【作者】 李扬；

【导师】 王冬梅；

【作者基本信息】 北京林业大学 ， 工程绿化， 2014， 博士

【摘要】 近年来漓江水陆交错带植被退化及其多样性下降已成为漓江旅游区生态旅游可持续发展的严重挑战,进行漓江水陆交错带植被恢复刻不容缓。本文通过对漓江水陆交错带不同淹没带植被与土壤特征空间分异规律进行分析研究,以及对典型旅游区域植被和土壤对水文影响的响应机制研究,详细分析了重点植被恢复区域的植被影响因子,探索了水陆交错带退化生态系统植被配置模式,以期为典型旅游区水陆交错带植被恢复与湿地管理提供科学依据,初步研究成果如下：(1)优选水文影响时间、相对高程、坡度、砾石含量和植被生物量作为划分指标。根据回归方程与主成分分析选取水文影响时间、相对高程和生物量作为主导性指标。通过聚类分析将水陆交错带分为重度淹没带、中度淹没带、轻度淹没带和微度淹没带4个不同淹没带类型。(2)漓江水陆交错带物种组成相对丰富,各淹没带共有植物种124种,其中乔木植物18种,灌木植物17种,草本植物89种。随着淹没带高程的增加,漓江水陆交错带植物种多样性、均匀度、优势度、覆盖度和生物量均呈现明显递增的趋势,植被情况趋于良好。受区域内人为干扰、水文条件影响,多样性、均匀度、优势度和覆盖度沿河流纵向上的分布规律有明显差异,均匀度指数呈现的规律基本与多样性指数相同,优势度指数呈现的规律与多样性指数和均匀度指数基本相反。随着人类干扰的减少,植被生物量从上游至下游呈现增加趋势。(3)水陆交错带土壤物理特征在不同淹没带分布有明显差异性。随着淹没带高程增加,水陆交错带土壤容重呈现先增后减的趋势,4个淹没带砂粒含量均远高于粉黏粒含量。砂粒含量随着淹没带高程增加呈现下降的趋势,而粉粒和黏粒则呈现相反的趋势。土壤化学特征受水文、人为干扰等多方面因素影响,在各淹没带分布具有不同的分布特点。土壤有机质含量呈现先减后增的“V”字型趋势；全氮含量由0.399g/kg增至0.556g/kg,呈现随着淹没带高程增加而升高的趋势；有效磷含量分布情况为T1(13.930mg/kg)、 T2(13.292mg/kg)淹没带远高于T3(4.317mg/kg)、 T4(4.685mg/kg)淹没带,漓江流域江边居民在江边进行洗衣等洗刷活动以及农业径流、生活污水的排放可能是造成这一非自然现象的重要原因,全钾含量在各淹没带差异不显著。土壤pH整体位于7.124-7.868之间,喀斯特偏碱性土壤与全氮含量呈现显著负相关,与土壤有效磷成极显著正相关,土壤有机质含量与全氮含量呈现明显正相关。植被各项指标与土壤粉粒含量、黏粒含量、全氮含量以及有机质含量呈现正相关,与砂粒含量、土壤容重、pH值、有效磷含量呈现负相关,土壤全氮是漓江水陆交错带对植被影响最大的土壤因子。(4)水文作用对草本植物的生活型产生影响,一年生草本物种在水陆交错带草本群落中占据绝对优势,经历一个水文周期后,各淹没带植物种类和植被多样性指数均呈现下降的趋势。土壤砂粒含量增加,而粉粒和黏粒含量则呈现下降趋势,土壤容重呈现上升的趋势,土壤pH、有机质、全氮、全磷和全钾含量呈现下降趋势,水文对漓江水陆交错带土壤和植被的影响基本呈负面作用。(5)重度淹没带和中度淹没带为植被恢复重点区域,这一区域草本植被空间自相关性与人类干扰强度呈负相关关系。受人为活动干扰程度较大的城区旅游型水陆交错带重点植被恢复区域所有植被指标具有中等程度的空间自相关性；受中等人为活动干扰强度的城郊生活型水陆交错带和基本不受人为活动干扰影响的天然型水陆交错带重点植被恢复区域的植被指标基本具有强烈的空间自相关性。重点植被恢复区域草本植被指标分布规律与结构因素(水文影响)、人类干扰强度和方式有密切关系。受人为活动干扰程度较强的城区旅游型水陆交错带各植被指标在东西方向呈现中间小,两侧大的分布规律,受中等人为活动干扰程度的城郊生活型水陆交错带各植被指标呈现条带状分布,但在高值分布带上出现零星斑块低值区；基本不受人为活动干扰影响的天然型水陆交错带各植被指标呈现从西向东逐渐增大的条带状分布。结构因素(水文影响)在空间异质性方面起主导作用,人类干扰起到次要作用,随机因素的影响相对较小。(6)以漓江桥、卫家渡和潜经村3个受不同人类干扰强度的漓江水陆交错带为例进行植被配置与恢复研究,受人为活动干扰程度较强的城区旅游型水陆交错带(漓江桥)植被配置注重景观性,受中等人为活动干扰程度的城郊生活型水陆交错带(卫家渡)注重生态价值和经济价值,基本不受人为活动干扰影响的天然型水陆交错带(潜经村)水陆交错带注重自然性。更多还原

