Bruno A. Djossa

Folk perception of sexual dimorphism, sex ratio, and spatial repartition: implications for population dynamics of Sclerocarya birrea [(A. Rich) Hochst] populations in Benin, West Africa

In Sub-Saharan Africa, indigenous fruit trees play vital roles in nutrition and food security particularly, in food shortage times. Sclerocarya birrea subsp. birrea, an indigenous dioecious fruit tree is such a resource with strong multipurpose use characteristics in semi-arid zones of West Africa. We assessed sex ratio, spatial distribution among male and female adult trees using second-order spatial statistics and assessed folk perception of dioecism among the natural populations in protected areas and surrounding agroforestry systems. A field survey showed that 55% of interviewees were aware of sex separation in the species. Some used bark appearance to make distinction between sexes, but this morphological criterion was not consistent with statistical results. The sex ratio did not deviate significantly from 0.5 in any of the districts or land use types. Bivariate spatial analysis with pair correlation function revealed no spatial association between male and female individuals. Moreover, a strict spatial segregation of sexes was not observed even though some individuals of the same sex could sometimes be found together. Results confirmed the functional dioecy of the species and showed that the species did not display any apparent sex-specific dimorphism outside the reproduction period or any apparent sex-specific requirement for environment conditions.

Hunting Affects Dry Season Habitat Selection by Several Bovid Species in Northern Benin

Multiple land uses including tourism, hunting, and agriculture around protected areas can be a serious complication for wildlife management. We calculated habitat selection indices (Manlys alpha) for 10 bovid species in the Pendjari Biosphere Reserve in Benin, west Africa, to assess if habitat use differed in each bovid species between hunting and non-hunting zones. Presence/absence data was used in resource-selection functions based on a generalized linear mixed effect model to examine factors that explained bovid species distribution. We observed stronger avoidance of open habitat types in the hunting zone than in the non hunting zone for the hartebeest Alcelaphus buselaphus, oribi Ourebia ourebi, roan Hippotragus equines, kob Kobus kob, Waterbuck Kobus ellipsiprymnus defassa and reedbuck Redunca redunca. In contrast, in grey duiker Sylvicapra grimmia, red-flanked duiker Cephalophus rufilatus, bushbuck Tragelaphus scriptus and buffalo Syncerus caffer we found no differences in habitat use between hunted and non-hunted areas. This may indicate that the latter species show more pronounced ecological and behavioural plasticity. Further, resource selection of bovid species on a small scale was influenced by other factors such as habitat structure, landscape characteristics, and human disturbance. This preliminary assessment of bovid habitat relationships in west Africa suggests that human hunting activities may cause species to alter their habitat selection. We therefore suggest habitat models may need to incorporate this source of variation if they are to accurately predict habitat use or distribution of a species.

Mangroves in Benin, West Africa: threats, uses and conservation opportunities

Mangrove ecosystems constitute valuable resource all over the world. They provide habitats for flora and fauna species, protect the coast against erosion and supply various products for local communities. Currently, mangroves are overused and degraded. Up to now, perceptions of local communities on the dynamic of mangrove forest and their acceptable participation forms for mangroves restoration have not been entirely understood. This study was undertaken in order to assess human pressure on mangroves from user perspective and to provide baseline information for its sustainable management in three districts (Grand-Popo, Ouidah and Sèmè-Kpodji) located in the coastal area of Benin. Structured and semi-structured questionnaire surveys regarding perceptions of mangrove forest dynamic, causes of mangrove forest degradation, indigenous restoration strategies and forms of participation were conducted among randomly selected informants. It has been reported that Beninese mangrove ecosystems supply timber and non-timber forest products, rich fishing grounds and salt for local communities. Local communities are aware of the need of restoring and ensuring sustainable conservation of mangrove ecosystems. Dominant measures for restoration and conservation indicated by informants for mangrove users include the reintroduction of traditional rules, avoidance of uncontrolled settlements, planting of mangrove trees, planting alternative fuelwood, use of solar energy for salt production and creation of alternative income generating activities. Planting mangrove trees and alternative cooking energy sources supplying to local communities to avoid mangrove destruction are urgent needs for the coastal area of Benin.

Vigilance efficiency and behaviour of Bohor reedbuck Redunca redunca (Pallas 1767) in a savanna environment of Pendjari Biosphere Reserve (Northern Benin)

Abstract. This study was performed to gain more knowledge about the Bohor reedbuck time budget and vigilance in a savanna habitat. Detailed data on the time-budget were collected through focal animal observation technique to determine whether the time budget activities of Bohor reedbuck was affected by vegetation cover and to test if herd size, position in herd, the age and sex affect vigilance efficiency. We fit generalized linear mixed-effect models to assess how herd size, sex, animal position in the herd and age affected individual time allocation to vigilance behaviour. The most parsimonious model averaging clearly showed how vigilance behaviour among Bohor reedbuck was strongly affected by age, sex, the total herd size and animal position in the herd accounting for the lowest value of Akaike Information Criterion (AIC). Vigilance and feeding behaviour occupied the largest percent of Bohor reedbuck daylight time budget. Herd size effects were significant on different behaviour categories only when the Bohor reedbuck was observed in sympatric association. Our findings support the herd size effect hypothesis only in sympatric grouping system. However, further study is needed to investigate the possible sex-specific functions and targets of vigilance behaviour with respect to the herd direction in the field.