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Wind dispersed tree species have greater maximum height
No full textInternational audienceAim: We test the hypothesis that wind dispersal is more common among emergent tree species given that being tall increases the likelihood of effective seed dispersal. Location Americas, Africa and the Asia‐Pacific. Time period 1970–2020. Major taxa studied Gymnosperms and Angiosperms. Methods: We used a dataset consisting of tree inventories from 2821 plots across three biogeographic regions (Americas, Africa and Asia‐Pacific), including dry and wet forests, to determine the maximum height and dispersal strategy of 5314 tree species. A web search was used to determine whether species were wind‐dispersed. We compared differences in tree species maximum height between biogeographic regions and examined the relationship between species maximum height and wind dispersal using logistic regression. We also tested whether emergent tree species, that is species with at least one individual taller than the 95% height percentile in one or more plots, were disproportionally wind dispersed in dry and wet forests within each biogeographic region. Results: Our dataset provides maximum height values for 5314 tree species, of which more than half (2914) had no record of this trait in existing global databases. We found that, on average, tree species in the Americas have lower maximum heights compared to those in Africa and the Asia Pacific. The probability of wind dispersal increased significantly with tree species maximum height and was significantly higher among emergent than non‐emergent tree species in both dry and wet forests in all three biogeographic regions. Main conclusion: Wind dispersal is more prevalent in tall, emergent tree species than in non‐emergent species and may thus be an important factor in the evolution of tree species maximum height. By providing the most comprehensive dataset so far of tree species maximum height and wind dispersal strategies, this study paves the way for advancing our understanding of the eco‐evolutionary drivers of tree size
Conceptualizing soil fauna effects on labile and stabilized soil organic matter
No full textInternational audienceFauna is highly abundant and diverse in soils worldwide, but surprisingly little is known about how it affects soil organic matter stabilization. Here, we review how the ecological strategies of a multitude of soil faunal taxa can affect the formation and persistence of labile (particulate organic matter, POM) and stabilized soil organic matter (mineral-associated organic matter, MAOM). We propose three major mechanisms - transformation, translocation, and grazing on microorganisms - by which soil fauna alters factors deemed essential in the formation of POM and MAOM, including the quantity and decomposability of organic matter, soil mineralogy, and the abundance, location, and composition of the microbial community. Determining the relevance of these mechanisms to POM and MAOM formation in cross-disciplinary studies that cover individual taxa and more complex faunal communities, and employ physical fractionation, isotopic, and microbiological approaches is essential to advance concepts, models, and policies focused on soil organic matter and effectively manage soils as carbon sinks, nutrient stores, and providers of food.In their review, Angst et al. conceptualize how the ecological strategies of a multitude of soil faunal taxa can influence the formation of particulate and mineral-associated organic matter. The authors highlight research gaps and ways forward
Managing climate-change refugia to prevent extinctions
No full textInternational audienceEarth is facing simultaneous biodiversity and climate crises. Climate-change refugiaareas that are relatively buffered from climate changecan help address both of these problems by maintaining biodiversity components when the surrounding landscape no longer can. However, this capacity to support biodiversity is often vulnerable to severe climate change and other stressors. Thus, management actions need to consider the complex and multidimensional nature of refugia. We outline an approach to understand refugia-promoting processes and to evaluate refugial capacity to determine suitable management actions. Our framework applies climate-change refugia as tools to facilitate resistance in modern conservation planning. Such refugia-focused management can reduce extinctions and maintain biodiversity under climate change. Refugia as safe havensEarth is heading toward a sixth mass extinction event [1]. While the current extinction crisis (see Glossary) is driven mainly by land-use change, overharvesting, and biological invasions, climate change is becoming a major contributor to extinction and is exacerbating existing drivers [2,3]. Extinctions can cause cascading effects that alter ecosystem structure and functioning [1,4].Climate change impacts are increasing in severity, and reversal is becoming unlikely, driving a paradigm shift in landscape conservation toward promoting climate-change resistance in low-vulnerability areas and facilitating inevitable transitions in more vulnerable areas [5,6]. In this context, climate-change refugia are seen as climate-resistant bastions [7-9] that remain relatively buffered from the effects of climate change. They constitute areas that biodiversity can retreat to and persist in [10,11], thereby facilitating persistence during periods of climate change [12,13]. As such, climate-change refugia are potential 'safe havens' for maintaining biodiversity under anthropogenic climate change and for abating the unfolding extinction crisis [8,14,15]. However, refugia must be integrated with other management considerations [7,10] and may have limits to how much climate change they can buffer [8,9,12,16,17]. Thus, it is important to understand the factors and processes that affect refugia function and quality and to prioritize areas for conservation that are likely to persist for longer time periods [15,17,18].Here we first develop a conceptual model of the biological and physical factors that affect climate-change refugia. We then build on the concept of refugial capacity to illustrate how it can assist in identifying the most buffered and most persistent (i.e., long-term) safe havens for biodiversity. We highlight how managing climate-change refugia as complex and dynamic systems that are affected by global change is key to conserving them. Finally, we integrate these considerations into a conceptual framework of refugia-focused management that extends to the restoration of urban and degraded habitats. HighlightsClimate-change refugia can support biodiversity by maintaining buffered conditions despite climate change and are a critical tool for the unfolding extinction crisis.</div
