The confusion between scale-defined levels and conventional levels of organization in ecology

Abstract. Conventional levels of organization in ecology can be hierarchically ordered, but there is not necessarily a time or space scale-dependent difference between the classes: cell, organism, population, community, ecosystem, landscape, biome and biosphere. The physical processes that ecological systems must obey are strictly scaled in time and space, but communities or ecosystems may be either large or small. Conventional levels of organization are not scale-dependent, but are criteria for telling foreground from background, or the object from its context. We erect a scheme that separates scale-ordered levels from the conventional levels of organization. By comparing landscapes, communities and ecosystems all at the same scale, we find that communities and ecosystems do not map onto places on the landscape. Rather, communities and ecosystems are wave interference patterns between processes and organisms interfering with and accomodating to each other, even though they occur at different scales on the landscape, and so have different periodicities in their waved behavior. Population members are usually commensurately scaled and so do not generally interact to give interference patterns. Populations are therefore tangible, oratleastcan be assigned a location at an instant in time.     

Ecological boundaries in the context of hierarchy theory

Ecological boundaries have been described as being multiscalar or hierarchical entities. However, the concept of the ecological boundary has not been explicitly examined in the context of hierarchy theory. We explore how ecological boundaries might be envisioned as constituents of scalar hierarchical systems. Boundaries may be represented by the surfaces of constituents or as constituents themselves. Where surfaces would correspond to abrupt transition zones, boundary systems might be quite varied depending on hierarchical context. We conclude that hierarchy theory is compatible with a functional vision of ecological boundaries where functions can be largely represented as the processing or filtering of ecological signals. Furthermore, we postulate that emergent ecological boundaries that arise on a new hierarchical level may contribute to the overconnectedness of mature ecosystems. Nevertheless, a thermodynamic approach to the emergence and development of boundary systems does indicate that in many situations, ecological boundaries would persist in time by contributing to the energy production of higher hierarchical levels.     

The Hierarchical Structure of Ecosystems: Connections to Evolution

Ecologic systems, which are involved mainly in the processing of energy and materials, are actually nested one inside another—they are simultaneously parts and wholes. This fundamental hierarchical organization is easy to detect in nature but has been undervalued by ecologists as a source of new insights about the structure and development of ecosystems and as a means of understanding the crucial connections between ecologic processes and large-scale evolutionary patterns. These ecologic systems include individual organisms bundled into local populations, populations as functional components of local communities or ecosystems, local systems making up the working parts of larger regional ecosystems, and so on, right up to the entire biosphere. Systems at any level of organization can be described and interpreted based on aspects of scale (size, duration, and “membership” in more inclusive entities), integration (all the vital connections both at a particular focal level and across levels of hierarchical organization), spatiotemporal continuity (the “life history” of each system), and boundaries (either membranes, skins, or some other kind of border criterion). Considering hierarchical organization as a general feature of ecologic systems could reinvigorate theoretical ecology, provide a realistic scaling framework for paleoecologic studies, and – most importantly – forge new and productive connections between ecology and evolutionary theory.     

昆虫生态学试验设计中时空转换的技巧

时空转换最初是研究植物群落演替的方法,目前作为一种理论推断在社会科学、地理信息和地质分析等领域应用,在昆虫生态学中的应用很少,本文介绍了空间换取时间与时间换取空间两种方法,能够巧妙地缩短很多昆虫生态学的试验时间,或增加研究范围内的样本数,在大尺度景观研究昆虫迁移、预测预报、栖境恢复等方面具有重要意义。这种时空转换的技巧在昆虫生态学的研究的有广阔的应用前景。     

3S技术在城市绿地生态研究中的应用

介绍了城市绿地生态研究中的遥感特点 ,并论述了 3S技术在城市绿地覆盖清查、绿地三维量估测、绿地生态质量监测、绿地景观格局及其动态分析、适宜度评价和城市绿地景观生态规划上的应用现状 ,提出了现存的问题 ,并对其未来发展的方向作了展望。     

