The Effect of Fragment Shape and Species' Sensitivity to Habitat Edges on Animal Population Size

Abstract:  Habitat fragmentation causes extinction of local animal populations by decreasing the amount of viable "core" habitat area and increasing edge effects. It is widely accepted that larger fragments make better nature reserves because core-dwelling species have a larger amount of suitable habitat. Nevertheless, fragments in real landscapes have complex, irregular shapes. We modeled the population sizes of species that have a representative range of preferences for or aversions to habitat edges at five spatial scales (within 10, 32, 100, 320, and 1000 m of an edge) in a nation-wide analysis of forest remnants in New Zealand. We hypothesized that the irregular shapes of fragments in real landscapes should generate statistically significant correlations between population density and fragment area, purely as a "geometric" effect of varying species responses to the distribution of edge habitat. Irregularly shaped fragments consistently reduced the population size of core-dwelling species by 10–100%, depending on the scale over which species responded to habitat edges. Moreover, core populations within individual fragments were spatially discontinuous, containing multiple, disjunct populations that inhabited small spatial areas and had reduced population size. The geometric effect was highly nonlinear and depended on the range of fragment sizes sampled and the scale at which species responded to habitat edges. Fragment shape played a strong role in determining population size in fragmented landscapes; thus, habitat restoration efforts may be more effective if they focus on connecting disjunct cores rather than isolated fragments.     

Human risk assessment of As,Cd, Cu and Zn in the abandoned metal mine site

The cancer risk and the non-cancer hazard index for inhabitants exposed to As, Cd, Cu and Zn in the soils and stream waters of the abandoned Songcheon Au–Ag mine area were evaluated. Mean concentrations of As, Cd, Cu, Pb and Zn in agricultural soils were 230, 2.5, 120, 160, and 164 mg kg⁻¹, respectively. Mean concentrations of As, Cd and Zn of the water in the stream where drinking water was drawn was 246 μg L⁻¹, 161 μg L⁻¹ and 3899 μg L⁻¹, respectively. These levels are significantly higher than the permissible levels for drinking water quality recommended by Korea and WHO. The resulting human health risks to farmers who inhabited the surrounding areas due to drinking water were summarized as follows: (1) the non-cancer health hazard indices showed that the toxic risk due to As and Cd in drinking water were 10 and 4 times, respectively, greater than those induced by the safe average daily dosages of the respective chemicals. (2) the cancer risk of As for exposed individuals through the drinking water pathway was 5 in 1000, exceeded the acceptable risk of 1 in 10,000 set for regulatory purposes.     

Mercury in surface sediments and benthic organisms from Guaymas Bay,east coast of the Gulf of California

In order to know the concentration of mercury in surface sediments, macroalgae and clams from Guaymas Bay, Mexico, 20 surface sediment samples and several individuals of Codium amplivesciculatum (3), Enteromorpha clathrata (4), Gracilaria subsecundata (2), Ulva lactuca (2), Chione subrugosa (80) and Crassostrea gigas (40) were collected and their Hg concentration was measured by a cold vapor Hg analyzer, after acid digestion. In addition, granulometric analysis and quantification of total organic carbon, aluminum, iron and manganese contents in sediments were performed. A Pearsons correlation matrix was determined and, the enrichment factor, the geoaccumulation index and the biota-sediment accumulation factor were calculated. Mercury concentrations in sediments ranged from 0.3 to 2.3 μg g⁻¹, with the central and northern portions showing the highest values. Macroalgae had a content of Hg that oscillated from 0.058 to 0.134 μg g⁻¹, while the average concentrations of this metal for clams and oysters were 0.063 and 0.230 μg g⁻¹, respectively. A clear effect of Guaymas City and the anthropogenic activities carried out around the Guaymas Bay has been observed and the enrichment factor and the geochemical index suggest that sediments from this coastal ecosystem are moderately to strongly contaminated with Hg. However, according to the figure of the maximum human consumption of Hg per week recommended by the World Health Organization, people can ingest clams without risk to their health.     

