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The climate of mango producing areas: a case study on three islands
Get PDFCultivation of mango (Mangifera indica L.) spread in the last 30 years to wider latitudes than the species' native area. This raises numerous questions regarding the species adaptation capacity, physiology and productivity. We described the climate of three different mango producing areas located in distant islands: La Réunion (21ºS, France), located in the Mascarene archipelago in the Indian ocean; Tenerife (28ºN, Spain), in the Canary archipelago in the Atlantic Ocean; and Sicily (38ºN, Italy), at the centre of the Mediterranean Sea. Air temperature, rainfall, evapotranspiration, solar radiation, wind speed and direction were collected from weather stations located as close as possible to experimental mango orchards for the period 2018-2022. The climate of each orchard was characterized and they were compared across the three islands. The orchards fell into micro-climatic areas that differed from each island's macro-climatic area as they are described in the literature. The three orchards differed greatly on the basis of several parameters. The absolute highest (43ºC) and lowest (2.5ºC) temperatures were recorded in Sicily. Temperatures showed little variability, both during the day and along the year, in La Réunion and in Tenerife, where the daily average temperatures ranged between 18ºC and 27ºC. Also the annual distributions of rainfall and potential evapotranspiration varied greatly: the cumulated pluviometric deficit was negative during half of the year in La Réunion, during two thirds of the year in Sicily, while it was constantly negative in Tenerife, which was characterized by a nearly arid climate. Rainfall and high temperatures occurred at different periods of the mango phenological cycle among the islands, probably affecting this cycle and the potential productivity. The results show that mango could be cultivated in a broad range of climatic conditions, if appropriate crop management is implemented to ensure sustainable fruit production
Habitat sharing and interspecies interactions in caves used by bats in the Republic of Congo
Get PDFBats play key roles in ecosystem functions and provide services to human populations. There is a need to protect bat populations and to mitigate the risks associated with pathogen spillover. Caves are key habitats for many bat species, which use them as roosting and breeding sites. Caves, bats and their guano also attract many other animals along trophic chains which might favor direct or indirect interspecies interactions. Two caves hosting colonies of insectivorous bats have been investigated in the Republic of Congo to characterize habitat sharing and interactions between bats, humans and animals. We set up a camera-trap monitoring protocol during 19 months at the entrance of and inside each cave. Our results demonstrated the richness and complexity of the species interactions around and within these caves. We identified and/or quantified mainly rodents, but also numerous categories of animals such as insects, birds, reptiles and carnivores using the caves. We investigated the temporal variation in the use of caves and the potential interactions between humans, wild animals and bat colonies. Our study contributes to the understanding of the interface and interactions, for the first time quantified, between cave-dwelling animal species, including humans. This knowledge is important to promote the conservation of cave ecosystems and better understand the ecology of infectious diseases
Le palmier à huile : plantation, fonctionnement et production. fiche n° 01.02.Q58
Get PDFLes palmiers, ou Arecaceae, sont une famille de plantes monocotylédones monocaules, semblables à des arbres. Ils jouent un rôle considérable en agriculture et dans la biodiversité au sens large, en particulier sous les tropiques. Le palmier à huile africain, originaire d'Afrique de l'Ouest, est sans doute, par son impact sur la production agricole, l'espèce de palmier la plus importante ; ses fruits sont disponibles toute l'année et, depuis plus de 7 000 ans, servent de ressources alimentaires semi-sauvages dans les sociétés traditionnelles
Spatiotemporal hotspots of juvenile bigeye and yellowfin tuna catches under drifting fish-aggregating devices in the Eastern Atlantic Ocean to define moratorium strata
No full textTo reduce catches of juvenile bigeye and yellowfin tuna, while maintaining skipjack catches under drifting fish aggregating devices (dFAD), we analyzed spatiotemporal distributions of dFAD catches by European purse seiners in the Eastern Atlantic Ocean during 1996–2019. To detect hotspots of juvenile dFAD catches, we: identified periods of maximum abundance using a seasonal sub-series diagram; normalized monthly FAD catches per unit effort; and used emerging hotspots analysis on spatiotemporal density. Two main spatiotemporal strata were identified in the Guinean Gulf, which could be used to establish moratoria on dFAD fishing. These spatiotemporal strata differed from the existing ICCAT moratorium, which spanned a larger part of the African coast. Our findings also indicated that time-area closures of dFAD-fishing lasting 3–4 months in smaller areas could be more effective than the current dFAD moratorium to reduce unwanted bycatch in the Eastern Atlantic region. The two metrics we developed for comparison provided clear and measurable evidence that demonstrated how strategic and data-informed moratoriums can lead to substantial improvements in conservation
Revealing the role of the AGO4 gene against rice hoja blanca virus: From transformation to protein structure
