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Abstract Environmental and anthropogenic stressors can interact (e.g., drought, harvest or herbivory) to shape plant demography and evolutionary strategies with implications for sustainable resource management plans. Harvest or recurrent biomass removal can act as a selective force. However, our understanding of how harvest and changes in climate can synergistically shape plant evolutionary strategies is limited. We used age-from-stage matrix modeling to investigate how chronic anthropogenic disturbance (severe foliage and bark harvest) affects age-specific mortality trajectories of a tropical tree, Khaya senegalensis in two contrasting climatic regions (dry versus moist) in West Africa. We then developed a stochastic model to test if changes in disturbance regime and the environmental conditions in which a cohort is born may alter stochastic age-specific mortality rates. The effect of harvest on age-specific mortality trajectories was modest and only noticeable in the moist region. Age-specific mortality trajectories differed significantly between regions. In the moist region, mortality rates decreased with age for the first 30 years of life to a minimum rate and then increased gradually after to reach an old age mortality plateau. In the dry region, mortality rates decreased with age to reach a plateau asymptotically. This difference in age-specific mortality trajectory is due to a greater delay in reaching reproductive size/age in the dry region. Our findings underscore intraspecific variation in age-specific mortality schedules and indicate that climatic effect may override the impact of anthropogenic activities on plant demography. Harvest, by favoring fast life stage transition to reproductive stages, can buffer the effect of drought.

Numerous threats impact coral reefs and conservation actions are urgently needed. Fast production of marine habitat maps promotes the use of habitat-only conservation plans, where a given percentage of the area of each habitat is set as conservation objectives. However, marine reserves can impact access to fishing grounds and generate opportunity costs for fishers that need to be minimized. In New Caledonia (Southwest Pacific), we used fine-scale fishery catch maps to define nineteen opportunity costs layers (expressed as biomass catch loss) considering i) total catches, ii) target fish families, iii) local marine tenure, and iv) gear type. The expected lower impacts on fishery catch when using the different cost constraints were ranked according to effectiveness in decreasing the costs generated by the habitat-only scenarios. The exercise was done for two habitat maps with different thematic richness. In most cases, habitat conservation objectives remained achievable, but effectiveness varied widely between scenarios and between habitat maps. The results provide practical guidelines for coral reef conservation and management. Habitat-only scenarios can be used to initiate conservation projects with stakeholders but the costs induced by such scenarios can be lowered by up to 50-60% when detailed exhaustive fishery data are used. When using partial data, the gain would be only in the 15-25% range. The best compromises are achieved when using local data.

This study analyzes the impact of climate change on several characteristics of rainfall in the Mekrou catchment for the twenty-first century. To this end, a multi-model ensemble based on regional climate model experiments considering two Representative Concentration Pathways (RCP4.5 and RCP8.5) is used. The results indicate a wider range of precipitation uncertainty (roughly between −10% and 10%), a decrease in the number of wet days (about 10%), an increase (about 10%) of the total intensity of precipitation for very wet days, and changes in the length of the dry spell period, as well as the onset and end of the rainy season. The maximum rainfall amounts of consecutive 24 h, 48 h and 72 h will experience increases of about 50% of the reference period. This change in rate compared to the reference period may cause an exacerbation of extreme events (droughts and floods) in the Mekrou basin, especially at the end of the century and under the RCP8.5 scenario. To cope with the challenges posed by the projected climate change for the Mekrou watershed, strong governmental policies are needed to help design response options.

