草地收缩趋势是气候向暖干方向发展在一定程度上的响应。裸地与气候变化相关关系较弱,很有可能是湿地境内迫于人口压力、为维持生计而大力开垦耕地、过渡放牧等行为导致裸地大幅减少。以上结论表明,扎龙湿地土地利用景观格局动态变化是气候变化和人类活动双重影响下发生的。(5)本文在研究区域可持续发展理论基础上,构建了扎龙湿地自然保护区的评价指标体系,应用投影寻踪评价方法,分析扎龙湿地社会-经济-资源环境三个子系统可持续发展性,得出扎龙湿地各系统可持续发展水平区域间协调性较差,资源环境可持续性发展状态呈现不良趋势,人口与资源环境对湿地可持续发展的制约表现最为突出。研究针对性地提出了湿地资源与环境保护切实可行的五大对策措施,为实现扎龙湿地土地资源可持续利用与社会经济可持续发展提供理论参考。更多还原

【Abstract】 As the research on global environment variation has been going to depth, more and more evidences indicate that the Earth’s climate gets warmer and warmer. How does wetlands, as the most sensitive part of the Earth system, responds to climate changes? The researches on the climate warming effects of wetlands ecosystem were extensive in domestic and abroad, it is sure that global warming caused a certain ecologic influence on ecological system in wetlands. Then for Zhalong wetlands, how to respond? Here, based on the evidence for land use and climate changes in Zhalong wetlands-Landsat TM images during 1979-2006 and daily meteorological data during 1960-2006, "3S" techniques, landscape ecology theory and climate statistical method were used to study the characteristics of climate changes during recent 46 years and the spatial pattern, the combination characteristic and the dynamic changes of LUCC in Zhalong wetlands, and the impact and response of climate change on land use and land cover change were discussed from the spatial and temporal scale to reveal the change condition of the landscape pattern and the major driving factors of climate changes, as a basis for the research on assessment of sustainable development in Zhalong wetlands. This study was scientific reference for achieving sustainable use of land resources and socio-economic sustainable development in Zhalong wetlands, the main conclusions were as follows:(1)The results of the dynamic change of LUCC showed that in Zhalong wetlands, marshland and grassland were the substrate landscape type. During the period of 1979-1989, 1989-1999 and 1999-2006, the area of farmland increased in different degrees, the area of marshland has been shrinked dramatically at the beginning of this century, during the whole period of 1979-2006, bareland declined significantly.During the period of 1979-2006, the transformation between each land cover types in Zhalong wetlands mainly represented that marshland transformed to grassland and farmland, grassland transformed to farmland and bareland transformed to grassland and farmland. It was obvious distribution in the core area of wetlands that the region of marshland transformed to grassland, which indicated that the degradation of wetlands has deepened to the core area.The analysis of the centrobaric migration of land cover types showed, in lately 30 years, migration directionin of marshland, farmland, grassland and bareland was northeast in Zhalong wetlands. As the substrate landscape type, migration directionin of marshland and grassland showed that the core area of Zhalong wetlands drifted to the north.Consequently, it could be speculated that the migration trend in the core area might be the response of the regional climate warming trend. With the constant development of land, from the 1970s to the beginning of this century, integrated index of land use degree was growing in Zhalong wetlands. Land use intensity of the counties within Zhalong wetlands were gradually increased. In addition to Tailai county, the highest level of land use intensity appeared in the beginning of this century. On the whole, the area of the farmland of Zhalong wetlands had increased and bareland had decreased, the change of Fuyu county was sharpest and Dumeng county, respectively. It was also assumed that, on account of the opposite trends between farmland and bareland, the occupier of the bare ground has become fact that could not be ignored.(2)The analysis results of the landscape pattern dynamic of land use of Zhalong wetlands showed that during 1980s~1990s, the patches quantity of various landscape types substantially increased in both,the degree of landscape fragmentation of these reached its height,due to low inter-connect between adjacent patches, patches tended to dispersed and fragmented. In 21st century, NP/CAof various landscape types showed a downward trend, the evidents of rising dominance index of farmland and gradual weakening of bareland and grassland lead to the equalization of landscape pattern since 1980s. In the late of 1990s, the fragmentation and dominance of marshland had reached the highest level. For the significant reduction of scattered marshland patches area in wetlands fringe, patches with higher connecting levels of the core area retained.Since 2001, the government repeatedly compensating water for Zhalong wetlands and strengthenning supervision may lead to the largest patch index rise and landscape shape index decrease, which, to some extent,alleviated the fragmentation trend of the marshland,but the reality of wetlands degradation was still grim.From the 1970s to the beginning of this century, the rising of landscape diversity index, evenness index, landscape shape index and perimeter area fractal dimension indicated the growing irregulation of landscape shape, the growing diversification and homogenization of land use change tend and the growing complicate landscape pattern.