生态承载力研究进展

从生态承载力角度研究区域资源-生态-环境问题,是当今生态学、地理学和经济学等学科研究的热点与前沿领域之一。在调研现有研究成果基础上,阐述了承载力的起源、演化与发展以及国内外研究进展,对生态承载力的概念、研究方法、研究趋势及其与可持续发展的关系等进行了评述。生态承载力内涵可以概括为“特定时间、特定生态系统自我维持、自我调节的能力,资源与环境子系统对人类社会系统可持续发展的一种支持能力以及生态系统所能持续支撑的一定发展程度的社会经济规模和具有一定生活水平的人口数量”。今后生态承载力研究的发展方向是:研究对象趋向多元化,研究领域呈现交叉综合趋势;生态脆弱带将继续成为研究的热点地区;研究重点将继续向动态模拟化方向发展;新方法、新技术手段将不断应用于生态承载力研究。     

城市生态学基本原理的探讨

城市生态学是一门正在发展中的生态学分支,因其产生历史较短,而尚未形成一套成熟的理论体系和研究方法.本文试图应用生态学基本原理来探讨城市生态系统的性质和特点,初步提出了城市生态学的一些原理和研究城市生态系统的指导原则,并提出了环境承载力—人类社会行为和生态环境之间的界面在城市生态系统研究的地位和作用.     

环境承载力理论在北京市和房山区的应用

基于环境承载力的相关理论,建立环境承载力评价指标体系,并对北京市和房山区进行了实证研究。分析结果表明,北京市和房山区经济系统和社会系统的承载状况良好,资源环境系统存在较多问题,房山区的问题尤为突出。基于上述结论,进一步提出了区域经济环境协调发展的对策建议。     

试论城市环境综合整治与环境目标管理

城市环境综合整治与城市污染单项治理和综合防治不同,它是把城市看作一个包括经济、社会和环境要素的大系统,力求在城市的发展过程中使其经济、社会与环境协调发展。由于城市人群是该系统的核心,因此城市环境综台整治必然要以城市生态系统原理作为基本的指导理论。在制定城市环境综合整治规划中,必须根据城市生态系统结构、功能的分析,对城市大系统进行总体调控。     

《东南亚地区农业系统人类生态学研究导论》简介

人类生态学作为生态学的一门分支学科已脱颖而出,它研究人类社会与自然环境间的相互作用,包括人类生活如何受到环境的影响以及人类活动如何改变着环境。但对学科的具体内容,目前还未被大多数人所了解。《东南亚地区农业系统人类生态学研究导论》(An Introduction to HumanEcology Research on Agricultural Systems in South-ast Asia)一书,论述了有关人类生态学的基本观点,同时介绍了将这些观点应用于研究东南亚农业生态系统的实际事例。     

长江上游高寒草地生态建设和管理中生态理论的若干质疑

现有的草地管理政策和措施建立在西方经典生态学理论的基础上，并在很大程度上改变了传统管理模式．本文针对长江上游高寒草地生态建设与管理中的问题，结合草地生态学的新进展，从草地生态系统特征、多样性与稳定性、草地承载力、平衡与非平衡等几个方面进行了讨论，旨在能引起今后草地生态建设中加强这些方面的针对性研究，并有效地避免由于理论自身偏差而导致不应有的技术失误．本文的中心观点在于，由于长江上游地区的高寒草地处在环境因子剧烈变化的条件之下，草地的生态过程在很大程度上受制于非生物条件(如气候)，而不是生物因子的相互作用(如放牧)，因此，已有的一些草地生态理论不能完全解释草地动态变化的机理，其适用性受到限制，而任何简单套用理论以及基于这些理论发展的技术和模式都有可能给生态治理和管理带来负面影响．图2参22     

论现代科学技术中的"生态化"

对现代科学技术所出现的“生态化”现象进行了初步探讨。首先，对生态学涵义的扩展和生态化研究方法进行了研究，认为其涵义已从生态学的生物学含义发展到现代生态学的新涵义，其方法就是研究在科学技术中的“对象”与“环境”的关系问题；在此基础上，对科学技术研究目标作了生态化表述，即要建设生态-经济-社会优质复合群；然后，对科学技术所出现的生态化理论与方法进行了初步研究，并对建设普遍优质的生态-经济-社会复合群理论及其应用进行了分析；最后，对生态化的研究方法进行了总结。     

生态经济系统的一种整合评价方法:能值理论与分析方法

能值理论与分析方法是目前系统生态学和生态经济学发展的新成果，为复合生态系统开拓了一条定量研究途径，是连接生态学和经济学的桥梁。其理论研究与实践应用具有重要的科学意义和应用意义。文章论述了能值分析理论与分析方法的产生背景、过程、主要的基本概念、特点，指出了其需要解决的问题；并以种植业系统为例，简要介绍了能值分析的基本方法和步骤以及能值指标的计算。     

基于生态足迹法的区域水资源生态承载力计算与评价——以珠海市为例

研究了人类社会对水资源的消耗、对自然生态环境的影响以及该影响的量化方法和量化指标,将生态足迹法引入区域水资源承载力系统,构建珠海市水资源生态承载力计算模型,分析计算水资源供给对区域经济社会发展的生态承载力,并对该地区的水资源生态承载力进行生态盈亏和敏感性评价.结果表明,总体上珠海市水资源系统呈现生态亏损,亏损率为37%,水资源生态承载呈现超载现象,珠海市城市化进程中流动人口增长对区域水资源的生态承载压力较大.研究结果还表明,将生态足迹模型运用到地区水资源承载力中具有较高的可信度,对地方尺度具有适用性.     