The use of decentralized renewable energy systems will continue to play a significant role in electricity generation especially in developing countries where grid expansion to most remote areas is uneconomical. The income levels of these off-grid communities are often low, such that there is a need for the delivery of cost-effective energy solutions through optimum control and sizing of energy system components. This paper aims at minimizing the net present cost (NPC) and the levelised cost of energy (LCOE). The study presents a hybrid power system involving a hydroelectric, solar photovoltaic (PV), and battery system for a rural community in Cameroon. The optimization of the system was done using HOMER Pro and validated using a meta-heuristic algorithm known as genetic algorithm (GA). The GA approach was programmed using the MATLAB software. After the HOMER simulation, the optimal power capacity of 3 kW solar PV, 334.89 Ah battery, and 32.2 kW microhydropower was used to meet the load. The village load profile had a daily energy usage of 431.32 kWh/day and a peak power demand of 38.49 kW. The optimized results showed an NPC and LCOE of $90,469.16 and 0.0453 $/kWh, respectively. The system configuration was tested against an increase in hydropower capacity, and it was observed that increasing the hydropower capacity has the ability to significantly reduce the LCOE as well as the battery and solar PV size. A comparative analysis of the two approaches showed that the optimization using GA was more cost-effective than HOMER Pro with the least LCOE of 0.0344 $/kWh and NPC of $86,990.94 as well as a loss of power supply probability (LPSP) of 0.99%. In addition, the GA method gave more hydropower generation than HOMER Pro. This supports the fact that stochastic methods are more realistic and economically viable. They also accurately predict system operation than deterministic methods.

AbstractThe city of Essaouira is located along the north-west coast of Morocco, where groundwater is the main source of drinking, domestic and agricultural water. In recent decades, the salinity of groundwater has increased, which is why geochemical techniques and environmental isotopes have been used to determine the main sources of groundwater recharge and salinization. The hydrochemical study shows that for the years 1995, 2007, 2016 and 2019, the chemical composition of groundwater in the study area consists of HCO3–Ca–Mg, Cl–Ca–Mg, SO4–Ca and Cl–Na chemical facies. The results show that from 1995 to 2019, electrical conductivity increased and that could be explained by a decrease in annual rainfall in relation to climate change and water–rock interaction processes. Geochemical and environmental isotope data show that the main geochemical mechanisms controlling the hydrochemical evolution of groundwater in the Cenomanian–Turonian aquifer are the water–rock interaction and the cation exchange process. The diagram of δ2H = 8 * δ18O + 10 shows that the isotopic contents are close or above to the Global Meteoric Water Line, which suggests that the aquifer is recharged by precipitation of Atlantic origin. In conclusion, groundwater withdrawal should be well controlled to prevent groundwater salinization and further intrusion of seawater due to the lack of annual groundwater recharge in the Essaouira region.

Tetranychus evansi Baker & Pritchard (Acari: Tetranychidae) is one of the main tomato pests in several countries, mainly in Africa, and applications of synthetic acaricides are the main strategy for its control. Efficient biopesticides to suppress pest populations, with low toxicity against natural enemies, is highly desirable for integrated pest management. Here, we evaluated under laboratory conditions the effect of azadirachtin- and oxymatrine-based formulations on each development stage of T. evansi and on the adult stage of the predatory mite Phytoseiulus longipes, the single promising predator of this pest. We also assessed the residual effect of these biopesticides on T. evansi under laboratory conditions on leaflets excised from treated tomato plants maintained in a screen-house 1, 5, and 10 days after application. Azadirachtin-based formulations were effective in controlling T. evansi immature stages. Oxymatrine-based treatments controlled T. evansi immatures and adult females faster than azadirachtin-based treatments. Both biopesticides had no effect on T. evansi eggs, but oxymatrine-based treatments were highly efficient on newly hatched T. evansi larvae. Oxymatrine displayed residual activity that controlled T. evansi up to 10 days after application. Azadirachtin formulations caused lower mortality of P. longipes adults (8–28%) and slightly reduced fecundity (24.8–56.1%). In contrast, oxymatrine treatments caused higher mortality (60–88%) of the predator and reduced substantiality its fecundity (73.1–90.7%). Our findings suggest that Azadirachtin and oxymatrine provide effective control of T. evansi. Azadirachtin may be relatively safer to the predatory mites whereas oxymatrine should be used with caution, to avoid suppression of P. longipes.

