Search results for "Ecosystem"
showing 10 items of 1752 documents
Création et réhabilitation de passages à faune favorables à plusieurs espèces : cas d'étude dans le Grésivaudan
2017
International audience
Graphab. 14 réalisations à découvrir. Actes de la journée "Retour d’expérience sur Graphab" du 27 juin 2017
2018
International audience
Impact des invertébrés sur les fonctions des sols et leurs applications dans les systèmes sol-plante
2017
EABIOMEAGROSUP; De par leur structure tridimensionnelle, leur large gamme de porosité, la diversité de leurs caractéristiques physicochimiques et des conditions microclimatiques, les sols abritent un nombre considérable, parfois inestimable d'organismes. Au sein des agroécosystèmes, les enjeux sont de comprendre les relations entre la plante cultivée et son environnement biophysique incluant les interactions biologiques et les effets de la biodiversité des organismes des sols. L’impact de la faune du sol sur la production primaire peut être vu au travers de leur effet sur les fonctions de (i) recyclage des nutriments, (ii) entretien de la stabilité/structure du sol, (iii) contrôle des bioag…
Seasonal fluctuations and long-term persistence of pathogenic populations of Agrobacterium spp. in soils.
2002
ABSTRACT Short- and long-term persistence of pathogenic (i.e., tumor forming) agrobacteria in soil was investigated in six nursery plots with a history of high crown gall incidence. No pathogenic Agrobacterium strains were isolated in soil samples taken in fall and winter in any plots, but such strains were isolated from both bulk soils and weed rhizospheres (over 0.5 × 10 5 pathogenic CFU/g of bulk soil or rhizosphere) in three out of six plots in spring and summer. PCR amplifications of a vir sequence from DNA extracted from soil confirmed the presence of Ti plasmids in summer and their absence in fall and winter. The results indicate that strains that harbor a Ti plasmid had an unforesee…
Host manipulation of a freshwater crustacean (Gammarus roeseli) by an acanthocephalan parasite (Polymorphus minutus) in a biological invasion context.
2006
8 pages; International audience; Several gammarid species serve as intermediate hosts for the acanthocephalan parasite Polymorphus minutus. This parasite influences gammarid behaviour in order to favour transmission to its ultimate host, generally a bird. We investigated this host manipulation in Gammarus roeseli, a gammarid species introduced in France 150 years ago which now coexists with several exotic species from different origins. In the field, vertical distribution of G. roeseli revealed a higher proportion of infected individuals close to the water's surface and the size distribution of infected gammarids revealed predation pressure on infected individuals. However, under laboratory…
Introduction. Ecological immunology.
2009
12 pages; International audience; An organism's fitness is critically reliant on its immune system to provide protection against parasites and pathogens. The structure of even simple immune systems is surprisingly complex and clearly will have been moulded by the organism's ecology. The aim of this review and the theme issue is to examine the role of different ecological factors on the evolution of immunity. Here, we will provide a general framework of the field by contextualizing the main ecological factors, including interactions with parasites, other types of biotic as well as abiotic interactions, intraspecific selective constraints (life-history trade-offs, sexual selection) and popula…
Modification of hosts' behavior by a parasite: field evidence for adaptive manipulation.
2007
9 pages; International audience; Parasites relying on trophic transmission to complete their life cycles often induce modifications of their host's behavior in ways that may increase their susceptibility to predation by final hosts. These modifications have often been interpreted as parasite adaptations, but very few studies have demonstrated that host manipulation has fitness benefits for the parasite. The aim of the present study was to address the adaptive significance of parasite manipulation by coupling observations of behavioral manipulation to estimates of trophic transmission to the definitive host in the natural environment. We show that the acanthocephalan parasite Pomphorhynchus …
Kerguelen, un observatoire scientifique dans le Grand Sud.
2018
8 pages; National audience
Conclusions: Present and Future of Southern Ocean Biogeography.
2014
7 pages; International audience
Biogeographic processes in the Southern Ocean.
2014
8 pages; International audience