Some Ecological Concepts and Their Implications ror Settlement Archaeology

Abstract

In the field of archaeology there has been an increasing concern for the standardization of terminology, units of measurement, and theoretical concepts. At the same time there has been a tremendous influx of new ideas, challenges to established concepts and theories, and a rethinking of the place of archaeology in the social sciences. Much of this re-evaluation has come about as a result of new insights into the nature of human society and, perhaps more importantly, a general opening up of the field in the sense that ideas, theories, and techniques developed in the social, biological, physical, and mathematical sciences are being introduced and tested for their application in the solution of anthropological and archaeological questions. One area which has become increasingly important as a source of concepts and theory is the field of biological ecology. This discussion considers two of these ecological concepts (seasonality, econiche) and proposes a sequence of socio-ecological units (individual, group, population, society, eco-community, eco-system) which it is believed are useful in the study of prehistoric social and settlement systems.     

Conceptual problems and scale limitations of defining ecological communities: a critique of the CI concept (Community of Individuals)

Recently, Looijen & van Andel (1999) proposed a new definition of an ecological community by using two criteria: (1) restricting membership by taxonomic relatedness, and (2) defining boundaries by the intersection of the area of population range boundaries. I analyze the implications of their definition and explore the limitations of the approach. Overall, I show this definition to be highly scale-limited, to not encompass many ecological concepts developed for the community level, and to have hidden assumptions that are not met in natural systems. An alternative model of the ecological community is proposed as a contrast, a model based on the community of an individual, in which individuals and interactions are used to develop the larger entity of an ecological community. This alternative model illustrates that the principal problems Looijen & van Andel (1999) discussed about previous community concepts with respect to application to vegetation classification are not ‘problems’ but are characteristics of ecological communities. Any definition of an ecological community must be able to incorporate these characteristics as well as current ecological concepts used at the community level.     

Ecological complexity for unifying ecological theory across scales: A field ecologist's perspective

The evening session in ecological complexity at the last Joint Meeting of the International Association for Ecology (INTECOL) and the Ecological Society of America (ESA) held in Montreal was an occasion to evaluate the pertinence and upcoming challenges of the complex systems approach (CSA) applied to ecology. Through concepts such as the interaction topology among biological objects, the phenotypic integration of individual traits, the meaning of biological objects and complexity measures in space and time, the management of human dominated ecosystems, and non-equilibrium thermodynamics as a paradigm for the development of ecosystems, the panel members covered some of the most active areas of research in ecological complexity. However, for many ecologists, and particularly field ecologists, a comprehensive framework clearly emphasizing how and why the CSA provides a unique corpus for studying ecosystem functions is missing. The purpose of this article is thus to provide an overview of the different themes visited during the evening session and to emphasize the distinctiveness of the CSA as an alternative to contemporary ecological issues. Examples from functional ecology and food webs are given to support the discussion.     

Application of ecological engineering principles in agriculture

To what extent modern industrialized agriculture violates the principles of ecological engineering and which changes agriculture needs to make to be consistent with these principles are discussed. The 12 ecological principles presented are used as the starting point for this discussion. For each principle it is discussed how the agriculture of today violates these principles and how relatively small changes could make the agriculture more according to ecological engineering concepts.     

Biological Films

The recording of epiphyte growth and diversity on tree trunks provides a simple field exercise for students of varying age and ability levels, and has potential for analysis, discussion, and extension work relevant to a wide range of biological and ecological concepts     

区域资源环境承载力科学概念及其生态学基础的讨论

资源环境承载力是生态学领域的一个重要概念,其理论和实践研究已成为衡量区域可持续发展的重要依据.但是有关生态学基础与资源环境承载力的科学联系仍未明确,其中有哪些生态学理论对资源环境承载力的发展起到了支撑作用还没被厘清,这使得资源环境承载力的科学概念十分模糊.本文在讨论资源环境、生态系统承载力科学概念及其发展的基础上,系统...     