Using the Bliss's theory [1] which assimilates the atmosphere as a column constituted of plane and parallel layers, the expression of the clear sky emissivity as a function of the zenithal direction is established. Other relations as the mean emissivity and the temperature of a part of the celestial vault are also established. The power emitted by some parts of the sky are calculated. Experiments have been conducted. This paper describes the study and presents the results.

Le changement climatique est une grave menace mondiale. La recherche sur le changement climatique et la vulnérabilité aux risques naturels a fait des progrès significatifs au cours des dernières décennies. La plupart des recherches ont été consacrées à l'amélioration de la qualité des informations climatiques et des données sur les dangers, y compris l'exposition à des phénomènes spécifiques, tels que les inondations ou l'élévation du niveau de la mer. Moins d'attention a été accordée à l'évaluation de la vulnérabilité et des conditions sociales, économiques et historiques intégrées qui favorisent la vulnérabilité des sociétés. Un certain nombre d'évaluations de la vulnérabilité mondiale basées sur des indicateurs ont été élaborées au cours des dernières années. Pourtant, une question essentielle reste de savoir comment valider ces évaluations à l'échelle mondiale. Cet article examine différentes options pour valider les évaluations mondiales de la vulnérabilité en termes de validité interne et externe, en se concentrant sur deux systèmes d'indicateurs de vulnérabilité mondiaux utilisés dans le WorldRiskIndex et l'indice INFORM. Le document examine ces systèmes d'index mondiaux en tant que meilleures pratiques et présente en même temps de nouvelles analyses et des résultats mondiaux qui montrent les liens entre le niveau de vulnérabilité et les résultats des catastrophes. L'examen et la nouvelle analyse se soutiennent mutuellement et aident à communiquer la validité et l'incertitude des évaluations de la vulnérabilité. À côté des méthodes de validation statistique, nous discutons de l'importance du lien approprié entre les indicateurs, les données et l'indicandum. Nous avons constaté que la mortalité par événement dangereux dû aux inondations, à la sécheresse et aux tempêtes est 15 fois plus élevée dans les pays classés comme très vulnérables par rapport à ceux classés comme faiblement vulnérables. Ces résultats mettent en évidence les différents points de départ des pays dans leur évolution vers un développement résilient au climat. La priorité devrait être donnée non seulement aux régions susceptibles de faire face à des risques climatiques plus graves à l'avenir, mais également à celles qui sont déjà confrontées à une vulnérabilité élevée. El cambio climático es una grave amenaza global. La investigación sobre el cambio climático y la vulnerabilidad a los peligros naturales ha logrado avances significativos en las últimas décadas. La mayor parte de la investigación se ha dedicado a mejorar la calidad de la información climática y los datos sobre peligros, incluida la exposición a fenómenos específicos, como inundaciones o aumento del nivel del mar. Se ha prestado menos atención a la evaluación de la vulnerabilidad y las condiciones sociales, económicas e históricas arraigadas que fomentan la vulnerabilidad de las sociedades. En los últimos años se han desarrollado una serie de evaluaciones globales de vulnerabilidad basadas en indicadores. Sin embargo, una pregunta esencial sigue siendo cómo validar esas evaluaciones a escala global. Este documento examina diferentes opciones para validar las evaluaciones de vulnerabilidad global en términos de su validez interna y externa, centrándose en dos sistemas de indicadores de vulnerabilidad global utilizados en el WorldRiskIndex y el índice INFORM. El documento revisa estos sistemas de índices globales como mejores prácticas y, al mismo tiempo, presenta nuevos análisis y resultados globales que muestran los vínculos entre el nivel de vulnerabilidad y los resultados de los desastres. Tanto la revisión como el nuevo análisis se apoyan mutuamente y ayudan a comunicar la validez y la