Diadromy,history and ecology: a question of scale

The existence of diadromous migrations has significant implications for understanding a broad series of biogeographical and ecological questions and for doing so across a broad range of spatial and temporal scales. Understanding these implications is important for interpretation of patterns in historical and ecological biogeography as well as in community ecology and conservation. This article explores these implications. Guest editors: S. Dufour, E. Prévost, E. Rochard & P. Williot Fish and diadromy in Europe (ecology, management, conservation)     

Defining the abundance body-size constraint space: data from a real food web

Using density and body-size data for a well-documented food web, the Ythan estuary, Aberdeenshire, we show that the shape of the constraint space is broadly similar to that proposed by Brown, and the slope (regression coefficient) of the plot of the central tendency is not significantly different from global or community data sets. However, the steepness of the plot is very sensitive to the degree of taxonomic resolution of species entities, particularly those of small body-size, although the overall shape of the constraint space does not change. When more fully resolved, the regression slope differs markedly from those of most freshwater and terrestrial studies. In addition, the upper bound of the constraint space is, contrary to theoretical expectations, insensitive to gross changes in the system's productivity. The dramatic increase in productivity that has led to an increase in abundance of invertebrates in the Ythan does not visibly affect the upper bound of the constraint space. Our results show that the traditional approach to comparing systems by the regression slopes of central trends is probably meaningless unless data sets are resolved to a similar degree of taxonomic resolution, and that detecting productivity effects on the location of the upper bound will be difficult.     

基于景感生态学的城市生态空间服务提升研究——以北京市顺义区为例

景感生态学思想融合自然要素、物理感知、心理认知等方面,并服务于土地利用与建设。北京市在迈向建设国际一流的和谐宜居之都目标过程中,极为重视城市居民对城市生态空间的感知和互动,充分体现了将城市生态空间与人居环境质量和心理健康耦合分析的景感生态学的理念。从结合景感生态学中景感营造的思想和顺义区生态规划实践的角度出发,分析了顺义区生态空间景观格局和视觉空间格局。结果表明,顺义区的森林、草地、湿地等斑块相对比较破碎,中心城区的森林、绿地较少;顺义区具有中等以下绿视率的路段长度占比近60%,中等以上水平尤其是较高水平绿视率的路段较少,具有较大的通过景感营造提升生态服务的空间。进而以提升顺义区的城市生态空间服务为目标,总结出了生态空间景观格局优化、视觉空间格局优化、生态空间科学规划及管控、生态系统服务综合提升4个核心愿景,并基于这4个愿景提出了针对性的景感营造措施。     

区域生态学时代来临——第十八届中国生态学大会区域生态专题研讨会述评

在简要分析区域生态从松散研究向学科方向演进历程的基础上,介绍了第十八届中国生态学大会区域生态专题研讨会的主要内容和特点,认为该次研讨体现了理论、方法和应用的融合,国家需求与学术前沿的结合,区域特色鲜明,较以往在学术水平和国际视野上都有所提升。国际生态学也正在经历着研究范式的不断丰富和发展,区域生态学在这个转型发展的过程中发挥了重要推动作用。区域生态学的兴起,恰逢生态文明建设和可持续发展转型的重大机遇。学科未来发展中要抓住这一机遇,面向区域生态文明建设和可持续发展的现实需求,深化学科的理论与方法体系,形成宏观生态学与社会需求相联接的前沿和桥梁。     

Spatial hierarchical approach in community ecology: a way beyond high context-dependency and low predictability in local phenomena

Patterns and functioning of communities, which are determined by a set of processes operating at a large variety of spatial and temporal scales, exhibit quite high context-dependency and low predictability at the fine spatial scales at which recent studies have concentrated. More attention to broader scale and across-scale phenomena may be useful to search for general patterns and rules in communities. In this context, it is effective to incorporate hierarchical spatial scale explicitly into the experimental and sampling design of field studies, an approach referred to here as the spatial hierarchical approach, focusing on a particular assemblage in which biological interaction and species life history are well known. The spatial hierarchical approach can provide insight into the effects of scale in operating processes and answers to a number of important questions in community ecology such as: (1) detection of patterns and processes in spatiotemporal variability in communities, including how to explain the partitioning of pattern information of species diversity at a broad scale into finer scales, and the pattern of spatial variability of community properties at the finest spatial scale; (2) evaluation of changes in patterns observed in macroecology at finer scales; (3) testing of models explaining the coexistence of competing species; and (4) detection of latitudinal patterns in spatiotemporal variability in communities and their causal processes.     

