An ecological perspective in aquatic ecotoxicology: Approaches and challenges

This paper aims to highlight the considerable potential of a better integration of ecological theory in aquatic ecotoxicology. It outlines how community ecology, studies on trophic interaction and disturbance ecology could provide an enhanced theoretical basis for aquatic ecotoxicology and increase ecological relevance in environmental risk assessment of chemicals. Based on the literature and own research, approaches from aquatic ecotoxicology are presented, which are based on ecological considerations and address a higher level of biological complexity for risk assessment strategies of chemicals. The concepts of species-sensitivity distribution (SSD), pollution-induced community tolerance (PICT), the use of model ecosystems and the sediment quality triad (SQT) in ecological risk assesment as well as inputs from ecotoxicology into landscape ecology are illustrated. These examples aim to evidence aquatic ecotoxicology as a rewarding field of ecological research.     

Hierarchical trade-offs between risk and reward mediated by behavior

Understanding the distribution of individuals in space is a primary concern to ecologists and managers. With the advent of remote monitoring technology, we have been able to answer where individuals are but we often lack an understanding of why they are located in a particular place from a behavioral perspective. Increasingly, ecologists are becoming aware of the crucial role individual behavior may play in ecological processes. The movement of individuals within fragmented landscapes is no exception. We used a dynamic state variable model to explicitly account for the behavioral trade-off between acquiring forage and predation risk in a spatial context. We found that when individuals were able to become behaviorally unavailable for predation within a patch as a result of their energetic state, foraging strategy, or the effectiveness of anti-predator behaviors, they were able to mitigate the potential travel costs associated with the spatial configuration of patches to use riskier patches. However, when this was not possible, patch choice became an effective way of minimizing the risk of predation. Individuals appear to trade-off predation risk and the acquisition of forage in a hierarchical fashion depending on whether or not the spatial arrangement and context of patches constrained their anti-predator behavior. We suggest that a better understanding how patch selection and the behavioral trade-offs associated with predation risk occur at multiple scales may help bridge the gap between animal behavior and landscape ecology.     

Riverine landscapes: taking landscape ecology into the water

1. Landscape ecology deals with the influence of spatial pattern on ecological processes. It considers the ecological consequences of where things are located in space, where they are relative to other things, and how these relationships and their consequences are contingent on the characteristics of the surrounding landscape mosaic at multiple scales in time and space. Traditionally, landscape ecologists have focused their attention on terrestrial ecosystems, and rivers and streams have been considered either as elements of landscape mosaics or as units that are linked to the terrestrial landscape by flows across boundaries or ecotones. Less often, the heterogeneity that exists within a river or stream has been viewed as a `riverscape' in its own right.
2. Landscape ecology can be unified about six central themes: (1) patches differ in quality (2) patch boundaries affect flows, (3) patch context matters, (4) connectivity is critical, (5) organisms are important, and (6) the importance of scale. Although riverine systems differ from terrestrial systems by virtue of the strong physical force of hydrology and the inherent connectivity provided by water flow, all of these themes apply equally to aquatic and terrestrial ecosystems, and to the linkages between the two.
3. Landscape ecology therefore has important insights to offer to the study of riverine ecosystems, but these systems may also provide excellent opportunities for developing and testing landscape ecological theory. The principles and approaches of landscape ecology should be extended to include freshwater systems; it is time to take the `land' out of landscape ecology.     

景观生态学——概念与理论

现代景观生态学是一门新兴的、正在深入开拓和迅速发展的学科。因此 ,不但欧洲和北美的景观生态学有显著不同 ,就是在北美景观生态学短暂的发展进程中也逐渐形成了不同的观点和论说。概括地说 ,景观生态学研究的重点主要集中在下列几个方面 ,即 :空间异质性或格局的形成及动态 ;空间异质性与生态学过程的相互作用 ;景观的等级结构特征 ;格局 -过程 -尺度之间的相互关系 ;人类活动与景观结构 ,功能的反馈关系以及景观异质性 (或多样性 )的维持和管理[1～ 6] 。反映这些研究重点的主要景观生态学概念和理论是什么呢 ?本文拟在总结该学科最近 2…     

