Browsing by Author "Hassan, S.N"

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Avifauna community in a threatened conservation landscape, western Tanzania: a baseline
(Tanzania Journal of Forestry and Nature Conservation, 2023) Mgelwa, A.S; Mpita, M.O; Rija, A.A; Kabalika, Z.; Hassan, S.N
Conservation of avian biodiversity in landscapes under immense anthropogenic pressures is dependent on sound population data that could guide informed conservation strategies. Using point count surveys, field observations and interviews, we assessed bird communities in Lake Rukwa, an anthropogenically threatened ecosystem in western Tanzania, to establish some vital parameters on this taxon. A total of 5840 bird individuals belonging to 85 species, 17 orders and 39 families were recorded. Of these, five were globally threatened and 19 were migrant species. Avian Shannon’s (H’) and Simpson’s (D) diversity indices were 2.936 and 0.8655, respectively. Bird species richness was different across foraging and habitat guilds (both p = 0.0001). Insectivores were the most species-rich foraging guild, while nectarivores were the least; similarly, non-forest birds were the most species-rich habitat guild, while forest generalists were the least. Grazing, bushfires, tree cutting, unsustainable fishing and bird harvesting are the major anthropogenic threats to bird biodiversity in the area. Regular provision of conservation-related education programs to local residents is a highly recommended conservation measure. This study serves as a baseline for avifaunal monitoring in Lake Rukwa and provides useful insights into the avifauna conservation planning in anthropogenically disturbed landscapes.
Foraging in a 3-D world: the influence of body size and sex on vertical and horizontal foraging behaviour of yellow baboons
(Tanzania Journal of Forestry and Nature Conservation, 2022) Kitegile, A.S; Hassan, S.N
Foraging is among complex animal behaviours, which involve making decisions on what and where to forage, so as to maximize nutritional gain and reduce predation risk. In ungulates, it is known to also be influenced by sexual size dimorphism, however, this is not clear in sexually size dimorphic yellow baboon. Using focal animal sampling techniques, we collected data from habituated troops of yellow baboons to test whether body size and/or sex has influence on their use of vertical and horizontal strata when foraging. Results showed that, yellow baboons foraged more frequently on the ground up to 1 m than beyond this height. However, adult females foraged on the ground significantly more frequently than adult and subadult males. While, adult and subadult males used higher canopy beyond 2 m, more frequently than adult females. Moreover, adult females and subadult males foraged more frequently at the troop centre than adult males. This study concludes that sex and to some extent body size significantly influence foraging decisions of yellow baboon in the use of vertical and horizontal strata. Detailed understanding of spacing behaviour of baboons is recommended as it is important towards better understanding f their complex social life