63 research outputs found

    Insecticidal effect of kaolin powder flavoured with essential oils of Lantana camara L. (Verbenaceae) and Annona senegalensis Pers. (Annonaceae) on Caryedon serratus Olivier (Coleoptera-Bruchidae), a groundnut stock pest

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    The groundnut weevil, Caryedon serratus, causes significant losses of groundnut stocks in Senegal by developing larvae in the seeds. Essential oils extracted from leaves of two plants that grow naturally in Senegal, i.e. the sugar apple (Annona senegalensis Pers.) and lantana (Lantana camara), were tested on adults of Caryedon serratus. Purified and pulverized kaolin was flavoured with essential oils of A. Senegalensis Pers. and L. camara (Lam) obtained through vapour distillation. Adults C. serratus aged 24 hrs at most were treated with 0.1 g of powder flavoured with increasing doses (12.5 to 50 ìl/g. of powder) of essential oil. Withincreasing doses (12.5 to 50 ìl/g of powder) of essential oil. The powder Aromatized with essential oil of A. senegalensis at concentration 25 ìl/g. induced 50% mortality after 36 hrs of contact at concentration 25 ìl/gand 100% after 48 hrs at 50 ìl/g. The powder mixed with the essential oil of L. camara induced after 12 hours of contact 22% mortality at the dose of 12.5 ìl/g, the mortality increased with dose duration of exposure andreached 97.22% after 36 hrs with 50ìl/g

    Senna occidentalis L., une plante prometteuse dans la lutte contre Caryedon serratus Ol. (Coleoptera, Bruchidae), insecte ravageur des stocks d’arachide au Sénégal

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    Dans la perspective de concevoir une stratégie de protection intégrée des nuisibles associés aux produits post-récolte au Sénégal, la bioactivité des extraits et huile essentielle de Senna occidentalis L. sur les oeufs et adultes de Caryedon serratus (Ol.), a été étudiée. Les extraits bruts (éthéré et méthanolique) et fractions d’extrait (hexane, acétate d’éthyle, méthanol) ont été appliqués sur l’insecteà 0,1 ; 0,01 et 0,001 g/ml. Les principaux résultats révèlent que S. occidentalis L. affectent significativement la survie des stades traités, selon sa concentration et sa polarité. L’extrait éthéré et la fraction hexanique provoquent 79,17% de mortalité embryonnaire en C1, tandis que la fraction méthanolique tue 39,58% des oeufs en C1. Les produits polaires (extrait et fraction méthanoliques) provoquent respectivement 69,92 ± 2,87% et 72,01 ± 6,86%de mortalités d’adulte. Par contre, ceux apolaires (éthéré et hexanique) tuent respectivement en moyenne 30,41 ± 1,74% et 27,9 ± 0,34% des adultes. L’activité adulticide de l’huile essentielle augmente avec la concentration (91,67% pour 3 ml/l et 30,56% pour 1 ml/l). Cette bioactivité s’exprime aussi par un déséquilibre du sex-ratio en faveur de mâles, une modification du cycle de développement, une fécondité réduite de 67,2% pour la fraction acétate et une fertilité limitée.Mots clés : Caryedon serratus, arachide, Senna occidentalis, plantes biocides

    Diversity of teachers’ conceptions related to environment and human rights. A survey in 24 countries

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    The environmental, social and economical dimensions of ESD include human rights as equality of all the human beings independently to their gender, ethnic group, religion or sexual orientation. To analyse teachers’ conceptions on environment and on human rights, and to identify eventual links between them and with controlled parameters, a large survey has been done in 24 countries (8 749 teachers). The data are submitted to multivariate analyses. In the less developed countries, the teachers’ conceptions are more anthropocentric, less awareness of the problem of the limit of resources in our planet, and less reticent to use GMO (genetically modified organisms). These teachers are more believing in God, more practicing religion, more for “a strong central power”, “against the separation between science and religion”. The priority of ESD in these countries is poverty and development, while it is to avoid wasting and excessive consumption in the most developed countries. The teachers with the most anthropocentric conceptions more agree with these propositions: “It is for biological reasons that women more often than men take care of housekeeping” and “Ethnic groups are genetically different and that is why some are superior to others”, and more disagree with: “Homosexual couples should have the same rights as heterosexual couples”. These points illustrate that some socio-cultural traditions can differ from values of ESD (the universal human rights).CIEC – FCT Research Unit 317

