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1.
Avian scavengers, by feeding on carrion and other organic matter, provide critical ecosystem services. Vultures, the only obligate avian scavengers, have reportedly experienced massive population declines in Africa yet current knowledge regarding their status in most West African countries is unknown. This study set out to ascertain the status of the avian scavenger community in Edo State, southern Nigeria. We made total counts of all scavenging birds at foraging and roosting sites in 13 urban areas. We recorded three species of avian scavenger which were, in order of decreasing relative abundance, Pied Crow Corvus albus, Yellow-billed Kite Milvus migrans and Hooded Vulture Necrosyrtes monachus. There was a positive correlation between relative abundance of avian scavengers and human population size, such that more populous urban centres had larger populations of scavengers. We counted more scavenging birds at roosting sites than at foraging sites. While the Pied Crow and Yellow-billed Kite appear to be thriving in Edo State, the Hooded Vulture appears to have experienced a massive population decline. Our results suggest that without immediate conservation effort such as protection, education and advocacy, the Hooded Vulture will be extirpated from this region in the near future. We suggest that these conservation efforts be focused on the largest urban areas. Furthermore, we recommend that other states in southern Nigeria be urgently surveyed in order for more general conclusions to be drawn about the fate of avian scavengers in this region.  相似文献   

2.
Basic ecological information is still lacking for many species of African vultures. The Hooded Vulture Necrosyrtes monachus is known as a rare breeding resident in north-eastern South Africa. This study set out to monitor the nests of Hooded Vultures and, secondarily, White-backed Vultures Gyps africanus in the Olifants River Private Nature Reserve over two breeding seasons in 2013 and 2014. A total of 12 Hooded Vulture nests, placed mostly in the tree Diospyros mespiliformis, were found along the Olifants River, with an average inter- nest distance of 0.76 km. Nest success was estimated to be between 0.44–0.89 offspring pair?1 y?1 in 2013 and 0.50–0.67 offspring pair?1 y?1 in 2014, which are the first estimates for Hooded Vultures in South Africa. It is thought that nests of this species have been under-reported due to the fact that they are placed within or below the canopy of densely leafed trees and hence difficult to view from aerial surveys. African White-backed Vultures also bred along the Olifants River, with nests placed in clusters of up to six. Nesting density of this species ranged from about 1.0 to 1.2 nests km?1 and nests were predominantly placed in Ficus sycomorus trees.  相似文献   

3.
Hooded Vulture Necrosyrtes monachus populations have declined dramatically in recent years, but we know little about their ecology. We radio-tagged four vultures in northern Botswana to gather data on animal movement and home-range patterns. Hooded Vultures were primarily sedentary at night. Hooded Vultures moved similar distances and speeds during the wet and dry season, and travelled over similar home ranges as measured using minimum convex polygons (MCP), but used much smaller core areas during the dry (breeding) season. We found significant differences in mean distances and speeds moved among different birds, and when comparing day to night, but not between the wet (non-breeding) and dry (breeding) season or by year. All of the variables we tested, including individual vulture differences, season, year and number of fixes, significantly influenced 95% MCP and kernel density estimate (KDE) home-range sizes. Hooded Vultures used significantly smaller KDE home-range sizes during the dry (breeding season) than in the wet (non-breeding) season. Hooded Vultures travelled smaller daily distances over smaller home ranges than most other vulture species for which data exist.  相似文献   

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Katja Werthmann 《Ethnos》2013,78(1):95-111
The article provides an example of how 'formal' and 'informal' modes of power and legitimacy, as well as material and symbolic leadership resources, may intersect and interrelate. It analyses the sources of power that a Big Man in West Africa mobilised in order to appropriate mining rights and to establish leadership in a gold mining camp. As an entrepreneur in an economic field directly regulated by state laws and authorities, he has to operate within these structures while at the same time subverting them by creating a 'system of personal power' that resembles Sahlins' classic model of the Big Man in Melanesia. Although he is elected to represent the gold diggers, his leadership position rests not so much on a formal vote as on wealth, violence, and charisma. These attributes are underscored in performances that draw on symbols of power and prestige, linking commonly held ideas about traditional rule and conspicuous consumption to personal legitimacy.  相似文献   

