322,902 research outputs found

    Artefact Ecologies: Supporting Embodied Meeting Practices with Distance Access

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    Frameworks such as activity theory, distributed cognition and structuration theory, amongst others, have shown that detailed study of contextual settings where users work (or live) can help the design of interactive systems. However, these frameworks do not adequately focus on accounting for the materiality (and embodiment) of the contextual settings. Within the IST-EU funded AMIDA project (Augmented Multiparty Interaction with Distance Access) we are looking into supporting meeting practices with distance access. Meetings are inherently embodied in everyday work life and that material artefacts associated with meeting practices play a critical role in their formation. Our eventual goal is to develop a deeper understanding of the dynamic and embodied nature of meeting practices and designing technologies to support these. In this paper we introduce the notion of "artefact ecologies" as a conceptual base for understanding embodied meeting practices with distance access. Artefact ecologies refer to a system consisting of different digital and physical artefacts, people, their work practices and values and lays emphasis on the role artefacts play in embodiment, work coordination and supporting remote awareness. In the end we layout our plans for designing technologies for supporting embodied meeting practices within the AMIDA project. \u

    Scratching the Surface and Digging Deeper: Exploring Ecological Theories in Urban Soils

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    Humans have altered the Earth more extensively during the past 50 years than at any other time in history (Millennium Assessment 2003). A significant part of this global change is the conversion of land covers from native ecosystems to those dominated by human activities (Kareiva et al. 2007; Ellis and Ramankutty 2008). Although agricultural needs have historicall

    SCALE, ECOLOGY AND COMPLEX SYSTEMS

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    The relationship between political jurisdictions and ecologically-sensible geographic areas is a central concern of political ecologists; few are the cities, provinces, states or countries which map closely onto watersheds, airsheds, aquifers, ranges of migratory birds or top predators, or any other terrestrial space which makes (more-than-human) ecological sense. As the need becomes more pressing to devise policies which help to reduce human impact on ecological systems, the inefficiencies and dysfunctionalities which result from this disjuncture between political spaces and ecological spaces are becoming more readily apparent. It is extremely difficult to devise and implement policies to protect Monarch butterflies, the ozone layer, North Atlantic groundfish stocks, or even the Oglalla aquifer, due in large part to the many political jurisdictions which must commit to policies and their enforcement. Ecological issues which are of central concern for some jurisdictions matter only peripherally or are swamped by other economic or foreign-policy considerations for other jurisdictions, leading to the familiar gridlock in environmental policy -- which of course exists not just at the international level, but also at regional and local scales (Press, 1994:84-107; Bhaskar and Glyn, 1995; Borgese, 1995:151-166; Schreurs and Economy, 1997; Adam, 1998:104-125; Altvater, 1998:34-39; O’Connor, 1994; Eckersley, 1998; Harvey, 1996:203-204; Rifkin, 1991:288-289). Even in the unlikely event that political (and other) ecologists were to reach a consensus on how to create a global, nested series of political jurisdictions and boundaries which respected the earth’s most important ecological features and systems, it would not be at all easy to redraw political boundaries in this way, especially if democratic principles were to be employed (Low, 1997). Moreover, much of the literature on globalization stresses the declining importance of political jurisdictions and policy-making anyway, in the face of increasing global corporate power (Korten, 1995; Sachs, 1993). So what is the point of discussing the relationship between political scales and ecological scales? In this paper, I will try to argue that the importance of political scale (both as a concept and in its grounded, appropriate ecological application) extends far beyond policy-making and supersedes corporate erosion. Political scale provides a primary means for humans to “make sense of” the world and come to terms with our place in it, as individuals and as a species.Its value is educational, epistemological, ontological, and cultural; in fact, political scale can be seen as both a motivator and agenda for action.Complex systems theory offers a number of insights about scale questions. After discussing some of these theoretical issues, I will return at the end of the paper to the role of political scale in a practical sense for activists

    Network analysis identifies weak and strong links in a metapopulation system

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    The identification of key populations shaping the structure and connectivity of metapopulation systems is a major challenge in population ecology. The use of molecular markers in the theoretical framework of population genetics has allowed great advances in this field, but the prime question of quantifying the role of each population in the system remains unresolved. Furthermore, the use and interpretation of classical methods are still bounded by the need for a priori information and underlying assumptions that are seldom respected in natural systems. Network theory was applied to map the genetic structure in a metapopulation system by using microsatellite data from populations of a threatened seagrass, Posidonia oceanica, across its whole geographical range. The network approach, free from a priori assumptions and from the usual underlying hypotheses required for the interpretation of classical analyses, allows both the straightforward characterization of hierarchical population structure and the detection of populations acting as hubs critical for relaying gene flow or sustaining the metapopulation system. This development opens perspectives in ecology and evolution in general, particularly in areas such as conservation biology and epidemiology, where targeting specific populations is crucial