Analyzing spatial variations in land use/cover distributions: A case study of Nanchang area,China

Quantification of spatial variation is important for analyzing and predicting the environmental and social impacts of land development. This paper presents a density-based framework to analyze spatial variations within land use/cover classes through a case study of the Nanchang area, China. By means of grid sampling, the categorical patches were represented by grid densities, and spatial indicators of class abundance, scale-area curve and neighborhood density were constructed to measure the spatial variables of area, distance and scale. The scale variations within each class were demonstrated by abundance indicators and were divided into three types with different similarity degrees, which were measured by coefficients of congruence. These variations roughly corresponded to the distribution patterns revealed by the scale-area indicators. The scaling behaviors of these patterns exhibited discontinuity and coherence, which were possibly affected by the change rates of some patch characteristics in the classes. The neighborhood density indicators showed that every class was more aggregated at short distances, while multimodal patterns fluctuating in nearly random distributions occurred at considerable distances. The degree of clumping correlated positively with the abundance of each class. The characteristics of distribution sizes, ranges and patch isolation in these classes left some imprints on the variations in aggregation intensity. These findings have implications for data integration, mechanism exploration and methodological framework, which are also needed for management practices.     

Effect of a mass of lead in the incubator space of growing cells

Mouse fibroblasts (3T3 line) growing in vitro in an incubator were subjected to inclusion in the incubator space of different masses and different arrangements of metallic lead. It was found that the mass of lead was positively correlated with death of a percentage of the 3T3 cells. Aside from mass, a second property of the lead, that of shape, was also found to be related to the percentage cell death. Progeny of 3T3 cells whose parents had been previously exposed to lead during their growth were found to have developed a resistance to its cytocidal effect on subsequent exposure. Such progeny cells showed no increase in cell death over the period of time which proved lethal to cells which had not had prior exposure to lead in their environment.     

WBE 模型及其在生态学中的应用：研究概述

介绍了WBE模型,综述了该模型在生态学中的应用进展。WBE模型,以及以该模型为基础的MTE模型,假设生物体为自相似分形网络结构,提出代谢速率和个体大小之间存在3/4指数关系,分别预测了从个体到生物圈多个尺度上的生物属性之间的异速生长关系,而且部分得到了验证。WBE模型的应用涵盖了个体组织生物量、年生长率,种群密度和生态系统单位面积产量、能量流动率等多个方面;即使在生物圈大尺度上,WBE模型也可用来预测试验中无法直接测量的特征变量的属性,如全球碳储量的估算等。至今,关于WBE和MTE模型仍然存在各种褒贬争论,讨论焦点主要集中于模型建立的前提假设以及权度指数的预测。今后的研究工作应规范试验技术和方法,考虑物种多样性和环境等因素的影响,提出符合各类生物的模型结构体系,使其具有更广泛的应用性和预测性。     

普氏野马繁殖群在组建和放归初期的争斗行为与社群等级建立

2007年5月下旬至6月下旬,针对新组群并放归于卡拉麦里有蹄类保护区第二放归点的普氏野马(Equus przewalskii)繁殖群,采用焦点动物取样法和全事件记录法,观测记录了组群和放归初期繁殖群内个体间的争斗行为(攻击行为和屈服行为),以优势指数法确定繁殖群内的个体等级序列。结果表明,新组群内个体的年龄与攻击行为发出次数不存在显著的相关性(r=0.60,t=1.62,rr0.05),攻击与屈服行为次数也无显著的相关性(r=0.56,t=1.41,rr0.05)。各个体之间从最初组群到野放争斗行为日趋减少,社群等级逐渐建立并趋于稳定。     

Partitioning the variation in a plot‐by‐species data matrix that is related to n sets of explanatory variables

Abstract. Variation partitioning by (partial) constrained ordination is a popular method for exploratory data analysis, but applications are mostly restricted to simple ecological questions only involving two or three sets of explanatory variables, such as climate and soil, this because of the rapid increase in complexity of calculations and results with an increasing number of explanatory variable sets. The existence is demonstrated of a unique algorithm for partitioning the variation in a set of response variables on n sets of explanatory variables; it is shown how the 2n– 1 non‐overlapping components of variation can be calculated. Methods for evaluation and presentation of variation partitioning results are reviewed, and a recursive algorithm is proposed for distributing the many small components of variation over simpler components. Several issues related to the use and usefulness of variation partitioning with n sets of explanatory variables are discussed with reference to a worked example.     

