La collection de moulages de champignons de Jean-Baptiste Barla

Les procédures de récolement nécessitent sur certaines collections historiques la compilation d’une documen­tation foisonnante qui dépasse le simple objectif de l’inventaire patrimonial réglementaire. Description de la collection Barla Cette collection monumentale constituée au XIXe siècle est composée de plusieurs ensembles : une sé­rie de 699 socles comportant chacun entre trois à dix sujets (voire plus) tous différents. S’ajoute à cette première série, une deuxième série appelée « mycothèq..

A trait-based trade-off between growth and mortality: Evidence from 15 tropical tree species using size-specific relative growth rates

A life-history trade-offbetween low mortality in the dark and rapid growth in the light is one of the most widely accepted mechanisms underlying plant ecological strategies in tropical forests. Differences in plant functional traits are thought to underlie these distinct ecological strategies; however, very few studies have shown relationships between functional traits and demographic rates within a functional group. We present 8 years of growth and mortality data from saplings of 15 species of Dipterocarpaceae planted into logged-over forest in Malaysian Borneo, and the relationships between these demographic rates and four key functional traits: wood density, specific leaf area (SLA), seed mass, and leaf C:N ratio. Species-specific differences in growth rates were separated from seedling size effects by fitting nonlinear mixed-effects models, to repeated measurements taken on individuals at multiple time points. Mortality data were analyzed using binary logistic regressions in a mixed-effects models framework. Growth increased and mortality decreased with increasing light availability. Species differed in both their growth and mortality rates, yet there was little evidence for a statistical interaction between species and light for either response. There was a positive relationship between growth rate and the predicted probability of mortality regardless of light environment, suggesting that this relationship may be driven by a general trade-offbetween traits that maximize growth and traits that minimize mortality, rather than through differential species responses to light. Our results indicate that wood density is an important trait that indicates both the ability of species to grow and resistance to mortality, but no other trait was correlated with either growth or mortality. Therefore, the growth mortality trade-offamong species of dipterocarp appears to be general in being independent of species crossovers in performance in different light environments. © 2014 The Authors

Tool development to understand rural resource users’ land use and impacts on land type changes in Madagascar

A majority of Madagascar’s rural people depend on the primary sector. The country’s agricultural hub, the Alaotra-Mangoro region, is mainly tied to fisheries and rice production. Increasing human population and decreasing output from fisheries and agriculture are pushing the rural resource users further into the protected marshlands. Understanding rural farmers’ decisions can help developing improved management plans to support long-term functioning of (socio-) ecological systems. We present here an example of inter- and transdisciplinary research which uses a participatory modelling approach to develop a shared vision of the Alaotra socio-ecological system. The purpose of this study is to introduce the used gaming approach in detail by documenting the process of co-construction of the Alaotra wetlands’ conceptual model. We then describe how the model is transcribed into a table-top role-playing game that will help researchers and stakeholders alike explore and understand decisions and management strategies. We finally report on first outcomes of the game including land use decisions, reaction to market fluctuation and landscape change.RÉSUMÉLa majorité des populations rurales de Madagascar dépendent du secteur primaire. Le centre agricole du pays, la région d'Alaotra- Mangoro, est principalement lié à la pêche et à la production de riz. L'accroissement de la population humaine et la baisse de la production agricole et de la pêche poussent les utilisateurs des ressources rurales vers les marais protégés. Comprendre les décisions des agriculteurs peut aider à développer de meilleursplans de gestion pour soutenir le fonctionnement à long terme des systèmes (socio-) écologiques. Nous présentons ici un exemple de recherche interdisciplinaire et transdisciplinaire qui utilise une approche de modélisation participative pour développer une vision partagée du système socio-écologique d'Alaotra. Le but de cette étude est de présenter en détail l'approche des jeux utilisée, en documentant le processus de co-construction du modèle conceptuel pour les zones humides d'Alaotra. Nous décrivons ensuite comment le modèle est transcrit dans un jeu de rôle sur plateau qui aidera les chercheurs et les parties prenantes à explorer et à comprendre les décisions et les stratégies de gestion. Nous présentons enfin les premiers résultats du jeu, y compris les décisions d'utilisation des terres, la réponse aux fluctuations du marché et aux changements des paysages.

