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The water-energy-food-ecosystem nexus in North Africa dryland farming: a multi-criteria analysis of climate-resilient innovations in Morocco
No full textInternational audienceSmallholder farmers, who mostly engage in low-value agriculture in the drylands of Northern Africa, were the first to have felt the effects of climate change, with threats to their livelihoods and food security. The increasing costs of agricultural production, poor water and energy infrastructure, loss of agricultural land due to urban expansion, fragmented resource management, and unsustainable management practices all contribute to this vulnerability to climate change. This highlights the urgent need for innovative practices in farming systems. Within the framework of the water-energy-foodecosystem nexus, this paper explores innovative practices in dryland farming systems, by assessing their impact on water, energy, food, and ecosystem through stakeholder perception. In this work, we aim to present a systems approach for assessing the resilience of the water-energy-food-ecosystem nexus in arid and semiarid regions. By using a multi-criteria analysis (MCA) approach, the study-which focuses on the Fès-Meknès region in Morocco-involves local actors to help researchers identify the key variables in order to assist farmers in their adaptation to climate change. The findings revealed different priorities between farmers and other stakeholders regarding the adoption of agricultural innovations. Farmers prioritize innovations that guarantee higher profitability and more market opportunities, such as integrating olive trees with cereal crops, by highlighting the importance of sustainable income sources. Meanwhile, stakeholders, such as researchers, engineers, government officials, and agribusiness entrepreneurs, prioritize innovations that emphasize high water use efficiency, which is crucial for the resilience of dryland farming areas: for instance, rainwater harvesting or the use of drought-resistant crop varieties that directly address the need for water conservation. But in doing so they are overlooking broader aspects within the water-energy-food-ecosystem nexus
Approche système de la mise en oeuvre des piliers de l’agriculture de conservation des sols
No full textPartie 1 - Concevoir le pilotage d’un système en agriculture de conservation des sols et la mise en œuvre de ses piliers, Chapitre 2.International audienc
Une nouvelle étude décortique l'origine des mutations génétiques PUBLIE LE 2 MARS 202 4 A 16:00 -PAR
No full textInternational audienceÀ l'occasion de la parution dans la revue PNAS de notre article scientifique sur les origines des mutations héritables chez deux espèces d'arbres tropicaux de la forêt guyanaise, plongeons dans le processus fascinant de la mutation. Les mutations sont des modifications accidentelles de l'ADN.Bien qu'accidentelles, les mutations génétiques sont essentielles. En ce sens, la mutation peut même être considérée comme le terreau de l'évolution. Toutes ces modifications contribuent à accroître la diversité génétique des espèces.</div
The Dicorynia guianensis population genomic structure mirrors the distribution of environmental variables in French Guiana
No full textInternational audienceEssential ecosystem services are provided by rainforests, which play a pivotal role in sustaining life on Earth. Habitat and biodiversity loss is an imminent threat to tropical rainforest regions worldwide because of agricultural development, mining, overexploitation of timber, and climate change. To ensure their continued adaptability and resilience in a changing world, it is imperative to preserve genetic diversity within tropical rainforest species. Within the smaller context of French Guiana, the specters of climate change, affecting temperature and rainfall, pose unprecedented challenges to this ecosystem, including on the hyperdominant tree species, Dicorynia guianensis (Fabaceae). The genetic data suggests a significant differentiation of populations in the western part of French Guiana and a demographic history of populations that is regionally variable. New genome resequencing data allows us to examine regional-scale genomic signatures of adaptation to climate and soil in this drought-sensitive species and to model genetics-informed distribution range projections under future climate regimes. The local-scale family structure will be better understood with High-throughput SSR-Seq data, which may explain differences between sites in colonization dynamics and local-scale spatial genetic structure. We can develop conservation strategies that can adapt to the challenges posed by future climate scenarios by understanding genetic responses to climate change
Insights into the evolution, virulence and speciation of Babesia MO1 and Babesia divergens through multiomics analyses
No full textAll datasets generated for the current study are accessible in the NCBI/SRA repository under Bioproject PRJNA1032622 (reviewer link). Specifically, the datasets include PacBio HiFi reads (SRA accession number SRR26661633), B. MO1 genome, RNA-Seq (SRA accession number SRR26661632), Hi-C reads (SRA accession number SRR26661630, SRR26661631), ChIP-Seq reads (SRA accession number SRR26661627, SRR26661629, SRR26661626, SRR26661628, SRR26661625).The Babesia MO1 genome was processed using the gene annotation pipeline FunAnnotate v1.8.9 (https://github.com/nextgenusfs/funannotate) and PAP (https://github.com/kjestradag/PAP) pipelines. FunAnnotate was supplied with the MO1 IsoSeq isoforms computed above, along with protein sets of B. bigemina, B. bovis, B. microti, P. falciparum, Toxoplasma gondii, T. orientalis, T. parva and all UniProt/SwissProt protein models. Functional annotations were obtained using InterProScan v5.55-88 