7.
The impact of landscape fragmentation resulting from human‐ and climate‐mediated factors on the structure of a population of Glossina tachinoides Westwood (Diptera: Glossinidae) in the Mouhoun River basin, Burkina Faso, was investigated. Allele frequencies at five microsatellite loci were compared in four populations. The average distance between samples was 72 km. The sampling points traversed an ecological cline in terms of rainfall and riverine forest ecotype, along a river loop that enlarged from upstream to downstream. Microsatellite DNA demonstrated no structuring among the groups studied (FST = 0.015, P = 0.07), which is contrary to findings pertaining to Glossina palpalis gambiensis Vanderplank in the same geographical area. The populations of G. tachinoides showed complete panmixia (FIS = 0, P = 0.5 for the whole sample) and no genetic differentiation among populations or global positioning system trap locations. This is in line with the results of dispersal studies which indicated higher diffusion coefficients for G. tachinoides than for G. p. gambiensis. The impact of these findings is discussed within the framework of control campaigns currently promoted by the Pan African Tsetse and Trypanosomosis Eradication Campaign.  相似文献   

8.
Bacterial wilt caused by the Ralstonia solanacearum species complex (RSSC) is a disease that negatively affects the cultivation of Solanaceae crops in Burkina Faso. Knowledge of the pathogen diversity is essential to deploy locally adapted control methods. In this study, diseased plants showing typical bacterial wilt symptoms were collected in the three main agroclimatic zones of Burkina Faso for the detection of RSSC isolates. Strain characterization was achieved through a phylogenetic and pathogenicity diversity assessment. A total of 102 isolates were sampled, and Phylotype I (Ralstonia pseudosolanacearum) was predominant (n = 101; sequevars 14, 31, 34, and 46). The remaining isolate was characterized as Phylotype IIA-35 (Ralstonia solanacearum). Phylotypes I-31 and I-46 were predominant and both characterized as the most the aggressive group of strains amongst a subset of 33 representative isolates. Our findings provide valuable information as regard RSSC diversity that breeders and resistance programme should target in order to fight this pathogen in Burkina Faso and around the world.  相似文献   

9.
In Sub‐Saharan Africa, An. gambiae sensu lato (s.l.) Giles 190, largely contributes to malaria transmission. Therefore, the authors carry out a proteomic analysis to compare its metabolic state, depending on different pesticide pressures by selecting areas with/without cotton crops. The proteomes data are available via ProteomeXchange with identifier PXD016300. From a total of 1.182 identified proteins, 648 are retained for further statistical analysis and are attributed to biological functions, the most important of which being energy metabolism (120 proteins) followed by translation‐biogenesis (74), cytoskeleton (71), stress response (62), biosynthetic process (60), signalling (44), cellular respiration (38), cell redox homeostasis (25), DNA processing (17), pheromone binding (10), protein folding (9), RNA processing (9), other proteins (26) and unknown functions (83). In the Sudano‐Sahelian region, 421 (91.3%) proteins are found in samples from areas both with and without cotton crops. By contrast, in the Sahelian region, only 271 (55.0%) are common to both crop areas, and 233 proteins are up‐regulated from the cotton area. The focus is placed on proteins with putative roles in insecticide resistance, according to literature. This study provides the first whole‐body proteomic characterisation of An. gambiae s.l. in Burkina Faso, as a framework to strengthen vector control strategies.  相似文献   

10.
ABSTRACT   Understanding how and why domestic groups alter their function and form has long been a theme within anthropology. Numerous accounts have detailed the processes that drive household transformations and their underlying mechanisms. Mostly, these studies describe how domestic groups fission and fuse between extended and nuclear forms. In recent years, scholars have emphasized that these transformations should be understood within larger contexts of social and environmental change. Mossi communities on the Central Plateau of Burkina Faso provide an excellent opportunity to explore such processes because the large extended households documented 30 years ago were predicted to decline and eventually disappear. In this study, I examine dynamics of household transformations and test the validity of this prediction. I use perspectives from sustainability science and computer-simulation modeling to understand how regional desiccation, agricultural intensification, and livelihood diversification articulate with domestic transitions.  相似文献   

