Measuring ecological characteristics of environmental building performance: Suggestion of an information-network model and indices to quantify complexity,power, and sustainability of energetic organization

The authors present preliminary study in pursuance of developing a flow network-based methodology of building performance evaluation, as current efficiency-centered methods do not fully account for the complex building performance in which nature, economy, and humans are inseparably involved. Based on the principle of entropy, this study defines building as a thermodynamic system that networks useful resources―energy, material and information―through close interconnection with the global environment. Measures of information content in energy-flow networking and ecological performance indicators from Shannon’s information theory, Ulanowicz’s ascendency principle, and Odum’s maximum empower principle are discussed and integratively applied to developing a generic building performance evaluation model. For the holistic indication of building sustainability, this work attempts to reconcile Ulanowicz’s and Odum’s statements about ecosystem development and also integrates emergy (spelled with an “m”) and information metrics. Environmental behaviour of the building model was tested with simulation to validate consistency with system-level principles. Results reveal that network complexity corresponds to system power and resilience (L) and fitness (F) tend to peak at an intermediate level of efficiency. This finding demonstrates applicability of Odum’s maximum power principle to building study, suggesting that increasing complexity (and power) of emergy-flow networking be a fundamental characteristic of sustainable building performance.     

生态系统生态学研究的关键问题及趋势——从“整体论与还原论的争论”看

在生态学领域中,存在着生态系统整体论与还原论的争论。Tansley A.G.提出,生态系统是"准有机体"。Odum兄弟提出的"生态系统能量说"被广泛接受,但也受到质疑,称其为"还原论者的整体论"。基于对上述质疑的回应以及对生态系统整体论的追求,Patten B.C.等提出"生态网络理论",运用"网络‘环境子’分析"方法,试图从物理层面分析解决生物层面的"涌现性"问题。不过,这一理论也受到批判,认为其在探究符号化的现象对生态系统的动态影响时,陷入了还原论困境。Jrgensen S.E.等更进一步,提出"系统论"的生态系统生态学,试图从系统科学的角度研究生态系统的"物质-能量-信息-网络"系统。这一理论受到生态学界高度重视,但是也存在着在具体研究过程中如何平衡能量视角和生物地球化学视角的问题。由上述争论可见,生态系统生态学研究的趋势是从"物质实体"到"能量流动",再到"网络信息",最后到"开放系统"层层递进。目前面临的关键问题是:如何在更好地定义生态系统整体性的基础上,采取相应的能够体现生态系统整体性的方法,去获得更多、更好的生态系统整体性的认识。     

土壤微生物群落构建理论与时空演变特征

土壤微生物作为陆地生态系统的重要组成部分,直接或间接地参与几乎所有的土壤生态过程,在物质循环、能量转换以及污染物降解等过程中都发挥着重要作用。对土壤微生物时空演变规律及其形成机制的研究,不仅是微生物演变和进化的基础科学问题,也是预测微生物及其所介导的生态功能对环境条件变化响应、适应和反馈的理论依据。讨论了土壤微生物群落的定义、测度方法和指标,认为群落是联系动植物宏观生态学与微生物生态学的基础,群落构建机制是宏观和微观生态学都需要研究的核心科学问题;从生态学的群落构建理论出发,阐述了包括生态位理论/中性理论、过程理论和多样性-稳定性理论在土壤微生物时空演变研究中的应用,以及微生物群落在时间和空间上的分布特征及其尺度效应;确立了以微生物群落构建理论为基础、不同时空尺度下土壤微生物群落演变特征为主要内容的微生物演变研究的基本框架。     

Energy transfer and molecular switching. I. The nerve action potential

In previous papers (Barrett, 1977b, 1980), the concept of chemical paramemetric excitation was applied to a number of diverse chemical phenomena and contrasted with the concept of chemical resonance, which is a special case of parametric excitation. In the present paper, its status as the fundamental concept of energy transfer and molecular switching is indicated, providing a mechanically sound explanation of nerve excitation at a basic level.The mechanism addressed by the parametric excitation concept is intermediate between macroscopic models of membrane assymetry and molecular models. No assumptions are made concerning the related macroscopic processes, but a systematic approach to organizational aspects of the processes involved in energy transfer is proposed.The chemical analog of the Manley-Rowe relations, which are the power conservation relations for parametrically excited electrical networks, is also derived. The demonstration of such Manley-Rowe relations for chemical systems indicates, for the first time, an explanation for the directionality of flow of power, and thus designates a pumping role. The generalized Manley-Rowe relations translated into flow, reaction, as well as oscillatory system terms, are suggested to be a universal law. Non-linearity is due to the coupling of three systems—each separately describable by Onsager linear relations—by the generalized Manley-Rowe conditions relating flows/reactions/oscillations.All phenomena considered are treated in accordance with a principle of power transfer optimization (Odum & Pinkerton, 1955). Parametric excitation involves three-body interaction, with one system as energy donor, the pump, another as energy receiving, the idler, and a third as mediator of this energy flow, the signal. A conservation law is mandatory for flows/reactions/oscillations, ω_i so that ω_pump= ω_idler±ω_signal. The macroscopic structure, which sets up the conditions for this law to be in operation, may be of diverse kinds, e.g. membrane-bounded compartments, macromolecules capable of multiple conformations and bound cations, etc. All are non-linear.     

