Search results for "ecosystem"
showing 10 items of 1752 documents
Characteristics, Main Impacts, and Stewardship of Natural and Artificial Freshwater Environments: Consequences for Biodiversity Conservation
2020
International audience; In this overview (introductory article to a special issue including 14 papers), we consider all main types of natural and artificial inland freshwater habitas (fwh). For each type, we identify the main biodiversity patterns and ecological features, human impacts on the system and environmental issues, and discuss ways to use this information to improve stewardship. Examples of selected key biodiversity/ecological features (habitat type): narrow endemics, sensitive (groundwater and GDEs); crenobionts, LIHRes (springs); unidirectional flow, nutrient spiraling (streams); naturally turbid, floodplains, large-bodied species (large rivers); depth-variation in benthic commu…
A spatially explicit risk assessment approach: Cetaceans and marine traffic in the Pelagos Sanctuary (Mediterranean Sea).
2017
15 páginas, 5 figuras, 2 tablas.-- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Interaction between Medicago truncatula and Pseudomonas fluorescens: evaluation of costs and benefits across an elevated atmospheric CO2.
2012
10 pages; International audience; Soil microorganisms play a key role in both plants nutrition and health. Their relation with plant varies from mutualism to parasitism, according to the balance of costs and benefits for the two partners of the interaction. These interactions involved the liberation of plant organic compounds via rhizodeposition. Modification of atmospheric CO2 concentration may affect rhizodeposition and as a consequence trophic interactions that bind plants and microorganisms. Positive effect of elevated CO2 on plants are rather well known but consequences for micoorganisms and their interactions with plants are still poorly understood. A gnotobiotic system has been devel…
A multi-site study to classify semi-natural grassland types
2009
International audience; Calibration and validation of simulation models describing herbage growth or feed quality of seminatural grasslands is a complex task for agronomists without investing effort into botanical surveys. To facilitate such modelling efforts, a limited number of grassland types were identified using a functional classification of species. These grassland types were characterized by three descriptors required to model herbage growth or feed quality: the abundance-weighted mean leaf dry matter content across grass species, the relative abundance of grasses, and an estimate of species richness. We conducted a multi-site analysis over 749 grasslands from eight temperate region…
Influence of plant traits, soil microbial properties, and abiotic parameters on nitrogen turnover of grassland ecosystems
2016
International audience; Although it is known that multiple interactions among plant functional traits, microbial properties , and abiotic soil parameters influence the nutrient turnover, the relative contribution of each of these groups of variables is poorly understood. We manipulated grassland plant functional composition and soil nitrogen (N) availability in a multisite mesocosm experiment to quantify their relative effects on soil N turnover. Overall, root traits, arbuscular mycorrhizal colonization, denitrification potential, as well as N availability and water availability, best explained the variation in measured ecosystem properties, especially the trade-off between nutrient sequest…
Modelling landscape constraints on farmland bird species range shifts under climate change
2018
Several studies estimating the effects of global environmental change on biodiversity are focused on climate change. Yet, non-climatic factors such as changes in land cover can also be of paramount importance. This may be particularly important for habitat specialists associated with human-dominated landscapes, where land cover and climate changes may be largely decoupled. Here, we tested this idea by modelling the influence of climate, landscape composition and pattern, on the predicted future (2021–2050) distributions of 21 farmland bird species in the Iberian Peninsula, using boosted regression trees and 10-km resolution presence/absence data. We also evaluated whether habitat specialist…
Contrasting olfactory responses of two egg parasitoids to buckwheat floral scent are reflected in field parasitism rates
2019
International audience; Conservation biological control programs advocate the planting of flower strips alongside crops to improve the survival and effectiveness of parasitoids. Ideally, the provided food plants are highly attractive and benefit the targeted biocontrol agents without promoting pests or intraguild competition. Previous laboratory studies showed that Trissolcus basalis, an egg parasitoid of the stink bug Nezara viridula, is highly attracted to floral odors of buckwheat and that its nectar increases the wasp’s fecundity. In the field, T. basalis competes with the co-occurring parasitoid Ooencyrtus telenomicida for host eggs. Therefore, in the present study, we explored whether…
Spatio-temporal dynamics of density-dependent dispersal during a population colonisation
2019
Predicting population colonisations requires understanding how spatio‐temporal changes in density affect dispersal. Density can inform on fitness prospects, acting as a cue for either habitat quality, or competition over resources. However, when escaping competition, high local density should only increase emigration if lower‐density patches are available elsewhere. Few empirical studies on dispersal have considered the effects of density at the local and landscape scale simultaneously. To explore this, we analyze 5 years of individual‐based data from an experimental introduction of wild guppies Poecilia reticulata. Natal dispersal showed a decrease in local density dependence as density at…
S-34 and N-15 labelling to model S and N flux in plants and determine the different components of N and S use efficiency
2013
International audience; In order to highlight our understanding on ecosystems functioning and resource sharing/competition, either in artificial environment or agrosystems, according to changes in the climatic conditions, it is necessary to measure accurately element fluxes within plants. Stable isotopes allow tracking safely and accurately on a short time frame the behavior of elements in plants. After a short review devoted to isotopic studies of elemental flux within plants, we explain how a direct multiple labelling study might be conducted in a plant, so as to measure over short time nitrogen and sulfur acquisition, and assimilates arising from a labelled source.
Eutrophic status influences the impact of pesticide mixtures and predation on Daphnia pulex populations
2021
Abstract Pesticides, nutrients, and ecological stressors such as competition or predation co‐occur in freshwater ecosystems impacted by agriculture. The extent to which combinations of these stressors affect aquatic populations and the role of nutrients availability in modulating these responses requires further understanding. In this study, we assessed how pesticides affecting different taxonomic groups and predation influence the response of Daphnia pulex populations under different trophic conditions. An outdoor experiment was designed following a factorial design, with the insecticide chlorpyrifos, the herbicide diuron, and the predation by Notonecta sp. individuals as key stressors. Th…