Get PDFRice hoja blanca virus (RHBV), transmitted by the insect vector Tagosodes orizicolus, poses a significant threat to rice cultivation. Here, we use CRISPR/ Cas9 technology to produce specific mutations in the AGO4 gene of Oryza sativa, using the Fedearroz 2000 variety, with the aim of elucidating the participation of the gene in resistance to RHBV. We obtained 14 edited plants that presented with deletions of one, two, and three nucleotides in the sequence of exon 23 of the AGO4 gene. Phenotypic evaluations showed an increase in susceptibility to RHBV in the edited lines. We identified the presence of RHBV in the leaf tissue of infected plants by amplifying the nucleoprotein, NS3, and NS4 genes of the virus. Using RT-qPCR, we analyzed the expression patterns of the AGO4 gene, showing that in the edited lines, the expression profiles are similar to the susceptible control. Furthermore, modeling of the tertiary structure of the AGO4 protein and its mutant variant demonstrated changes in the PIWI domain and the presence of the DDH catalytic triad, confirming its role in mediating resistance to RHBV. Our study reveals the functional importance of the rice AGO4 gene in RHBV resistance
Assessing the effectiveness of mangrove rehabilitation using above-ground biomass and structural diversity
Get PDFUnderstanding the carbon sequestration potential of undisturbed and rehabilitated mangrove ecosystems is crucial for mitigating the effects of climate change. In this study, the above-ground biomass (AGB) and structural complexity of natural, rehabilitated and regenerated mangrove forest stands were investigated. Using 32 years of Landsat time series-based normalized difference infrared index data and transect field inventory methods, we examined species and structural diversity as well as AGB distribution across 24 plots spanning a gradient from sea to land. A common allometric model and linear regression analysis were used to evaluate the influence of species diversity, structural complexity, and tree density on AGB. The results revealed that natural mangrove stands exhibited higher AGB, structural complexity, and species diversity than the rehabilitated and regenerated stands. The Shannon diversity index had a negligible effect on AGB, whereas structural complexity significantly influenced AGB in natural stands. This may be attributed to the predominance of rehabilitated monoculture and less diverse scrub mangroves in natural stands. Total AGB ranged from 45.05 to 536.48 tons/ha in natural stands and from 61.57 to 98.99 tons/ha in rehabilitated stands. Our findings illustrate the challenges (e.g., high-density plantation practices, lack of species diversity, and unsuitable site conditions for planted species) associated with current rehabilitation efforts and provide insights for optimizing future rehabilitation strategies
Agricultural value chain transformations: A comparative analysis of milling segment upgrading in the rice value chains in Ghana and Ivory Coast
Get PDFThis paper investigates the extent of technical and organisational transformations in the milling segment of the rice value chains in Ghana and Ivory Coast, which is discussed against the literature on agricultural value chain transformations. The method is based on rice miller's quantitative data and stakeholders' interviews. The results reveal that both countries are undergoing technical change and a shift of value chain governance towards vertical integration, implemented at larger scale in Ghana. The differences observed are attributed to variations in production systems, demand for local rice, currency conditions, and policy approaches in the respective countries
SARRA-Py: A Python-based geospatial simulation framework for agroclimatic modeling
Get PDFSARRA-Py is an open-source, Python-based adaptation of the long-standing SARRA crop model family–specifically building upon SARRA-H to enable spatially explicit agroclimatic simulations in tropical and data-limited environments. By leveraging Python's geospatial libraries (e.g., Xarray), SARRA-Py extends SARRA-H's proven crop physiology routines to large-scale, raster-based analyses, streamlines ingestion of diverse climate inputs with minimal preprocessing, and eases model customization via a modular code structure. Users interact with SARRA-Py primarily through Jupyter notebooks that provide guided workflows for data preparation, parameter configuration, and visualization of results. This design closes the gap between point-based crop models and broader geospatial frameworks, offering a practical tool for agricultural risk management, climate adaptation studies, and yield forecasting. Consequently, SARRA-Py fosters reproducible, scenario-based analyses and informs decision-making in vulnerable regions where water deficits, sparse ground observations, and climate variability threatens food security
Exploring the combination of agroecological and conventional farming practices through the hybrid farming concept
No full textSubstantial improvements in resource-use efficiency and conservation are required to fulfill the rising and evolving global food demand, while addressing environmental degradation issues. Agroecology has emerged as a promising pathway to tackle these challenges. A binary stance often prevails in traditional discussions on agricultural transitions, where conventional farming is pitted against agroecological cropping. The reality is that farming practices blend conventional and agroecological features, hence are hybrid. Here we propose a conceptual representation of hybrid farming, that combines diverse farming practices from contrasting agricultural models, aiming to meet production goals. A schematic representation is provided and illustrated by a case study located in the Merguellil downstream plain region in central Tunisia. Hybrid farming involves multiple combinations of agroecological and conventional farming practices with a range of different outlooks and objectives. In the case study, farmers implemented these combinations to increase their income and mitigate risks. The blend of practices used in hybrid farming is not static and can be ever-changing. Various factors, such as shifting socioeconomic and environmental conditions, market trends and interactions with upstream and downstream supply chains fuel this dynamism