无定河及延河流域不同时空尺度下土地利用对水质的影响

为探究不同土地利用格局的流域在不同时空尺度下土地利用与水质之间的关系,以无定河和延河两流域为研究对象,基于2020年土地利用数据和两个时期的水质监测数据,采用冗余分析方法定量探讨多个尺度上土地利用对水质的影响.结果表明：①两流域内主要土地利用类型均为耕地和草地,差异主要在裸地和林地面积占比上;②两流域内部分水质指标存在明显时空差异,春季水质优于秋季且中下游水质相对较差;③两流域河岸尺度上的土地利用对总体水质的解释率最大;④无定河流域土地利用在秋季对水质影响比春季更显著,延河流域呈相反趋势;⑤不同的土地利用对水质有不同的影响,无定河流域内裸地、耕地和香农多样性指数（SHDI）对水质影响较为显著,延河流域则为草地、耕地、人造地表、斑块密度（PD）和SHDI.无定河流域内耕地和人造地表对水质有负面影响,草地和裸地与大部分化学指标呈现负相关性;延河流域人造地表和草地对水质有负面影响,林地对水质有明显净化效果.研究结果为可持续土地利用和多尺度景观规划提供了重要信息,可用于改善水质.     

基于碳储量最大化的流域多目标土地利用分区优化模拟—以广西西江清水河为例

土地利用变化是影响碳固存变化的重要因素,土地利用优化对实现区域碳平衡具有重要作用。以广西西江清水河流域为研究对象,基于2000年、2010年和2020年土地利用数据,通过FLUS-InVEST耦合模型预测2060年清水河流域4种模拟情景（基线情景、耕地保护情景、水域保护情景、高碳储用地保护情景）下土地利用变化与碳储量的时空发展特征;针对高、中、低碳储能力等级区域适宜发展的方向,构建基于碳储量最大化的灰色线性规划模型,优化土地利用数量结构并运用FLUS模型模拟土地利用空间布局;利用Fragstats软件分析流域上、中、下游区域不同土地利用类型的形态格局,探讨其与碳储量的相关性并提出相应的优化策略。结果表明：1）4种模拟情景下,2060年流域碳储量仅在高碳储用地保护情景下稳定提升,其他3种情景都大幅下降;2）基于优化方案,2060年流域内林地、湿地和水域面积增加,建设用地面积稳定增长,草地、耕地面积相对减少且连片耕地保持不变,流域整体碳储量增长达1.32×10⁶ t;3）流域土地利用形态格局影响碳储量,且不同流段存在空间异质性,整体上斑块呈现复杂不规则的形态和较高的聚集度、连接度,有利于提高区域整体碳储量。优化策略能更好地满足流域不同区域的发展需求并统筹流域整体发展,增加流域碳储量的同时推动总体效益最优化。

     

以氢气为主要成分的其他可燃气体对低浓度甲烷爆炸特性的影响

为研究矿井火区中一氧化碳(CO)、氢气(H_2)、乙烯(C_2H_4)和乙烷(C_2H_6)等其他可燃气体对甲烷(CH_4)爆炸特性的影响,利用可视球形气体爆炸系统开展了多元可燃气体爆炸压力特性试验,观察并分析了峰值爆炸压力、最大爆炸压力上升速率及其相应时间。通过高速摄影系统拍摄了视窗范围内爆炸火焰传播图像,基于边缘检测方法确定了火焰前锋位置,继而得到最大火焰传播速度。分析了以氢气为主要成分的其他可燃气体对低浓度CH_4-空气混合物压力特性和火焰传播行为的影响。结果表明,多元可燃气体的存在增加了低浓度CH_4-空气混合物的爆炸危险性。随混合气体体积分数增加,低浓度CH_4-空气混合物的峰值爆炸压力、最大爆炸压力上升速率和最大火焰传播速度非线性增加;此外,到达峰值爆炸压力、最大爆炸压力上升速率的时间显著缩短。     

水中色度测定的研究

针对目视比色法色度测定不足之处,利用分光光度法进行改进.(1)在天然水的测定中,研究了以往的380nm作最大吸收波长测吸光度方法的问题.寻找到最佳波长455nm,吸收池5cm测定天然水吸光度A.(2)在5～400℃测定温度对吸光度无影响,溶液浊度、pH值对吸光度测定的影响呈线性关系.(3)在工业废水的测定中,先扫描出其最大吸收波长,以仪器检测限吸光度0.010为稀释终点.改进废水稀释倍数法.     

