Search results for "Ecosystem"
showing 10 items of 1752 documents
Biotic homogenisation in bird communities leads to large‐scale changes in species associations
2021
The impact of global change on biodiversity is commonly assessed in terms of changes in species distributions, community richness and community composition. Whether and how much associations between species are also changing is much less documented. In this study, we quantify changes in large-scale patterns of species associations in bird communities in relation to changes in species composition. We use network approaches to build three community-aggregated indices reflecting complementary aspects of species association networks. We characterise the spatio–temporal dynamics of these indices using a large-scale and high-resolution dataset of bird co-abundances of 109 species monitored for 17…
Black currant project: Multidisciplinary approach to agro-ecological measures
2022
The decline of wild pollinators leads to a drastic drop in the associated ecosystem service, resulting in significant lossesin agricultural yields. The production of blackcurrant “Noir de Bourgogne” could potentially be tripled, if populationsof wild pollinators were restored. Various agroecological measures beneficial to pollinators are discussed here, as wellas ongoing experimental tests. We discuss the practical possibilities of implementing these measures by blackcurrantgrowers as well as the technical locks that still exist. The return to an agroecological equlibrium for which pollinationbecomes again a free ecosystem service for agriculture, requires the integration of multiple agroec…
Synchronie entre l'offre et la demande dans le cycle des nutriments: apprendre des écosystèmes naturels pour construire des agrosystèmes durables
2023
Redesigning agrosystems with more ecological regulations can help feed a growing population, preserve soils for future productivity and reduce environmental impacts. However, guidelines for redesigning agrosystems from natural systems are limited. Reviewing the last knowledge of ecosystem functioning, we outlined four ecological systems synchronizing the supply of soluble nutrients by soil biota to fluctuating plant nutrient demand. This synchrony limits deficiencies and excesses of soluble nutrient, which usually penalize both production and regulating services of agrosystems such as nutrient retention and soil carbon storage. We detail how ecological systems promoting synchrony can be ins…
La pollinisation du cassis : État des lieux dans un contexte de changements anthropiques.
2019
Cultivated plants are part of their agroecosystem. Recent anthropic changes modified and decreased the wildcompartment of agroecosystems leading to a lowering of ecosystemic services such as pollination. Blackcurrant ispollinated at least partially by insects. In a study on 8 sites in Côte-d’Or, Burgundy, France we showed that pollinatordensity is lower than 0.5 pollinators per minute of observation in blackcurrant orchards. Blackcurrant are preferentiallyvisited by Bombus sp. and to a lesser extent by Andrena and Apis sp. Comparison of pollinator abundance between2018 data and data from ancient publications show that even if the floral abortion rate did not vary significantly, thenumber of…
Indicators of agricultural intensity and intensification: a review of the literature
2015
Since the 1960s, research has dealt with agricultural intensification (AI) as a solution to ensure global food security. Recently, sustainable intensification (SI) has increasingly been used to describe those agricultural and farming systems that ensure adequate ecosystem service provision. Studies differ in terms of the application scales and methodologies, thus we aim to summarize the main findings from the literature on how AI and SI are assessed, from the farm to global levels. Our literature review is based on 7865 papers selected from the Web of Science database and analysed using CorText software. A further selection of 105 relevant papers was used for an in-depth full-text analysis …
Microbial diversity and structure are drivers of the biological barrier effect against Listeria monocytogenes in soil
2013
International audience; Understanding the ecology of pathogenic organisms is important in order to monitor their transmission in the environment and the related health hazards. We investigated the relationship between soil microbial diversity and the barrier effect against Listeria monocytogenes invasion. By using a dilution-to-extinction approach, we analysed the consequence of eroding microbial diversity on L. monocytogenes population dynamics under standardised conditions of abiotic parameters and microbial abundance in soil microcosms. We demonstrated that highly diverse soil microbial communities act as a biological barrier against L. monocytogenes invasion and that phylogenetic compos…
DIAGSOL : development of a new functional marker of exposure to herbicides B-triketones in an agricultural soil
2020
Numerous herbicides target an enzyme found not only in weeds but also in « non-target organisms » such as microorganisms. This proof-of-concept study aims to use microbial gene encoding the targeted enzyme or the targeted enzyme itself as a marker for herbicide exposure in soils. The hppd gene and the encoded enzyme (HPPD; 4-hydroxyphenylpyruvate dioxygenase), targeted by B-triketone herbicides, are the subject of this study. In silico analyses reveal that the hppd gene is spread out in all bacterial phyla. Primers specific to this gene were designed. This primer pair is used to measure the abundance, the composition and the diversity of the hppd bacterial community in soil microcosms expos…
Quantification des flux d’azote induits par les cultures de légumineuses et étude de leurs déterminants : comparaison de 10 espèces de légumineuses à…
2019
In the context of agroecological transition, the reintroduction of legume crops should play a key role in cropping system sustainability by allowing a reduction of nitrogen (N) inputs. But few references are available concerning the agronomical and ecological services provided by a wide range of legume crops, particularly within crops succession scale. Thus, the main objective of our study is to quantify the N fluxes during and after the legume crops taking into account 10 legume crops (peas, lupin, faba bean, soybean...). Our experiment consists in i) quantifying symbiotic N fixation depending on the amount of soil inorganic N, the mineralisation of N present in legume crop residues after …
Functionnal aspects of biodiversity in relation to plant health
2009
Texte intégral; The most visible impact of human activities on biodiversity concerns species which are part of our cultural heritage but a huge part of the diversity is still hidden, mainly in the ocean, in extreme environments and of course in the soil. Although some estimations can be proposed, they are all considered as under-evaluations of the putative number of taxa that could be present on (in?) the planet Earth. Despite it is not yet known, this biodiversity contributes to different services through the functioning of ecosystems, and thus influences the sustainability of these ecosystems. This was the case for instance when the unsuspected major roles of the archeabacteria in the bi…