    Ecological indicators to capture the effects of fishing on biodiversityand conservation status of marine ecosystems

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    IndiSeas (“Indicators for the Seas”) is a collaborative international working group that was established in2005 to evaluate the status of exploited marine ecosystems using a suite of indicators in a comparative framework. An initial shortlist of seven ecological indicators was selected to quantify the effects of fishing on the broader ecosystem using several criteria (i.e., ecological meaning, sensitivity to fishing, data avail-ability, management objectives and public awareness). The suite comprised: (i) the inverse coefficient of variation of total biomass of surveyed species, (ii) mean fish length in the surveyed community, (iii)mean maximum life span of surveyed fish species, (iv) proportion of predatory fish in the surveyed community, (v) proportion of under and moderately exploited stocks, (vi) total biomass of surveyed species,and (vii) mean trophic level of the landed catch. In line with the Nagoya Strategic Plan of the Convention on Biological Diversity (2011–2020), we extended this suite to emphasize the broader biodiversity and conservation risks in exploited marine ecosystems. We selected a subset of indicators from a list of empirically based candidate biodiversity indicators initially established based on ecological significance to complement the original IndiSeas indicators. The additional selected indicators were: (viii) mean intrinsic vulnerability index of the fish landed catch, (ix) proportion of non-declining exploited species in the surveyed community, (x) catch-based marine trophic index, and (xi) mean trophic level of the surveyed community. Despite the lack of data in some ecosystems, we also selected (xii) mean trophic level of the modelled community, and (xiii) proportion of discards in the fishery as extra indicators. These additional indicators were examined, along with the initial set of IndiSeas ecological indicators, to evaluate whether adding new biodiversity indicators provided useful additional information to refine our under-standing of the status evaluation of 29 exploited marine ecosystems. We used state and trend analyses,and we performed correlation, redundancy and multivariate tests. Existing developments in ecosystem-based fisheries management have largely focused on exploited species. Our study, using mostly fisheries independent survey-based indicators, highlights that biodiversity and conservation-based indicators are complementary to ecological indicators of fishing pressure. Thus, they should be used to provide additional information to evaluate the overall impact of fishing on exploited marine ecosystems

    Ecological indicators to capture the effects of fishing on biodiversityand conservation status of marine ecosystems

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    IndiSeas (“Indicators for the Seas”) is a collaborative international working group that was established in2005 to evaluate the status of exploited marine ecosystems using a suite of indicators in a comparative framework. An initial shortlist of seven ecological indicators was selected to quantify the effects of fishing on the broader ecosystem using several criteria (i.e., ecological meaning, sensitivity to fishing, data avail-ability, management objectives and public awareness). The suite comprised: (i) the inverse coefficient of variation of total biomass of surveyed species, (ii) mean fish length in the surveyed community, (iii)mean maximum life span of surveyed fish species, (iv) proportion of predatory fish in the surveyed community, (v) proportion of under and moderately exploited stocks, (vi) total biomass of surveyed species,and (vii) mean trophic level of the landed catch. In line with the Nagoya Strategic Plan of the Convention on Biological Diversity (2011–2020), we extended this suite to emphasize the broader biodiversity and conservation risks in exploited marine ecosystems. We selected a subset of indicators from a list of empirically based candidate biodiversity indicators initially established based on ecological significance to complement the original IndiSeas indicators. The additional selected indicators were: (viii) mean intrinsic vulnerability index of the fish landed catch, (ix) proportion of non-declining exploited species in the surveyed community, (x) catch-based marine trophic index, and (xi) mean trophic level of the surveyed community. Despite the lack of data in some ecosystems, we also selected (xii) mean trophic level of the modelled community, and (xiii) proportion of discards in the fishery as extra indicators. These additional indicators were examined, along with the initial set of IndiSeas ecological indicators, to evaluate whether adding new biodiversity indicators provided useful additional information to refine our under-standing of the status evaluation of 29 exploited marine ecosystems. We used state and trend analyses,and we performed correlation, redundancy and multivariate tests. Existing developments in ecosystem-based fisheries management have largely focused on exploited species. Our study, using mostly fisheries independent survey-based indicators, highlights that biodiversity and conservation-based indicators are complementary to ecological indicators of fishing pressure. Thus, they should be used to provide additional information to evaluate the overall impact of fishing on exploited marine ecosystems

