生境评价程序在规划环境影响评价中的应用——以大东港区规划为例

对美国广泛应用的生境评价程序(HEP)在程序和方法上进行了改进和简化,在分析现有各生境单元指示物种密度的基础上,根据项目拟占用生境情况,预测拟议项目对指示物种的影响.以丹东港大东港区规划为例,应用改进的HEP,定量分析了大东港区规划对指示物种(涉禽和水鸟)觅食生境的影响,并制定了生境弥补计划和生态减缓措施.     

农药生态风险评价研究进展

介绍了美国和欧盟农药生态风险评价研究工作的最新进展,包括农药生态风险评价涉及的重要及最新概念、评价程序、不同地区多层次评价方法的比较,同时重点介绍了农药生态风险评价的关键技术--暴露评价及暴露场景的建立,最后提出了加强我国农药生态风险评价研究工作的具体建议.     

生态风险评价研究概述

生态风险评价是预测环境污染物对生态系统或其中某些部分产生有害影响可能性的过程。本文简要论述了生态风险评价研究的现状,介绍了生态风险评价的研究方法,以及生态风险评价中的研究重点和发展趋向。     

国内外农药生态风险评价研究综述

从生态风险评价的准则、评价方法、风险评价模型及生态风险评价在农药登记管理中的重要作用等方面对比，阐述了美国、世界经济合作与发展组织(OECD)及我国农药生态风险评价的研究概况。指出了我国在农药生态风险评价方面存在的不足，并针对这些不足之处提出了对策建议。     

水体和沉积物中毒害污染物的生态风险评价方法体系研究进展

人类活动导致大量毒害污染物进入水体和沉积物,从而对水生生物产生诸多不利影响.开展毒害污染物的生态风险评价,筛选高风险毒害污染物,是毒害污染物风险管控和生态系统保护的基础.对美国和欧盟等发达国家和地区毒害污染物的生态风险评价方法进行了综述.水体和沉积物中毒害污染物风险评价的基本方法首先是采用预测或测定环境浓度(PEC或M...     

我国无人岛保护与持续利用途径研究：生境更新的方法及应用

通过对我国无人岛保护和开发现状及其开发模式演变趋势的分析，阐明生境更新的内涵和方法，提出1种新型的保护性海岛开发模式，包括建设自然保护区，实施生态旅游，开发海洋牧场、港口等。按照保护性开发和生态恢复等原则，运用生境更新的原理和方法，将我国无人岛划分为生态型、开发型、居民迁出型及国防型4种类型，以利于实行有效的分类管理。     

有毒有机污染物环境风险性评价研究

有毒有机污染物环境风险性评价一般包括四个主要方面:污染物的环境转归;暴露势评价;对生物体系统影响的确定和风险性表征。本文就这四个方面的研究方法作了简要介绍,并就如何开展有毒污染物环境风险性评价工作提出了几点建议。     

非污染生态影响评价的生产力方法—以广东南亚热带地区为例

国家环境保护总局于1998年正式颁布实施非污染生态影响评价。非污染生态影响评价的方法很多，就以广东南亚热带地区为例研究非污染生态影响评价的生产力方法，并分析了这种方法的优点和存在的不足，以给区域建设项目的非污染生态影响评价提供借鉴。     

生态风险评价框架进展研究

生态风险评价是评价生态压力引起的不利生态效应的可能性的过程,可为环境风险管理提供理论及技术支持。生态风险评价框架是一套标准化的方法体系,规定了生态风险评价的总体工作内容、技术路线、关键方法步骤和各阶段产出成果,为生态风险评价的科学方法有效转化为生态环境管理策略提供途径。从20世纪90年代起,以美国为代表的一批发达国家逐步构建了生态风险评价技术框架,并颁布了一系列相关标准、导则和技术文件,直接支撑了上述国家生态环境保护相关的现行法律法规,影响了有关国家的生态环境管理与决策。而我国对于生态风险评价的具体实施还缺乏规范性的指导方法。该文以美国、英国和澳大利亚的4套与土壤环境污染关系密切的生态风险评价框架为例,介绍国际生态风险评价框架的内容,并结合我国在环境影响评价和农药安全评价领域的生态风险评价方法研究进展,对我国生态风险评价框架的研究发展方向进行分析。     

钱江源国家公园黑麂(Muntiacus crinifrons)生境适宜性评价及廊道设计

黑麂(Muntiacus crinifrons)是国家Ⅰ级重点保护野生动物,由于人类活动干扰致使其栖息地破碎化,进而威胁黑麂种群生存。因此,识别黑麂适宜生境关键区,构建破碎栖息地之间的生境廊道显得尤为重要。以钱江源国家公园为研究区域,基于黑麂分布点位数据和环境数据,通过MaxEnt模型评价黑麂的生境适宜性,利用Linkage Mapper廊道设计模型和最小累积阻力模型(minimum cumulative resistance model, MCR)设计黑麂生境廊道。结果表明,训练集和验证集受试者工作特征曲线(ROC)与横坐标围成的面积(AUC值)分别为0.959和0.943,MaxEnt模型结果达到优秀水平;黑麂适宜生境面积为44.78 km~2,仅占国家公园总面积的17.8%;影响黑麂生境分布的主要环境因子为距阔叶林距离(29.4%)、海拔(19.2%)和距水源距离(15.2%);在选取的黑麂适宜生境关键区设计了3条黑麂潜在生境廊道,主要位于里秧田村、田畈村、库坑村及霞川村,廊道最小宽度设置为766 m,廊道总长度为12.70 km。该研究结果可为黑麂保护提供科学依据。     