with default parameters. For B. divergens Rouen 87, gene annotations were transferred to the improved assembly presented here using the PATT pipeline (https://github.com/kjestradag/PATT). Gene models form B. MO1 were constructed based on annotations of evolutionarily-related species and further refined using PacBio Iso-seq data specific to B. MO1.Babesia MO1, B. divergens Rouen 87 and a B. divergens clinical isolate from Spain were cultured using human A+ blood obtained from healthy volunteer donors [Citation6]. The blood was sourced from the American red cross (US), the Interstate Blood Bank (US), or the Blood Transfusion Center (Spain), adhering to approved protocols and in compliance with the relevant institutional guidelines and regulations.International audienceBabesiosis, caused by protozoan parasites of the genus Babesia, is an emerging tick-borne disease of significance for both human and animal health. Babesia parasites infect erythrocytes of vertebrate hosts where they develop and multiply rapidly to cause the pathological symptoms associated with the disease. The identification of new Babesia species underscores the ongoing risk of zoonotic pathogens capable of infecting humans, a concern amplified by anthropogenic activities and environmental changes. One such pathogen, Babesia MO1, previously implicated in severe cases of human babesiosis in the United States, was initially considered a subspecies of B. divergens, the predominant agent of human babesiosis in Europe. Here we report comparative multiomics analyses of B. divergens and B. MO1 that offer insight into their biology and evolution. Our analysis shows that despite their highly similar genomic sequences, substantial genetic and genomic divergence occurred throughout their evolution resulting in major differences in gene functions, expression and regulation, replication rates and susceptibility to antiparasitic drugs. Furthermore, both pathogens have evolved distinct classes of multigene families, crucial for their pathogenicity and adaptation to specific mammalian hosts. Leveraging genomic information for B. MO1, B. divergens, and other members of the Babesiidae family within Apicomplexa provides valuable insights into the evolution, diversity, and virulence of these parasites. This knowledge serves as a critical tool in preemptively addressing the emergence and rapid transmission of more virulent strains
Contributions of birds to the feeding of ticks at host community level: Effects of tick burden, host density and yearly fluctuations
No full textInternational audienceThe eco-epidemiology of tick-borne diseases hinges on the abundance and distribution of hosts that sustain tick populations and the pathogens they carry. Research into the role of bird species in the feeding of Ixodes ricinus ticks, the primary tick species of veterinary and public health importance in Europe, remains scarce. This study endeavors to bridge these knowledge gaps by (i) assessing the density of feeding ticks (DFT) within a bird community to pinpoint species making substantial contributions, and (ii) exploring interannual variations in DFT over an extended timeline. Furthermore, we investigate whether variations in individual tick burden (TB) were more closely associated with the characteristics of bird species or interannual variations affecting the density of questing tick, using interannual TB variation as a surrogate. To fulfill these aims, we conducted a 13-year longitudinal study monitoring I. ricinus ticks feeding on a bird community in a periurban forest in France, covering breeding periods from 2007 to 2019. Within this community, we identified seven principal bird species significantly contributing to I. ricinus tick feeding: the Common Blackbird (Turdus merula), the Song Thrush (Turdus philomelos), the European Robin (Erithacus rubecula), the Dunnock (Prunella modularis), the Eurasian Blackcap (Sylvia atricapilla), the Great Tit (Parus major), and the Common Nightingale (Luscinia megarhynchos). Our results show that the bird community’s contribution to tick feeding remained relatively consistent from year-to-year, though certain years displayed higher or lower DFT values related to the average over the study period. Moreover, five out the seven major species accounted for 80 % to 95 % of DFT annually. Consequently, we emphasized the need to broaden the scope of future research on bird contributions to tick population dynamics beyond merely thrushes (Turdidae species), to encompass a more diverse range of species, particularly those common birds that engage in ground foraging activities. Furthermore, variations in individual tick burden were predominantly influenced by the characteristics of bird species rather than by interannual variability in infestation rates. This finding suggests a significant role for species-specific traits in determining tick exposure and susceptibility. In conclusion, our study offers new insights into the medium-term dynamics of tick-bird ecological systems, underscoring the need for future study of tick populations and their interactions with vertebrate hosts to improve our understanding of tick-borne disease circulation
Bioeconomic Viability and Resilience of Savanna