    Observed controls on resilience of groundwater to climate variability in sub-Saharan Africa

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    Groundwater in sub-Saharan Africa supports livelihoods and poverty alleviation1,2, maintains vital ecosystems, and strongly influences terrestrial water and energy budgets. Yet the hydrological processes that govern groundwater recharge and sustainability—and their sensitivity to climatic variability—are poorly constrained4. Given the absence of firm observational constraints, it remains to be seen whether model-based projections of decreased water resources in dry parts of the region4 are justified. Here we show, through analysis of multidecadal groundwater hydrographs across sub-Saharan Africa, that levels of aridity dictate the predominant recharge processes, whereas local hydrogeology influences the type and sensitivity of precipitation–recharge relationships. Recharge in some humid locations varies by as little as five per cent (by coefficient of variation) across a wide range of annual precipitation values. Other regions, by contrast, show roughly linear precipitation–recharge relationships, with precipitation thresholds (of roughly ten millimetres or less per day) governing the initiation of recharge. These thresholds tend to rise as aridity increases, and recharge in drylands is more episodic and increasingly dominated by focused recharge through losses from ephemeral overland flows. Extreme annual recharge is commonly associated with intense rainfall and flooding events, themselves often driven by large-scale climate controls. Intense precipitation, even during years of lower overall precipitation, produces some of the largest years of recharge in some dry subtropical locations. Our results therefore challenge the ‘high certainty’ consensus regarding decreasing water resources in such regions of sub-Saharan Africa. The potential resilience of groundwater to climate variability in many areas that is revealed by these precipitation–recharge relationships is essential for informing reliable predictions of climate-change impacts and adaptation strategies

