Search results for "Tram"
showing 10 items of 1979 documents
Ecological response hides behind the species abundance distribution : Community response to low-intensity disturbance in managed grasslands
2017
Land-use and management are disturbance factors that have diverse effects on community composition and structure. In traditional rural grasslands, such as meadows and pastures, low-intensity management is maintained to enhance biodiversity. Maintenance of road verges, in turn, creates habitat, which may complement traditional rural grasslands. To evaluate the effect of low-intensity disturbance on insect communities, we characterized species abundance distributions (SAD) for Carabidae, Formicidae, and Heteroptera in three grassland types, which differed in management: meadows, pastures, and road verges. The shape of SAD was estimated with three parameters: abundance decay rate, dominance, a…
Functional responses of intertidal bivalves to repeated sub-lethal, physical disturbances
2019
In coastal habitats, physical disturbances of benthic organisms can be caused by natural events like wave-born objects and human activity like trampling, and these disturbances can be sub-lethal (e.g., resulting in the organism's displacement). We know little of how sessile organisms respond to physical disturbances such as displacements. Using Mytilaster minimus, a mussel that is native to the Mediterranean Sea, we tested how byssus production and oxygen uptake rates changed in response to different frequencies of disturbance events (10-60 events h-1). Mussels increased oxygen uptake rates but not byssus production with increasing disturbance frequencies (50-60 events h-1). Our results sho…
Rapid response of a long-lived species to improved water and grazing management: the case of the European pond turtle (Emys orbicularis) in the Camar…
2014
7 pages; International audience; Among human activities, the effect of habitat management by grazing on population viability is ambiguous. Indeed, beneficial effects of grazing are expected by maintaining open meadows, but overgrazing is supposed to increase mortality by trampling. Grazing has been shown to negatively impact the survival of European pond turtle (Emys orbicularis) in the Camargue. Consequently, a new management plan was defined. We investigated the consequences of this management using capture-recapture methods to estimate variations of population sizes in this managed site and a control site over a 17 years period. Results show an increase of the number of adults and juveni…
Local consumers are the first line to control biological invasions: a case of study with the whelk Stramonita haemastoma (Gastropoda: Muricidae)
2016
The increasing spread of invasive species in the Mediterranean Sea determines several alterations in local food webs, changing the feeding habits of native organisms. The whelk Stramonita haemastoma is a widespread Mediterranean gastropod that consumes bivalves, barnacles and limpets. Previous studies showed a shift in its diet from the bivalve Mytilaster minimus to the invasive mussel Brachidontes pharaonis, presumably due to a higher energy gain. Here we tested whelks’ preference among natives and a novel prey, calculating the profitability ratio, and integrating those results with biochemical analysis on prey tissues and the routine metabolism of the whelks. Further, we used the scaled f…
Intégrer la connectivité paysagère dans la séquence ERC : une approche par la quantité d'habitat atteignable
2019
Des engagements nationaux, européens et internationaux ont été pris pour maintenir et restaurer la connectivité entre habitats naturels face à la perte et à la fragmentation de ces habitats. Dans le même temps, les politiques environnementales dans différents pays mettent en oeuvre la séquence Eviter-Réduire-Compenser (ERC) pour atteindre l’objectif d’absence de perte nette de biodiversité (PPN). La séquence ERC a pour principe d’évaluer l’ensemble des impacts écologiques d’un aménagement, mais les critères et indicateurs permettant de quantifier les impacts sur la connectivité paysagère ne sont pas satisfaisants. Nous proposons une démarche opérationnelle pour évaluer les impacts environne…
β-Amyrin Synthase1 Controls the Accumulation of the Major Saponins Present in Pea (Pisum sativum)
2021
Abstract The use of pulses as ingredients for the production of food products rich in plant proteins is increasing. However, protein fractions prepared from pea or other pulses contain significant amounts of saponins, glycosylated triterpenes that can impart an undesirable bitter taste when used as an ingredient in foodstuffs. In this article, we describe the identification and characterization of a gene involved in saponin biosynthesis during pea seed development, by screening mutants obtained from two Pisum sativum TILLING (Targeting Induced Local Lesions IN Genomes) populations in two different genetic backgrounds. The mutations studied are located in a gene designated PsBAS1 (β-amyrin s…
Grazers increase β-diversity of vascular plants and bryophytes in wood-pastures
2016
Questions How does the presence of grazers impact plant diversity at various spatial scales? What are the effects on plant β-diversity and its two components, species turnover and nestedness? Are the effects caused by defoliation, trampling or defecating? Location Twenty-four currently grazed and 24 abandoned wood-pasture sites in Central Finland. Methods The species richness of vascular plants and bryophytes was studied at four spatial scales: within 4-m2 subplots (α1), within 100-m2 plots (α2), within sites (α3) and within the landscape (γ). β-Diversity was studied between subplots within plots (β1), between plots within sites (β2) and between sites within the landscape (β3). Results Curr…
Abiotic Stress Tolerance of Coastal Accessions of a Promising Forage Species, Trifolium fragiferum
2021
Crop wild relatives are valuable as a genetic resource to develop new crop cultivars, better adapted to increasing environmental heterogeneity and being able to give high quality yields in a changing climate. The aim of the study was to evaluate the tolerance of different accessions of a crop wild relative, Trifolium fragiferum L., from coastal habitats of the Baltic Sea to three abiotic factors (increased soil moisture, trampling, cutting) in controlled conditions. Seeds from four accessions of T. fragiferum, collected in the wild, were used for experiments, and cv. ‘Palestine’ was used as a reference genotype. Plants were cultivated in asymbiotic conditions of soil culture. Treatments wer…
Colorimetic biosensing dispositive based on reagentless hybrid biocomposite: Application to hydrogen peroxide determination
2016
Abstract An efficient approach to enhance the performance of colorimetric biosensors has been developed. The biosensor is based on the co-immobilization of the reagent 3,3′,5,5′-teramethylbencidine (TMB) and the enzyme horseradish peroxidase (HRP) in a PDMS-TEOS-SiO2NPs support. The HRP, in presence of H2O2, catalyzes the oxidation of TMB, producing a blue color. The generated biosensor, doped with the substrate (TMB) and the enzyme (HRP) (entrapped or adsorbed), has been used to determine H2O2 in real samples. Firstly, the immobilization of TMB and HRP in the composite has been studied in order to find the best suitable configuration. The kinetic parameters Vmax (maximum reaction rate) and…
Cytoplasmic incompatibility between Old and New World populations of a tramp ant
2020
Reproductive manipulation by endosymbiotic Wolbachia can cause unequal inheritance, allowing the manipulator to spread and potentially impacting evolutionary dynamics in infected hosts. Tramp and invasive species are excellent models to study the dynamics of host-Wolbachia associations because introduced populations often diverge in their microbiomes after colonizing new habitats, resulting in infection polymorphisms between native and introduced populations. Ants are the most abundant group of insects on earth, and numerous ant species are classified as highly invasive. However, little is known about the role of Wolbachia in these ecologically dominant insects. Here, we provide the first d…