25 research outputs found
Usages Socioeconomiques Des Espèces Ligneuses Au Sahel: Cas De Guidan Roumdji Au Niger
Woody species are of multiple use in the department of Guidan- Roumdji, in Niger. The present study carried out in Garin-yahaya and Tsayin-daka aims to identify the woody species, their different uses and to determine their present state. Data collection methodology consisted of a floristic inventory at the level of 80 plots and ethnobotanical surveys on a sample of 250 respondents. 46 species, divided into 38 genera and 22 families, were recorded. There were 24 species used in food, 19 fodder species and 38 others species used in the treatment of several ailments in the area. Also, in handicrafts and construction, a dozen species are used respectively against 19 others species in the production of wood energy. These diverse and wide-ranging uses, associated with the effects of climate change, affect the woody species populations. Thus, in the area, 25 species are declared extinct, 18 and 14 others are respectively considered threatened and rare. The study also reported on woody species management practices in the area, including the conservation of 7 local species and the introduction of 11 exotic species because of various products and services they provide. Also, 96% of the local population practices the trees’ farming natural regeneration management (FNRM) in their farms for various reasons. This would be a start in the sustainable and rational management of forest resources in the area with the maintenance of several woody species in the area
Diversité Inter Décennale De La Végétation De La Vallée De Goulbi N’Kaba
The present study is conducted in the Sylvo-Pastoral Zone (ZSP) of the Goulbi N'Kaba Valley and the agricultural zone (fields on adjacent terraces), in the southern center of Niger. The objective of the study is to evaluate the inter-decennial plant biodiversity (2004-2014). Thus, the phytosociological surveys (Daget and Poissonet, 1971) were carried out in plots of 2500 m², along the 6.5 km transects following stratified sampling. An ascending hierarchical classification, followed by an ordination by Nonmetric Multi-dimensional Scaling (NMS) allowed to identify the plant groups. The diversity of each group was evaluated. The results show that the families of Poaceae and Fabaceae are the most abundant in 2004 (15.58% and 11.69%) and in 2014 (18.75% and 7.29%). However, compared to the genera, Indigofera (10.53%), Cassia (6.58%), Acacia (5.26%), Aristida (5.26%) are the most abundant in 2004, while Aristida (4 , 17%), Cassia (4.17%), Spermacoce (3.13%), in 2014. Three groups (mixed, fields, ZSP) have been identified. The 2004 and 2014 index, of Margalef (18,38 and 11,28), Menhinick (2,55 and 1,52), Shannon-Weaver (4,77 and 4,14), the fairness of Pielou (0, 66 and 0.63), the Simpson index (0.89 and 0.91) and Hill (0.95 and 0.93) are high in all the groups, mixed, fields and ZSP (respectively for G1, G2 and G3). But the beta diversity (Whittaker (24), Jaccard (0.52), Sorensen (0.69) index) for each of these groupings remains low. There was no significant change in inter-decennial diversity at the Guidan Tawayé and Korin Habdjia sites from 2004 to 2014
Field evaluation of two rapid diagnostic tests for Neisseria meningitidis serogroup A during the 2006 outbreak in Niger.