晋北大型露天矿区景观生态风险时空异质性

矿产资源开采对生态环境产生了剧烈扰动,加剧了矿区生态环境的风险性,严重威胁区域的可持续发展。从景观生态学角度将景观格局与生态风险相结合对矿区生态环境进行评估,从而揭示矿区景观生态风险的时空异质性,促进土地资源的可持续利用。以1990-2018年7期Landsat TM影像解译后的土地利用现状数据为数据源,构建景观生态风险指数,结合空间统计学及地统计学理论,探究1990-2018年平朔矿区景观生态风险的时空异质性。结果表明:1990-2018年平朔矿区景观生态风险的空间分布呈集聚分布模式,Moran’s I指数处于0.53~0.68,Z得分远高于检验阈值1.96,风险的空间集聚效应明显。1990-2018年平朔矿区的景观生态风险等级以中低、中、中高水平为主,占全区总面积的70%~90%,低风险区域主要分布于井坪镇以及白堂乡与向阳堡乡的大片林地,耕地是中等风险的主要分布区域,高风险区域逐渐向矿界内的矿业核心区收缩。1990-2018年平朔矿区景观生态风险空间异质性中的随机变异均小于空间自相关变异,由空间自相关部分引起的空间异质性占据主导地位。研究表明,在0.50 km×0.50 km的研究尺度下,1990—2018年平朔矿区景观生态风险具有很强的时空异质性,时间上呈现先增加后降低的趋势,空间相关性显著,空间分异特征明显。     

景观生态学的核心:生态学系统的时空异质性

1　景观生态学与景观异质性景观生态学是研究在一个相当大的区域内 ,由许多不同生态系统所组成的整体 (即景观 )的空间结构、相互作用、协调功能以及动态变化的生态学新分支[1 ] 。它的出现促进了空间关系模型和理论、空间格局与动态的数据类型的获取以及经典生态学很少涉及的空间尺度检测等方面的发展[2 ] 。Ｒｉｓｓｅｒ等认为景观生态学研究就是异质性的研究[3] 。其实 ,“景观”本身就具有“变化的异质性整体”的含义[4] 。景观生态学集中关注于对生态系统空间关系的研究 ,它把景观视为空间上镶嵌出现和紧密联系的生态系统组合 ,景观可…     

苔草草丘恢复湿地的景观格局变化——以哈尔滨太阳岛为例

湿地景观变化是湿地生态学领域研究的重要内容。湿地景观要素在不同时间和空间的变化过程研究是揭示湿地演变规律,开展生态恢复实践的重要科学基础。以哈尔滨太阳岛苔草草丘恢复湿地为例,采用野外调查与3S技术相结合的方法,选取草丘面积、斑块形状特征、草丘数量及形态特征等指标,探究草丘湿地恢复过程中的景观变化,为开展湿地恢复提供了重要的科学依据。结果表明:经过8年的恢复,苔草草丘景观变化明显。草丘数量增多,丘墩高度、直径、植株高度、冠幅显著增加(P0.05);湿地恢复后,苔草群落向外扩展722 m~2,苔草草丘总面积达2222 m~2,扩展率为48.13%;在湿地微地貌和水文条件等因素的综合作用下,草丘群落扩展方向具有一定规律性,斑块边界和质心分别向西南方向扩展了29.91 m和迁移了5.9 m,扩展度和曲线边界比重不断增加,斑块形状和边界趋于复杂,景观空间异质性增强;利用根茎克隆繁殖结合水位调控可实现苔草草丘的快速恢复。     

Quantifying surface gradients with a 2-band Enhanced Vegetation Index (EVI2)

Quantification of spatial and temporal heterogeneity has been given much attention in order to link ecological patterns to processes. The patch mosaic model, as an operational paradigm, has led to major advances in the field of quantitative landscape ecology. However, it is more realistic to conceptualize landscapes based on continuous rather than discrete spatial heterogeneity. While a conceptual shift has been proposed to supplement the patch mosaic model, few studies use the surface gradient model as a context. This paper explores some comparatively less-utilized metrics to quantify surface gradients in a protected landscape in Central India. Since surface metrics would require continuous variables capable of representing landscape characteristics, this study also explores the utility of a 2-band Enhanced Vegetation Index (EVI2) as a gradient surface. Findings suggest EVI2 relates strongly with discrete land cover classes and thus has potential to describe landscape characteristics without incorporating error through subjectivity. Surface metrics used in this study show potential to be effectively used in landscape level studies. However, these metrics were not developed for landscape level studies and should be used with caution, especially when dealing with multi-scale patterns and processes. Nevertheless, with the rapidly emerging field of surface metrology more studies need to apply these tools to quantify surface gradients and test the robustness of such metrics.     