Fragments as Islands: a Synthesis of Faunal Responses to Habitat Patchiness

Abstract:  Scientific interest in the impact of habitat fragmentation on biodiversity is increasing, but our understanding of fragmentation is clouded by a lack of appreciation for fundamental similarities and differences across studies representing a wide range of taxa and landscape types. In an effort to synthesize data describing ecological responses of animals to fragmentation across two classes of independent variables (taxonomic group and landscape), we sampled 148 studies of five major faunal groups from the primary literature and analyzed data on 13 variables extracted from those studies. We focused our analyses on three classes of dependent variables (effects of area and isolation on species richness, z values, and nestedness and species composition). Area ranged over more orders of magnitude than isolation and tended to explain more variation in species richness than isolation. There were few matrix or taxon effects on the patterns we investigated, although we did find that sky islands tended to manifest isolation effects on both species richness and nestedness more frequently than other patch types. Sky islands may offer insight into the future of habitat patches fragmented by contemporary habitat loss, and because they show a stronger effect of isolation than other patch types, we suggest that isolation will play an increasing role in the biology of habitat fragments. We use multiple lines of evidence to suggest that our understanding of the role of isolation on community assembly in fragmented landscapes is inadequate. Finally, our observation that consistent taxonomic differences in community patterns were minimal suggests that conservation actions intended to mitigate the negative effects of extinction may have far-reaching effects across taxonomic groups.     

Conservation Value of Remnant Riparian Forest Corridors of Varying Quality for Amazonian Birds and Mammals

Abstract:  Forest corridors are often considered the main instrument with which to offset the effects of habitat loss and fragmentation. Brazilian forestry legislation requires that all riparian zones on private landholdings be maintained as permanent reserves and sets fixed minimum widths of riparian forest buffers to be retained alongside rivers and perennial streams. We investigated the effects of corridor width and degradation status of 37 riparian forest sites (including 24 corridors connected to large source-forest patches, 8 unconnected forest corridors, and 5 control riparian zones embedded within continuous forest patches) on bird and mammal species richness in a hyper-fragmented forest landscape surrounding Alta Floresta, Mato Grosso, Brazil. We used point-count and track-sampling methodology, coupled with an intensive forest-quality assessment that combined satellite imagery and ground truthed data. Vertebrate use of corridors was highly species-specific, but broad trends emerged depending on species life histories and their sensitivity to disturbance. Narrow and/or highly disturbed riparian corridors retained only a depauperate vertebrate assemblage that was typical of deforested habitats, whereas wide, well-preserved corridors retained a nearly complete species assemblage. Restriction of livestock movement along riparian buffers and their exclusion from key areas alongside deforested streams would permit corridor regeneration and facilitate restoration of connectivity .     

An Index of Risk as a Measure of Biodiversity Conservation Achieved through Land Reform

Abstract:  We measured the net progress of land reform in achieving a national policy goal for biodiversity conservation in the context of ongoing clearing of native vegetation and additions of land to a highly nonrepresentative (residual) reserve network, interior South Island, New Zealand. We used systematic conservation-planning approaches to develop a spatially explicit index of risk of biodiversity loss (RBL). The index incorporated information from national data sets that describe New Zealand's remaining indigenous land cover, legal protection, and land environments and modeled risk to biodiversity on the basis of stated assumptions about the effects of past habitat loss and legal protection. The index identified irreplaceable and vulnerable native habitats in lowland environments as the most at risk of biodiversity loss, and risk was correlated with the density of threatened plant records. To measure achievement, we used changes in the index that reflected gains made and opportunity costs incurred by legal protection and privatization. Application of the index to measure the difference made by land reform showed it had caused a net increase in the risk of biodiversity loss because most land vulnerable to habitat modification and rich in threatened plant species was privatized and land at least risk of biodiversity loss was protected. The application revealed that new high-elevation reserves did little to mitigate biodiversity decline, that privatization of low-elevation land further jeopardized the most vulnerable biodiversity in lowland native habitats, and that outcomes of land reform for biodiversity deteriorated over time. Further development of robust achievement measures is needed to encourage more accountable biodiversity conservation decisions.     

