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- PublicationAccès libreFunctional responses of multi-taxa communities to disturbance and stress gradients in a restored floodplain(2015-1-1)
; ; ; ; Moretti, Marco1. Trait-based approaches can reveal the mechanisms through which disturbances or stress impact communities, allowing comparisons of the role of different mechanisms in shaping communities among taxonomic groups. Such information can lead to higher comparability, transferability and predictability of the outcome of restoration projects. However, multitaxa trait-based approaches were rarely used in the context of ecosystem restoration. 2. We investigated the responses to environmental gradients of seven taxa (vascular plants, staphylinid and carabid beetles, spiders, isopods, diplopods and earthworms) in a restored floodplain using a species traits approach. We assessed the impact of flood disturbances and soil hydric stress on the functional diversity (FD) and community-weighted mean (CWM) response of traits for each taxon. 3. Ordination of hydrological variables revealed two main gradients. The first was related to the spatiotemporal dynamics of flood disturbances and the second to the average changes in soil hydric conditions. 4. The analysis of CWM revealed that larger, poorly mobile species with narrow ecological tolerances were filtered by regular floods and/or changes in soil hydric conditions. 5. Functional diversity patterns differed between the two gradients: decreasing with increasing flood disturbance, but increasing along the soil hydric stress gradient. This suggests that the mechanisms shaping community composition differ between the two gradients with environmental filtering being dominant with increasing flood disturbances and competition decreasing with more soil hydric stress. 6. Synthesis and applications. Our study shows that the impact of restored flood disturbances and soil hydric stress on plant and invertebrate functional diversity and community- weighted mean can be positive, negative or more complex depending on the taxonomic group and environmental gradient considered. The patterns can to some extent be explained by the specific characteristics of each group. Larger, poorly mobile species with narrow ecological tolerances were particularly vulnerable to changes in disturbance and stress regime following floodplain restoration. These species may therefore be lost in the initial phases of restoration projects, but other more characteristic species of dynamic floodplains will be favoured. Understanding the consequences of these contrasted responses for biodiversity conservation and ecosystem functioning constitutes the next challenge for ecosystem restoration. - PublicationMétadonnées seulementPATUMOD: a compartment model of vegetation dynamics in wooded pastures(2002)
; ; A system of wooded pasture can be described by seven biological state variables (trees, shrubs, underwood grasslands, fallows, eutrophic meadows, oligrotrophic lawns and cattle) linked by a network of dynamic interactions, which are controlled by altitude and human activities. PATUMOD is a spatially implicit compartment model designed to simulate vegetation dynamics in such silvopastoral ecosystems at community level and according to an equilibrium paradigm. Computer simulations show that the state variables generally end up on a steady-state (one-point attractor), independent on their initial values but strongly dependent on cattle load. At a given altitude, to each value of the stock density is corresponding a stable equilibrium characterised by a given relative cover of each vegetation component. If the initial values are very far of the attractor, a long succession of intermediate stages is required before leading to the steady-state. A remarkable exception to this rule can occur at low altitude, with a repellor between switching trajectories towards two attractors, corresponding to a threshold between scarcely and densely wooded pastures. PATUMOD can be applied to simulate different management scenarios, which include changing global stock density and cutting trees or shrubs. (C) 2002 Elsevier Science B.V. All rights reserved. - PublicationMétadonnées seulementPATUMOD: a compartment model of vegetation dynamics in wooded pastures(2002)
; ; A system of wooded pasture can be described by seven biological state variables (trees, shrubs, underwood grasslands, fallows, eutrophic meadows, oligrotrophic lawns and cattle) linked by a network of dynamic interactions, which are controlled by altitude and human activities. PATUMOD is a spatially implicit compartment model designed to simulate vegetation dynamics in such silvopastoral ecosystems at community level and according to an equilibrium paradigm. Computer simulations show that the state variables generally end up on a steady-state (one-point attractor), independent on their initial values but strongly dependent on cattle load. At a given altitude, to each value of the stock density is corresponding a stable equilibrium characterised by a given relative cover of each vegetation component. If the initial values are very far of the attractor, a long succession of intermediate stages is required before leading to the steady-state. A remarkable exception to this rule can occur at low altitude, with a repellor between switching trajectories towards two attractors, corresponding to a threshold between scarcely and densely wooded pastures. PATUMOD can be applied to simulate different management scenarios, which include changing global stock density and cutting trees or shrubs. (C) 2002 Elsevier Science B.V. All rights reserved. - PublicationMétadonnées seulementModeling and simulating hierarchies using an agent-based approach(2005)
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- PublicationMétadonnées seulementSeasonal dynamics of plant species at fine scale in wooded pastures(Budapest: Akademiai Kiado, 2005)
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- PublicationMétadonnées seulementEcological determinants of fungal diversity on deadwood in European forests(2008)
; ; The fine-scale ecological determinants for wood-inhabiting aphyllophoroid basidiomycetes were investigated with statistical analyses of the occurrence of fruit bodies on woody debris collected in Switzerland and Ukraine. Three substrate descriptors were considered: diameter, degree of decomposition to those local environmental descriptors were detected. Three classes for diameter, as well as for degree of decomposition were thus delimited. They revealed the importance of very small sizes, which were not reported in the literature so far: the relevant diameter class limits were about 0.72 cm and 1.35 cm. Within the host tree species, a clear distinction between coniferous and broadleaf species was found. The next splits followed rather climatic determinants of tree distribution than taxonomical entities such as families or genera. The fidelity of the 59 fungal species to diameter classes, decomposition classes and host tree species was measured by the Dufrene-Legendre index and only significant responses after permutation tests were retained. This brought new insights on the ecology of many wood-inhabiting aphyllophoroid basidiomycetes. Redundancy Analysis was applied to investigate the response of fungal species to diameter and degree of decompostion of woody debris from the most common host tree species, Fagus sylvatica. This direct gradient analysis made it possible to reconstruct the succession of fungal species along the wood decomposition process. - PublicationMétadonnées seulementToward a general formalism for modelling and simulating ecological hierarchies in constructive dynamical systems(2007)
; - PublicationMétadonnées seulementInfluence of tree cover on the diversity of herbaceous communities in subalpine wooded pastures(1999)
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