Adapting the RUSLE and GIS to model soil erosion risk in a mountains karst watershed, Guizhou Province, China

Soil erosion is a serious environmental problem in Guizhou Province, which is located in the centre of the karst areas of southwestern China. Unfortunately, Guizhou Province suffers from a lack of financial resources to research, monitor and model soil erosion at large watershed. In order to assess the soil erosion risk, soil erosion modeling at the watershed scale are urgently needed to be undertaken. This study integrated the Revised Universal Soil Loss Equation (RUSLE) with a Geographic Information System (GIS) to estimate soil loss and identify the risk erosion areas in the Maotiao River watershed, which is a typical rural watershed in Guizhou Province. All factors used in the RUSLE were calculated for the watershed using local data. It was classified into five categories ranging from minimal risk to extreme erosion risk depending on the calculated soil erosion amount. The soil erosion map was linked to land use, elevation and slope maps to explore the relationship between soil erosion and environmental factors and identify the areas of soil erosion risk. The results can be used to advice the local government in prioritizing the areas of immediate erosion mitigation. The integrated approach allows for relatively easy, fast, and cost-effective estimation of spatially distributed soil erosion. It thus indicates that RUSLE-GIS model is a useful and efficient tool for evaluating and mapping soil erosion risk at a large watershed scale in Guizhou Province.     

烟台西港倾倒区海域浮游生物的群落特征

分析了倾倒活动结束后烟台西港倾倒区海域浮游生物的群落结构特征。结果表明,浮游植物群落具有硅藻为主、甲藻为次的特征,生态性质以温带近岸性物种为主。倾倒区停用后,硅藻数量大幅增加。桡足类、浮游幼虫及毛颚类的强壮箭虫是浮游动物群落的主要组成。浮游动物丰度、生物量与浮游植物丰度变化趋势大体一致。多样性分析表明,浮游生物群落结构比较稳定,倾倒区海域生态环境质量尚好。     

New rig on the block: spatial policy discourse and the new suburban geography of energy production on Colorado's Front Range

ABSTRACT

Drawing from the Critical Discourse Analysis and Cultural Sociology of Space frameworks, this empirical analysis explores the discursive struggle between stakeholders of divergent viewpoints as they respond to the newfound spatial proximity of oil and gas extraction to homes and schools in suburban residential areas on Colorado's northern Front Range. Through an analysis of media, policy-making, and neighborhood meeting discourse, this study examines the social construction of space through policy narratives and regional debates about the American West's relationship to extractive industries. Results reveal that the discursive struggle over suburban drilling hinges upon the question of whether industrial activities belong in residential areas and is carried out through competing policy narratives that invoke differing (spatial versus aspatial) policy solutions. The deliberative quality of these policy narratives is constrained by existing spatial policy practices and further constrains democratic engagement.     

西部的生态恢复与水土保持对策

水资源和土地资源的不合理开发利用是造成西部严重生态环境问题的根源。因此,西部的生态恢复,必须从解决水生态失衡和控制严重的水土流失、土地荒漠化入手,以提高植被整体覆盖度为手段,逐步达到恢复西部生态环境功能的目的。     

西部欠发达地区城市污水处理产业化市场化探析

就目前我国西部欠发达地区城市污水处理存在的诸多问题，探析了国内产业化市场化背景和现状、产业化市场化目标、任务及其相互关系、改革模式、政府的作用等方面的问题，最后，提出了有关改革的几项建议。     

西湖浮游植物的演替及富营养化治理措施的生态效应

1999年1月～2000年12月对杭州西湖浮游植物群落进行了为期2年的逐月调查.结合以前的研究资料,着重分析了20世纪80年代先后采取的截污、疏浚、引水冲污等一系列治理富营养化措施所产生的长期生态效应.结果表明,大部分湖区浮游植物群落结构与治理前基本相同,仍以蓝藻占绝对优势.1980～2000年,浮游植物密度增加了55.4%.蓝藻种类趋于小型化,20年来西湖的富营养化仍在发展.西湖子湖之一小南湖区经一系列工程治理后,出现了大面积的沉水植物,水体透明度大大提高,藻量明显下降,水体富营养特征逐渐从浮游植物响应型向大型高等水生植物响应型转化.因此,建立和恢复以沉水植物为主的生态系统,是治理西湖富营养化的有效途径.     