    Testing Ecological Theory with Lianas

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    Lianas constitute a diverse polyphyletic plant group that is advancing our understanding of ecological theory. Specifically, lianas are providing new insights into the mechanisms that control plant distribution and diversity maintenance. For example, there is now evidence that a single, scalable mechanism may explain local, regional, and pan‐tropical distribution of lianas, as well as the maintenance of liana species diversity. The ability to outcompete trees under dry, stressful conditions in seasonal forests provides lianas a growth advantage that, over time, results in relatively high abundance in seasonal forests and low abundance in aseasonal forests. Lianas may also gain a similar growth advantage following disturbance, thus explaining why liana density and diversity peak following disturbance at the local, forest scale. The study of ecology, however, is more than the effect of the environment on organisms; it also includes the effects of organisms on the environment. Considerable empirical evidence now indicates that lianas substantially alter their environment by consuming resources, suppressing tree performance, and influencing emergent properties of forests, such as ecosystem functioning, plant and animal diversity, and community composition. These recent studies using lianas are transcending classical tropical ecology research and are now providing novel insights into fundamental ecological theory

    The physiology of movement

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    Movement, from foraging to migration, is known to be under the influence of the environment. The translation of environmental cues to individual movement decision making is determined by an individual's internal state and anticipated to balance costs and benefits. General body condition, metabolic and hormonal physiology mechanistically underpin this internal state. These physiological determinants are tightly, and often genetically linked with each other and hence central to a mechanistic understanding of movement. We here synthesise the available evidence of the physiological drivers and signatures of movement and review (1) how physiological state as measured in its most coarse way by body condition correlates with movement decisions during foraging, migration and dispersal, (2) how hormonal changes underlie changes in these movement strategies and (3) how these can be linked to molecular pathways. We reveale that a high body condition facilitates the efficiency of routine foraging, dispersal and migration. Dispersal decision making is, however, in some cases stimulated by a decreased individual condition. Many of the biotic and abiotic stressors that induce movement initiate a physiological cascade in vertebrates through the production of stress hormones. Movement is therefore associated with hormone levels in vertebrates but also insects, often in interaction with factors related to body or social condition. The underlying molecular and physiological mechanisms are currently studied in few model species, and show -in congruence with our insights on the role of body condition- a central role of energy metabolism during glycolysis, and the coupling with timing processes during migration. Molecular insights into the physiological basis of movement remain, however, highly refractory. We finalise this review with a critical reflection on the importance of these physiological feedbacks for a better mechanistic understanding of movement and its effects on ecological dynamics at all levels of biological organization

    MPA network design based on graph network theory and emergent properties of larval dispersal

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    Despite the recognised effectiveness of networks of Marine Protected Areas (MPAs) as a biodiversity conservation instrument, nowadays MPA network design frequently disregards the importance of connectivity patterns. In the case of sedentary marine populations, connectivity stems not only from the stochastic nature of the physical environment that affects early-life stages dispersal, but also from the spawning stock attributes that affect the reproductive output (e.g., passive eggs and larvae) and its survivorship. Early-life stages are virtually impossible to track in the ocean. Therefore, numerical ocean current simulations coupled to egg and larval Lagrangian transport models remain the most common approach for the assessment of marine larval connectivity. Inferred larval connectivity may be different depending on the type of connectivity considered; consequently, the prioritisation of sites for marine populations' conservation might also differ. Here, we introduce a framework for evaluating and designing MPA networks based on the identification of connectivity hotspots using graph theoretic analysis. We use as a case of study a network of open-access areas and MPAs, off Mallorca Island (Spain), and test its effectiveness for the protection of the painted comber Serranus scriba. Outputs from network analysis are used to: (1) identify critical areas for improving overall larval connectivity; (2) assess the impact of species' biological parameters in network connectivity; and (3) explore alternative MPA configurations to improve average network connectivity. Results demonstrate the potential of graph theory to identify non-trivial egg/larval dispersal patterns and emerging collective properties of the MPA network which are relevant for increasing protection efficiency.Comment: 8 figures, 3 tables, 1 Supplementary material (including 4 table; 3 figures and supplementary methods
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