The Pastorex((R)) (BioRad) rapid agglutination test is one of the main rapid diagnostic tests (RDTs) for meningococcal disease currently in use in the "meningitis belt". Earlier evaluations, performed after heating and centrifugation of cerebrospinal fluid (CSF) samples, under good laboratory conditions, showed high sensitivity and specificity. However, during an epidemic, the test may be used without prior sample preparation. Recently a new, easy-to-use dipstick RDT for meningococcal disease detection on CSF was developed by the Centre de Recherche Médicale et Sanitaire in Niger and the Pasteur Institute in France. We estimate diagnostic accuracy in the field during the 2006 outbreak of Neisseria meningitidis serogroup A in Maradi, Niger, for the dipstick RDT and Pastorex((R)) on unprepared CSF, (a) by comparing each test's sensitivity and specificity with previously reported values; and (b) by comparing results for each test on paired samples, using McNemar's test. We also (c) estimate diagnostic accuracy of the dipstick RDT on diluted whole blood. We tested unprepared CSF and diluted whole blood from 126 patients with suspected meningococcal disease presenting at four health posts. (a) Pastorex((R)) sensitivity (69%; 95%CI 57-79) was significantly lower than found previously for prepared CSF samples [87% (81-91); or 88% (85-91)], as was specificity [81% (95%CI 68-91) vs 93% (90-95); or 93% (87-96)]. Sensitivity of the dipstick RDT [89% (95%CI 80-95)] was similar to previously reported values for ideal laboratory conditions [89% (84-93) and 94% (90-96)]. Specificity, at 62% (95%CI 48-75), was significantly lower than found previously [94% (92-96) and 97% (94-99)]. (b) McNemar's test for the dipstick RDT vs Pastorex((R)) was statistically significant (p<0.001). (c) The dipstick RDT did not perform satisfactorily on diluted whole blood (sensitivity 73%; specificity 57%).Sensitivity and specificity of Pastorex((R)) without prior CSF preparation were poorer than previously reported results from prepared samples; therefore we caution against using this test during an epidemic if sample preparation is not possible. For the dipstick RDT, sensitivity was similar to, while specificity was not as high as previously reported during a more stable context. Further studies are needed to evaluate its field performance, especially for different populations and other serogroups
Impact des changements climatiques sur la dynamique de l'habitat potentiel de Balanites aegyptiaca (L.) Del. au Niger
The objective of this study is to model the potential distribution of Balanites aegyptiaca under the influence of climate change in Niger. The principle of maximum entropy (MaxEnt) was used to determine the favorable habitats of the species based on variations in current and future climatic conditions (horizon 2050). The presence data of the species combined with bioclimatic data derived from the Worldclim database allowed to generate three climate models for future projections (the CCCMA, CSIRO and HadCM3 models) under the A2 scenario of the IPCC. The coldest quarter precipitation (BIO19) and the wettest period precipitation (BIO13) are the environmental variables that most contributed to the model prediction. Under current climatic conditions, 67.7% of the Nigerien territory is very favorable to the development of Balanites aegyptiaca. The CCCMA and HadCM3 models which predict an increase in precipitation by 2050 as well as the CSIRO model which predicts a decrease for this same horizon show that very favorable habitats will be converted into moderately favorable habitats. Terrestrial protected areas in Niger, located mainly in the Sahelo-Sudanian region, are more effective for the conservation of Balanites aegyptiaca both under current climatic conditions and by 2050. These are mainly the Tamou and Gadbédji total wildlife reserves. The present study shows that Balanites aegyptiaca is one of the few species that is well adapted to the arid conditions of the Sahelo-Sudanian zone. The results of this study constitute a tool that can serve as a basis for the conservation and management of natural stands of Balanites aegyptiaca.
Keywords: Balanites aegyptiaca, MaxEnt, ecological niche, climate change, protected areas, Niger.La présente étude a pour objectif de modéliser la distribution potentielle de Balanites aegyptiaca sous l’influence des changements climatiques au Niger. Le principe d’entropie maximale (MaxEnt) a été utilisé pour déterminer les habitats favorables de l’espèce en fonction des variations des conditions climatiques actuelles et futures (horizon 2050). Les données de présence de l’espèce combinées aux données bioclimatiques dérivées de la base de données Worldclim ont permis de générer trois modèles climatiques pour les projections futures (les modèles CCCMA, CSIRO et HadCM3) sous le scénario A2 du GIEC. Les précipitations du trimestre le plus froid (BIO19) et les précipitations de la période la plus humide (BIO13) sont les variables environnementales qui ont plus contribué à la prédiction du modèle. Sous les conditions climatiques actuelles, 67,7% du territoire nigérien est très favorable au développement de Balanites aegyptiaca. Les modèles CCCMA et HadCM3 qui prédisent une augmentation des précipitations à l’horizon 2050 tout comme le modèle CSIRO qui prédit une diminution pour ce même horizon montrent que les habitats très favorables seront convertis en habitats moyennement favorables. Les aires protégées terrestres du Niger, situées majoritairement en sahélo-soudanienne, sont plus efficaces pour la conservation de Balanites aegyptiaca aussi bien dans les conditions climatiques actuelles qu’à l’horizon 2050. Il s’agit surtout des réserves totales de faune de Tamou et de Gadbédji. La présente étude montre que Balanites aegyptiaca est l’une des rares espèces qui sont bien adaptées aux conditions d’aridité de la zone sahélo-soudanienne. Les résultats de cette étude constituent un outil pouvant servir de base pour la conservation et la gestion des peuplements naturels de Balanites aegyptiaca.