No full textInternational audienceOur paper investigates the bioeconomic sustainability and resilience of savanna social-ecological systems (SES). A stylized dynamics of an exploited grass-tree systems is thus considered accounting both for the competition between trees and grass along with logging and grass harvesting activities. Regarding sustainability, we rely on bioeconomic viability goals including consumption security for grass, profitability of logging, and coexistence of tree-grass states. A first analytical result relates to the elicitation of sufficient sustainability conditions through the non-emptiness of the so-called viability kernel. Such sufficient conditions rely on coupled MSY (maximum sustainable yield)-MEY (maximum economic yield) reference states-controls. A larger viable set including these MSY-MEY equilibria is also identified. The resilience of such viability states-controls for savanna SES facing shocks such as fire is then put forward from both recovery through stability analysis and resistance viewpoints. These analytical results provide managers with different upper and lower bioeconomic thresholds on the savanna SESs to promote their sustainability and resilience. Simulations inspired from savanna systems in Cameroon exemplify the analytical findings
Prevalence of dermal trypanosomes in suspected and confirmed cases of gambiense human African trypanosomiasis in Guinea
No full textInternational audienceThe skin is an anatomical reservoir for African trypanosomes, yet the prevalence of extravascular parasite carriage in the population at risk of gambiense Human African Trypanosomiasis (gHAT) remains unclear. Here, we conducted a prospective observational cohort study in the HAT foci of Forecariah and Boffa, Republic of Guinea. Of the 18,916 subjects serologically screened for gHAT, 96 were enrolled into our study. At enrolment and follow-up visits, participants underwent a dermatological examination and had blood samples and superficial skin snip biopsies taken for examination by molecular and immuno-histological methods. In seropositive individuals, dermatological symptoms were significantly more frequent as compared to seronegative controls. Trypanosoma brucei DNA was detected in the blood of 67% of confirmed cases (22/33) and 9% of unconfirmed seropositive individuals (3/32). However, parasites were detected in the extravascular dermis of up to 71% of confirmed cases (25/35) and 41% of unconfirmed seropositive individuals (13/32) by PCR and/or immuno-histochemistry. Six to twelve months after treatment, trypanosome detection in the skin dropped to 17% of confirmed cases (5/30), whereas up to 25% of unconfirmed, hence untreated, seropositive individuals (4/16) were still found positive. Dermal trypanosomes were observed in subjects from both transmission foci, however, the occurrence of pruritus and the PCR positivity rates were significantly higher in unconfirmed seropositive individuals in Forecariah. The lower sensitivity of superficial skin snip biopsies appeared critical for detecting trypanosomes in the basal dermis. These results are discussed in the context of the planned elimination of gHAT
Community ionomics reveals a diversity of mineral nutrition in a species‐rich shrubland on infertile soil
No full textThe raw ionomic data are openly available in DataSuds repository (IRD, France) at https://doi.org/10.23708/OJGC5S. Data reuse is granted under a CC-BY license.International audienceQuestions: High species richness is observed in certain shrublands on infertile substrates. Mineral nutrients are likely to be the primary limiting resources in these ecosystems, and below-ground plant interactions may be crucial to understanding their diversity. Using ionomics, we investigated whether there were nutritional variations between plant species that coexist in a shrubland located in an edaphically extreme environment.Location: New Caledonia.Methods: We set up a 20 m × 20 m plot in a diverse shrubland (“maquis”) on ultramafic (infertile) substrate, in which we sampled all 475 plants taller than 1 m and characterized their ionome (22 elements).Results: In our study, 37 species were identified in the plot, representing all major forms of mycorrhizal symbioses, as well as nitrogen-fixing plants, cluster rooted and parasitic plants. Notably, both nickel hyperaccumulating and manganese hyperaccumulating species were present. Hypervolume approaches were used to assess ionome overlap among the nine most abundant species, with the results revealing limited overlap. Moreover, it was observed that the rarest species in the plot also had the most functionally distinct features.Conclusions: Different nutritional strategies were present in the plot, as demonstrated by the variety of root symbioses and leaf ionomes. Our findings indicate coexistence of multiple species within this infertile shrubland may be achieved by species partitioning into different highly specialized biogeochemical niches
A new Late Miocene stem Octodontoid (Rodentia: Caviomorpha: Octochinchilloi) from the Solimões Formation (Brazil): paleobiogeographic implications
No full textInternational audienceCaviomorphs are the neotropical hystricognathous rodents (Ctenohystrica: Hystricognathi: Caviomorpha). Octodontoidea are today the richest and most speciose clade of caviomorphs. Their fossil record also reveals a wide array of extinct species, including Acarechimys, a taxon with a widespread South American distribution and extensive temporal range. This genus comprises at least five species documented in deposits ranging from the late Oligocene to the Middle Miocene. Here, we report the discovery of a new species of Acarechimys from Upper Miocene deposits of the Envira River (PRE06 outcrop), situated in the Acre State, western Brazilian Amazonia. The new species differs from the other species of the genus in having lower molars with a strong posterior arm of the metaconid, the presence of a mesostylid (usually prominent) and a neomesolophid forwardly directed and connected to the metalophulid I on m1 but not on m2–3, and the absence of posterior arm of the protoconid. This taxon represents the youngest known species of the Acarechimys lineage to date. Its occurrence in Western Amazonia strengthens support for the hypothesis that South American rodent lineages survived longer during the Neogene at low latitudes than in the southern regions of the continent