Model-checking ecological state-transition graphs

Model-checking is a methodology developed in computer science to automatically assess the dynamics of discrete systems, by checking if a system modelled as a state-transition graph satisfies a dynamical property written as a temporal logic formula. The dynamics of ecosystems have been drawn as state-transition graphs for more than a century, ranging from state-and-transition models to assembly graphs. Model-checking can provide insights into both empirical data and theoretical models, as long as they sum up into state-transition graphs. While model-checking proved to be a valuable tool in systems biology, it remains largely underused in ecology apart from precursory applications.This article proposes to address this situation, through an inventory of existing ecological STGs and an accessible presentation of the model-checking methodology. This overview is illustrated by the application of model-checking to assess the dynamics of a vegetation pathways model. We select management scenarios by model-checking Computation Tree Logic formulas representing management goals and built from a proposed catalogue of patterns. In discussion, we sketch bridges between existing studies in ecology and available model-checking frameworks. In addition to the automated analysis of ecological state-transition graphs, we believe that defining ecological concepts with temporal logics could help clarify and compare them.     

Conceptualizing communities as natural entities: a philosophical argument with basic and applied implications

Recent work has suggested that conservation efforts such as restoration ecology and invasive species eradication are largely value-driven pursuits. Concurrently, changes to global climate are forcing ecologists to consider if and how collections of species will migrate, and whether or not we should be assisting such movements. Herein, we propose a philosophical framework which addresses these issues by utilizing ecological and evolutionary interrelationships to delineate individual ecological communities. Specifically, our Evolutionary Community Concept (ECC) recognizes unique collections of species that interact and have co-evolved in a given geographic area. We argue this concept has implications for a number of contemporary global conservation issues. Specifically, our framework allows us to establish a biological and science-driven context for making decisions regarding the restoration of systems and the removal of exotic species. The ECC also has implications for how we view shifts in species assemblages due to climate change and it advances our understanding of various ecological concepts, such as resilience.     

Evolutionary Phycology: Toward a Macroalgal Species Conceptual Framework

Species concepts formalize evolutionary and ecological processes, but often conflict with one another when considering the mechanisms that ultimately lead to species delimitation. Evolutionary biologists are, however, recognizing that the conceptualization of a species is separate and distinct from the delimitation of species. Indeed, if species are generally defined as separately evolving metapopulation lineages, then characteristics, such as reproductive isolation or monophyly, can be used as evidence of lineage separation and no longer conflict with the conceptualization of a species. However, little of this discussion has addressed the formalization of this evolutionary conceptual framework for macroalgal species. This may be due to the complexity and variation found in macroalgal life cycles. While macroalgal mating system variation and patterns of hybridization and introgression have been identified, complex algal life cycles generate unique eco-evolutionary consequences. Moreover, the discovery of frequent macroalgal cryptic speciation has not been accompanied by the study of the evolutionary ecology of those lineages, and, thus, an understanding of the mechanisms underlying such rampant speciation remain elusive. In this perspective, we aim to further the discussion and interest in species concepts and speciation processes in macroalgae. We propose a conceptual framework to enable phycological researchers and students alike to portray these processes in a manner consistent with dialogue at the forefront of evolutionary biology. We define a macroalgal species as an independently evolving metapopulation lineage, whereby we can test for reproductive isolation or the occupation of distinct adaptive zones, among other mechanisms, as secondary lines of supporting evidence.     

动物个性研究进展

"个性"是指不同时空条件下动物种群个体间行为的稳定差异。大量的理论和实验性研究表明,个性差异在动物界普遍存在,其是种群多度和分布、物种共存及群落构建的重要驱动因子。介绍了动物个性的概念、分类及衡量指标,将前人测量个性类型的方法加以总结;随后介绍了动物个性的生态学意义,尤其是个性对动物生活史策略、种群分布与多度、群落结构和动态、生态系统功能和过程以及疾病与信息传播等的影响。在此基础上,进一步分析了在人类活动增加等全球变化背景下,动物个性如何调控动物个体行为、种群和群落动态对这些环境变化的响应。阐述了动物个性的形成与维持机制,并对未来的研究方向进行了展望。     