城市绿地生态效果评价方法的改进

城市绿地在改善城市环境、为居民提供游憩服务等方面具有重要作用。目前衡量绿地效果的指标从总量上规定城市绿地应达到的指标，但缺乏绿地空间分布合理性的表征。本文采用景观生态学中的异质性指数和均一性指数，提出判断城市绿地分布合理程度的两种新指标。     

基于网络SBM-DEA模型和GML指数的中国各省工业用水效率研究

近年来,中国工业用水占全部用水的比例在20%~30%左右,提升工业用水效率、节约集约利用水资源已经成为影响中国国民经济可持续发展的重要问题之一。本文基于网络SBM-DEA模型和GML指数,研究了2007-2015年中国各省工业用水效率,实证结果发现：（1） 从年度平均值来看,与污水治理阶段相比,生产阶段处于前沿面的省份更多,各省份与前沿面的差距相对较小。北京、天津、内蒙古、山东、广东、海南等省份生产阶段工业用水效率较高,但是污水治理阶段的效率值却较低;辽宁、吉林、安徽、福建、江西、湖北、湖南、广西、贵州、云南、青海等省份生产阶段效率值较低,但是污水治理阶段的效率值却较高。（2） 从各时间段的几何平均值来看,大部分省份网络和污水治理阶段的GML指数值小于1,但是生产阶段的GML指数值大于1。因此,在提升生产阶段的工业用水效率的同时,需要加大工业污水的治理力度,提升污水治理阶段的效率,并树立工业生产和治污同步进行的意识,特别是北京、天津、内蒙古、山东、广东、海南等污水治理效率较低的省份。     

规划环境影响评价指标体系的建立与应用

以沈阳市浑南新区规划为案例,研究和探讨了规划环境影响评价指标的确定原则、理论依据、方法和程序,建立了以目标层、准则层、指标层三个层次,包括社会生态、经济生态、环境生态和环境资源支撑四大类三十项指标构成的规划环境影响评价指标体系,利用这三十项评价指标对规划进行了定量评价。     

大庆地区主要排水干渠水质和底质遗传生物毒性测试的探索

探讨了用蚕豆根尖细胞微核技术测试大庆地区主要排水干渠水质及底质的遗传毒性.并且通过污染指数PI值来研究水质底质的的综合毒性.结果表明作为一种灵敏度高、成本低廉的生物毒性监测方法,将在环境监测领域中有着广阔的应用前景.     

火电厂生态工业园评价指标体系研究

建立了火电厂生态工业园评价指标体系,运用层次分析法确定了指标体系中各指标的权重,建立了火电厂生态工业园模糊综合评价模型,确定了火电厂生态工业园综合评价的程序和方法,并将这一模型应用于包头铝电生态工业园。     

松花江同江断面高锰酸盐指数通量估算与分析

结合松花江同江断面2001-2005年流量和高锰酸盐指数监测数据,选用适当的数学模型对高锰酸盐指数通量进行估算.结果显示,高锰酸盐指数通量与流量变化趋势大体相同,8月份左右达到峰值.同江断面高锰酸盐指数通量与流量呈显著正相关,因此可用同江断面流量及建立的回归方程估计和预测汛期的高锰酸盐指数通量,节省工作量,为同江断面污染物通量估算提供理论基础.     

炼油企业合理用水评价方法研究

炼油企业是用水大户,也是水污染大户,如何降低该类企业的用水量和排污量是当前节水研究的焦点之一,也是环境管理的重要内容.以提高企业节水减排的积极性为目标,本文依据层次分析法原理建立了炼油企业合理用水评价指标体系,分别采用相关系数法、相似系数法来确定指标体系中各层指标的权重,这样即保留了层次分析法分类清楚、解释性强的特点,又发挥了客观赋权法人为因素少的优点.