景观空间异质性及城市化关联——以江苏省沿江地区为例

空间异质性是揭示地理现象空间分异规律的重要标志.基于高分辨率卫星遥感影像数据,利用景观生态指数和统计学方法,构建景观空间异质性综合模型,定量测度了江苏省沿江地区景观空间异质性特征及城市化关联,并基于二者的相关性将研究区域划分为6个异质性梯度区,提出了应对城市化干扰的景观空间协调对策.结果表明:景观空间异质性综合模型是对景观斑块结构、形态、数量3个组分特征的反映,是揭示景观连通性、稳定性和破碎化的重要依据;景观空间异质性与3个城市化参数之间存在显著的正相关,城镇空间扩张模式和城镇人口的集聚强度对景观空间异质性影响较大;景观空间异质性梯度分异与区域开发强度、开发时序存在显著的耦合关系;同时,面对城市化的干扰,应该实施保护生态景观空间、减少建设空间与其它景观的接触概率和实施差别化的城市化战略等政策协调城市化发展与景观生态保护之间的矛盾.     

宏观生态学研究的特点与方法

宏观生态学是研究生态系统以上层次的生态学,研究对象为大尺度复杂系统,研究内容和方法都具有不同于传统生态学的明显特点。重视对空间异质性的研究,重视人类的生态作用,注意运用等级结构理论,其研究结果常常是非实验性和非稳定性的。遥感和地理信息系统是空间数据采集和管理、分析的主要手段,景观分析和景观模型是宏观生态研究的重要方法,定位观测试验的网络研究则是实现宏观整体研究的必由之路。     

Landscape-level toxicant exposure mediates infection impacts on wildlife populations

Anthropogenic landscape modification such as urbanization can expose wildlife to toxicants, with profound behavioural and health effects. Toxicant exposure can alter the local transmission of wildlife diseases by reducing survival or altering immune defence. However, predicting the impacts of pathogens on wildlife across their ranges is complicated by heterogeneity in toxicant exposure across the landscape, especially if toxicants alter wildlife movement from toxicant-contaminated to uncontaminated habitats. We developed a mechanistic model to explore how toxicant effects on host health and movement propensity influence range-wide pathogen transmission, and zoonotic exposure risk, as an increasing fraction of the landscape is toxicant-contaminated. When toxicant-contaminated habitat is scarce on the landscape, costs to movement and survival from toxicant exposure can trap infected animals in contaminated habitat and reduce landscape-level transmission. Increasing the proportion of contaminated habitat causes host population declines from combined effects of toxicants and infection. The onset of host declines precedes an increase in the density of infected hosts in contaminated habitat and thus may serve as an early warning of increasing potential for zoonotic spillover in urbanizing landscapes. These results highlight how sublethal effects of toxicants can determine pathogen impacts on wildlife populations that may not manifest until landscape contamination is widespread.     

矿区生态风险评价研究述评

作为世界上矿产资源最丰富的国家之一,我国的矿山开采活动在给经济发展注入强大拉动力的同时,也给矿区生态环境带来了巨大的生态风险。总结前人相关研究,在对比分析了矿区生态风险及其评价与区域生态风险评价异同的基础上,初步明晰矿区生态风险具有风险源的多样性、空间影响边界的模糊性、随空间距离的衰减性及时间累积的延续性等特性。目前矿区生态风险评价的矿区类型过多集中于金属矿区的重金属污染等单项风险,对综合生态风险评价的重视不充分,多基于景观格局、生态环境问题视角,结果多对斑块或生态系统风险评价进行拼接,欠缺基于空间异质性的整体综合;风险度量模型、指标体系法和空间分析法则是较为常用的矿区生态风险评价方法,但在模型模拟方面略显不足。基于现有研究进展,预期矿区独特性的体现、空间格局的关注、"3S"技术的综合应用、生态安全阈值的设定、不确定性表征、基于评价结果的风险规避等将有望成为未来研究的重点。     

景观生态学与退化生态系统恢复

退化生态系统的恢复是一项艰巨任务,它需要考虑到所要恢复的退化生态系统的结构,多样性和其动态的整体性和长期性。现在对于退化生态系统恢复研究已经要使生态学家们关注受损生态系统的理论和实际问题。退化生态系统恢复所面临的挑战是理解和利用生态演替理论来完成并加速恢复进程。恢复的主要目标是建立一个自维持的,由不同的群落或生态系统组成的能够满足不同需要如生物保护和粮食生产需要的景观。景观生态学关注于大的空间尺度的生态学问题。景观生态学研究方法可以为退化生态系统恢复实践提供指导。在解决退化生态系统的恢复问题时,景观生态学的方法在理论和实践上是有效的。景观生态学中的核心概念和其一般原理斑块形状、生态系统间相互作用、镶嵌系列等都同退化生态系统的恢复有着密切的关系。如恢复地点的选择和适当的恢复要素的空间配置。在评价退化生态系统的恢复是否取得成功,利用景观生态学也具有重要的意义。景观生态学理论如景观格局与景观异质性理论,干扰理论和尺度理论都能够指导退化生态系统的恢复实践。同样地,退化生态系统的恢复可以为景观生态学的研究提供非常恰当的实验场。寓景观生态学思想于退化生态系统恢复过程是一种新的有效途径。     