Causes and consequences of ontogenetic dietary shifts: a global synthesis using fish models

Ontogenetic dietary shifts (ODSs), the changes in diet utilisation occurring over the life span of an individual consumer, are widespread in the animal kingdom. Understanding ODSs provides fundamental insights into the biological and ecological processes that function at the individual, population and community levels, and is critical for the development and testing of hypotheses around key concepts in trophic theory on model organisms. Here, we synthesise historic and contemporary research on ODSs in fishes, and identify where further research is required. Numerous biotic and abiotic factors can directly or indirectly influence ODSs, but the most influential of these may vary spatially, temporally and interspecifically. Within the constraints imposed by prey availability, we identified competition and predation risk as the major drivers of ODSs in fishes. These drivers do not directly affect the trophic ontogeny of fishes, but may have an indirect effect on diet trajectories through ontogenetic changes in habitat use and concomitant changes in prey availability. The synthesis provides compelling evidence that ODSs can have profound ecological consequences for fish by, for example, enhancing individual growth and lifetime reproductive output or reducing the risk of mortality. ODSs may also influence food‐web dynamics and facilitate the coexistence of sympatric species through resource partitioning, but we currently lack a holistic understanding of the consequences of ODSs for population, community and ecosystem processes and functioning. Studies attempting to address these knowledge gaps have largely focused on theoretical approaches, but empirical research under natural conditions, including phylogenetic and evolutionary considerations, is required to test the concepts. Research focusing on inter‐individual variation in ontogenetic trajectories has also been limited, with the complex relationships between individual behaviour and environmental heterogeneity representing a particularly promising area for future research.     

Modelling Environmental Responses of Plant Associations: A Review of Some Critical Concepts in Vegetation Study

The definition of vegetation types at different hierarchical levels, both to study the vegetation processes and for practical cartographic representation, is still considered a critical issue in many circles of plant ecologists. The problems are mainly related to the misleading idea that classification of the vegetation system, as developed by European phytosociologists during the last century within the discipline called syntaxonomy, would imply the assumption of the organismic concept of the plant community. After a short discussion on the role of Braun-Blanquet approach in plant ecology and in landscape ecology, the methods to detect multispecies responses along environmental gradients are briefly reviewed. In the main part of this article, we intend to stress that concepts considered critical, such as plant association and its ecological niche, are just operational tools that have nothing to do with the individualistic or organismic interpretation of plant communities in vegetation studies. Important to our views on vegetation, we believe that plant associations as well as the higher syntaxa can be regarded as fuzzy sets in an operational context for describing vegetation along ecological gradients in synthetic ways and can further the understanding of vegetation variation.     

Movement‐mediated community assembly and coexistence

Organismal movement is ubiquitous and facilitates important ecological mechanisms that drive community and metacommunity composition and hence biodiversity. In most existing ecological theories and models in biodiversity research, movement is represented simplistically, ignoring the behavioural basis of movement and consequently the variation in behaviour at species and individual levels. However, as human endeavours modify climate and land use, the behavioural processes of organisms in response to these changes, including movement, become critical to understanding the resulting biodiversity loss. Here, we draw together research from different subdisciplines in ecology to understand the impact of individual‐level movement processes on community‐level patterns in species composition and coexistence. We join the movement ecology framework with the key concepts from metacommunity theory, community assembly and modern coexistence theory using the idea of micro–macro links, where various aspects of emergent movement behaviour scale up to local and regional patterns in species mobility and mobile‐link‐generated patterns in abiotic and biotic environmental conditions. These in turn influence both individual movement and, at ecological timescales, mechanisms such as dispersal limitation, environmental filtering, and niche partitioning. We conclude by highlighting challenges to and promising future avenues for data generation, data analysis and complementary modelling approaches and provide a brief outlook on how a new behaviour‐based view on movement becomes important in understanding the responses of communities under ongoing environmental change.     

