基于水文分析的动物通道选址——以龙栖山自然保护区为例

自然保护区内道路等基础设施的建设不可避免地会对动物生境产生影响，造成动物死亡率提升。动物通道的设置是改善由道路建设引起的生境破碎化的有效途径，而正确选择动物通道的位置才能使其真正发挥作用。以福建省将乐县龙栖山国家级自然保护区为对象，选取对林区生境影响较大的6种环境因子:树种类型、树种平均年龄、胸径、坡度、海拔以及郁闭度，使用层次分析法(AHP)进行权重分析，相对权重依次为0.296、0.235、0.163、0.085、0.076、0.145。将因子进行叠加构建出生境适宜性指数(HSI)评价模型，并对研究区的生境适宜性进行评价。在此基础上采用ArcGIS的水文分析模块模拟动物潜在的活动路径与道路叠加，从而确定合适的动物通道位置。结果表明，HSI较高的区域多集中在自然保护区中部高海拔地区与缓坡地带，植被主要以天然阔叶林为主，树种的平均年龄大，覆盖面积广，郁闭度高，能够为大中型的走兽提供较好的觅食、隐蔽、繁殖场所，结合量化出的动物活动路径，得到2处动物通道的理想位置。此经HSI模型模拟出的路线只能是一种大概率情况，所建议的通道建设完成后，还需进行持续的野生动物利用情况监测，以评估通道的有效性，进而进行有针对性的改造设计，直到野生动物通道的利用效果良好。对于所得到的动物活动路径，不仅可以为动物通道选址提供参考，也可为动物迁移廊道修正、林区择伐等提供科学依据。     

嫩江流域中下游地区植被与水文关系研究

本文通过对嫩江流域中下游地区土地利用现状的调查 ,并通过区域性试验表明 ,合理调整农业、林业、牧业等产业结构 ,是提高嫩江流域中下游地区经济发展水平的有效措施 ;通过测定 ,林木对地表径流、土壤水分、空气湿度有很大影响 ,均比无林地及耕地的影响效果显著。     

人工毛竹林土壤的水文生态效应

本文研究了人工毛竹林土壤的容重、毛管孔隙度、非毛管孔隙度、总孔隙度、贮水容量等土壤物理性质在小流域内随坡位和土层深度变化的规律及入渗性能随坡位的变化规律。并与同一地点的人工杉木林、阔叶混交林进行了比较。研究表明,当取各点0—60cm均值时和取各土层均值时,土壤物理性质在小流域内的空间分布规律相当明显,但入渗性能随坡位的变化规律则不很明显。人工毛竹林具有优良的森林水文功能。就所研究小流域内各测点的平均值而言,0—60cm土层的贮水容量为430.44mm,最大有效贮水容量为312.73mm,均大于杉木林和阔叶林;干旱条件下用双环法测定的10℃水温时的初渗速度为29.10mm/min,稳渗速度为8.28mm/min,都大于杉木林而小于阔叶混交林;入渗速度衰退参数为0.2391,介于杉木林和阔叶林之间。     

我国与森林植被和水资源有关的环境问题及研究趋势

我国存在水资源数量不足和时空分布不均、水质下降、水环境恶化、旱涝灾害频繁、水土流失严重等生态环境问题;增加森林植被是解决水资源水环境问题的重要途径,我国正在进行空前大规模的林业生态环境建设,非常需要生态水文学的科学理论和技术支持。已有的森林水文学研究结果存在内容完整性和系统性差、尺度偏小、过程单一、缺乏对森林植被的水分稳定性认识、不能预测森林植被的区域水文影响等不足,还没有形成能有效指导调控林水关系和进行流域水资源管理的成熟理论和技术;未来需要加强的研究重点,包括鼓励跨部门和跨学科的交叉、森林植被的耗水特性和水分稳定性、森林水文作用的形成机理及其尺度效应和尺度转换、森林植被对区域水文影响的预测和评价、森林对水质的影响及作为重要水源保护区和流域水资源管理途径的森林植被建设技术等。     

祁连山森林土壤的水文生态效应

祁连山水源涵养林受立地水热条件的影响和自然、历史干扰,多世代演替共存,分布占祁连山3个垂直气候带,主要由湿性灌丛林、青海云杉林、祁连圆柏林、干性灌丛林4种类型组成,6个林型即湿性灌丛林、藓类青海云杉林、灌木青海云杉林、草类青海云杉林、祁连圆柏林、干性灌丛林。调查研究表明,各类森林枯落物(层)的现存量,组成成分、持水率、持水量等均不相同。森林土壤矿质层的主要物理性质因森林类型而不同,并均随着土壤的深度呈某种规律性的变异。森林土壤的持水量主要受土壤孔隙度的影响。在祁连山林区,森林土壤的持水量较非林地(牧坡草地)土壤为高,在各森林类型中青海云杉林和灌丛林的持水量,较祁连圆柏林为高。     

