Search

In West Africa, whether in forests or savannahs, most of the large mammal species have a scattered spatial distribution. Monitoring their population size represents a logistic, financial, theoretical challenge because counting of transects is not appropriate, unlike elsewhere in Africa. In this study, we (i) analyse the patterns of interannual (2006–2008) changes in population density of seven sympatric species of savannah herbivores in a protected area of Burkina Faso with two alternative methods: dung counts versus direct counts and (ii) quantify the economic costs for these two methods. The seven species of mammals we considered are the following: Hippotragus equinus, Alcelaphus busephalus, Sylvicapra grimmia, Tragelaphus scriptus, Ourebia ourebi, Kobus ellipsiprymnus and Phacochoerus africanus. A distance methodology was used to generate estimates with both methods. There were significant correlations between estimates of mammal density obtained using dung counts and direct counts, and an analysis of covariance revealed that the interannual trends in population densities were consistently detected with both methods. In addition, the dung count method costs 55% less. Thus, our study documents that dung counts can be used as a proxy of population size fluctuations for the seven studied species, offering a methodological alternative that is much less expensive, less sophisticated in terms of equipment compared to other methods and that can be performed by field staff with moderate professional qualification. We suggest that standardized campaigns of dung count surveys may be applied to all protected areas and savannah in Burkina Faso, West Africa, in order to improve evidence-based, large-scale conservation and management planning in the region.

To explore the patterns of bushmeat trade in the Sahel we carried out a multidisciplinary study, focusing on Burkina Faso. We conducted baseline interview surveys to examine the variation in people's perceptions of bushmeat in relation to their place of residence (urban vs rural), sex and age. We also analysed the long-term (1985–2010) population dynamics of two ungulate species, the oribi Ourebia ourebi and the common duiker Sylvicapra grimmia, known to be among the main targets of the bushmeat trade locally. For the antelopes we chose as our study area a protected area (Nazinga Game Ranch) where poaching activities occur and are likely to represent a threat to the local wildlife. The results of the interviews underlined significant differences in bushmeat consumption between rural and urban areas. In particular, the probability of finding people who did not consume bushmeat increased in the urban area, where bushmeat is less available than in the rural areas. Sex and age did not have any effect on people's perceptions of bushmeat. In Burkina Faso bushmeat is still widely consumed, and this could be because the bushmeat trade is poorly controlled, with a lack of enforcement of the legislation. Long-term field surveys revealed that the oribi and the common duiker have declined significantly in Nazinga Game Ranch, suggesting that the bushmeat trade in Burkina Faso may have negative consequences in terms of the conservation outlook for these species.

1. An age and sex structure study of the West African savannah elephant (Loxodonta africana africana) population of the Nazinga Game ranch (Burkina Faso) was carried out using direct sightings of individuals near water points, where they group during hot periods of the day, and droppings circumference measurements of dung pile along line transects, during the dry seasons of 2007 and 2008. The age structure, from direct observation data, was estimated by classifying the individuals into 9 age-class-categories based on body size and eruption (length) of tusks.2. The frequency distribution of number of individuals into the age-class-categories showed high similarity with the distribution of circumference measurements of dung-piles that the individuals were seen depositing. Fifty dung-piles measured soon after they were deposited (Class A) and after they dried (to class C) showed a significant difference between the circumference measurements in relation to the time elapsed between the measurements.3. The frequency distribution of dung circumference classes of the observed elephants was similar to that of the dung-piles measured along the transects in 2008. Therefore, dung-piles measurements were used to estimate the Nazinga Game Ranch savanna elephant population’s age and sex structures at the end of dry seasons of 2007 and 2008. We advocated that the Nazinga elephant population consisted mainly of sub-adults.4. The sex ratio was estimated to be in favour of females (1/2). The age-class-specific sex ratio was uneven for calves and young individuals, while being in favour of females with adults. Individuals of less than 1 year represented 6% of the population during the study period.

African elephants (Loxodonta africana) are ecosystem engineers in African savannahs, but their role in the modifications of the populations of trees by means of their browsing activities has been poorly studied so far in West Africa. We studied the disturbance of elephants to eight selected species of trees in the Nazinga Game Ranch (Burkina Faso), in 54 transects at the end of dry season 2008. We fitted simple models describing the number of dead individuals for each tree species in relation to their initial population density, and in relation to dung-pile density, in the assumption that there should be a positive relationship between elephant density and dung-pile density. Generalized Linear Model analyses and regression analyses showed that the more dense the woodland cover, the least the percentage of damaged plants by elephants. For each plant species, the initial density and density of elephant dung-piles explained a high proportion of the variance in the density of dead individuals. Stochastic models, generated by a purposely created simple computer program written in GW-BASIC programming language, predicted changes in tree and shrub abundance under different assumptions about elephant numbers. The models suggested that elephant browsing may cause considerable change in the selected plant populations, especially with regard to such species as Acacia gourmaensis, Vitellaria paradoxa and Maytenus senegalensis. These changes may possibly increase the meat harvest from controlled hunting activities, thus improving the income for surrounding communities.