生态学系统的空间异质性

空间异质性是生态学系统的一个普遍牧场生,生态学家对它在生态学中的重要性已取得了比以往更深刻的认识。试图从空间异质性的含义,空间异质性与尺度和等级的关系,空间异质性的定量描述,空间异质性对生物和非生物过程的影响,以及空间异质性的动态等5个方面综述了有关空间异质性的生态学研究的新进展。     

川滇生态屏障区景观生态风险评价及影响因素

探究重点生态功能区景观生态风险时空演变特征,揭示人类活动对景观生态风险恶化的潜在影响,对防范和化解景观生态风险、促进区域可持续发展具有重要意义。以2000、2010、2020年土地覆被数据为基础,运用ArcGIS 10.8和Fragstats 4.2等软件,基于景观格局指数和脆弱度指数构建景观生态风险评价模型,借助空间分析方法,揭示川滇生态屏障区景观生态风险时空演变特征,采用地理探测器测度不同区域范围的自然和社会经济因素对景观生态风险的影响。结果表明: 2000—2020年间,研究区人造地表、水体、灌木地面积总体呈上升趋势,林地、耕地、草地、湿地、裸地、冰川永久积雪面积总体呈下降趋势,景观类型转移以林地、草地、耕地间转移为主,其中,耕地转人造地表最显著;景观生态风险平均值有所下降,景观生态风险等级分布与景观类型变化及转移特征较为一致;研究区整体上以低生态风险、较低生态风险和较高生态风险等级为主;景观生态风险的时空演化特征总体受高程、降水等自然因素影响,经济社会及区域可达性对局部风险恶化区的影响较为突出。     

A conceptual framework for the spatial analysis of landscape genetic data

Understanding how landscape heterogeneity constrains gene flow and the spread of adaptive genetic variation is important for biological conservation given current global change. However, the integration of population genetics, landscape ecology and spatial statistics remains an interdisciplinary challenge at the levels of concepts and methods. We present a conceptual framework to relate the spatial distribution of genetic variation to the processes of gene flow and adaptation as regulated by spatial heterogeneity of the environment, while explicitly considering the spatial and temporal dynamics of landscapes, organisms and their genes. When selecting the appropriate analytical methods, it is necessary to consider the effects of multiple processes and the nature of population genetic data. Our framework relates key landscape genetics questions to four levels of analysis: (i) node-based methods, which model the spatial distribution of alleles at sampling locations (nodes) from local site characteristics; these methods are suitable for modeling adaptive genetic variation while accounting for the presence of spatial autocorrelation. (ii) Link-based methods, which model the probability of gene flow between two patches (link) and relate neutral molecular marker data to landscape heterogeneity; these methods are suitable for modeling neutral genetic variation but are subject to inferential problems, which may be alleviated by reducing links based on a network model of the population. (iii) Neighborhood-based methods, which model the connectivity of a focal patch with all other patches in its local neighborhood; these methods provide a link to metapopulation theory and landscape connectivity modeling and may allow the integration of node- and link-based information, but applications in landscape genetics are still limited. (iv) Boundary-based methods, which delineate genetically homogeneous populations and infer the location of genetic boundaries; these methods are suitable for testing for barrier effects of landscape features in a hypothesis-testing framework. We conclude that the power to detect the effect of landscape heterogeneity on the spatial distribution of genetic variation can be increased by explicit consideration of underlying assumptions and choice of an appropriate analytical approach depending on the research question.     