新安江流域土地利用结构对水质的影响

以新安江上游流域为研究区域,用该流域2010年5月TM遥感影像图作为底图,通过实地野外调查获取了新安江流域的土地利用图.运用ArcGIS的水文、空间分析功能,将流域划分为8个子流域,并分析各子流域的土地利用结构.根据2010年1～12月的水质监测数据,分析TN、TP、高锰酸盐指数、NH4+-N、粪大肠菌群的时空变化特征,以及与土地利用结构之间的定量关系.结果表明,TN和NH4+-N有明显的时间变化特征,为枯时期>丰水期>平水期,而其他几种指标没有明显的时间变化.在空间上,整体上呈现出渔梁、浦口污染最为严重.流域内土地利用结构与水质之间的相关关系表现为:耕地、水体、建筑用地起源作用,林地、草地起汇作用.在年度上看,耕地对TN、NH4+-N、高锰酸盐指数影响最大,草地对TP影响最大;不同水期上,枯水期和丰水期,对各指标影响最大的土地利用类型为耕地,在平水期,对TN、TP、粪大肠菌群影响最大的土地利用类型分别为耕地、草地、林地.     

一种赤腹松鼠种群数量的估计方法

赤腹松鼠剥食树皮的行为对林木危害严重,根据野外长期的观察和研究发现,赤腹松鼠在剥落树皮上遗留下来的上门齿齿印间距具有个体差异,可以用作个体识别的依据.对2003年监测样地内赤腹松鼠在剥落树皮上的齿印间距测量记录,并统计分析以估计赤腹松鼠的个体数量.结果表明:种群数量与危害率的相关系数为0.876,P=0.01,表现出很强的正相关关系;显示在较小面积内,该方法可以用来估计赤腹松鼠的个体数量.同时对该方法的基本条件和局限进行了讨论.图2表4参10     

SELECTION AND SUSTAINABILITY OF LAND AND WATER RESOURCE MANAGEMENT SYSTEMS1

ABSTRACT: Most spatial decision support systems for natural resource planning and management are limited by their scenario-based (non-behavioral), deterministic (non-stochastic) structure. A spatial decision support system is developed that uses a multiple attribute decision-making model to explain how a property manager selects a land and water resource management system (LWRMS) based on its multiple, stochastic economic and environmental attributes. The decision support system assesses sustainable resource management at the property and watershed scales and identifies the most cost-effective policy for enhancing sustainable resource management. Economic attributes are determined with an economic model and environmental attributes are simulated with an environmental model. Input parameters for both models are generated with a geographic information system. The decision support system is used to rank five LWRMS for a sample of 20 farmers in Missouri's Goodwater Creek watershed and for two hypothetical watershed alliance groups. Results indicate that the average farmer and the two alliance groups would rank the five LWRMS in the same manner. From the viewpoint of the watershed alliance, the most preferred LWRMS for the average farmer in the watershed is sustainable.     

A framework for allocating conservation resources among multiple threats and actions

Land managers decide how to allocate resources among multiple threats that can be addressed through multiple possible actions. Additionally, these actions vary in feasibility, effectiveness, and cost. We sought to provide a way to optimize resource allocation to address multiple threats when multiple management options are available, including mutually exclusive options. Formulating the decision as a combinatorial optimization problem, our framework takes as inputs the expected impact and cost of each threat for each action (including do nothing) and for each overall budget identifies the optimal action to take for each threat. We compared the optimal solution to an easy to calculate greedy algorithm approximation and a variety of plausible ranking schemes. We applied the framework to management of multiple introduced plant species in Australian alpine areas. We developed a model of invasion to predict the expected impact in 50 years for each species-action combination that accounted for each species’ current invasion state (absent, localized, widespread); arrival probability; spread rate; impact, if present, of each species; and management effectiveness of each species-action combination. We found that the recommended action for a threat changed with budget; there was no single optimal management action for each species; and considering more than one candidate action can substantially increase the management plan's overall efficiency. The approximate solution (solution ranked by marginal cost-effectiveness) performed well when the budget matched the cost of the prioritized actions, indicating that this approach would be effective if the budget was set as part of the prioritization process. The ranking schemes varied in performance, and achieving a close to optimal solution was not guaranteed. Global sensitivity analysis revealed a threat's expected impact and, to a lesser extent, management effectiveness were the most influential parameters, emphasizing the need to focus research and monitoring efforts on their quantification.     

‘A powerful alternative to Williams’ test with application to toxicological dose-response relationships of normally distributed data

The comparison of increasing doses of a treatment to a negative control is frequently part of toxicological studies. For normally distributed data Williams (1971, 1972) introduced a maximum likelihood test under total order restriction. But until now there seems to have been no solution for the arbitrary unbalanced case. According to the idea proposed by Robertson et al. (1988) we will apply in this article the basic concept of Williams on the class of multiple contrast tests for the general unbalanced parametric set-up. Simulation results for size and power and two examples for estimating the minimal toxic dose (MTD) are given.