The use of multimetric indices as tools for assessing aquatic ecosystem health in most of the developing countries such as Togo is still lacking. To fill this gap, we developed a macroinvertebrates-based multimetric index for the Zio river basin of Togo. Forty-two sites were assessed for the development and the validation of the Multimetric Index of Zio River Basin (MMIZB). Thirty-nine candidate metrics belonging to four categories (composition metrics, functional feeding metrics, diversity metrics and tolerance measure metrics) were evaluated. After comprehensive multiple selection procedure, six core metrics were retained to provide the final MMIZB. The results showed that the MMIZB responded to a set of organic pollution (chemical oxygen demand, ammonium, total suspended solid) and hydromorphological alterations, which corresponded to a set of gradients of human pressures affecting the ecological integrity of Zio river basin water bodies (r = 0.78, p

The meat of wild animals (bushmeat) is consumed extensively in many tropical regions. Over the past few decades bushmeat consumption has greatly increased, threatening the survival of some hunted species and the supply of animal protein to countless numbers of people. Understanding patterns of bushmeat consumption is thus vital to ensure the sustainable use of this resource. Although the economic drivers of bushmeat consumption have been well studied, non-wealth correlates have been poorly considered. Here, we analyse how variables such as age and gender may influence bushmeat consumption in four West African countries, within the Guinean forests (Togo and Nigeria) and Sahel (Burkina Faso and Niger). We interviewed a total of 2453 persons (1253 urban, 1200 in rural areas) to determine frequency of consumption of bushmeat as well as the main species eaten. We found significant differences in bushmeat consumption between rural and urban areas in all four countries. In particular, the proportion of persons not consuming any bushmeat was highest in urban areas. Gender differences in bushmeat consumption were not generally important but young people consistently avoided eating bushmeat, especially in Togo and Nigeria, and in urban areas. The complicated interplay between tradition and evolution of social systems (especially the trends towards westernization) may explain the different perceptions that people may have towards consuming bushmeat in the four studied countries. In addition, we found considerable variation in types of bushmeat eaten, with antelopes and large rodents eaten by the great majority of interviewees, but bats, monkeys, and snakes being avoided, especially in urban settlements.

During the last decades, the critically endangered Hooded Vulture Necrosyrtes monachus has strongly declined across its African range. Although direct persecution has been suggested as a major cause of this decline, little is known about the impact of humans on reproductive output in West Africa. We studied the impact of human activities on the reproductive output of Hooded Vultures in the Garango area of Burkina Faso. Twenty and 56 nesting attempts were monitored, respectively, during the breeding season in 2013/14 and 2014/15, to determine reproductive success and identify causes of nest failure. Annual breeding success varied between 0.68 and 0.71 chicks fledged per breeding pair per year and productivity was assessed at 0.57 chicks fledged per territorial pair in 2014/15. The main threats imposed by humans were poaching of eggs, chicks and collection of nest materials, leading to 20% (13 out of 64 breeding attempts) of nest failures over the two years. An additional important reason for nest failure was the pruning and (partial) cutting of nest trees. Despite this high level of human interference, we found that Hooded Vulture nest success increased with proximity to human settlements, probably because breeding vultures benefit from protection by people against persecution and disturbance.Keywords: Burkina Faso, conservation, Hooded Vulture, human impact, reproduction

Few studies are available on the population dynamics of medium and large mammals in gallery forests of the Sudan and Sahel regions of West Africa. Line-transect studies of the abundance (estimated by KIA) of nine species of ungulates and three species of primates were carried out between 2004 and 2013 in the Comoé-Leraba protected area of Burkina Faso, West Africa. No peer-reviewed study of population sizes of mammals in this protected area has been published, making the data presented of special relevance. Population size trends varied significantly across years in both primates and ungulates, with some species (Papio anubis, Phacochoerus africanus, Alcelaphus busephalus and Tragelaphus scriptus) decreasing consistently. Significant relationships were observed between poaching intensity and population oscillations in Erythrocebus patas, Kobus ellipsiprymnus, Kobus kob, Ourebia ourebi and Cephalophus rufilatus.

The benthic macroinvertebrates communities dynamic were investigated in rivers from Burkina Faso in the purpose to analyze the taxonomic composition, the structure of benthic macroinvertebrates community and the composite environmental variables that correspond to the major distribution patterns of this community. The results showed that a total of 132 taxa was recorded and the large majority of these (103 taxa) belonged to 57 families from 8 orders of insects that represent 95% of relative abundance. We also observed some distinct differences relative to the spatial and temporal variation in the taxonomic composition. The canonical correspondance analysis (CCA) revealed a strong correlationship between Chironomidae, Syrphidae, Culicidae, Psychodidae, as well as the Pulmonates molluscs and organic nutriments feeding dynamics. These findings showed the sensitivity of benthic macroinvertebrates at different level: sensitivity which could be attributable to man-induced activities. © 2016 International Formulae Group. All rights reserved. Keywords: Benthic macroinvertebrates, enviromental variables, dynamic, Burkina Faso