Breeding population status and habitat preferences of white- backed vulture in Ikorongo- Grumeti Game Reserves and Ikona Wildlife Management area in Western Serengeti
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Date
2024-05
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Sokoine University of Agriculture
Abstract
White -backed vulture (Gyps africanus) is a critically endangered
species since its population has significantly declined across its
geographical ranges. Apparently, vultures provide the ecosystem
with cleaning service hence reduced risk of disease spread through
their feeding behaviour. Studying the breeding population status and
habitat of these species is of paramount importance in maintaining a
healthy population as well as managing and mitigating threats to the
species and their associated habitats.
This study aimed at investigating the breeding population status and
the nesting preferences of the Gyps africanus population in the
Ikorongo-Grumeti Game Reserves and Ikona wildlife management
area (WMA) in the western corridor of the Greater Serengeti
Ecosystem along the primary riparian zones (PRZ). The PRZ
consisted of the Grumeti, Manchira, Nyabeu, Samisami, Rokare,
Romoti, Maruru and Muyambi Rivers and their tributaries. This study
used the project historical aerial surveys data gathered from 2013 to
2021 to produce breeding population trend and conducted ground
nest surveys in 2021 and 2022 to estimate the breeding success
and nesting preferences of the species. Due to the colonial nesting
behaviour of the species, cluster analysis was used to group the
nesting hotspots as well as remote sensing analysis to assess the
tree cover in their breeding habitat.
According to results of the aerial survey data, the breeding
population in the game reserves and their contiguous WMA has
declined by 56%, and based on the active nest survey, breeding
success was 29%, that being lower than the previously documented
information for the Greater Serengeti Ecosystem which was 90%.
Individuals were found nesting along the rivers in the Ficus and
Vachellia and Senegalia woodlands. Majority of the nests (57%)
were found on Ficus sycomoras whereas the least number (1%) was
found on Ficus indica. The tree height was the most significant tree
factor for nesting tree as observed from the generelized linear
model. Nesting hotspots were classified as former or intermittent hotspots, and none were classified as persistent hotspots. Net tree
loss was observed in all hotspot categories, and a 28% reduction in
riparian tree cover was detected.
The study concludes that the Gyps africanus population in the area
is declining, parallel with dropping breeding success and
deteriorating breeding habitats. Seemingly, habitat loss/deterioration
is a driving factor, which together with other potential threats to the
population, need further investigation. Such baseline information is
of critical importance to the management and conservation efforts of
vultures and their overall breeding habitats in the ecosystem.
Description
MSc Dissertation
Keywords
White-Backed Vulture, breeding population, breeding success, tree cover, Greater Serengeti Ecosystem