Ecological units: definitions and application

Concepts of ecological units, such as population, community, and ecosystem, are at the basis of ecological theory and research and have increasingly become the focus of conservation strategies. Concepts of these units still suffer from inconsistencies and confusions over terminology. The different concepts are treated here together as a common "conceptual cluster," with similar ecological functions (roles) and similar problems in their definition and use. An analysis of the multitude of existing terms and concepts that have been developed for these units reveals that they differ with respect to at least four basic criteria: (i) the questions as to whether they are defined statistically or via a network of interactions; (ii) if their boundaries are drawn by topographical or process-related criteria; (iii) how high the required internal relationships are; and (iv) if they are perceived as "real" entities or abstractions by an observer The various definitions cannot be easily sorted into just a few types, but they can be characterized by several independent criteria. I argue that serious problems arise if the different possibilities of defining ecological units are not recognized and if the concepts are perceived as self-evident. The different concepts of ecological units should be defined and used in a philosophically informed manner I propose a dual approach to the use of ecological units. Generic meanings of the main concepts (especially population, community, and ecosystem) should be retained only as heuristically useful perspectives, while specific and "operational" definitions of the concepts as units should be developed, depending on specific purposes of their use. Some thoughts on the basic requirements for such definitions and the domains of their uses are briefly explained.     

Collective decision‐making and fission–fusion dynamics: a conceptual framework

Sociality exists in an extraordinary range of ecological settings. For individuals to accrue the benefits associated with social interactions, they are required to maintain a degree of spatial and temporal coordination in their activities, and make collective decisions. Such coordination and decision‐making has been the focus of much recent research. However, efforts largely have been directed toward understanding patterns of collective behaviour in relatively stable and cohesive groups. Less well understood is how fission–fusion dynamics mediate the process and outcome of collective decisions making. Here, we aim to apply established concepts and knowledge to highlight the implications of fission–fusion dynamics for collective decisions, presenting a conceptual framework based on the outcome of a small‐group discussion INCORE meeting (funded by the European Community's Sixth Framework Programme). First, we discuss how the degree of uncertainty in the environment shapes social flexibility and therefore the types of decisions individuals make in different social settings. Second, we propose that the quality of social relationships and the energetic needs of each individual influence fission decisions. Third, we explore how these factors affect the probability of individuals to fuse. Fourth, we discuss how group size and fission–fusion dynamics may affect communication processes between individuals at a local or global scale to reach a consensus or to fission. Finally, we offer a number of suggestions for future research, capturing emerging ideas and concepts on the interaction between collective decisions and fission–fusion dynamics.     

Ecological Thresholds: The Key to Successful Environmental Management or an Important Concept with No Practical Application?

An ecological threshold is the point at which there is an abrupt change in an ecosystem quality, property or phenomenon, or where small changes in an environmental driver produce large responses in the ecosystem. Analysis of thresholds is complicated by nonlinear dynamics and by multiple factor controls that operate at diverse spatial and temporal scales. These complexities have challenged the use and utility of threshold concepts in environmental management despite great concern about preventing dramatic state changes in valued ecosystems, the need for determining critical pollutant loads and the ubiquity of other threshold-based environmental problems. In this paper we define the scope of the thresholds concept in ecological science and discuss methods for identifying and investigating thresholds using a variety of examples from terrestrial and aquatic environments, at ecosystem, landscape and regional scales. We end with a discussion of key research needs in this area.     

The current flow of migrants and its contribution to butterfly faunas (Lepidoptera, Rhopalocera) on marine islands with young allochthonous biota

The concept that the mechanisms limiting immigration of new Lepidoptera species are analogous for islands with different ages and degrees of endemism of their biotas is discussed. Specific features of individual species play a key role in establishment of the fauna and population on small islands rather than competitive interactions between these species. It is most likely that the species stably coexisting on an island will display similar ecological characteristics and life cycles, which complies with the concepts of the neutral theory of biodiversity and biogeography.