Green Tongues into the Arid Zone: River Floodplains Extend the Distribution of Terrestrial Bird Species

Floodplain and riparian ecosystems have cooler, wetter microclimatic conditions, higher water availability and greater vegetation biomass than adjacent terrestrial zones. Given these conditions, we investigated whether floodplain ecosystems allow terrestrial bird species to extend into more arid regions than they otherwise would be expected to occupy. We evaluated associations between aridity and the occurrence of 130 species using bird survey data from 2998 sites along the two major river corridors in the Murray–Darling Basin, Australia. We compared the effects of aridity on species occurrence in non-floodplain and floodplain ecosystems to test whether floodplains moderate the effect of aridity. Aridity had a negative effect on the occurrence of 58 species (45%) in non-floodplain ecosystems, especially species dependent on forest and woodland habitats. Of these 58 species, the negative effects of aridity were moderated in floodplain ecosystems for 22 (38%) species: 12 showed no association with aridity in floodplain ecosystems and the adverse effects of aridity on species occurrence were less pronounced in floodplain ecosystems compared to non-floodplain ecosystems for ten species. Greater vegetation greenness indicated that floodplain vegetation was more productive than vegetation in non-floodplain ecosystems. Floodplain ecosystems allow many terrestrial species to occur in more arid regions than they otherwise would be expected to occupy. This may be due to higher vegetation productivity, cooler microclimates or connectivity of floodplain vegetation. Although floodplain and riparian ecosystems will become increasingly important for terrestrial species persistence as climate change increases drying in many parts of the world, many are also likely to be highly affected by reduced water availability.     

关于蝗虫多样性与草原生态系统可持续发展的若干科学问题

蝗虫多样性既是草原生态系统演化的产物 ,反过来也影响着草原生态系统的结构与功能。蝗虫多样性状况与草原生态系统的持续发展有着密切的关联 ,这其中的科学问题包括 :(1 )蝗虫多样性及其空间变异机理 ;(2 )蝗虫多样性对草原生态系统过程的影响 ;(3 )蝗虫多样性空间格局与草原生态系统演化中的自然和人文因素的关联 ;(4 )蝗虫种群暴发的多样性阈值与草原生态系统的调控 ;(5 )蝗虫多样性和稳定性与草原生态系统的健康等。深入发掘生物多样性所包含的科学内涵 ,将一个物种的多样性与生态系统的结构和功能耦合起来研究 ,从重要物种蝗虫的生物多样性入手 ,深入探讨草原生态系统的持续发展问题 ,将为减少或减轻我国西部草原蝗灾发生提供科学的支持     

Assessing the Need for Groundwater Quality Guidelines for Pesticides Using the Species Sensitivity Distribution Approach

The water quality needs of groundwater ecosystems are rarely considered. It is currently assumed that water quality guidelines for surface waters will also protect groundwater ecosystems and their fauna, but this assumption has not been tested. The aim of this study is to determine whether water quality guidelines specifically for groundwater ecosystems are needed and to provide a preliminary risk assessment for groundwater ecosystems in Australia. In the absence of sufficient toxicity data for true groundwater fauna, 48–96 h LC50 data for groundwater-dwelling invertebrate orders (e.g., Crustacea, Rotifera) are used as a surrogate and were compared, using Species Sensitivity Distribution (SSD) curves, to a full suite of surface taxa (including fish, insects, and algae). SSD curves were derived for a range of pesticides previously detected in Australian groundwaters and were fitted using the Burr Type III distribution. Significant differences in the sensitivities of surface and groundwater taxa to Atrazine and Chlorpyrifos were detected, indicating surface water quality guidelines are not always suitable to protect or best manage groundwater ecosystems. Water quality guideline values derived from the SSDs highlighted a significant threat of contamination to groundwater ecosystems from agricultural chemicals. Clearly water quality guidelines specifically for groundwater ecosystems are needed.     

