2,457 research outputs found

    Marine ecosystem services: Linking indicators to their classification

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    © 2014 Elsevier Ltd. All rights reserved. There is a multitude of ecosystem service classifications available within the literature, each with its own advantages and drawbacks. Elements of them have been used to tailor a generic ecosystem service classification for the marine environment and then for a case study site within the North Sea: the Dogger Bank. Indicators for each of the ecosystem services, deemed relevant to the case study site, were identified. Each indicator was then assessed against a set of agreed criteria to ensure its relevance and applicability to environmental management. This paper identifies the need to distinguish between indicators of ecosystem services that are entirely ecological in nature (and largely reveal the potential of an ecosystem to provide ecosystem services), indicators for the ecological processes contributing to the delivery of these services, and indicators of benefits that reveal the realized human use or enjoyment of an ecosystem service. It highlights some of the difficulties faced in selecting meaningful indicators, such as problems of specificity, spatial disconnect and the considerable uncertainty about marine species, habitats and the processes, functions and services they contribute to

    Landsliding and its multiscale influence on mountainscapes

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    Landsliding is a complex process that modifies mountainscapes worldwide. Its severe and sometimes long-lasting negative effects contrast with the less-documented positive effects on ecosystems, raising numerous questions about the dual role of landsliding, the feedbacks between biotic and geomorphic processes, and, ultimately, the ecological and evolutionary responses of organisms. We present a conceptual model in which feedbacks between biotic and geomorphic processes, landslides, and ecosystem attributes are hypothesized to drive the dynamics of mountain ecosystems at multiple scales. This model is used to integrate and synthesize a rich, but fragmented, body of literature generated in different disciplines, and to highlight the need for profitable collaborations between biologists and geoscientists. Such efforts should help identify attributes that contribute to the resilience of mountain ecosystems, and also should help in conservation, restoration, and hazard assessment. Given the sensitivity of mountains to land-use and global climate change, these endeavors are both relevant and timel

    Ecology and the Common Good: Sustainability and Catholic Social Teaching

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    In recent years official Roman Catholic documents have addressed the ecological crisis from the perspective of Catholic social teaching. This expansion of Catholic social thought addresses the social and ecological question. This paper links environmental and human ecology with the concept of sustainability and proposes an interpretation of the common good and a definition of sustainability within Catholic social teaching. Our treatment of sustainability and Catholic social teaching includes: an analysis of the ecological processes that sustain nature; insights from human ecology, and an examination of models of sustainability as a foundation for re-structuring society to promote the common good. The paper provides a summary of the historical expansion of the common good within modern Catholic social thought, and concludes with an ecological interpretation of the common good and a definition of sustainability within the Catholic understanding of justice

    Multifractal Spatial Patterns and Diversity in an Ecological Succession

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    We analyzed the relationship between biodiversity and spatial biomass heterogeneity along an ecological succession developed in the laboratory. Periphyton (attached microalgae) biomass spatial patterns at several successional stages were obtained using digital image analysis and at the same time we estimated the species composition and abundance. We show that the spatial pattern was self-similar and as the community developed in an homogeneous environment the pattern is self-organized. To characterize it we estimated the multifractal spectrum of generalized dimensions Dq. Using Dq we analyze the existence of cycles of heterogeneity during succession and the use of the information dimension D1 as an index of successional stage. We did not find cycles but the values of D1 showed an increasing trend as the succession developed and the biomass was higher. D1 was also negatively correlated with Shannon's diversity. Several studies have found this relationship in different ecosystems but here we prove that the community self-organizes and generates its own spatial heterogeneity influencing diversity. If this is confirmed with more experimental and theoretical evidence D1 could be used as an index, easily calculated from remote sensing data, to detect high or low diversity areas

    The influence of soil structure on microbial processes in microfluidic models

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    The way microbes behave in nature can vary widely depending on the spatial characteristics of the habitats they are located in. The spatial structure of the microbial environment can determine whether and to which extent processes such as organic matter degradation, and synergistic or antagonistic microbial processes occur. Investigating how the different spatial characteristics of microhabitats influence microbes has been challenging due to methodological limitations. In the case of soil sciences, attempts to describe the inner structure of the soil pore space, and to connect it to microbial processes, such as to determine the access of nutrient limited soil microorganisms to soil organic matter pools, has been one of the main goals of the field in the last years. The present work aimed at answering the question of how spatial complexity affects microbial dispersal, growth, and the degradation of a dissolved organic substrate. Using microfluidic devices, designed to mimic the inner soil pore physical structures, we first followed the dispersal and growth of soil microbes in the devices, using soil inocula or burying the microfluidic devices in the top layer of a soil (Paper I). We found that inter-kingdom interactions can play an important role for the dispersal of water-dwelling organisms and that these physically modified their environment. To reveal the effect of the different structures on microbes in more detail we tested the influence of increasing spatial complexity in a porespace on the growth and substrate degradation of bacterial and fungal laboratory strains. The parameters we used to manipulate the pore space’s complexity were two: via the turning angle and turning order of pore channels (Paper II), and via the fractal order of a pore maze (Paper III). When we tested the effect of an increase in turning angle sharpness on microbial growth, we found that as angles became sharper, bacterial and fungal growth decreased, but fungi were more affected than bacteria. We also found that their substrate degradation was only affected when bacteria and fungi grew together, being lower as the angles were sharper. Our next series of experiments, testing the effect of maze fractal complexity, however, showed a different picture. The increase in maze complexity reduced fungal growh, similar to the previous experiments, but increased bacterial growth and substrate consumption, at least until a certain depth into the mazes, contrary to our initial hypothesis. To increase the relevance of our studies, we performed experiments in both microfluidic device designs inoculated with a soil microbial extract and followed the substrate degradation patterns over time (Paper IV). We found that as complexity increased, both in terms of angle sharpness and fractal order, substrate consumption also increased. Our results, specially in mazes, might be caused by a reduced competition among bacterial communities and individuals in complex habitats, allowing co-existence of different metabolic strategies and the onset of bacterial biofilm formation leading to a higher degradation efficiency, but further studies are required to confirm this. Our results show that the spatial characteristic of microhabitats is an important factor providing microbes with conditions for a wide variety of ecological interactions that determine their growth and their organic matter turnover