【Abstract】 In recent years, ecological problems such as the shortage of water and vegetation degeneration occurred in the Li River, which has become a serious challenge to sustainable development for eco-tourism of Li River, and vegetation restoration is urgently needed. In this paper, we studied the spatial distribution of vegetation and soil in different inundation zone of aquatic-terrestrial ecotones in Li River, research on the response mechanism of vegetation, soil and hydrology, and analysised vegetation impact factors of focus revegetation area, explored vegetation configuration mode of the degraded ecosystem in aquatic-terrestrial ecotone, that aims to provide a scientific basis to vegetation restoration, landscaping, wetland protection and management and its sustainable use in aquatic-terrestrial ecotones of the Li River.The preliminary research results are as follows:(1) Preferred hydrological effect, relative elevation, slope, gravel content and vegetation biomass as the partitioning index, according to the regression equation and principal component analysis, we choose flood time, relative height and biomass as a leading indicator. Through clustering analysis, we divided aquatic-terrestrial ecotones into four inundation zone, such as, severe degree inundation zone, middle degree inundation zone, light degree inundation zone, and micro degree inundation zone.(2) Species composition of aquatic-terrestrial ecotones were relatively abundant, and there were124species of plants, including18species of arbor plants,17species of shrub plants,89species of herbaceous plants, that species composition were relatively abundant. With the increase of riverbank elevation, diversity trend, evenness, dominance, coverage and biomass presented an increasing trend, the number of species had become increasingly diverse, and species composition structure had become complicated.The vertical distribution of diversity, evenness, dominance and coverage along the river had obvious difference, evenness index showed same law with the diversity index basically, on the contrary, dominance index presented opposite withdiversity index and evenness index, vegetation biomass present a tendency of increase from upstream to downstream.(3) The soil physical characteristics in different inundation zone were obvious different, with the increase of riverbank elevation, Soil bulk density increased initially and then decreased. Sand content declined significantly. Silt and clay content increased significantly, Sand content was much higher than silt and clay content, which was related to the improvement effect of vegetation. Soil organic matter decreased initially and then increased. Total nitrogen content continuously increased, the content was form0.399g/kg to0.556g/kg. Available phosphorus content presented a reducing trend that was unnatural, related to non-point source pollution on the shore of Li River. Total potassium content was not significant difference in different inundation zone. The soil pH value was between7.124and7.868, and the alkaline soil pH of Karst ecotone was negatively correlated with total nitrogen content while it was positive correlated with available phosphorus content. Soil properties influence vegetation diversity. The results showed that vegetation diversity trend, evenness, dominance biomass and coverage were positively correlated with the content of silt, clay, total nitrogen and soil organic matter, but negatively with sand content, soil bulk density, soil pH and available phosphorus content. Furthermore, the results demonstrated that the total nitrogen content was one soil factor that had the largest influence on vegetation growth.(4) Under the influence of the hydrological effect, annual herb species occupied the absolute superiority in herbaceous community of aquatic-terrestrial ecotone. After a hydrological cycle, vegetation type and vegetation diversity index showed a trend of decline in all of inundation zone. Soil sand content increased, but silt and clay content showed a trend of decline. The soil bulk density showed a trend of rising, soil pH, organic matter, total nitrogen, total phosphorus and total potassium content showed a trend of decline.(5) We choose severe degree inundation zone and middle degree inundation zone as the key area of vegetation restoration, in this area, space correlation of herbaceous vegetation were negative related with human disturbance intensity. The results showed that the distribution of vegetation index had obvious spatial structure in the three study area, and were in accordance with different variation function theory model. Vegetation index of city tourism type had a moderate spatial correlation, except for evenness index of Weijiadu, the vegetation index of Suburban life type and natural type has a strong spatial correlation.Vgetation indexes of herbaceous vegetation had a close relationship with structure factors, human disturbance intensity. Vegetation index of urban tourism type presented a distribution of middle small and large of both sides. The spatial distribution of vegetation index were different in three study area. Vegetation indicators of suburban life type showed a banded distribution, but in high value distribution band, there were many low areas Vegetation indicators of natural type showed a banded distribution from west to east. The natural structure factors had significant effects on the spatial variability, while human disturbance played a secondary role, and the effects of random factors were relatively low.(6) Based on three different intensity of human disturbance of aquatic-terrestrial ecotone in Li River, such as Lijiangqiao, Weijiadu and Qianjingcun, vegetation configuration of urban tourism type (With a strong degree of human disturbance) will focus on landscape, vegetation configuration of suburban life type (Medium artificial disturbance) will focus on ecological value and economic value, and aquatic-terrestrial ecotone for natural type (Little human interference) will pay attention to the naturalness.更多还原