基于时空分析的生态保护与修复试点工程实施效果评估——以赣州市为例

以“山水林田湖草生命共同体”为中心思想,从生态系统的格局和质量两个方面,对赣州市山水林田湖生态保护与修复试点工程实施效果进行了综合评估。结果如下：（1）从生态系统格局来看,2015到2018年,赣州市森林、农田和城镇生态系统面积明显增加,超过40%的草地生态系统转变为森林生态系统,且近45%的城镇生态系统面积增量由草地生态系统贡献。此外,多数自然生态系统的斑块破碎化加剧,森林生态系统破碎化现象最为明显,最大斑块指数从54.36降低到37.41,而半自然生态系统最大斑块指数增大。（2）从生态系统质量来看,赣州市归一化植被指数稳定在0.7以上并呈增长趋势,水土流失综合治理面积从16543.8 km²增长到18550.4 km²,重点流域水质基本稳定在Ⅱ、Ⅲ级,城镇生态系统受土壤重金属污染的风险较小,但部分县区农田生态系统受一种或多种土壤重金属污染的风险较大。整体而言,赣州市山水林田湖生态保护与修复试点工程取得了显著成效,较好的完成了实施方案中的规划目标。在进一步的生态保护与修复工作中,应重视赣州市自然生态系统斑块破碎化严重地区、水质出现波动较大的河流断面以及农田生态系统受土壤重金属污染威胁较大的县区。     

自控与受控棉田生态系统稳定性的比较

1　前　言稳定性是生物种群、群落与生态系统研究的重要内容之一。稳定性是预测和调控一个系统的基础。棉田生态系统稳定性的研究对于指导棉田生态系统的优化管理 ,对于棉田系统生产力的稳定提高和持续发展具有非常重要的意义。然而 ,生态学的稳定性研究在概念、度量指标 (或称研究方法 )上至今仍未统一[1,2 ],因而研究结果也不一致。Ｗｅｂｓｔｅｒ等[3]认为 ,生态学家关心的不是生态学的系统是否稳定 ,而是系统有多么稳定 ,即稳定的相对程度 ,并提出了绝对稳定性概念(判断是否稳定 )和相对稳定性概念 (判断相对稳定程度 )。其相对稳定性意…     

生态边缘效应与生态平衡变化方向

边缘效应作为一个生态现象和生态学概念越来越为更多的人所重视 ,因为它与物种保护、生态环境保护等自然保护和开发利用以及生态恢复、生态建设等人类参与自然活动的关系十分密切 ,并逐渐被人们所认识。1　边缘效应研究现状及重要性　　早在 1 933年 Leopold对森林片段的边缘效应进行了开创性的研究[1] 。1 942年 Beecher便指出 ,在两个或多个不同生物地理群落交界处 ,往往结构复杂 ,出现不同生境的种类共生 ,种群密度变化较大 ,某些物种特别活跃 ,生产力亦相应较高 ,这种现象即边缘效应。随着人们对这一概念的逐渐重视 ,该领域的研究愈加…     

农业生态系统中的AM真菌多样性

农业生态系统复杂庞大,是由如麦田生态系统、水稻田生态系统、果园生态系统、草地生态系统、保护地生态系统等组成的一个复合生态系统。重点介绍农业生态系统中丛枝菌根(AM)和AM真菌多样性,探讨农业生态系统中调控AM真菌多样性的途径以及今后研究的动向。     

退化森林生态系统评价指标体系研究进展

森林是陆地生态系统的主要组成部分,而森林退化是全球面临的主要环境问题之一,准确评价退化森林生态系统是进行森林生态系统恢复与重建的重要前提,建立合理的评价指标体系目前已成为生态学研究的热点问题。在研究国内外提出的关于退化森林生态系统评价理论的基础上,综述了森林退化的定义、特征和一般过程,梳理了退化森林生态系统评价指标筛选的一般原则和指标体系构建的主要方法,分析比较了不同学者所提出的主要评价指标。并在此基础上,重新筛选、构建了一套退化森林生态系统评价指标体系,即从生态系统的组成结构、功能和生境这3个方面选取了32个能够较全面反映退化生态系统主要特征的评价指标,以期为构建我国区域尺度上的退化森林生态系统评价指标体系提供参考,为退化森林生态系统的恢复和重建提供科学依据。总结分析了退化森林生态系统评价指标体系在构建过程中产生的一些问题和不足,提出了今后开展研究和探索应该深入的方向,以提高评价指标体系的科学性、准确性和合理性。     

