Comparison of two biophysical indicators under different landscape complexity

Ecological Footprint (EF) and Energy-Landscape Integrated Analysis (ELIA) estimate human societies' imprint on nature. Both methods aim to provide overviews regarding biophysical society-nature interactions. The purposes of this article are to compare how EF and ELIA conceptualize human-nature relationships, and what results they produce when applied to the same landscape scale, in order to consider how their methodological similarities and differences can account for Land Use and Cover Change (LUCC). This conceptual comparison acknowledges the 'ecocentric' perspective of EF adopted to relate end consumption baskets of human populations with the land biocapacities, and the 'social metabolism' perspective of ELIA to take into account biophysical transformations and spatial distribution of matter-energy flows in different land uses. The two methods were applied to a case study of 46 municipalities in the Qazvin Province (Iran). These municipalities were grouped according to the values of the two methods by cluster analysis and correlated with landscape heterogeneity. The correlation analysis demonstrates that EF and ELIA indicators only overlap when landscape structure is highly simplified. However, lower accuracy of EF compared to ELIA as an indicator of socioecological impacts of different types of agricultural practices is confirmed. Although EF remains a useful indicator of unequal appropriation of Earth's biocapacity, it does so by taking average patterns of food production and consumption as given. To distinguish environmentally friendly from degrading practices, more precise indicators at the landscape level such as ELIA are required for farmers, consumers and policymakers to choose more sustainable options in their decisions

Functional Effects of Parasites on Food Web Properties during the Spring Diatom Bloom in Lake Pavin: A Linear Inverse Modeling Analysis

This study is the first assessment of the quantitative impact of parasitic chytrids on a planktonic food web. We used a carbon-based food web model of Lake Pavin (Massif Central, France) to investigate the effects of chytrids during the spring diatom bloom by developing models with and without chytrids. Linear inverse modelling procedures were employed to estimate undetermined flows in the lake. The Monte Carlo Markov chain linear inverse modelling procedure provided estimates of the ranges of model-derived fluxes. Model results support recent theories on the probable impact of parasites on food web function. In the lake, during spring, when ‘inedible’ algae (unexploited by planktonic herbivores) were the dominant primary producers, the epidemic growth of chytrids significantly reduced the sedimentation loss of algal carbon to the detritus pool through the production of grazer-exploitable zoospores. We also review some theories about the potential influence of parasites on ecological network properties and argue that parasitism contributes to longer carbon path lengths, higher levels of activity and specialization, and lower recycling. Considering the “structural asymmetry” hypothesis as a stabilizing pattern, chytrids should contribute to the stability of aquatic food webs

Comparative Energy-Landscape Integrated Analysis (ELIA) of past and present agroecosystems in North America and Europe from the 1830s to the 2010s

Along the last century there has been an unprecedented growth in both global food production and related socioecological impacts. The objective of this paper is to analyse the effects of long-term metabolic patterns of agrarian systems on land use and cover changes (LUCC) (...

Investigating the Health of a Rice Field Ecosystem Using Thermodynamic Extremal Principles

This study investigates the dynamic behaviour of a rice field ecosystem and aims to define its integral features using the stability concept of an ecological goal function. This function is based on the extremal principles of thermodynamics, which assume that certain energetic processes of ecosystems—such as the rate of exergy destruction—are directed by the self-organizing informatics of the systems towards maxima or minima.  In our study, we exploit the availability of substantially long time-series data relating to a rice field ecosystem to gain an evocative understanding of its growth trajectory in light of the thermodynamic principles. We accomplished this by constructing a model based on the STELLA 9.0 software and calculating the extremal values of growth rates (storage) and those of exergy destruction and entropy creation. The results showed that the values of both maximum dissipation and maximum exergy progressed apace with that of maximum storage till the maturation of rice and became stable thereafter, whereas maximum residence time and maximum specific dissipation values initially decreased before their asymptotic rise. A similar pattern was also observed for the maximum specific exergy. However, the maximum power dissipation curve followed a highly fluctuated course before becoming stable on the maturation of rice

Research on the Structure Invulnerability and Development of the National Economic Complex Network

物质与非物质生产消费部门之间以及部门与国民大系统之间存在着相互制约、相互依赖的交互式经济技术复杂关系，形成国民经济复杂性系统。相互作用的局部机制存在于系统中，从而可以形成全局网络结构。新古典经济学一般均衡理论和魁奈经济表作为基础形成投入产出经济学可以描述产业投入产出关系。系统个体以及系统集体行为可以通过复杂性科学展开研究。本文从系统论角度出发， 以复杂性网络分析、国民经济大系统投入产出研究、热力学信息论以及生态上升性为理论基础，以国民经济关联网络结构为研究对象。改变传统研究数据平面性特征，将研究对象结构性立体化。从投入产出网络结构静态拓扑特征、产业部门结构抗毁特性到包含资源环境耗散系统的动态...There are interactive relationships between material and non-material production departments in the large national system forming the complexity of the national economy system. Industrial connections between various departments are relations of economic and technological interdependent and mutual influence. There is global network structure in complexity system of the national economy by the local...学位：经济学博士院系专业：经济学院_统计学学号：1542011015379