Ripp-Viti: un projet ECOPHYTO pour réfléchir à la réduction d'usage et d’impact des produits phytosanitaires en viticulture méridionale à l'échelle territoriale
No full textInternational audienc
Rift Valley fever virus is able to cross the human blood–brain barrier <i>in vitro</i> by direct infection with no deleterious effects
No full textInternational audienceRift Valley fever (RVF) is a zoonotic arboviral disease that causes recurrent epidemics in Africa that may trigger fatal neurological disorders. However, the mech anisms of neuroinvasion by which the RVF virus (RVFV) reaches the human central nervous system (CNS) remain poorly characterized. In particular, it is not clear how RVFV is able to cross the human blood-brain barrier (hBBB), which is a neurovascular endothelium that protects the brain by regulating brain and blood exchanges. To explore these mechanisms, we used an in vitro hBBB model to mimic in vivo hBBB selectiveness and apicobasal polarity. Our results highlight the ability of RVFV to cross the hBBB by direct infection in a non-structural protein S (NSs)-independent but strain-dependent manner, leading to astrocyte and pericyte infections. Interestingly, RVFV infection did not induce hBBB disruption and was associated with progressive elimination of infected cells with no impairment of the tight junction protein scaffold and barrier function. Our work also shows that NSs, a well described RVFV virulence factor, limited the establishment of the hBBB-induced innate immune response and subsequent lymphocyte recruitment. These results provide in vitro confirmation of the ability of RVFV to reach human CNS by direct infection of the hBBB without altering its barrier function, and provide new directions to explore human RVFV neurovirulence and neuroinvasion mechanisms
L'ergonomie au cœur d’un processus de création interespèces : penser la scénographie comme interface du travail animal
No full textInternational audienceEn utilisant les termes « ergonomie du travail » en relation avec le terme « scénographie », cet article développe l’idée que la conception d’outils numériques adaptés à être utilisés par les chevaux sur scène leur permet de participer activement à la représentation théâtrale jusqu’à produire des formes inédites. Nous aborderons quelques dispositifs scénographiques et la manière dont ils induisent des modifications comportementales ou engagent le travail du cheval sur scène dans un sens émancipateur
An unexpected late paroxyclaenid (Mammalia, Cimolesta) out of Europe: dental evidence from the Oligocene of the Bugti Hills, Pakistan
No full textInternational audienceBetween 1999 and 2004, eight isolated molars of a strange mammal were discovered from lower Oligocene deposits of the Bugti Hills, Pakistan (Paali Nala, Dera Bugti locus C2; Bugti Member; lower Chitarwata Formation). Because of their unusual morphology, these molars have long remained enigmatic. Extensive comparisons with fossil eutherian and metatherian mammals and the recent description of new paroxyclaenids (Mammalia, Cimolesta) from the early Eocene (Ypresian) of Europe have highlighted the plausible affinities of these teeth from the Oligocene of Pakistan, and pointed to a referral to Paroxyclaenidae. The dental morphology of this taxon is singular among Paroxyclaenidae, and as such it allows us to propose here a new species and a new genus: Welcommoides gurki. The occurrence of a paroxyclaenid in the Oligocene of Pakistan remains somewhat unexpected inasmuch as these mammals were so far only known in the Eocene of Europe. Welcommoides gurki is the largest paroxyclaenid (ca. 4.2 kg) ever discovered, and is assigned to the subfamily Merialinae, which became extinct in Europe around the Ypresian/Lutetian transition, long before the occurrence of this new taxon from Pakistan. Welcommoides displays a suite of unusual characters compared with merialines, suggesting that this South Asian lineage had diverged for some time from its European Ypresian counterparts. Such a hypothesis is supported by the faunal similarities between European and Indian Subcontinent faunas during the Ypresian. Moreover, our discovery strengthens support for the hypothesis that low latitudes of South Asia were a tropical refugium, at least during the first steps of the global climatic deterioration started at the Eocene/Oligocene transition
A novel use of agricultural survey data for food security studies: correlating satellite-derived rainfall indices with declared sowing dates for millet in Niger
No full textInternational audienceThe study utilised LSMS-ISA 2014 survey data for Niger, providing information on the sowing and resowing dates, along with department-level location data. Satellite-based rain estimation products, such as TAMSAT (Maidment et al., 2017), CHIRPS (Funk et al., 2015), and PrISM (Pellarin et al., 2022), were employed to derive rainfall onset indices such as the first wet day after April 15th of a 3day wet spell receiving at least x mm of rain (referred to as FWO) (Marteau et al, 2011). Along with climate data derived from Copernicus ERA5 models, spatial onset date simulations were performed with the SARRA-Py crop simulation model (doi:10.5281/zenodo.10125716) to compute water balance in the topsoil layer. A statistical analysis was conducted to investigate the correlation between the rainfall onset date map aggregated at departmental levels, and the mean successful sowing date per department from the survey
Le Plan Régional d'Actions en faveur de l'Économie Circulaire et le Pacte Vert pour l’Occitanie. Deux dispositifs « participatifs » de la transition écologique porté par la Région Occitanie ?: Deux dispositifs « participatifs » de la transition écologique porté par la Région Occitanie
No full textInternational audienceLe Plan Régional d'Actions en faveur de l'Économie Circulaire et le Pacte Vert pour l’Occitanie
Le paradoxe des données climatiques en Afrique de l'Ouest : plus que jamais urgentes mais de moins en moins accessibles
No full texthttps://theconversation.com/le-paradoxe-des-donnees-climatiques-en-afrique-de-louest-plus-que-jamais-urgentes-mais-de-moins-en-moins-accessibles-235222Pour aider les populations à prévoir les aléas climatiques et réfléchir à la meilleure façon de s'adapter, les données relatives au climat et à l'agriculture n'ont jamais été aussi importantes. L'essor de nouvelles technologies a permis de multiplier les façons de les collecter. Mais par un triste paradoxe, alors que ces données n'ont jamais été aussi nombreuses et importantes, en Afrique de l'Ouest elles sont aussi de moins en moins accessibles, du fait d'aléas diplomatiques, sécuritaires, mais aussi d'une privatisation grandissante de la data