山水林田湖草生态保护修复的理论支撑体系研究

山水林田湖草生态保护修复关系到我国生态文明建设和美丽中国建设进程,关系到国家生态安全和中华民族永续发展。开展山水林田湖草生态保护修复是生态文明建设的重要内容,是贯彻绿色发展理念的有力举措,也是破解当前生态环境与经济发展之间难题的必然要求。通过总结梳理当前我国山水林田湖草生态保护修复工作的进展与概况,立足于“山水林田湖草是生命共同体”的理论核心,详细阐释了山水林田湖草生态保护修复的内涵及理论体系。山水林田湖草生命共同体的基础理论是以生态系统生态学为支撑,基于流域生态学、恢复生态学和景观生态学的理论诠释山水林田湖草生命共同体的时空区域尺度及流域内部各生态系统之间的耦合机制,通过复合生态系统理论构建山水林田湖草生命共同体的社会、经济、自然生态系统的“架构”体系,明确了流域可持续发展是山水林田湖草生命共同体的最终发展目标。在构建山水林田湖草生态保护修复理论支撑体系的基础上,进一步总结凝练了山水林田湖草生态保护修复的技术体系,包括生态保护、修复与恢复技术、生态建设技术、生态功能提升技术、生态服务优化技术与监督管理技术等,为我国山水林田湖草生态保护修复工作提供坚实的理论和技术支撑体系。     

Mapping the actual and original distribution of the ecosystems and the chorological types for conservation planning in Colombia

A key requirement for systematic conservation planning is the availability of good quality and comparable data about the biodiversity. However, for many highly diverse countries, this information is not available. Here we present the methodology and the results of the three‐part construction of a conservation planning database in Colombia: (1) the actual distribution of the ecosystems; (2) their original‐potential distribution, which is important to calculate fixed targets for conservation; and (3) the chorological types, which are groups of spatial related ecosystems that account for biodiversity process that operate at larger scales. The procedure consists of integrating the results of the interpretation of satellite images, and the construction of ecological diagrams and biogeographical regions. The limits of the original‐potential ecosystems in the transformed landscapes can either still be seen on the images or are reconstructed on the base of the information from the ecological diagrams. The chorological types are constructed by clustering of ecosystems on the base of the shared boundary length. The implementation for Colombia resulted in maps of 337 ecosystems and 63 chorological types. This database was successfully used for the identification of the priorities for conservation.     

气候变化对我国自然生态系统影响的研究综述

现代工业的迅速发展 ,伐林、垦荒、过牧、矿石燃料燃烧及化工合成产品的使用等人类活动 ,导致大气中温室气体含量剧增 ,全球气候变暖 ,荒漠化扩展 ,海平面上升等一系列环境变化 ,对人类及生物赖以生存的环境及生态系统将产生重大影响。因此 ,研究气候变化及其对自然生态系统的影响已引起各国政府、科学界及公众的极大关注。我国在“八五”科技攻关中 ,曾开展了气候变化对我国自然地带、冰雪圈及冻土带、山区生态系统的研究。在美国支持的气候变化国家研究中曾对我国森林、草地生态系统的影响进行了模拟实验研究。在国家自然科学基金和有关部…     

2000—2010年我国重点生态功能区生态系统变化状况

分析了2000—2010年我国水源涵养型、水土保持型、防风固沙型、生物多样性维护型重点生态功能区的生态系统结构、质量与核心服务的变化.结果表明: 近11年来,水源涵养型重点生态功能区的森林、草地面积减少,水体与湿的面积增加,森林、草地、湿地生态系统水源涵养总量增加了2.9%,该类区域需要遏制森林、草地的减少趋势.水土保持型重点生态功能区的农田面积减少,而森林、草地、水体与湿地的面积增加,土壤侵蚀总量减少了28.2%,生态系统土壤保持总量增加了38.1%.防风固沙型重点生态功能区的农田、森林面积增加,草地、水体与湿地的面积减少,单位面积土壤风蚀量下降,单位面积防风固沙服务量有所提升,该类区域多位于干旱半干旱区,需要减少农田面积,优先保护原有生态系统.生物多样性维护型重点生态功能区的草地、荒漠面积减少,其他类型的面积有所增加,人类扰动呈现微弱的上升趋势,该类区域需要减少人类干扰.重点生态功能区应该针对核心服务和保护目标,分类分区开展生态系统保护、改善及其效果的定量综合评估.     