集合生态系统研究15年回顾与展望

集合生态系统(meta-ecosystem)由法国的Loreau教授等于2003年提出,是指"由跨生态系统边界的物质流、能量流和生物体流所连接起来的一系列生态系统的集合",是对只关注生物体(organism)迁移交换的集合种群(meta-population)和集合群落(meta-community)概念的外推,也是为了给生态系统空间异质性研究提供一个重要的分析路径,对研究和理解生态系统的结构、过程、功能和异质性具有重要意义。通过对相关文献的梳理分析,简述了集合生态系统研究的基本状况,分析了对集合生态系统概念的狭义和广义两种理解,指出了探讨集合生态系统结构的两个方向,构建了分析集合生态系统研究的六维整体框架,综述了研究集合生态系统的两类方法,探讨了经验化的集合生态系统(empirical meta-ecosystem)的3种空间结构和两种构建路径。将集合生态系统概念和理论引入流域复合生态系统(integrated watershed ecosystem)的分析,为流域生态学研究提供新的概念框架。     

Ecological subsystems via graph theory: the role of strongly connected components

In this paper we investigate ecological flow networks via graph theory in search of the real sequential chains through which energy passes from producers to consumers in complex food webs. We obtain such fundamental pathways by identifying strongly connected components (SCCs), subsystems that groups species that take part in cycling, and performing topological sorting on the acyclic graphs that are obtained. Topological sorting identifies preferential directions for energy to flow from sources to sinks, while recycling remains confined within each SCC. Resolving food web networks for SCC highlights the possibility that compartments can be found in ecosystems, but this does not seem a general rule. The four aquatic food webs described in detail show a rather clear subdivision between benthic and pelagic subcommunities, a result that is discussed in the light of other studies. Should further research confirm these results, new insight into the way ecosystems use energy will be provided, with implications on cycling, reciprocal dependency of variables and indirect effects.     

Food web models: a plea for groups

The concept of a group is ubiquitous in biology. It underlies classifications in evolution and ecology, including those used to describe phylogenetic levels, the habitat and functional roles of organisms in ecosystems. Surprisingly, this concept is not explicitly included in simple models for the structure of food webs, the ecological networks formed by consumer–resource interactions. We present here the simplest possible model based on groups, and show that it performs substantially better than current models at predicting the structure of large food webs. Our group-based model can be applied to different types of biological and non-biological networks, and for the first time merges in the same framework two important notions in network theory: that of compartments (sets of highly interacting nodes) and that of roles (sets of nodes that have similar interaction patterns). This model provides a basis to examine the significance of groups in biological networks and to develop more accurate models for ecological network structure. It is especially relevant at a time when a new generation of empirical data is providing increasingly large food webs.     

A thermodynamic perspective on food webs: quantifying entropy production within detrital-based ecosystems

Because ecosystems fit so nicely the framework of a "dissipative system", a better integration of thermodynamic and ecological perspectives could benefit the quantitative analysis of ecosystems. One obstacle is that traditional food web models are solely based upon the principles of mass and energy conservation, while the theory of non-equilibrium thermodynamics principally focuses on the concept of entropy. To properly cast classical food web models within a thermodynamic framework, one requires a proper quantification of the entropy production that accompanies resource processing of the food web. Here we present such a procedure, which emphasizes a rigorous definition of thermodynamic concepts (e.g. thermodynamic gradient, disequilibrium distance, entropy production, physical environment) and their correct translation into ecological terms. Our analysis provides a generic way to assess the thermodynamic operation of a food web: all information on resource processing is condensed into a single resource processing constant. By varying this constant, one can investigate the range of possible food web behavior within a given fixed physical environment. To illustrate the concepts and methods, we apply our analysis to a very simple example ecosystem: the detrital-based food web of marine sediments. We examine whether entropy production maximization has any ecological relevance in terms of food web functioning.     