Agroecological Landscape Modelling as a Deliberative Tool, Learning from Social Metabolism Assessment of Historical Transitions to Industrial Agriculture for Future Sustainable Food System

[eng] The fundamental objective of this thesis is setting up a model to optimize the functioning of agricultural activity at the landscape level. It is a thesis with a strong methodological component. However, to base how the functioning of agrarian systems would have to improve their efficiency in the use of natural resources, as well as their organic logic, I base myself on the study of agrarian systems in historical perspective. Thus, in the first three chapters of this doctoral thesis I analyze the socio-metabolic transition from organic to industrial agriculture using the methodology of social metabolism and the analysis of material and energy flows (chapter 2) as well as incorporating the analysis in terms of landscape ecology (chapter 3) and food systems analysis (chapter 4). I apply it for a case study located in the Catalan pre-littoral Mediterranean (the historical region of Vallés), in three different historical moments: i) around 1860, in a context of viticultural specialization and in full development of agrarian capitalism; ii) in 1956, just at the time of the departure of the autarchic period in Spain and in a transition prior to the Green Revolution; iii) in 1999, after the Green Revolution and in a situation of livestock specialization, derived from the integration of local agriculture in the global regime. Once the keys to the functioning of the agrarian systems prior to the green revolution have been identified, I have laid the foundations for the second part of the doctoral thesis. In it I propose first (chapter 5) the theoretical development of an optimization model that allows us to analyze what would have been (or could be in the future) the most optimal functioning of the various assets of agroecosystems that allow to meet certain objectives social. In chapter 6 I apply this model in the case of Sentmenat (El Vallès) for 1860, to see what would have been, in a context of non-existence of inequality, the best way to have organized the territory in order to meet different objectives: minimize the amount of surface needed per family, minimize the amount of work required, or deepen the specialization by maximizing the amount of vineyard that existed in the territory and could be maintained in a sustainable manner. Finally, chapter 7 is dedicated to applying the model again but at a prospective level of future agroecological scenarios. This allows us to characterize the limits of agroecological landscape strategies, basically due to the prevailing condition of closing the nutrient cycles. In spite of this, if a rational use of the nutrient stocks of the soil were made, it would be possible to reach sustainable population densities of up to more than 150 people / km2 with a depletion horizon of the phosphorus stock of about 1000 years. In addition, we verified how the current diet strongly limits the sustainable population density (around 70 people / km2) due to the high consumption of animal products. Thus, following a Mediterranean diet, which allows a balance between the wills of the consumer and the capacity of the territory, would achieve levels of satisfaction of much higher needs. Lastly, the strategy of maximizing production instead of meeting local needs could allow an increase of up to 30% in the final product (in terms of metabolizable energy). With this, we consider that this new proposed methodology opens a new tool that facilitates these social debates, taking into account the complexity of the functioning of the agrarian systems and without trying to simplify them to purely technical decisions.[spa] El objetivo fundamental de esta tesis es la generación de un modelo de optimización del funcionamiento de la actividad agraria a nivel de paisaje. Se trata de una tesis con un fuerte componente metodológico. Sin embargo, para fundamentar cómo tendría que ser el funcionamiento de los sistemas agrarios para que mejoraran su eficiencia en el uso de los recursos naturales, así como su lógica orgánica, me baso en el estudio de los sistemas agrarios en perspectiva histórica. Así, en los tres primeros capítulos de esta tesis doctoral analizo la transición socio-metabólica de las agriculturas orgánicas a las industriales haciendo uso de la metodología del metabolismo social y el análisis de flujos de materiales y energía (capítulo 2) así como incorporando el análisis en términos de ecología del paisaje (capítulo 3) y de sistema alimentario (capítulo 4). Lo aplico para un caso de estudio situado en el pre-litoral mediterráneo catalán (la comarca histórica del Vallés), en tres momentos históricos distintos: cerca de 1860, en 1956 y 1999. Una vez identificadas las claves del funcionamiento de los sistemas agrarios previos a la revolución verde, he sentado las bases para la segunda parte de la tesis doctoral. En ella propongo en primer lugar (capítulo 5), el desarrollo teórico de un modelo de optimización que permite analizar cuál hubiera sido (o podría ser en un futuro) el funcionamiento más óptimo de los distintos bienes fondo de los agroecosistemas que permitan satisfacer determinados objetivos sociales. En primer lugar lo aplico como análisis contrafactual de las posibles configuraciones del territorio bajo un contexto de desigualdad en las agriculturas orgánicas avanzadas, para 1860 (capítulo 6). Posteriormente se aplica a nivel prospectivo de futuros escenarios agroecológicos (capítulo 7). Esto nos permite caracterizar los límites de las estrategias a nivel agroecológico de paisaje, básicamente debidos al condicionante imperante del cierre de ciclos de nutrientes. Con ello, consideramos que esta nueva metodología propuesta abre una nueva herramienta que facilite estos debates sociales, teniendo en cuenta la complejidad del funcionamiento de los sistemas agrarios y sin pretender simplificarlos a decisiones puramente técnicas