Nutrient dynamics in a mangrove creek (North Brazil) during the dry season

During the dry season, dissolved inorganic nutrients and organic carbon (DOC) in a mangrove tidal creek (Bragança, North Brazil) presented a clear tidal signature: silicate, phosphate, ammonium and DOC covaried with salinity, with minima at high tide and maxima at low tide. Hydrodynamical calculations explained most diel variability as dilution of nutrientrich groundwater input by estuarine water. Creek nutrients tended to lower concentrations towards the end of the dry season, probably due to changes in groundwater dynamics. Ammonium was about 44% higher in the night than during the day, while silicate, phosphate nitrate + nitrite showed differences < 5%, indicating preferential autotrophic uptake of ammonium as nitrogen source. Nitrification and/or nitrogen fixation are probably sources of nitrate + nitrite, which contributed only 12% to the dissolved inorganic nitrogen pool. Dissolved oxygen (7%) and DOC (11%) were lower during the night, suggesting the existence of a labile, algalderived DOC pool. There is a loose coupling between aquatic primary production, groundwater dynamics and tidal regime.     

Inhibiting soil loss and runoff from small plots induced by an individual freeze-thaw cycle using three rangeland species

This study investigated the role of three rangeland species viz. Agropyron trichophorum, Medicago sativa, and Lolium prenne on mitigating of effects of a freeze-thaw (FT) cycle on runoff generation and soil loss from small experimental plots. Small plots (0.5 × 0.5m) were prepared in three replicates for control (i.e., under a FT cycle only) and treatments (i.e., individually planted with the study species and subject to a FT cycle). The treated plots were then placed at a slope of 20% and subjected to simulated rainfall with intensity of 70 mm h⁻¹ and 30 min duration. The results of the study showed a significant effect (P < 0.05) of the plants on controlling runoff and soil loss after a FT cycle. Also, the detrimental effects of the FT cycle due to performance of ice lenses and formation of an active melting layer in the soil surface were ameliorated by the presence of litter on the soil and root-binding effect of the plants. Time to runoff increased by 54, 111 and 10%, runoff volume decreased by 27, 68 and 0.4% and soil loss changed by −34, −62, and +6.5% in the plots planted with A. trichophorum, L. prenne and M. sativa, respectively. The results of the current study indicated that L. prenne had the maximum benefit on reducing runoff and soil loss from the plots undergoing a FT cycle.     

沿渡河流域分布式水文模型的构建

按照综合分布式概念性水文模型和分布式水文物理模型长处的建模思路，应用改进的格林-安普特下渗理论和地貌水文学的水滴运动理论，建立了一个具有物理基础的松散结构分布式流域水文模型。模型的产流方法融合了邓恩产流理论和霍顿超渗产流理论，考虑土壤水分剖面、土壤各向异性和地形坡度等对流域产流的影响；模型的汇流方法利用地貌水文学理论，寻求水文过程与流域地形地貌的相互作用及定量关系，以确定模型参数，其优势在于可以考虑净雨空间分布不均和流速空间分不均对流域汇流的影响问题。以湿润地区典型流域沿渡河为对象进行水文模拟应用研究，结果良好,说明模型较为可靠。     

Hydraulic-hydrological simulations of canal-command for irrigation water management

A modelling system that combines the hydraulic simulations of the canal and hydrological simulations of the irrigated command is introduced. It uses MIKE 11 and MIKE SHE, two well-established modelling systems, for the hydraulic and hydrological simulations respectively. In addition, it also has an irrigation scheduling module and a crop growth module. The modelling system is applied to the Mahanadi Reservoir Irrigation Scheme, a large irrigation project in Central India. The results show that presently a significant amount of water is wasted in the command during the monsoon season. It is demonstrated that the minimization of this wastage could lead to a substantial crop production in the subsequent dry season. Furthermore, the simulations illustrate the versatility of the modelling system for planning and analysing the various aspects of an irrigation project.     

用DRAINMOD模型预测不同气候条件下排水及来水量对湿地水文的影响

水量减少是目前威胁湿地生存的一个重要原因.本文采用原美国农业部水土保持局(现美 国自然资源保护局,US-NRCS)所推荐的水管理模型DRAINMOD,根据该局1991年所 建议的湿地水文识别准则,利用不同气候条件下的降水资料,对湿润地区由于排水而引起湿 地水文情势的变化,以及干旱地区湿地形成过程中所需要的基本水量进行了预测分析.模拟结果表明对于年降水量大于1 000 mm的温暖湿润地区,在没有人工排水的情况下,湿地特征十分明显;当排水间距大于150 m时,仍可在50%的年份内满足湿地判别准则的湿润条件.而 对于年降水量小于250 mm的干旱模拟区,形成满足生长期内湿润时段的最小来水量在初春( 3月)时为173 mm,在生长期末(11月)为155 mm,分别是同期月平均降雨量的22倍和16倍 .