Farmland biodiversity benefits from small woody features

International audienceAlthough positive effects on biodiversity of woody features in agricultural landscapes are widely recognized, questions remain as to which landscape context to prioritize their implementation and in what proportion. To investigate the response of farmland biodiversity to small woody features (SWF) density in different landscape compositions (cropland, grassland, mixed), we analyzed fine-resolution data from standardized monitoring schemes on 111 birds, 22 bats, and 25 bush cricket's species, at national scale (relying on 3772, 834 and 727 monitoring points) over the period 2015–2019, in metropolitan France. We used Generalized Additive Mixed Models to analyze population and community responses, through different metrics (abundance, species diversity, and functional composition). We found a positive response exhibited by the three taxa to SWF, more especially in cropland where the SWF density is the lowest relative to grassland and mixed landscapes. Also, our results suggested a non-linear response common to the three taxa, with an increased benefit up to at least 6 % of SWF density in cropland, and beyond for most of the metrics but to a lesser extent (e.g., maximum abundance reached at 7–12 % SWF). We note, however, that some species among farmland bird specialists are negatively impacted by SWF. Overall, we emphasize the benefits to promote woody features in agricultural landscapes, notably in cropland, to support biodiversity and its associated ecosystem functions. Our study provides crucial empirical evidence to the recommendations from previous studies and the relevance of the EU Biodiversity Strategy for 2030 to dedicate at least 10 % of farmland to high-diversity landscape features

One step microwave-assisted synthesis of nanocrystalline WO ^x –ZrO ² acid catalysts

International audienceNanocrystalline ZrO2 and WOx–ZrO2 catalysts with good control over the zirconia phase and the nature of the W species were synthesized by a microwave-assisted aqueous route. The monoclinic ZrO2 (m-ZrO2) and tetragonal ZrO2 (t-ZrOz) polymorphs were isolated through accurate control of the synthetic conditions, in acidic and basic media, respectively. The evolution of the zirconia and W species under annealing of the WOx–ZrO2 nanocomposites at 500 °C and 800 °C was studied, and the resulting materials were tested as catalysts for aldoxime dehydration and hydration of alkynes for the production of nitriles and carbonyls, respectively. In the dehydration reaction, the most active species are W(VI) in tetrahedral coordination, independently of the ZrO2 polymorph, while in the hydration reaction the zirconia phase plays a key role, as the tungsten doped t-ZrO2 appears to be the most active catalyst

Reassessment of French breeding bird population sizes using citizen science and accounting for species detectability

Version acceptée après relecture par Peer Community In Ecology (PCIEcology)Large-scale and long-term biodiversity monitoring can be improved by the use of Essential Biodiversity Variables, among which species population sizes provide key data for conservation programs. Relevant estimations and assessment of actual population sizes are critical for species conservation, especially in the current context of global biodiversity erosion. However, knowledge on population size varies greatly, depending on species conservation status and ranges. While the most threatened or restricted-range species generally benefit from exhaustive counts and surveys, monitoring efficiently common and widespread species tends to be neglected or is simply more challenging to achieve.In such a context, citizen science (CS) is a powerful tool for the long-term monitoring of common species through the engagement of various volunteers, permitting data acquisition on the long term and over large spatial scales. Despite this substantially increased sampling effort, detectability issues imply that even common species may remain unnoticed at suitable sites. The use of structured CS schemes, including repeated visits, enables to model the detection process, permitting reliable inferences of population size estimates.Here, we relied on a large French structured CS scheme (EPOC-ODF) comprising 27 156 complete checklists over 3 873 sites collected during the 2021-2023 breeding seasons to estimate the population size of 63 common bird species using Hierarchical Distance Sampling (HDS). These population size estimates were compared to the previous expert-based French breeding bird atlas estimations, which did not account for detectability issues.Our results indicate strong under-estimations for 65% of species in the French atlas, likely due to more conservative estimates inferred from semi-quantitative expert-based assessments. We also found a few over-estimations for species with long-range songs such as Cuculus canorus, Upupa epops or Turdus merula. Our study highlights the need to rely on sound statistical methodology to ensure unbiased ecological inferences with adequate uncertainty estimation and advocates for a higher reliance on structured CS in support of biodiversity monitoring