(3) During the period of 1960-2006, the analysis results of climate change showed that,in Zhalong wetlands, annual average temperature,annual minimum temperature, annual maximum temperature and annual accumulated temperature≥10℃rose significantly, in lately 46 years,showing a strong warming trend. The statistically significant mutation of annual average temperature occurred in 1988. The annual average temperature,annual minimum temperature and annual accumulated temperature≥10℃was warming significantly since the 1990’s. The fluctuation periods(2-6a) of the annual average temperature,minimum temperature,maximum temperature and annual accumulated temperature≥10℃were statistically significant.In recent 46a, in Zhalong wetlands,the general trend of annual precipitation, annual moderate precipitation and annual heavy precipitation showed fall and the mutation trend of these was weaker. During the period of 1960s-1970s and the beginning of this century, precipitation was less than normal. Annual precipitation, annual moderate precipitation and annual heavy precipitation switched frequently between high and low in 2-4a scale.Annual relative humidity of Zhalong wetlands showed a downward trend in lately 46a. The mutation that occurred in 1995 reached a significant level. The periodic vibration signal of annual relative humidity in 2a time scale was strongest, the partial dry period of that hold the dominant position in the whole time.In Zhalong wetlands, the spatial difference of annual average temperature was from southwest to northeast, that was to say, the southwest was higher, the northeast was lower. Compared with annual average temperature, the spatial pattern of annual precipitation and annual relative humidity were to the contrary.After 1988 of the mutant year, the frequency and intensity of hot summer and warm winter events had conspicuous increased and atmospheric moisture had declined since the mid of 1980s, which showed that there was the warm-dry direction in climate trend in Zhalong wetlands.(4)The analysis results of canonical correlation between land use landscape dynamics and climate change showed that, in Zhalong wetlands, the index of patches area had significant representation in the farmland,marshland, lake and bareland, the typical climate factors corresponding to the different land use types were the annual minimum temperature, annual maximum temperature, annual accumulated temperature≥10℃and annual relative humidity. The joint outcome in the annual temperature, annual precipitation and annual relative humidity lead to the complex landscape pattern of grassland.In terms of the residuals, there were statistically significant correlations between typical factor of every land use types and annual minimum temperature. Periodic characteristics of land use dynamics and climate change in farmland, marshland, grassland, landscape scale were not significant. 10-year fluctuations in dynamics change of lake and bareland 9-year fluctuations in annual minimum temperature.In recent 30 years, correlations between land use pattern changes of marshland, lake and climate change were strongest, followed by farmland and grassland, bareland was weakest in Zhalong wetlands. It was also assumed that the contraction trend of marshland and grassland responded to warm-dry climate trend to a certain extent. On the weak correlation between bareland and climate change, the acts of earning a living, vigorously cultivating land and overgrazing in population pressure were likely to result in drastical reduction of bareland within the wetland. The above results suggested that land use landscape dynamic changes was caused by the interaction of climate factors and human activities in both.(5)Based on the study of sustainable development theory, this paper constructed the sustainable development indicator system for Zhalong wetlands nature reserve, then analysed the level of sustainable development of the three subsystem of social-economic-resource and environment application of projection pursuit method in Zhalong wetlands. It confirmed that it was not satisfactorily coordinated for the level of interregional sustainable development in Zhalong wetlands, resources and environmental sustainability status showed a worse trend. The limits of population and resources environment to the sustainable development in wetlands were the most prominent. The papers put forward practically five recommendations against wetlands resources and environmental protection which provide a theoretical reference for achieving sustainable use of land resources and socio-economic sustainable development in Zhalong wetlands.更多还原