Mots-clés: Balanites aegyptiaca, MaxEnt, niche écologique, changements climatiques, aires protégées, Niger
Species diversity and distribution of ruderal flora on landfills in Maradi city, Niger
Waste management continues to be a critical environmental issue in cities. It impacts on the well being of the population, the environment and the biodiversity. In the city of Maradi, in Niger, more interest is given to the problem in order to understand the whole waste management system. It is in this context that this study is carried out to investigate on the role of ruderal flora on the municipal solid wastes dumpsites and landfill sites in Maradi city. The specific objectives are to determine the floristic diversity and distribution of ruderal flora on the municipal solid waste disposal sites, and to identify potential species that can play an important role in the phytoremediation of these sites. In total, 65 species belonging to 52 genera and 24 families were recorded. These species can be categorised into two groups containing anthropic and nitrophilic species according to the ascending Hierarchical Classification (AHC) at 25% similarity. Characteristic species of the first group G1 are Amaranthus viridis and Cucurbita pepo, and Datura innoxia and Cucumis melo for the second group G2. Other ruderal species, namely Amaranthus spinosus L., Amaranthus viridis L., Celosia trygina L., Datura innoxia Mill., and an introduced woody species, Cuphea hyssopifolia Kunth., found are not included in the Maradi city list of species. Datura innoxia, Amaranthus viridis and Amaranthus spinosus are species known to tolerate different degrees of pollution and their ecology should be further study to better understand how they can be used for phytoremediation on this kind of sites
Evaluation and use of surveillance system data toward the identification of high-risk areas for potential cholera vaccination: a case study from Niger.
In 2008, Africa accounted for 94% of the cholera cases reported worldwide. Although the World Health Organization currently recommends the oral cholera vaccine in endemic areas for high-risk populations, its use in Sub-Saharan Africa has been limited. Here, we provide the principal results of an evaluation of the cholera surveillance system in the region of Maradi in Niger and an analysis of its data towards identifying high-risk areas for cholera
Health care seeking behavior for diarrhea in children under 5 in rural Niger: results of a cross-sectional survey
Diarrhea remains the second leading cause of death in children under 5 years of age in sub-Saharan Africa. Health care seeking behavior for diarrhea varies by context and has important implications for developing appropriate care strategies and estimating burden of disease. The objective of this study was to determine the proportion of children under five with diarrhea who consulted at a health structure in order to identify the appropriate health care levels to set up surveillance of severe diarrheal diseases
Correction: A Seroepidemiological Study of Serogroup A Meningococcal Infection in the African Meningitis Belt.
[This corrects the article DOI: 10.1371/journal.pone.0147928.]
Relationships between fire history, edaphic factors and woody vegetation structure and composition in a semi-arid savanna landscape (Niger, West Africa)
Question. What are the relationships between edaphic factors, fire regime and woody vegetation structure and composition in savannas at landscape to regional scales?Location. The Transboundary ‘W’ Regional Park, Niger, West Africa.Methods. We focused on a protected savanna ecosystem with rainfall of 700 mm yr−1, where rainfall is not expected to be a strong limiting factor for tree cover, and with historically low grazer and browser densities. A burned area history map was created over 7 yr using the high temporal resolution Aqua MODIS space-borne sensor. In the field, the composition and structural parameters of the woody layer, as well as soil samples, were acquired in 137 plots of 0.09 ha each, based on a stratified random sampling approach to sampling the fire regime (seasonality and frequency). Using classical multivariate methods, we analysed the correlations between woody cover characteristics, fire regime and soil and geomorphological factors.Results. In spite of management practices aimed at generalizing early fire every year, the fire regime created a diverse spatial structure, with some vegetation less prone to burning (fire-free) and other types that burned very frequently. These diverse fire histories showed correlations with gradients of both structure and composition of the woody layer. Soil variables had a higher explanatory power for vegetation structure and composition than fire.Conclusions. Among the plausible causal chains between fire regime, soil factors and woody vegetation structure and composition, our results showed better agreement with a model in which fire regime is more a consequence than a cause of the other factors. This contrasts with bottleneck/perturbation theories as well as management practices, but meets the common sense opinions of field practitioners. Although our regional approach should be complemented by controlled experiments at a local scale, it does appear that investments in annual efforts to organize early fire campaigns in many protected areas may need to be reassessed.FLWINinfo:eu-repo/semantics/publishe