Nanocomposite hydrogels for cartilage tissue engineering: mesoporous silica nanofibers interlinked with siloxane derived polysaccharide

International audienceInjectable materials for mini-invasive surgery of cartilage are synthesized and thoroughly studied. The concept of these hybrid materials is based on providing high enough mechanical performances along with a good medium for chondrocytes proliferation. The unusual nanocomposite hydrogels presented herein are based on siloxane derived hydroxypropylmethylcellulose (Si-HPMC) interlinked with mesoporous silica nanofibers. The mandatory homogeneity of the nanocomposites is checked by fluorescent methods, which show that the silica nanofibres dispersion is realized down to nanometric scale, suggesting an efficient immobi-lization of the silica nanofibres onto the Si-HPMC scaffold. Such dispersion and immobilization are reached thanks to the chemical affinity between the hydrophilic silica nanofibers and the pendant silanolate groups of the Si-HPMC chains. Tuning the amount of nanocharges allows tuning the resulting mechanical features of these injectable biocom-patible hybrid hydrogels. hASC stem cells and SW1353 chondrocytic cells viability is checked within the nanocom-posite hydrogels up to 3 wt% of silica nanofibers

Spatialisation des rumeurs chez Jules Verne

Les romans de Jules Verne sont riches en rumeurs, souvent spatialisées. Une analyse rapide proposée par des étudiants du CERES (Centre de formation sur l’environnement et la société) lors du séminaire « Rumeurs et fake news en environnement » donnera un aperçu de la mise en scène de ces rumeurs dans cinq œuvres : 20 000 lieues sous les mers (1870), Une ville flottante (1871), Les Indes noires (1877), Sens dessus dessous (1889) et Le château des Carpathes (1892). La naissance des rumeurs est s..

Global monitoring of the vegetation dynamics from the Vegetation Optical Depth (VOD): A review

International audienceVegetation is a key element in the energy, water and carbon balances over the land surfaces and is strongly impacted by climate change and anthropogenic effects. Remotely sensed observations are commonly used for the monitoring of vegetation dynamics and its temporal changes from regional to global scales. Among the different indices derived from Earth observation satellites to study the vegetation, the vegetation optical depth (VOD), which is related to the intensity of extinction effects within the vegetation canopy layer in the microwave domain and which can be derived from both passive and active microwave observations, is increasingly used for monitoring a wide range of ecological vegetation variables. Based on different frequency bands used to derive VOD, from L-to Ka-bands, these variables include, among others, the vegetation water content/status and the above ground biomass. In this review, the theoretical bases of VOD estimates for both the passive and active microwave domains are presented and the global long-term VOD products computed from various groups in the world are described. Then, major findings obtained using VOD are reviewed and the perspectives offered by methodological improvements and by new sensors onboard satellite missions recently launched or to be launched in a close future are presented

Spatialiser les rumeurs environnementales

Numéro suivi par Yves-François Le La

Genetic and demographic trends from rear to leading edge are explained by climate and forest cover in a cold adapted ectotherm

International audienceAim: Determining whether altitudinal shifts in species distributions leave molecular footprints on wild populations along their range margins from rear to leading edge. Location: South-west France. Methods: We compared the demographic and genetic variation in 42 wild populations of the Western oviparous subclade B2 of a cold adapted lizard (Zootoca vivipara louislantzi). These populations can be divided into four ecological units across altitudinal clines in South-west France (rear edge: 1300 m above sea level). Results: Within the rear edge were found the highest levels of inbreeding, genetic differentiation and evidence of interrupted gene flow compared to central or colonising areas. Within the leading edge, altitudinal range expansion occurred over the last centuries and populations showed relatively low genetic diversity. These demographic and genetic trends were better explained by inhospitable (warm and dry) climate conditions and forest cover. Main conclusions: This empirical evidence illustrates that molecular footprints of climate conditions and habitat quality on wild population trends can be perceived after recent events, which should be of particular importance to accurately understand and anticipate human-induced global change on wild species and ecosystems