The dark side of the “redundancy hypothesis” and ecosystem assessment

Intricacy of biotic interactions (predator-prey relationship, strength of food web links and other type of intra- and inter-specific relationships), as well as shifts in species functions in ecosystems, could affect the accuracy of predictions derived from the theory of redundancy of species, when applied to ecosystems assessment.This opinion paper is based on three main considerations: 1) some fundamental differences between ecological and engineering definition of “redundancy”, underlying the main concerns related to the use frameworks derived from economical or engineering disciplines, as the ecosystems services paradigm; 2) presence of empirical obstacles to establish whether two different species are fully or partially redundant. When species redundancy in a particular community is estimated using a matrix with species-specific functional traits, often forgetting potential biotic interactions not directly related to the trophic chains or neglecting the variability in strengths of the links connecting these species; and 3) recent evidence offered by studies that shed doubts on the validity of the ecological redundancy hypothesis.Finally, we claim that more attention must to be paid to intrinsic ecological aspects of ecosystem components (per se values rather than derived values), and a precautionary principle is necessary for decisions related to the assessment of ecosystems.     

Macroecology: the organizing forces

The fundamental problem in ecology is the relationship between organisms and the physical world. This question is approached through the study of ecosystems as wholes. Pristine, autonomous Arctic lakes provide an invaluable starting point for such investigations. Studies on these lakes, initiated in 1958, indicate that the dominant fish populations assume a recognizable and repeatable structure, which if not disturbed by external forces, is maintained indefinitely. The observable characteristics are high biomass, large individual size, great age, uniformity of individuals despite great variation in age, and relatively few juveniles. This configuration expresses a state of least specific energy dissipation or least specific entropy production and may be regarded as a standing wave in the energy flow. Similar characteristics were found in the dominant species in a wide range of ecosystems worldwide. A state of least dissipation develops when two energy transport processes interfere with each other in the vicinity of thermodynamic equilibrium. Thus it is postulated that living organisms originated through the agonistic interaction between two energy transport processes within materials, initially occurring in an environment close to thermodynamic equilibrium. These two processes, fundamental to energy transfer, are recognized as the principle of least action and its diametrical opposite, the principle of most action. Each force dominates system behavior in a different time frame: most action in the short-term (ecological time) and least action over the long-term (evolutionary time). Interaction between the countervailing forces provides an understanding of a wide range of emergent ecological generalities such as succession, r- and K-selection, the stability and diversity of ecosystems, and the directionality of evolutionary change.     

Competition theory,evolution, and the concept of an ecological niche

This article examines some of the main tenets of competition theory in light of the theory of evolution and the concept of an ecological niche. The principle of competitive exclusion and the related assumption that communities exist at competitive equilibrium - fundamental parts of many competition theories and models - may be violated if non-equilibrium conditions exist in natural communities or are incorporated into competition models. Furthermore, these two basic tenets of competition theory are not compatible with the theory of evolution. Variation in ecologically significant environmental factors and non-equilibrium in population numbers should occur in most natural communities, and such changes have important effects on community relations, niche overlap, and the evolution of ecosystems. Ecologists should view competition as a process occurring within a complexdynamic system, and should be wary of theoretical positions built upon simple laboratory experiments or simplistic mathematical models.In considering the relationship between niche overlap and competition, niche overlap should not be taken as a sufficient condition for competition; many factors may prevent or diminish competition between populations with similar resource utilization patterns. The typically opposing forces of intraspecific and interspecific competition need to be simultaneously considered, for it is the balance between them that in large part determines niche boundaries.     

The fundamental processes in ecology: a thought experiment on extraterrestrial biospheres

Ecological science is often organised as a hierarchical series of entities: genes, individuals, populations, species, communities, ecosystems and biosphere. Here, I consider an alternative process‐based approach to ecology, and analyse the nature of the fundamental processes in ecology. These fundamental processes are discussed in the context of the following question:‘for any planet with carbon‐based life, which persists over geological time scales, what are the minimum set of ecological processes that must be present?‘I suggest that the following processes would be present on any such planet: energy flow, multiple guilds, ecological tradeo ffs leading to within‐guild biodiversity, ecological hypercycles, merging of organismal and ecological physiology, carbon sequestration and possibly photosynthesis. Nutrient cycling is described as an emergent property of these fundamental processes. I discuss reasons why a biosphere based on a single species with no nutrient cycling is very unlikely to exist. I also describe the concept of ‘Gaian effect’. This suggests that some processes will always tend to extend the lifespan of a biosphere in which they develop (positive Gaian effect) while others could either increase or decrease (negative Gaian effect) such a lifespan. These ideas are discussed in the context of astrobiology, ecosystem services, conservation biology and Gaia theory.     