incertidumbre de las evaluaciones de vulnerabilidad. Junto a los métodos de validación estadística, discutimos la importancia del vínculo apropiado entre los indicadores, los datos y el indicador. Descubrimos que la mortalidad por evento de peligro de inundaciones, sequías y tormentas es 15 veces mayor para los países clasificados como altamente vulnerables en comparación con los clasificados como poco vulnerables. Estos hallazgos destacan los diferentes puntos de partida de los países en su avance hacia un desarrollo resiliente al clima. Se debe dar prioridad no solo a aquellas regiones que probablemente enfrenten peligros climáticos más graves en el futuro, sino también a aquellas que ya se enfrentan a una alta vulnerabilidad. Climate change is a severe global threat. Research on climate change and vulnerability to natural hazards has made significant progress over the last decades. Most of the research has been devoted to improving the quality of climate information and hazard data, including exposure to specific phenomena, such as flooding or sea-level rise. Less attention has been given to the assessment of vulnerability and embedded social, economic and historical conditions that foster vulnerability of societies. A number of global vulnerability assessments based on indicators have been developed over the past years. Yet an essential question remains how to validate those assessments at the global scale. This paper examines different options to validate global vulnerability assessments in terms of their internal and external validity, focusing on two global vulnerability indicator systems used in the WorldRiskIndex and the INFORM index. The paper reviews these global index systems as best practices and at the same time presents new analysis and global results that show linkages between the level of vulnerability and disaster outcomes. Both the review and new analysis support each other and help to communicate the validity and the uncertainty of vulnerability assessments. Next to statistical validation methods, we discuss the importance of the appropriate link between indicators, data and the indicandum. We found that mortality per hazard event from floods, drought and storms is 15 times higher for countries ranked as highly vulnerable compared to those classified as low vulnerable. These findings highlight the different starting points of countries in their move towards climate resilient development. Priority should be given not just to those regions that are likely to face more severe climate hazards in the future but also to those confronted with high vulnerability already. يمثل تغير المناخ تهديدًا عالميًا خطيرًا. حققت الأبحاث المتعلقة بتغير المناخ والتعرض للمخاطر الطبيعية تقدمًا كبيرًا على مدى العقود الماضية. تم تخصيص معظم الأبحاث لتحسين جودة المعلومات المناخية وبيانات المخاطر، بما في ذلك التعرض لظواهر محددة، مثل الفيضانات أو ارتفاع مستوى سطح البحر. تم إيلاء اهتمام أقل لتقييم الضعف والظروف الاجتماعية والاقتصادية والتاريخية المتأصلة التي تعزز ضعف المجتمعات. تم تطوير عدد من تقييمات الضعف العالمية بناءً على المؤشرات على مدى السنوات الماضية. ومع ذلك، لا يزال هناك سؤال أساسي حول كيفية التحقق من صحة تلك التقييمات على المستوى العالمي. تبحث هذه الورقة في خيارات مختلفة للتحقق من صحة تقييمات الضعف العالمية من حيث صلاحيتها الداخلية والخارجية، مع التركيز على نظامين لمؤشرات الضعف العالمية المستخدمة في WorldRiskIndex ومؤشر INFORM. تستعرض الورقة أنظمة المؤشرات العالمية هذه كأفضل الممارسات وتقدم في الوقت نفسه تحليلًا جديدًا ونتائج عالمية تُظهر الروابط بين مستوى الضعف ونتائج الكوارث. يدعم كل من المراجعة والتحليل الجديد بعضهما البعض ويساعدان في الإبلاغ عن صحة تقييمات الضعف وعدم اليقين بشأنها. إلى جانب طرق التحقق من الصحة الإحصائية، نناقش أهمية الرابط المناسب بين المؤشرات والبيانات والمؤشر. وجدنا أن الوفيات لكل حدث خطر من الفيضانات والجفاف والعواصف أعلى 15 مرة بالنسبة للبلدان المصنفة على أنها شديدة التأثر مقارنة بتلك المصنفة على أنها منخفضة التأثر. تسلط هذه النتائج الضوء على نقاط الانطلاق المختلفة للبلدان في تحركها نحو التنمية القادرة على التكيف مع المناخ. يجب إعطاء الأولوية ليس فقط للمناطق التي من المحتمل أن تواجه مخاطر مناخية أكثر حدة في المستقبل ولكن أيضًا للمناطق التي تواجه بالفعل درجة عالية من الضعف.