山西关帝山神尾沟植物群落物种多样性与环境关系的研究I．丰富度、均匀度和物种多样性指数

以89个植物群落调查样地数据为基础,运用8个多样性指数对山西关帝山神尾沟物种多样性与环境之间的关系进行了分析.（1）群落总的表现为多样性和均匀度随海拔升高而下降,丰富度从1700m下降到2400m后开始升高;（2）群落不同层次表现为乔木层和灌木层多样性、丰富度和均匀度随海拔升高而下降,草本多样性和均匀度表现为上升趋势,丰富度下降到1900m后开始上升;（3）乔灌草三者多样性和丰富度指数值以及变化幅度都表现为草本层>灌木层>乔木层,三者均匀度相差不大;（4）群落不同坡向表现为阳坡多样性和丰富度都大于阴坡,均匀度相差不大.图6参7     

Lake variability: key factors controlling mercury concentrations in New York State fish

A 4year study surveyed 131 lakes across New York State beginning in 2003 to improve our understanding of mercury and gather information from previously untested waters. Our study focused on largemouth and smallmouth bass, walleye and yellow perch, common piscivorous fish shown to accumulate high mercury concentrations and species important to local fisheries. Fish from Adirondack and Catskill Forest Preserve lakes generally had higher mercury concentrations than those from lakes in other areas of the state. Variability between nearby individual lakes was observed, and could be due to differences in water chemistry, lake productivity or the abundance of wetlands in the watershed. We found the following factors impact mercury bioaccumulation: fish length, lake pH, specific conductivity, chlorophyll a, mercury concentration in the water, presence of an outlet dam and amount of contiguous wetlands.     

1960~2014年秦岭南北无霜期时空变化特征及对比分析

全球气候变暖背景下,自然生态环境敏感区农业热量资源的时空特征研究具有重要的现实意义。依据1960~2014年秦岭南北47个气象站数据,利用线性趋势、M-K检验和kriging插值法对无霜期时空变化进行分析。结果显示：从时间上看,秦岭南北无霜期随纬度增加而减少,初霜日和无霜期在年际波动中略有下降后快速上升,终霜日在波动中略有上升后快速下降。55年来无霜期呈显著的延长趋势且发生增多突变,秦岭以北、秦岭南坡、汉水流域和巴巫谷地的延长速率分别为0.400 6、0.280 4、0.396 1和0.407 5 d/a,突变年份分别为1999、2002、2001和1990年。从空间上看,无霜期平均值和标准差由南向北增加,80%站点初霜日推后、终霜日提前和无霜期延长。多数无霜期延长是初霜日推后与终霜日提前的共同影响。无霜期在28个站点呈波动变化,19个站点发生突变,突变时间多在1990s~2000s,2000s的突变区域面积最大且集中分布在东北部。分析结果可为气候变化对生态环境和农业生产布局的影响提供参考。     

天山北坡城市群碳储量时空变化及预测研究

为了有效评估城市群碳储量变化,以天山北坡城市群为研究对象,运用PLUS模型和InVEST模型,动态评估2000～2020年及2030年不同情景下土地利用变化及碳储量变化特征.结果表明,2000～2020年天山北坡城市群碳储量呈现持续增加趋势,且碳储量变化与土地利用变化密切相关,主要表现为2000～2010年林地面积的减少导致其碳储量减少约266×106t,2010～2020年草地面积的增加使其碳储量增加约69.14×10⁶t.2030年自然发展情景、生态保护情景和经济快速发展情景下碳储量预测值分别为8875.88×10⁶t、8895.58×10⁶t和8841.58×10⁶t;经济快速发展情景下碳储量最低,生态保护情景下碳储量最高.土地利用是影响碳储量空间变化分布的第一主导因素,贡献率接近于90%,土地利用强度与碳储量协调性分析与两者双变量空间自相关分析进一步验证了这一结论.土地利用变化在一定程度上能够对碳储量产生积极影响,对于本研究区而言,生态保护发展情景可能更符合未来城市发展模式,研究结果能够为土...