基于景观结构的生态移民安置区生态风险评价——以宁夏红寺堡区为例

以宁夏自治区红寺堡区为例,以1995年、2000年、2005、2010年和2015年5期遥感影像为数据源,综合运用景观格局指数、生态风险指数、空间分析法以及地理探测器等多种研究方法,研究了移民安置区生态风险时空特征。结果表明:1995—2015年研究区景观格局发生了较大的变化,草地面积减少了2.97×10~4hm~2,耕地、林地、建设用地分别增加了1.90×10~4hm~2,0.42×10~4hm~2和0.43×10~4hm~2;在研究期间景观整体斑块数不断增加,其景观整体破碎度随之变大;研究区生态风险主要以较低风险和中风险为主,其中建设用地、沙地和未利用地生态风险值较高,在研究期间生态风险平均值由0.166降低至0.154,研究区生态风险值呈降低趋势。通过地理探测器诊断得出景观斑块数、景观破碎度、景观优势度、景观损失度、斑块密度等因素是安置区生态风险的主要影响因素。     

1975—2018年南四湖流域景观生态风险时空变化及其驱动因素研究

研究区域的景观生态风险变化趋势及其驱动因素,可以更加科学地保护和开发流域生态系统。以南四湖流域1975—2018年9期土地利用数据为基础,借助ArcGIS 10.2和Fragstats 4.2等软件计算景观生态指数,并构建景观生态风险评估模型,通过空间自相关性分析,探究南四湖流域自改革开放40年来生态风险的时空变化,并用地理探测器定量研究驱动因子的贡献量。研究结果表明:流域最大斑块指数不断减小,景观破碎化加剧,且与景观生态风险指数呈正相关;而平均分维数、香浓多样性和香浓均匀度与生态风险指数呈负相关。在空间上,生态风险指数具有较强集聚性,东部草地和林地区域主要是高值区,湖区北部以及西部耕地和建设用地则主要是低值区;总体上,研究区大部分为低风险和较低风险区,且生态风险平均值不断降低;地理探测器分析表明,海拔和人为干扰度因子贡献量在35%以上,对生态风险有显著的解释力。据此,以后应减少人类行为对南四湖流域生态系统的干预,降低流域的景观生态风险,实现经济、社会和生态的可持续发展。     

Continuum or discrete patch landscape models for savanna birds? Towards a pluralistic approach

Conceptualising landscapes as a mosaic of discrete habitat patches is fundamental to landscape ecology, metapopulation theory and conservation biology. An emerging question in ecology is: when is the discrete patch model more appropriate than alternative and conceptually appealing models such as the continuum model? There is limited empirical testing of the utility of alternative landscape models compared to the discrete patch model for a range of species. In this paper, we constructed three alternative sets of models for testing the effect of landscape structure on diversity and abundance of a suite of woodland birds in a savanna landscape of northern Australia: the null model (only site‐scale habitat variables, landscape context not important), the continuum model, and the discrete patch model. We utilised high‐spatial resolution satellite images to quantify spatial gradients in tree cover density (the continuum model), and to then aggregate the fine‐scale heterogeneity in tree cover into discrete patches of trees, with grass cover forming the “matrix” (the discrete patch‐model). We then evaluated the relative importance of the alternative models using generalised linear models and an information theoretic approach. We found that the importance of the models varied among species, with no single model dominant. Species that move between open grassy areas and woody shelter responded well to the continuum model, reflecting the importance of gradients in density of forage (grasses) and cover (trees), while the discrete model performed best for species that forage in all vegetation strata, and nest predominantly in dense woody vegetation. This finding supports a pluralistic approach, highlighting the need for adopting and testing more than one landscape model in savanna landscapes, and in other landscapes that do not have a well defined patch structure.     

Testing alternative models for the conservation of koalas in fragmented rural–urban landscapes

Abstract Predicting the various responses of different species to changes in landscape structure is a formidable challenge to landscape ecology. Based on expert knowledge and landscape ecological theory, we develop five competing a priori models for predicting the presence/absence of the Koala (Phascolarctos cinereus) in Noosa Shire, south‐east Queensland (Australia). A priori predictions were nested within three levels of ecological organization: in situ (site level) habitat (<1 ha), patch level (100 ha) and landscape level (100–1000 ha). To test the models, Koala surveys and habitat surveys (n = 245) were conducted across the habitat mosaic. After taking into account tree species preferences, the patch and landscape context, and the neighbourhood effect of adjacent present sites, we applied logistic regression and hierarchical partitioning analyses to rank the alternative models and the explanatory variables. The strongest support was for a multilevel model, with Koala presence best predicted by the proportion of the landscape occupied by high quality habitat, the neighbourhood effect, the mean nearest neighbour distance between forest patches, the density of forest patches and the density of sealed roads. When tested against independent data (n = 105) using a receiver operator characteristic curve, the multilevel model performed moderately well. The study is consistent with recent assertions that habitat loss is the major driver of population decline, however, landscape configuration and roads have an important effect that needs to be incorporated into Koala conservation strategies.