Envisioning ecological engineering education: An international survey of the educational and professional community

Nearly half a century ago, H.T. Odum envisioned a sustainable approach to systems design where human intervention would be supplementary to nature. He referred to this concept as ecological engineering and suggested that practitioners should receive an education beyond the rigors of engineering. To understand natural processes needed to design, develop, and restore natural systems successfully, Odum suggested ecological engineers should have an expanded knowledge of environmental systems and ecology. Furthermore, he recommended broadening educational exposure to social science and liberal arts. The field of ecological engineering has blossomed in the years since Odum expressed his vision, but universities have not adopted his suggested curriculum, and undergraduate engineering students have generally seen a reduction in social science and liberal arts courses. This paper compares Odum's vision with the surveyed visions of an international group of ecological engineers, who assessed the value and characteristics of an ecological engineering undergraduate education. The respondents’ perspectives vary with their location, education, and profession; however, most participants in this survey share Odum's vision, and are dissatisfied with existing curricula. Participants outside of the United States were more confident that something approaching Odum's vision for a program in ecological engineering could be delivered at the undergraduate level.     

The maximum empower principle: An invisible hand controlling the self-organizing development of forest plantations in south China

Derived from the maximum power principle (MPP), the maximum empower principle (MePP) is considered as the foundation of emergy theory and evaluation methods. However, it has often encountered some doubts since proposed, because of lacking sufficient empirical evidence. To test the validity of the MePP in the self-organization of forest ecosystems, this paper applied a process-based ecosystem model (Biome-BGC) to simulate the dynamics of biomass, litter and soil organic matter (SOM) of three forest plantations in south China during 1985–2007, and attempted to replicate their self-organizing processes. The simulated results and input flows were transformed to emergy as a common basis and, from the viewpoint of emergy synthesis, the dynamics of the production efficiency and empower of the three forest ecosystems were revealed along with their self-organizing developments over time. The results showed that three forest plantations had similar dynamic change patterns of emergy efficiency and empower, but the production efficiencies of them were not always consistent with their empower performances. The production efficiency firstly increased rapidly to maximums, and then decreased to optimal moderate values. However, the empower came to the maximums after the efficiency peaked and then fluctuated up and down, dependent on weather. These results implied that, a forest ecosystem in its self-organizing process tends toward maximum empower at optimal efficiency. Behind the maximum empower of the forest ecosystem is the desynchrony development of different components, e.g., biomass, litter and SOM; leaf, stem and root; biomass and biodiversity. As a whole, the MePP functions like an invisible hand controlling the general self-organizing development of forest ecosystems and pointing out the direction of their development.     

一种城市生态系统现状评价方法及其应用

生态城市建设是未来城市发展的最终趋势。从结构、功能、活动、发展演化规律等方面来看,城市生态系统都可以被看作一个动态变化的系统。将可持续发展理论引入到城市生态系统现状评价中,提出和解释了城市生态系统可持续发展概念;从可持续发展的角度,评价城市生态系统的现状,建立城市生态系统可持续发展评价指标体系。在此基础上,利用集对分析方法,将评价城市生态系统可持续发展水平的多个指标系统合成一个与最优评价集的相对贴近度,用来描述城市生态系统可持续发展水平,并将该方法应用于兰州市城市生态系统现状评价。结果表明,在2004—2010年间,兰州市城市生态系统可持续发展水平呈现折线型关系,而且有明显的陡降现象。具体变化趋势是从2004年的0.5081平缓上升到2005年的0.5581、然后陡降到2006年的0.4073、接着平缓上升直到2009年的0.5010、最后平缓下降到2010年的0.4706。尽管不同时期城市生态系统可持续发展水平有所变化,但是总体来说,一直处在基本可持续发展的水平,协调程度一般;该评价方法能够很好的反映城市生态系统的发展现状,为建设生态城市提供科学依据。     

Habitat coupling in lake ecosystems

Lakes are complex ecosystems composed of distinct habitats coupled by biological, physical and chemical processes. While the ecological and evolutionary characteristics of aquatic organisms reflect habitat coupling in lakes, aquatic ecology has largely studied pelagic, benthic and riparian habitats in isolation from each other. Here, we summarize several ecological and evolutionary patterns that highlight the importance of habitat coupling and discuss their implications for understanding ecosystem processes in lakes. We pay special attention to fishes because they play particularly important roles as habitat couplers as a result of their high mobility and flexible foraging tactics that lead to inter-habitat omnivory. Habitat coupling has important consequences for nutrient cycling, predator-prey interactions, and food web structure and stability. For example, nutrient excretion by benthivorous consumers can account for a substantial fraction of inputs to pelagic nutrient cycles. Benthic resources also subsidize carnivore populations that have important predatory effects on plankton communities. These benthic subsidies stabilize population dynamics of pelagic carnivores and intensify the strength of their interactions with planktonic food webs. Furthermore, anthropogenic disturbances such as eutrophication, habitat modification, and exotic species introductions may severely alter habitat connections and, therefore, the fundamental flows of nutrients and energy in lake ecosystems.     