Resolving Critical Habitat Designation Failures: Reconciling Law, Policy, and Biology

Abstract:  The U.S. Endangered Species Act (ESA) requires designation of critical habitat concurrent with species listing. The U.S. Fish and Wildlife Service often has not designated critical habitat, based on the legal exceptions in the ESA of "not prudent" or "not determinable." This lack of habitat designation has led to numerous lawsuits and court orders to designate critical habitat for listed species. Court-mediated implementation of critical habitat is costly and delays listing for at-risk species. Legal, policy, judicial, and biological issues all contribute to the current inability of the law as enforced to lead to timely and cost-effective critical habitat designation. Although increased appropriations and delaying critical habitat designation until recovery planning have been proposed as solutions, we find that it will be essential to change the critical-habitat guidelines to a decision-analysis framework to make critical habitat scientifically and legally workable as a conservation tool.     

Habitat association studies in conjunction with adaptive cluster samples

Habitat association studies investigate the relationships between habitat characteristics and animal usage of study regions. These studies are often conducted in conjunction with surveys designed primarily to estimate population totals. This paper shows that habitat association studies may proceed from surveys using adaptive cluster sampling. The manner in which units appear in the sample turns out not be relevant to the habitat association study, which proceeds as though the units came from a simple random sample. However, it is also shown that the information about the habitat association parameters is greater than one would expect from a simple random sample of the same general size.     

Connectivity in an Agricultural Landscape as Reflected by Interpond Movements of a Freshwater Turtle

Abstract:  Connectivity is a measure of how landscape features facilitate movement and thus is an important factor in species persistence in a fragmented landscape. The scarcity of empirical studies that directly quantify species movement and determine subsequent effects on population density have, however, limited the utility of connectivity measures in conservation planning. We undertook a 4-year study to calculate connectivity based on observed movement rates and movement probabilities for five age-sex classes of painted turtles ( Chrysemys picta ) inhabiting a pond complex in an agricultural landscape in northern Virginia (U.S.A.). We determined which variables influenced connectivity and the relationship between connectivity and subpopulation density. Interpatch distance and quality of habitat patches influenced connectivity but characteristics of the intervening matrix did not. Adult female turtles were more influenced by the habitat quality of recipient ponds than other age-sex classes. The importance of connectivity on spatial population dynamics was most apparent during a drought. Population density and connectivity were low for one pond in a wet year but dramatically increased as other ponds dried. Connectivity is an important component of species persistence in a heterogeneous landscape and is strongly dependent on the movement behavior of the species. Connectivity may reflect active selection or avoidance of particular habitat patches. The influence of habitat quality on connectivity has often been ignored, but our findings highlight its importance. Conservation planners seeking to incorporate connectivity measures into reserve design should not ignore behavior in favor of purely structural estimates of connectivity.     

Demographic Limitations of the Ability of Habitat Restoration to Rescue Declining Populations

Abstract:  Habitat restoration is often recommended in conservation without first evaluating whether populations are in fact habitat limited and thus whether declining populations can be stabilized or recovered through habitat restoration. We used a spatially structured demographic model coupled with a dynamic neutral landscape model to evaluate whether habitat restoration could rescue populations of several generic migratory songbirds that differed in their sensitivity to habitat fragmentation (i.e., severity of edge effects on nesting success). Simulating a best-case scenario, landscapes were instantly restored to 100% habitat before, at, or after habitat loss exceeded the species' vulnerability threshold. The vulnerability threshold is a measure of extinction risk, in which the change in population growth rate ( δλ ) scaled to the rate of habitat loss ( δh ) falls below −1% ( δλ/δh ≤ −0.01). Habitat restoration was most effective for species with low-to-moderate edge sensitivities and in landscapes that had not previously experienced extensive fragmentation. To stabilize populations of species that were highly edge sensitive or any species in heavily fragmented landscapes, restoration needed to be initiated long before the vulnerability threshold was reached. In practice, habitat restoration is generally not initiated until a population is at risk of extinction, but our model results demonstrate that some populations cannot be recovered at this point through habitat restoration alone. At this stage, habitat loss and fragmentation have seriously eroded the species' demographic potential such that halting population declines is limited more by demographic factors than the amount of available habitat. Evidence that populations decline in response to habitat loss is thus not sufficient to conclude that habitat restoration will be sufficient to rescue declining populations.     

How Corridors Reduce Indigo Bunting Nest Success

Abstract:  Corridors are a popular strategy to conserve biodiversity and promote gene flow in fragmented landscapes. Corridor effectiveness has been bolstered by the fact that no empirical field studies have shown negative effects on populations or communities. I tested the hypothesis that corridors increase nest predation in connected habitat fragments relative to unconnected fragments. I evaluated this hypothesis in a large-scale experimental system of open-habitat fragments that varied in shape and connectivity. Corridors increased nest predation rates in connected fragments relative to unconnected fragments with lower edge:area ratios. Nest predation rates were similar between connected and unconnected fragments with higher edge:area ratios. These results suggest that the increase in predator activity is largely attributable to edge effects incurred through the addition of a corridor. This is the first field study to demonstrate that corridors can negatively impact animal populations occupying connected fragments.