11.
The use of vegetables in two rural communities in Burkina Faso is quantified through the use of food diaries kept by 13 households during one year. Interviews on preferences, field registration, and a market survey supplement the diaries. The use of wild species is concentrated onParkia biglobosa, Corchorus spp.,Adansonia digitata, andBombax costatum. At least five other wild species are mentioned as important but very rarely occur in the diet, indicating the usefulness of diaries compared to interviews.Capsicum frutescens, Abelmoschus esculentus, Allium cepa, andSolanum lycopersicon are the most commonly used cultivated species. Wild vegetables constitute 35% and 59% of the total vegetable consumption in the two communities. Most products are highly seasonal in supply and prices vary accordingly. Households compensate for the seasonality by drying products, but stocks are often insufficient and vegetable purchases needed. Many of the vegetable species studied should be integrated in agricultural research and extension programs.  相似文献   

12.
Melissopalynological analysis of 60 honey samples collected from 50 Kenyan Top Bar Hives in the North Sudanian phytogeographical region of Burkina Faso established the plant species foraged by honeybees Apis mellifera adansonii. Forty-three pollen types from 29 families were identified in the honey samples. The most common families were Mimosaceae (9.30%), Asteraceae (6.98%) and Anacardiaceae (6.98%). The most frequently visited plants were Combretum (66.66%), Tridax procumbens (66.66), Acacia seyal-group (50%), Cleome viscosa-group (50%) and Cyperus esculentus (41.67%). The results showed that Apis mellifera adansonii is polylectic with a heterogeneous foraging behaviour. Pollen analysis showed that the honeys from the two main honey flows of Burkina Faso were polyfloral.  相似文献   

13.
A multidisciplinary work was undertaken in the agropastoral zone of Sidéradougou, Burkina Faso to try to elucidate the key factors determining the presence of tsetse flies. In this study the PCR was used to characterize trypanosomes infecting the vector ( Glossina tachinoides and Glossina palpalis gambiensis ) and the host, i.e. cattle. A 2-year survey involved dissecting 2211 tsetse of the two Glossina species. A total of 298 parasitologically infected tsetse were analysed by PCR. Trypanosoma vivax was the most frequently identified trypanosome followed by the savannah type of T. congolense and, to a lesser extent, the riverine forest type of T. congolense , and by T. brucei . No cases of T. simiae were found. From the 107 identified infections in cattle, the taxa were the same, but T. congolense savannah type was more frequent, whereas T. vivax and T. congolense riverine forest types were found less frequently. A correlation was found between midgut infection rates of tsetse, nonidentified infections and reptile bloodmeals. These rates were higher in G.p. gambiensis , and in the western part of the study area. T. vivax infections were related to cattle bloodmeals, and were more frequent in G. tachinoides and in the eastern study area. The PCR results combined with bloodmeal analysis helped us to establish the relationships between the vector and the host, to assess the trypanosome challenge in the two parts of the area, to elucidate the differences between the two types of T. congolense , and to suspect that most midgut infections were originating from reptilian trypanosomes.  相似文献   