    State of the climate in 2013

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    In 2013, the vast majority of the monitored climate variables reported here maintained trends established in recent decades. ENSO was in a neutral state during the entire year, remaining mostly on the cool side of neutral with modest impacts on regional weather patterns around the world. This follows several years dominated by the effects of either La Niña or El Niño events. According to several independent analyses, 2013 was again among the 10 warmest years on record at the global scale, both at the Earths surface and through the troposphere. Some regions in the Southern Hemisphere had record or near-record high temperatures for the year. Australia observed its hottest year on record, while Argentina and New Zealand reported their second and third hottest years, respectively. In Antarctica, Amundsen-Scott South Pole Station reported its highest annual temperature since records began in 1957. At the opposite pole, the Arctic observed its seventh warmest year since records began in the early 20th century. At 20-m depth, record high temperatures were measured at some permafrost stations on the North Slope of Alaska and in the Brooks Range. In the Northern Hemisphere extratropics, anomalous meridional atmospheric circulation occurred throughout much of the year, leading to marked regional extremes of both temperature and precipitation. Cold temperature anomalies during winter across Eurasia were followed by warm spring temperature anomalies, which were linked to a new record low Eurasian snow cover extent in May. Minimum sea ice extent in the Arctic was the sixth lowest since satellite observations began in 1979. Including 2013, all seven lowest extents on record have occurred in the past seven years. Antarctica, on the other hand, had above-average sea ice extent throughout 2013, with 116 days of new daily high extent records, including a new daily maximum sea ice area of 19.57 million km2 reached on 1 October. ENSO-neutral conditions in the eastern central Pacific Ocean and a negative Pacific decadal oscillation pattern in the North Pacific had the largest impacts on the global sea surface temperature in 2013. The North Pacific reached a historic high temperature in 2013 and on balance the globally-averaged sea surface temperature was among the 10 highest on record. Overall, the salt content in nearsurface ocean waters increased while in intermediate waters it decreased. Global mean sea level continued to rise during 2013, on pace with a trend of 3.2 mm yr-1 over the past two decades. A portion of this trend (0.5 mm yr-1) has been attributed to natural variability associated with the Pacific decadal oscillation as well as to ongoing contributions from the melting of glaciers and ice sheets and ocean warming. Global tropical cyclone frequency during 2013 was slightly above average with a total of 94 storms, although the North Atlantic Basin had its quietest hurricane season since 1994. In the Western North Pacific Basin, Super Typhoon Haiyan, the deadliest tropical cyclone of 2013, had 1-minute sustained winds estimated to be 170 kt (87.5 m s-1) on 7 November, the highest wind speed ever assigned to a tropical cyclone. High storm surge was also associated with Haiyan as it made landfall over the central Philippines, an area where sea level is currently at historic highs, increasing by 200 mm since 1970. In the atmosphere, carbon dioxide, methane, and nitrous oxide all continued to increase in 2013. As in previous years, each of these major greenhouse gases once again reached historic high concentrations. In the Arctic, carbon dioxide and methane increased at the same rate as the global increase. These increases are likely due to export from lower latitudes rather than a consequence of increases in Arctic sources, such as thawing permafrost. At Mauna Loa, Hawaii, for the first time since measurements began in 1958, the daily average mixing ratio of carbon dioxide exceeded 400 ppm on 9 May. The state of these variables, along with dozens of others, and the 2013 climate conditions of regions around the world are discussed in further detail in this 24th edition of the State of the Climate series. © 2014, American Meteorological Society. All rights reserved

    Effect of climate variability on decadal changes in small pelagic fisheries in the West African upwelling Ecosystem : the case of Sardinella aurita in Senegal [résumé]

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    ICAWA : International Conference AWA, Dakar, SEN, 13-/12/2016 - 15/12/2016In Northwest African upwelling system, the populations of Sardinella aurita show evidence of important log-term natural fluctuations in their abundance, which have implications for medium and long-term forecasting of catches. These fluctuations seem to be related, among other factor, to large-scale climatic variability, raising important scientific and economics concerns. Understanding the processes affecting recruitment/abundance is a fundamental objective of fisheries biology. Thus, this study assesses the effect of climatic variability on the abundance of S. aurita in Northwest African upwelling system. Monthly data indicating the abundance of sardinella were first estimated from commercial statistics, using Generalized Linear Model techniques over the period 1966- 2011. Abundance indices were then compared with environmental indices, at the local scale, a Coastal Upwelling Index (CUI) and a coastal Sea Surface Temperature (SST) index, and on a large scale, the North Atlantic Oscillation (NAO), the Atlantic Multidecadal Oscillation (AMO) and the Multivariate El Niño Southern Oscillation Index (MEI), using times series analyses, linear models and generalized additive models. The results showed that the abundance of sardinella is determined by a strong seasonal pattern and inter-annual fluctuations. The abundance of S. aurita peaked in spring and in autumn. The trend of the sardinella abundance was significantly correlated with the CUI, especially in autumn and spring. Interannual fluctuations of S. aurita abundance are respectively driven by the precocity and the duration of the upwelling season that is attributed to distinct migration patterns. Sardinella species also respond with a delay of around 4 years to the winter NAO index and the autumn CUI, and the AMO index respectively, either related to migration patterns. The wide variations in sardinella biomass are caused by variations in environmental conditions, which should be considered in the implementation of an ecosystem-based approach in sardinella stocks management
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