城市人口与城市环境

人口问题是其他问题(资源、能源、粮食、环境)的主要根源。城市人口与城市环境的关系密切。本文从世界、全国、湖北省及武汉市的人口发展分析,指出城市环境的研究核心问题是城市生态系统。提出今后城市应用生态和理论生态学方面可开展研究的内容,以及城市生态系统的调控中应注意应用耗散结构理论、协同论和黑箱方法。研究城市化的过程,重点应是城市人口的增长和分布、土地利用方式、工业化过程、目前的水平和趋势。适宜的人口密度及其良好素质,可提高社会经济活力,提高城市的经济效益,有利于搞好城市环境保护。     

Rapid,recurring, structured survey versus bioblitz for generating biodiversity data and analysis with a multispecies abundance model

A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.     

Compliance with and ecosystem function of biodiversity offsets in North American and European freshwaters

Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.     

A palaeo-hydrogeological model for arsenic contamination in southern and south-east Asia

An argument is presented in which areas of natural arsenic contamination of modern groundwaters throughout Asia have a common origin. Arsenic originally accumulated in oceanic ferro-manganoan sediments of the eastern Palaeo-Tethys. This was further concentrated through oceanic crustal extinction in what later became the south-east Chinese accreted mineralised terrain. Proto-Himalayan uplift of this area created the palaeo-drainage systems of the Ganges – Brahmaputra, Irrawaddy, Mekong, and Red Rivers, with consequent headwater erosion of arsenic-rich sediments. Their downstream deposition as immature and easily redistributed Neogene sandstones, silts, and iron-rich clays has created secondary and tertiary reservoirs of adsorbed and authigenic arsenic, from which the current arsenic-rich groundwaters have evolved. Considering river basins within the above palaeo-hydrogeological framework provides a basis for assessing the risk of arsenic in groundwater basins of south and south-eastern Asia.     

Cost‐effective conservation of an endangered frog under uncertainty

How should managers choose among conservation options when resources are scarce and there is uncertainty regarding the effectiveness of actions? Well‐developed tools exist for prioritizing areas for one‐time and binary actions (e.g., protect vs. not protect), but methods for prioritizing incremental or ongoing actions (such as habitat creation and maintenance) remain uncommon. We devised an approach that combines metapopulation viability and cost‐effectiveness analyses to select among alternative conservation actions while accounting for uncertainty. In our study, cost‐effectiveness is the ratio between the benefit of an action and its economic cost, where benefit is the change in metapopulation viability. We applied the approach to the case of the endangered growling grass frog (Litoria raniformis), which is threatened by urban development. We extended a Bayesian model to predict metapopulation viability under 9 urbanization and management scenarios and incorporated the full probability distribution of possible outcomes for each scenario into the cost‐effectiveness analysis. This allowed us to discern between cost‐effective alternatives that were robust to uncertainty and those with a relatively high risk of failure. We found a relatively high risk of extinction following urbanization if the only action was reservation of core habitat; habitat creation actions performed better than enhancement actions; and cost‐effectiveness ranking changed depending on the consideration of uncertainty. Our results suggest that creation and maintenance of wetlands dedicated to L. raniformis is the only cost‐effective action likely to result in a sufficiently low risk of extinction. To our knowledge we are the first study to use Bayesian metapopulation viability analysis to explicitly incorporate parametric and demographic uncertainty into a cost‐effective evaluation of conservation actions. The approach offers guidance to decision makers aiming to achieve cost‐effective conservation under uncertainty.     

Threats to intact tropical peatlands and opportunities for their conservation

Large, intact areas of tropical peatland are highly threatened at a global scale by the expansion of commercial agriculture and other forms of economic development. Conserving peatlands on a landscape scale, with their hydrology intact, is of international conservation importance to preserve their distinctive biodiversity and ecosystem services and maintain their resilience to future environmental change. We explored threats to and opportunities for conserving remaining intact tropical peatlands; thus, we excluded peatlands of Indonesia and Malaysia, where extensive deforestation, drainage, and conversion to plantations means conservation in this region can protect only small fragments of the original ecosystem. We focused on a case study, the Pastaza‐Marañón Foreland Basin (PMFB) in Peru, which is among the largest known intact tropical peatland landscapes in the world and is representative of peatland vulnerability. Maintenance of the hydrological conditions critical for carbon storage and ecosystem function of peatlands is, in the PMFB, primarily threatened by expansion of commercial agriculture linked to new transport infrastructure that is facilitating access to remote areas. There remain opportunities in the PMFB and elsewhere to develop alternative, more sustainable land‐use practices. Although some of the peatlands in the PMFB fall within existing legally protected areas, this protection does not include the most carbon‐dense (domed pole forest) areas. New carbon‐based conservation instruments (e.g., REDD+, Green Climate Fund), developing markets for sustainable peatland products, transferring land title to local communities, and expanding protected areas offer pathways to increased protection for intact tropical peatlands in Amazonia and elsewhere, such as those in New Guinea and Central Africa which remain, for the moment, broadly beyond the frontier of commercial development.     