Tool development to understand rural resource users’ land use and impacts on land type changes in Madagascar

A majority of Madagascar’s rural people depend on the primary sector. The countrie’s agricultural hub, the Alaotra-Mangoro region, is mainly tied to fisheries and rice production. Increasing human population and decreasing output from fisheries and agriculture are pushing the rural resource users further into the protected marshlands. Understanding rural farmers’ decisions can help developing improved management plans to support long-term functioning of (socio-) ecological systems. We present here an example of inter- and transdisciplinary research which uses a participatory modelling approach to develop a shared vision of the Alaotra socio-ecological system. The purpose of this study is to introduce the used gaming approach in detail by documenting the process of co-construction of the Alaotra wetlands’ conceptual model. We then describe how the model is transcribed into a table-top role-playing game that will help researchers and stakeholders alike explore and understand decisions and management strategies. We finally report on first outcomes of the game including land use decisions, reaction to market fluctuation and landscape change. RésuméLa majorité des populations rurales de Madagascar dépendent du secteur primaire. Le centre agricole du pays, la région d'Alaotra-Mangoro, est principalement lié à la pêche et à la production de riz. L'accroissement de la population humaine et la diminution de la production de la pêche et de l'agriculture poussent les utilisateurs des ressources rurales vers les marais protégés. Comprendre les décisions des agriculteurs peut aider à développer de meilleurs plans de gestion pour soutenir le fonctionnement à long terme des systèmes (socio-) écologiques. Nous présentons ici un exemple de recherche interdisciplinaire et transdisciplinaire qui utilise une approche de modélisation participative pour développer une vision partagée du système socio-écologique d'Alaotra. Le but de cette étude est de présenter en détail l'approche des jeux utilisée ici, en documentant le processus de co-construction du modèle conceptuel pour les zones humides d'Alaotra. Nous décrivons ensuite comment le modèle est transcrit dans un jeu de rôle sur plateau qui aidera les chercheurs et les parties prenantes à explorer et à comprendre les décisions et les stratégies de gestion. Nous présentons enfin les premiers résultats du jeu, y compris les décisions d'utilisation des terres, la réponse aux fluctuations du marché et aux changements de paysages

Forest diversity promotes individual tree growth in central European forest stands

Most experimental evidence on the relationship between biodiversity and ecosystem functioning comes from ecosystems with fast-growing plants, such as grasslands. Although forests provide essential ecological services, they have been less well investigated.  We used dendrochronology to compare the tree radial growth rates of four important timber species in replicated, spatially mapped stands that differed in tree composition and diversity within a central European managed forest.  Growth rates differed among species but were largely unaffected by the density of neighbouring trees.  Increasing stand diversity enhanced individual growth rates, after accounting for the effects of tree density and size. These increases were statistically indistinguishable among the four species. In contrast, the effects of stand and neighbourhood species composition on growth rates were non-significant.  Policy implications. Our study of long-established central European forest stands revealed levels of tree diversity can be increased in managed forests, with the potential for modest increases in tree growth rates. These results suggest that in addition to the biodiversity and risk mitigation benefits associated with shifting practices away from monoculture management, increased carbon sequestration and yields in mature forests are likely to be realized. Our results suggest that it is possible to increase forest diversity with little or no costs to production and even with the potential for modest increases in tree growth rates

Graphite flake self-retraction response based on potential seeking

The high elastic modulus and interlayer strengths of graphite flakes make them a durable solid superlubricant. Apart from this, they have configurable electrical properties, exhibit quantum Hall effects, and possess a myriad of useful photonic properties. The self-retraction behavior of graphite flakes can have significant impact on the creation of ordered stacks for various applications because any accidental or intentional displacement of the top flake over the stacks below may result in a misalignment of the carbon-carbon atomic arrangement which, in turn, can have influence over the electrical and photonic properties. It has also been revealed that there was a tendency of the displaced microflake to fail at times to return to its original starting position and orientation. Here, we elucidate this behavior by considering the influence of the interlayer potential forces based on minimal potential energy seeking. The maps of the parameters interrogated here provide the ability for precautions to be undertaken. They also potentially permit the creation of an array of microflake stacks in which the metastable states permit different information to be encoded by virtue of the differentiated photonic or electrical characteristics readable from each array site