Evaluating the relationship between natural resource management and agriculture using embodied energy and eco-exergy analyses: A comparative study of nine countries

By shifting from animate labor to ever-increasing fossil fuel and other supplement energy subsidies, energy use in human food supply systems continues to increase. As agriculture is the fundamental manner in which humans interact with the environment, it is especially important to understand the relationships between humans, energy, and food. Many researchers evaluate the material and energy resources involved in the food production chain. Energy return on energy investment (EROI) analyses have been particularly useful in assessing the quantity of energy dissipated versus the energy eventually acquired, thus helping to evaluate the overall efficiency of human food systems (i.e., energy invested versus dietary Calories harvested). A complimentary measure, eco-exergy, has been used to evaluate the quality of energies dissipated and generated in ecosystems. To deepen our insight into the dynamic between humans and their food system, we combine these two measures for a food production analysis. Focusing on meat production, adjusted EROI and eco-exergy ratios are used to evaluate both the quantity and quality of energy accumulated and dissipated in nine country's agricultural processes. Each country's food production indicators are then compared with more established methods of sustainability measurement including ecological footprint and biocapacity. The results reveal a significant, highly correlated relationship between these food production indicators and each country's ecological footprint (resources being consumed) while also showing no correlation to their respective biocapacity (resources actually available), thus quantifying a food production disconnect from the local ecosystem. Using these new metrics, we evaluate which changes in each country's food system could result in more environmentally balanced practices, and also how these changes can be realized.     

Pattern, process and prediction in aquatic ecology. A limnological view of some general ecological problems

1. New scientific concepts such as models of chaos, complex dynamics and non-linear interactions have the potential to contribute to an improved understanding of ecological patterns and processes. This paper discusses some of the known dynamics of phytoplankton, pelagic food chains and nutrient cycles in the light of some of these new concepts. The paper brings these new conceptual models together with data from a wide range of sources in an attempt to produce a synthesis of system behaviour which allows us to understand why some things are inherently more predictable than others. In particular it looks at the limnological management tools of empirical biomass models and biomanipulation and at the need for prediction of species composition. 2. The structures observed in ecosystems (nutrient pools, sizes, species, temporal/spatial patterns) show properties at a spectrum of scales, as do the processes (fluxes, grazing, competition). Both respond to a spectrum of external perturbations that may be climatologically or anthropogenically induced. Empirical biomass models work because of the annual averaging of pattern and process and because of some inherent properties of the functioning of pelagic ecosystems. Many aspects of ecosystem pattern and process vary in a regular way with trophic state. Examination of empirical data sets can lead to an improved understanding of system behaviour if questions are asked about why things happen the way they do. 3. Feedbacks between pattern, process and periodicity are seen to be an inherent property of the system. Understanding the fundamental dynamics of non-linear interactions in ecosystems may make it possible to exploit the external spectrum of environmental perturbations and to control system function. For example, by imposing external physical perturbations on pelagic systems it may be possible to manipulate the species composition of the phytoplankton community. Because of the complexity of possible interactions both ‘horizontally’ between species and ‘vertically’ within the food chain, any prediction of species composition will necessarily be probabilistic.     

整体大于部分之和: 生态自组织斑图及其涌现属性

近30年来, 自组织理论已经发展成为解释生态系统呈现规则空间格局的有效理论。伴随着生态系统自发有序空间格局的生成, 自组织过程产生一系列的涌现属性, 这些特征对生态系统功能至关重要。在此, 我们将介绍这一正蓬勃发展的研究领域的主要理论进展。首先, 叙述了自组织这一概念的发展历程与定义, 详细阐述了自组织理论的两个经典理论框架: 图灵原理与相分离原理。然后, 根据几个典型的生态自组织研究案例, 描述了图灵原理与相分离原理在不同生态系统中的具体数学模型表达形式。接着, 分别阐述了图灵原理的涌现属性对生态系统功能以及相分离原理的涌现属性对细胞功能的作用。最后, 从多尺度自组织斑图、瞬态斑图和生物个体行为自组织3个方面对未来生态自组织理论发展方向进行了探讨。自组织研究在生态学与生物学研究中方兴未艾, 希望更多的学者在未来关注与参与该领域的发展。