Spatial energetics:a thermodynamically-consistent methodology for modelling resource acquisition, distribution, and end-use networks in nature and society

Resource acquisition, distribution, and end-use (RADE) networks are ubiquitous in natural and human-engineered systems, connecting spatially-distributed points of supply and demand, to provide energy and material resources required by these systems for growth and maintenance. A clear understanding of the dynamics of these networks is crucial to protect those supported and impacted by them, but past modelling efforts are limited in their explicit consideration of spatial size and topology, which are necessary to the thermodynamically-realistic representation of the energetics of these networks. This thesis attempts to address these limitations by developing a spatially-explicit modelling framework for generalised energetic resource flows, as occurring in ecological and coupled socio-ecological systems. The methodology utilises equations from electrical engineering to operationalise the first and second laws of thermodynamics in flow calculations, and places these within an optimisation algorithm to replicate the selective pressure to maximise resource transfer and consumption and minimise energetic transport costs. The framework is applied to the nectar collection networks of A. mellifera as a proof-of-concept. The promising performance of the methodology in calculating the energetics of these networks in a flow-conserving manner, replicating attributes of foraging networks, and generating network structures consistent with those of known RADE networks, demonstrate the validity of the methodology, and suggests several potential avenues for future refinement and application

GENERALIZAÇÕES ECOLÓGICAS

In recent years, several studies about the issue of the existence and status of laws in ecology have been published. This paper is a review which intends to play the role of a critical study guide to the debates about ecological generalizations. A series of studies about generalizations in ecology are critically discussed, as well as some developments of the epistemological discussion about the status of biological laws in the last fifteen years. My position is that biology has generalizations with some degree of nomic necessity and explanatory and/or predictive power. No matter if they are called ‘laws' or not, they play an important role in the construction of biological knowledge and should be investigated in order to give room to a better understanding of their nature and characteristics. Biological generalizations have a restricted domain of application, and a sufficiently developed theoretical understanding is required in order to reach a general abstract scheme for establishing these domains. Therefore, the construction of ecological (and, generally speaking, biological) theories is the way to establish testable generalizations with explanatory and predictive power. Those are not properties that a statement can have in isolation, but only as a member of an integrated set of assertions or a theoretical network, in which each member helps delimiting the domain of application of every other member. This epistemological conception about the relationships and nature of general statements and theories in biology, and, in particular, ecology, has methodological implications, which are addressed in this study.Nos últimos anos, foram publicados vários trabalhos sobre a questão da existência e do estatuto das leis na ecologia. O presente artigo é uma revisão que pretende servir como um guia de estudo crítico dos debates sobre generalizações ecológicas. Uma série de trabalhos sobre generalizações na ecologia é discutida criticamente, bem como alguns desenvolvimentos da discussão epistemológica sobre o estatuto das leis biológicas dos últimos quinze anos. Minha posição é que a biologia apresenta generalizações com certo grau de necessidade nômica e poder explicativo e/ou preditivo. Sejam ou não chamadas de ‘leis', elas cumprem importante papel na construção do conhecimento biológico e devem ser investigadas, de modo que possamos compreender melhor sua natureza e suas características. As generalizações biológicas têm domínio de aplicação restrito e uma compreensão teórica suficientemente desenvolvida é necessária para que se alcance um esquema geral abstrato para o estabelecimento destes domínios. Assim, a construção de teorias ecológicas (e, em termos gerais, biológicas) é o caminho para estabelecer generalizações testáveis, com poder explicativo e preditivo. Estas não são propriedades que uma proposição pode ter isoladamente, mas apenas como membro de um conjunto integrado de proposições ou uma rede teórica, na qual cada membro ajuda a delimitar o domínio de aplicação de qualquer outro membro. Esta concepção epistemológica sobre as relações e a natureza de proposições e teorias gerais na biologia, e, em particular, na ecologia, tem implicações metodológicas, destacadas ao longo do artigo