14.
In Burkina Faso, Glossina palpalis gambiensis Vanderplank and G. tachinoides Westwood (Diptera: Glossinidae) are the main cyclic vectors of trypanosomiasis. The vegetation type along river banks is an important factor determining the distribution and abundance of these tsetse. The following work investigated the relation between the plant species present (including the disturbance level) and tsetse distribution and abundance, using three ecotypes, described by P.C. Morel in 1978. These were the Guinean, Sudano-Guinean and Sudanese gallery forests. In the Mouhoun River basin, these three ecotypes are found successively from upstream to downstream. Berlinia grandiflora, Syzygium guineense and Cola laurifolia and finally Acacia seyal and Mitragyna inermis were the best indicators for the Guinean, Sudano-Guinean and Sudanese gallery forest ecotypes, respectively, as suggested by Morel. However, other species such as Pterocarpus santalinoides and Mimosa pigra were not ecotype specific. Trap catches confirmed that G. palpalis and G. tachinoides are predominant in Guinean and Sudanese gallery forests, respectively, and that both species are well represented in the Sudano-Guinean ecotype. Tsetse densities dropped significantly in disturbed Sudano-Guinean and Sudanese gallery forest sites. However, this was not the case for both species in Guinean or for G. tachinoides in half-disturbed Sudanese gallery forest sites, confirming their high resilience to human-made changes. The importance of a detailed consideration of riverine ecotypes when predicting tsetse densities is discussed.  相似文献   

15.
We have studied To study the incidence of hemoglobinopathies (Hb C and Hb S) we have examined in 15,367 students, aged 11.4+/−4.64 years (median 11; range 1–26), living in Burkina Faso (12,019 were students of 23 public schools of Ouagadougou and 3348 students of 7 public schools situated in six villages about 12–35 Km from Ouagadougou). In all groups studied, β S and β C gene frequencies were age dependent there was an age dependency of the β S and β C gene frequencies, since the advantage of HbS carriers in a malarial region is prevalently expressed in the first years of life. In fact, β C the gene frequency of β C increases, and the β S decreases with age. The Mossi, living prevalently mainly in Ouagadougou, show a gene frequency which is similar to the Bissa ethnic groups, where the C gene frequencies (0.116 and 0.118) wereare more higher than the S (0.049 and 0.044 respectively). On the contrary in the Peuhl ethnic group the β C and β S gene frequencies (0.049 and 0.049) were are the same, while in the Yorouba ethnic group immigrated from Nigeria a prevalence of β S gene frequency is higher (0.117) than over the β C (0.068)gene frequencies was found in the Yorouba ethnic group, who is immigrated from Nigeria, showing that different gene frequencies are found in different ethniae ethnic groupscorrespond to different gene frequencies.  相似文献   

16.
Objective: To study the incidence of hemoglobinopathies (Hb C and Hb S) we have examined 15,367 students, aged 11.4+/-4.64 years (median 11; range 1–26), living in Burkina Faso (12,019 were students of 23 public schools of Ouagadougou and 3348 students of 7 public schools situated in six villages about 12–35 Km from Ouagadougou). Results: In all schools, we found a prevalence of females (54.2%) over males (45.8%) with a high incidence of Hb AC (19.16%), over Hb AS (8.35%). As expected, the gene frequency of β C in the schools of Ouagadougou was 0.112+/-0.015 and of β S 0.049+/-0.012, and this was similar in village schools (0.128+/-0.010 and 0.049+/-0.09 respectively), irrespective of town latitude. In all groups studied, β S and β C gene frequencies were age dependent since the advantage of HbS carriers in a malarial region is prevalently expressed in the first years of life. In fact, β C gene frequency increases, and β S decreases with age. The Mossi, living mainly in Ouagadougou, show a gene frequency which is similar to the Bissa ethnic groups, where the β C gene frequencies (0.116 and 0.118) are higher than the β S (0.049 and 0.044 respectively). On the contrary in the Peuhl ethnic group β C and β S gene frequencies (0.049 and 0.049) are the same, while in the Yorouba ethnic group immigrated from Nigeria β S gene frequency is higher (0.117) than the β C (0.068), showing that different gene frequencies are found in different ethnic groups. Conclusion: The difference in β S and β C genes frequencies (0.049 and 0.116) found in comparison with a previously performed study (Labie et al, 1984) in the same region (0.03 for the β S gene and 0.14 for the β C gene), may be due to migration flow of β S genes from the near Sahel region or to changes in life expectancy of children with β C and β S phenotypes. Moreover, the high percentage of SC (1,06%) and SS (0.188%) individuals detected with the present screening, compared with the lower percentages found by Labie et al in 1984, suggest that a modified environment can play an important role in reducing the morbility and lethality of β S genotype. However, even today the number of students affected by HbSC and Hb SS attending the schools remains low. Stricter controls of correlated diseases are necessary to guarantee healthier life conditions.  相似文献   