氮稳定同位素技术在陆地生态系统氮循环研究中的应用

在过去几十年中, 氮(N)稳定同位素技术的发展提高了人们对于陆地生态系统氮循环的认识。该文回顾了氮稳定同位素技术在研究生态系统氮循环中的历史, 综述了最近十多年来氮稳定同位素技术在陆地生态系统氮循环研究中的典型案例, 包括利用氮同位素自然丰度鉴定植物氮来源、指示生态系统氮状态和量化过程速率, 利用¹⁵N标记技术示踪氮的去向和再分布等。该文同时指出这些应用中存在的问题, 以及在陆地生态系统上氮稳定同位素技术今后研究的重点发展方向。     

海平面上升影响下广西钦州湾红树林脆弱性评价

全球气候变化所导致的海平面上升等现象对海岸带产生显著影响。红树林是生长在热带、亚热带沿海潮间带的生态系统,对海平面上升极为敏感。以广西钦州湾红树林生态系统为对象,采用SPRC(Source-Pathway-Receptor-Consequence)评估模式分析了气候变化所导致的海平面上升对红树林生态系统的主要影响。构建了以海平面上升速率、地面沉降/抬升速率、生境高程、日均淹水时间、潮滩坡度和沉积速率为指标的脆弱性评价体系。在GIS平台上量化各脆弱性指标,计算脆弱性指数并分级,建立了定量评价红树林生态系统脆弱性方法,实现了在不同海平面上升情景(近40年来广西海平面平均上升速率、IPCC预测的B1和A1FI情景)和时间尺度下(2030年、2050和2100年),广西钦州湾红树林生态系统脆弱性的定量空间评价。研究结果表明,在近40年广西海平面平均上升速率与B1情景下,钦州湾红树林在各评估时段表现为不脆弱。而在A1FI情景下,至2050年研究区域41.3%红树林为低脆弱,至2100年增加至69.8%。研究采用的SPRC评估模型、脆弱性评价指标体系和定量空间评估方法能够客观定量评价气候变化所导致的海平面上升影响下红树林生态系统脆弱性,可为制定切实可行的应对措施和保障海岸带生态系统安全提供科学依据。     

Spatial-typological differentiation of ecosystems of the West Siberian Plain. Communication V: Terrestrial ecosystems

Results of classification of terrestrial ecosystems using an average similarity matrix are reported for the West Siberian Plain. Initial indices are first calculated separately for four components of an ecosystem. These components (blocks) include the underground block (soil humus, mortmass, and underground phytomass), above-ground vegetation, and invertebrates and vertebrates. Mismatch of boundaries in separate blocks of ecosystems and in comparison with the inhomogeneity of ecosystems in general was demonstrated. These differences are observed in both the typological and typological-chorological analysis. The indicated features of spatial succession within the blocks generate continuity of ecosystems and the conventional character of all the classifications and drawn boundaries.     

Cross-ecosystem differences in stability and the principle of energy flux

Here, we review consumer-resource (C-R) theory to show that the paradox of enrichment is a special case of a more general theoretical result. That is, we show that increased energy flux, relative to the consumer loss rate, makes C-R interactions top heavy (i.e., greater C:R biomass ratio) and less stable. We then review the literature on the attributes of aquatic and terrestrial ecosystems to argue that empirical estimates of parameters governing energy flux find that aquatic ecosystems have higher rates of relative energy flux than terrestrial ecosystems. Consistent with theory, we then review empirical work that shows aquatic ecosystems have greater herbivore:plant biomass ratios while we produce novel data to show that aquatic ecosystems have greater variability in population dynamics than their terrestrial counterparts. We end by arguing that theory, allometric relationships and a significant, negative correlation between body size and population variability suggest that these results may be driven by the smaller average body sizes of aquatic organisms relative to terrestrial organisms.     