Generalizing Levins metapopulation model in explicit space: models of intermediate complexity

A recent study [Harding and McNamara, 2002. A unifying framework for metapopulation dynamics. Am. Nat. 160, 173-185] presented a unifying framework for the classic Levins metapopulation model by incorporating several realistic biological processes, such as the Allee effect, the Rescue effect and the Anti-rescue effect, via appropriate modifications of the two basic functions of colonization and extinction rates. Here we embed these model extensions on a spatially explicit framework. We consider population dynamics on a regular grid, each site of which represents a patch that is either occupied or empty, and with spatial coupling by neighborhood dispersal. While broad qualitative similarities exist between the spatially explicit models and their spatially implicit (mean-field) counterparts, there are also important differences that result from the details of local processes. Because of localized dispersal, spatial correlation develops among the dynamics of neighboring populations that decays with distance between patches. The extent of this correlation at equilibrium differs among the metapopulation types, depending on which processes prevail in the colonization and extinction dynamics. These differences among dynamical processes become manifest in the spatial pattern and distribution of “clusters” of occupied patches. Moreover, metapopulation dynamics along a smooth gradient of habitat availability show significant differences in the spatial pattern at the range limit. The relevance of these results to the dynamics of disease spread in metapopulations is discussed.     

Environmental diversity: on the best-possible use of surrogate data for assessing the relative biodiversity of sets of areas

The conservation goal of representation of biodiversity (in the broad sense of all species) in protected areas requires best-possible use of available surrogate information. One standard approach is based on indicator groups of taxa. A minimum set of areas having at least one representation of each indicator species is taken to be representative of other organisms. This same minimum-set approach is adapted to other attributes of biodiversity, for example, derived environmental clusters. A weakness of these approaches is that useful information is lost; for example, for environmental clusters, there is no distinction made either among or within clusters. A more powerful surrogate approach can use some expression of environmental and/or biotic pattern so that variation among areas is seen as part of a continuum rather than partitioned into arbitrary clusters/attributes. The challenge in using pattern effectively is to adopt a robust model for the relationship between pattern and the underlying units of biodiversity, i.e. species. An environmental space (a continuum or ordination pattern), combined with the standard ecological continuum model relating species to environmental space, has advantages over other patterns based on hierarchy or distance matrices. Because an environmental space can be estimated either directly (observed environmental data) or indirectly (data on indicator groups), the corresponding surrogate-measure of biodiversity, environmental diversity (ED) makes best-possible use of either kind of data. We conclude that the arbitrariness of the attribute approach can be replaced by a robust surrogate pattern approach that is flexible and avoids unwarranted assumptions.     

Synthesizing traditional biogeography with microbial ecology: the importance of dormancy

The discovery of biogeographical patterns among microbial communities has led to a focus on the empirical evaluation of the importance of dispersal limitation in microbial biota. As a result, the spatial distribution of microbial diversity has been increasingly studied while the synthesis of biogeographical theory with microbial ecology remains undeveloped. To make biogeographical theory relevant to microbial ecology, microbial traits that potentially affect the distribution of microbial diversity need to be considered. Given that many microorganisms in natural environments are in a state of dormancy and that dormancy is an important microbial fitness trait, I provide a first attempt to account for the effects of dormancy on microbial biogeography by treating dormancy as a fundamental biogeographical response. I discuss the effects of dormancy on the equilibrium theory of island biogeography and on the unified neutral theory of biodiversity and biogeography, and suggest how the equilibrium theory of island biogeography can produce predictions approaching those of the Baas‐Becking hypothesis (i.e. everything is everywhere, but the environment selects). In addition, I present a conceptual model of the unified neutral theory of biodiversity and biogeography, generalized to account for dormancy, from which a full model can be constructed for species with or without dormant life history stages.