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18.
The present study was conducted in five villages around the Nazinga Game Ranch, Burkina Faso. Fifty informants of the Gourounsi ethnic group were used. Eighty-one useful woody species were identified, out of a total of 110 woody species in the area. Woody plant use was quantified as: edible fruits (28 species), vegetable sauce (22 species), firewood (33 species), construction (29 species) and medicine (64 species and 167 remedies). Further, species accumulation curves were used to estimate that more than 650 remedies for medicine are used in the area. The community's knowledge of plants was analysed in relation to age, gender, village of residence and amount of intercultural visits. The knowledge pattern was remarkably uniform, with only two variations: (1) men generally identified more edible fruit trees than women, and (2) one village reported more firewood species than the other four villages. The informants had a variety of opinions concerning the availability of useful plants, but the majority found the availability to be fine and 47% of the informants searched for useable products in the savanna on a daily basis. No correlation was found between an informant's impression of useful products availability and his/her frequency of visits into the savanna. The results show that the Gourounsi people live in intimate relation with the savanna surrounding their villages. They are aware of the environment and are willing to learn and adopt new conservation practices.  相似文献   

19.
Species distribution modelling is gaining popularity due to significant habitat shifts in many plant and animal species caused by climate change. This issue is particularly pressing for species that provide significant ecosystem goods and services. A prominent case is the valuable African rosewood tree (Pterocarpus erinaceus) that is threatened in sub-Saharan Africa, while its present distribution, habitat requirements and the impact of climate change are not fully understood. This native species naturally occurs in various savanna types, but anthropogenic interventions have considerably reduced its natural populations in the past decades. In this study, ensemble modelling was used to predict the current and future distribution potential of the species in Burkina Faso. Fifty-four environmental variables were selected to describe its distribution in the years 2050 and 2070 based on the greenhouse gas concentration trajectories RCP4.5 and 8.5, and the general circulation models CNRM-CM5 and HadGEM2-CC. A network of protected areas in Burkina Faso was also included to assess how many of the suitable habitats may contribute to the conservation of the species. The factors isothermality (31%), minimum temperature of coldest month (31%), pH in H2O at horizon 0–5 cm (11%), silt content at horizon 60–100 cm (9.2%) and precipitation of warmest quarter (8%) were the most influential distribution drivers for the species. Under current climate conditions, potentially highly suitable habitats cover an area of 129,695 km2, i.e., 47% of Burkina Faso. The projected distribution under RCP4.5 and 8.5 showed that this area will decrease, and that the decline of the species will be pronounced. The two models used in this study, forecast a habitat loss of up to 61% for P. erinaceus. Hence, development and implementation of a conservation programme are required to save the species in its native range. This study will help land managers prioritise areas for protection of the species, and avoid introducing it to inappropriate areas unless suitable conditions are artificially created through the management options applied.  相似文献   

20.
We tested the hypothesis that elephant distribution inside the Nazinga Game Ranch (Southern Burkina Faso) during the wet season is influenced by villages outside, while in the dry season elephants are restricted only by water. Occupancy was evaluated by recording elephant dung‐piles on 54 line transects in each of three seasons: wet 2006, dry 2007 and dry 2008. We measured the distance of each transect from nearest villages, nearest permanent water sources, nearest guard posts and tourist camps. The results were unexpected: elephant occupancy in the wet season was independent of villages but influenced by poaching, while their occupancy in both dry seasons was determined by the proximity of villages as well as water. In the dry season, elephants were attracted to villages by grain stores and fruiting trees. There has been a dramatic shift in the dry season distribution of elephants, and consequently in browsing pressure, over the last two decades. We suggest that this change is a consequence of the expansion of human activities outside the ranch. This study shows that the effects of growing human disturbance on elephant populations in small protected areas are not predictable. Correcting for spatial autocorrelation had a negligible effect upon the models.  相似文献   

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