Beyond Paradise—Meeting the Challenges in Tropical Biology in the 21st Century

Tropical ecosystems support a diversity of species and ecological processes that are unparalleled anywhere else on Earth. Despite their tremendous social and scientific importance, tropical ecosystems are rapidly disappearing. To usher tropical ecosystems and the human communities dependent upon them through the environmental transformations of the 21st century, tropical biologists must provide critical knowledge in three areas: 1) the structure and function of tropical ecosystems; 2) the nature and magnitude of anthropogenic effects on tropical ecosystems; and 3) the socio‐economic drivers of these anthropogenic effects. To develop effective strategies for conservation, restoration, and sustainable management of tropical ecosystems, scientific perspectives must be integrated with social necessities. A new set of principles built on a framework for pursuing relevant tropical biological research will facilitate interdisciplinary approaches, integrate biological knowledge with the social sciences, and link science with policy. We propose four broad recommendations for immediate action in tropical biology and conservation that are fundamental to all biological and social disciplines in the tropics: 1) assemble and disseminate information on life's diversity in the tropics; 2) enhance tropical field stations and build a worldwide network to link them with tropical field biologists at their field sites; 3) bring the field of tropical biology to the tropics by strengthening institutions in tropical countries through novel partnerships between tropical and temperate zone institutions and scientists; and 4) create concrete mechanisms to increase interactions between tropical biologists, social scientists, and policy makers.     

Novel and designed ecosystems

Growing attention to novel and designed ecosystems, and the confusion that follows from the overlap of these distinct ecosystem approaches, risks a loss of focus on ecological values at the core of restoration ecology. Novel ecosystems originate in ecosystems that are transformed beyond which the practical efforts of conventional restoration are feasible. They are also self‐sustaining in the sense that they take time to form, and do not typically receive regular management. In this respect, they arise differently than designed ecosystems, which are assembled with specific goals in mind and are often heavily managed. Designed (or engineered) ecosystems comprise a variety of ecological approaches including reclamation (return a degraded ecosystem to productive capacity), green infrastructure, and agroecological systems. There are three elements that distinguish novel and designed ecosystems. Designed ecosystems typically require intensive intervention to create them, and ongoing management to sustain them; novel ecosystems do not. Second, the human intentions behind designed and novel ecosystems are usually different. Designed ecosystems exist in the service of human interests, including specific services (e.g. filtration, cooling, nature appreciation), aesthetics, and shifting value commitments toward green infrastructure; novel ecosystems arise typically through inadvertent human activity. Third, designed and novel ecosystems have different developmental pathways. Historical ecosystems are the starting point for restored, hybrid, and novel ecosystems; designed ecosystems are intentionally created. Designed ecosystems stand apart as providing a new origin for ecosystems of the future, including those that become novel ecosystems.     

Complexity and stability of ecological networks: a review of the theory

Our planet is changing at paces never observed before. Species extinction is happening at faster rates than ever, greatly exceeding the five mass extinctions in the fossil record. Nevertheless, our lives are strongly based on services provided by ecosystems, thus the responses to global change of our natural heritage are of immediate concern. Understanding the relationship between complexity and stability of ecosystems is of key importance for the maintenance of the balance of human growth and the conservation of all the natural services that ecosystems provide. Mathematical network models can be used to simplify the vast complexity of the real world, to formally describe and investigate ecological phenomena, and to understand ecosystems propensity of returning to its functioning regime after a stress or a perturbation. The use of ecological-network models to study the relationship between complexity and stability of natural ecosystems is the focus of this review. The concept of ecological networks and their characteristics are first introduced, followed by central and occasionally contrasting definitions of complexity and stability. The literature on the relationship between complexity and stability in different types of models and in real ecosystems is then reviewed, highlighting the theoretical debate and the lack of consensual agreement. The summary of the importance of this line of research for the successful management and conservation of biodiversity and ecosystem services concludes the review.