Human Influence and Classical Biogeographic Predictors of Rare Species Occurrence

Biogeographic theory predicts that rare species occur more often in larger, less‐isolated habitat patches and suggests that patch size and connectivity are positive predictors of patch quality for conservation. However, in areas substantially modified by humans, rare species may be relegated to the most isolated patches. We used data from plant surveys of 81 meadow patches in the Georgia Basin of Canada and the United States to show that presence of threatened and endangered plants was positively predicted for patches that were isolated on small islands surrounded by ocean and for patches that were isolated by surrounding forest. Neither patch size nor connectivity were positive predictors of rare species occurrence. Thus, in our study area, human influence, presumably due to disturbance or introduction of competitive non‐native species, appears to have overwhelmed classical predictors of rare species distribution, such that greater patch isolation appeared to favor presence of rare species. We suggest conservation planners consider the potential advantages of protecting geographically isolated patches in human‐modified landscapes because such patches may represent the only habitats in which rare species are likely to persist. Influencia Humana y Predictores Biogeográficos Clásicos de la Ocurrencia de Especies Raras     

Seasonal dynamics of macro-algae in the South Lake of Tunis

The macro-algae communities observed in the south lake of Tunis are characterized by the predominance of nitrophilous algae which are in the order of biomass importance:Ulva, Cladophora andEnteromorpha. We have noted seasonal changes of alga distribution. The wind appears to be one of the most important factors influencing this distribution. The total biomass reaches a maximum in the spring. Rapid decomposition of the biomass leads to a severe ecological imbalance, resulting in crises of anoxia and fish death. A restoration project has already started. It aims at removal of contaminated muds and the introduction of a new circulation system. The main objectives of this work were to collect information on the distribution and biomass of the phytobenthic communities as a first step in the constitution of a database for further comparison.     

Patterns and biases of climate change threats in the IUCN Red List

International Union for Conservation of Nature (IUCN) Red List assessments rely on published data and expert inputs, and biases can be introduced where underlying definitions and concepts are ambiguous. Consideration of climate change threat is no exception, and recently numerous approaches to assessing the threat of climate change to species have been developed. We explored IUCN Red List assessments of amphibians and birds to determine whether species listed as threatened by climate change display distinct patterns in terms of habitat occupied and additional nonclimatic threats faced. We compared IUCN Red List data with a published data set of species’ biological and ecological traits believed to infer high vulnerability to climate change and determined whether distributions of climate change‐threatened species on the IUCN Red List concur with those of climate change‐threatened species identified with the trait‐based approach and whether species possessing these traits are more likely to have climate change listed as a threat on the IUCN Red List. Species in some ecosystems (e.g., grassland, shrubland) and subject to particular threats (e.g., invasive species) were more likely to have climate change as a listed threat. Geographical patterns of climate change‐threatened amphibians and birds on the IUCN Red List were incongruent with patterns of global species richness and patterns identified using trait‐based approaches. Certain traits were linked to increases or decreases in the likelihood of a species being threatened by climate change. Broad temperature tolerance of a species was consistently related to an increased likelihood of climate change threat, indicating counterintuitive relationships in IUCN assessments. To improve the robustness of species assessments of the vulnerability or extinction risk associated with climate change, we suggest IUCN adopt a more cohesive approach whereby specific traits highlighted by our results are considered in Red List assessments. To achieve this and to strengthen the climate change‐vulnerability assessments approach, it is necessary to identify and implement logical avenues for further research into traits that make species vulnerable to climate change (including population‐level threats).     

Parasitic wasps orient to green leaf volatiles

Summary Undamaged plants emit low levels of green leaf volatiles (GLVs), while caterpillar-damaged and artificially damaged plants emit relatively higher levels of certain GLVs. Female braconid parasitoids,Microplitis croceipes, oriented to both damaged plants and to individual GLVs in no-choice tests in a wind tunnel, but seldom oriented to undamaged plants. Female ichneumonid parasitoids,Netelia heroica, also oriented to individual GLVs in a wind tunnel. Males of both wasp species failed to orient to the GLVs. These data show that leaf-feeding caterpillars can cause the release of GLVs, and that parasitic wasps can respond to these odors by flying upwind (chemoanemotactic response), which brings the wasps to their caterpillar hosts. This supports the hypothesis that plants communicate with members of the third trophic level,i.e., plants under herbivore attack emit chemical signals that guide natural enemies of herbivores to sites of plant damage. In this interaction, the GLVs serve as tritrophic plant-to-parasitoid synomones. That parasitoids from two different wasp families oriented to GLVs suggests that the response may be widespread among the Hymenoptera.Mention of a commercial or proprietary product does not constitute an endorsement by the U.S. Department of Agriculture