    Self-organization, scaling and collapse in a coupled automaton model of foragers and vegetation resources with seed dispersal

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    We introduce a model of traveling agents ({\it e.g.} frugivorous animals) who feed on randomly located vegetation patches and disperse their seeds, thus modifying the spatial distribution of resources in the long term. It is assumed that the survival probability of a seed increases with the distance to the parent patch and decreases with the size of the colonized patch. In turn, the foraging agents use a deterministic strategy with memory, that makes them visit the largest possible patches accessible within minimal travelling distances. The combination of these interactions produce complex spatio-temporal patterns. If the patches have a small initial size, the vegetation total mass (biomass) increases with time and reaches a maximum corresponding to a self-organized critical state with power-law distributed patch sizes and L\'evy-like movement patterns for the foragers. However, this state collapses as the biomass sharply decreases to reach a noisy stationary regime characterized by corrections to scaling. In systems with low plant competition, the efficiency of the foraging rules leads to the formation of heterogeneous vegetation patterns with 1/fα1/f^{\alpha} frequency spectra, and contributes, rather counter-intuitively, to lower the biomass levels.Comment: 11 pages, 5 figure

    Benthic biomass size spectra in shelf and deep-sea sediments

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    The biomass distributions of marine benthic metazoans (meio- to macro-fauna, 1 ?g–32 mg wet weight) across three contrasting sites were investigated to test the hypothesis that allometry can consistently explain observed trends in biomass spectra. Biomass (and abundance) size spectra were determined from observations made at the Faroe–Shetland Channel (FSC) in the Northeast Atlantic (water depth 1600 m), the Fladen Ground (FG) in the North Sea (150 m), and the hypoxic Oman Margin (OM) in the Arabian Sea (500 m). Observed biomass increased with body size as a power law at FG (scaling exponent, b = 0.16) and FSC (b = 0.32), but less convincingly at OM (b = 0.12 but not significantly different from 0). A simple model was constructed to represent the same 16 metazoan size classes used for the observed spectra, all reliant on a common detrital food pool, and allowing the three key processes of ingestion, respiration and mortality to scale with body size. A micro-genetic algorithm was used to fit the model to observations at the sites. The model accurately reproduces the observed scaling without needing to include the effects of local influences such as hypoxia. Our results suggest that the size-scaling of mortality and ingestion are dominant factors determining the distribution of biomass across the meio- to macrofaunal size range in contrasting marine sediment communities. Both the observations and the model results are broadly in agreement with the "metabolic theory of ecology" in predicting a quarter power scaling of biomass across geometric body size classes

    Spatial Patterns in Chemically and Biologically Reacting Flows

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    We present here a number of processes, inspired by concepts in Nonlinear Dynamics such as chaotic advection and excitability, that can be useful to understand generic behaviors in chemical or biological systems in fluid flows. Emphasis is put on the description of observed plankton patchiness in the sea. The linearly decaying tracer, and excitable kinetics in a chaotic flow are mainly the models described. Finally, some warnings are given about the difficulties in modeling discrete individuals (such as planktonic organisms) in terms of continuous concentration fields.Comment: 41 pages, 10 figures; To appear in the Proceedings of the 2001 ISSAOS School on 'Chaos in Geophysical Flows

    Body size in ecological networks

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    Body size determines a host of species traits that can affect the structure and dynamics of food webs, and other ecological networks, across multiple scales of organization. Measuring body size provides a relatively simple means of encapsulating and condensing a large amount of the biological information embedded within an ecological network. Recently, important advances have been made by incorporating body size into theoretical models that explore food web stability, the patterning of energy fluxes, and responses to perturbations. Because metabolic constraints underpin body-size scaling relationships, metabolic theory offers a potentially useful new framework within which to develop novel models to describe the structure and functioning of ecological networks and to assess the probable consequences of biodiversity change. © 2005 Elsevier Ltd. All rights reserved.Peer Reviewe
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