Population Structure, Behavioural Ecology and Habitat Vulnerability of Gelada (Theropithecus gelada) in Guassa Community Protected Area, Ethiopia
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Date
2015-03
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Addis Ababa University
Abstract
Gelada is the only survivor of the genus Theropithecus, which once included several successful
extinct species that lived in Africa and Asia. The wild populations of gelada are now restricted
only to the Ethiopian plateau. The present investigation deals with population structure,
behavioural ecology and habitat vulnerability analysis of gelada (Theropithecus gelada)
population in Guassa Community Protected Area, Ethiopia. To collect data on population
structure and behavioural ecology, three units were identified from six bands of geladas. In
order to examine the social bonds among geladas, a total of 2,467 grooming interactions in 320
hours of grooming bouts were extracted from the data set. A total of 7, 890 and 6,250 feeding
records were obtained from scan sampling during wet and dry seasons, respectively. Nutritive
value of food plants of geladas was determined. For habitat vulnerability analysis, land-cover
data from Landsat images of 1986, 2002 and 2013 were used. Structured interviews and group
discussions were held with the local people to assess their attitude towards gelada and the
protected area. The mean number of females per harem varied from 4.1 to 7.1 for the six
studied bands. The sex ratio (females per males), the adult sex ratio and the mean number of
reproductive females within the units were not statistically significant between seasons (P >
0.05). In the study bands, there was an overall increase of the population by 17.1 % per annum.
The mean annual mortality rate of geladas was 1.4 %. Geladas spent significantly more time in
foraging and moving during the dry season compared to the wet season, whereas the time spent
in grooming, playing and resting were significantly more during the wet season. The food
plants of geladas were better in protein, crude fibre and neutral detergent fibre constituents, but
poor in fat. Change detection matrices revealed that within a representative subset of the study
area, grassland, Helichrysum, farmland and shrubland have decreased from their previous
extent of cover, whereas extents of forest and Erica have increased. The difference in the unit
size and variations in time spent on activity patterns of geladas between seasons were related to
seasonal variability. The extent of grassland, Helichrysum and shrubland decreased during the
period 1986 - 2013. This might be due to human induced and ecological process, whereas the
extents of forest and Erica have increased, which might be correlated with the increasing forest
conservation efforts in the area. This investigation provides useful information on gelada
population structure, habitat changes and attitude of local community towards gelada and their
conservation in the study area.
Keywords: Behaviour, band, community participation, geladas, Guassa, habitat change
detection, land-use/land-cover changes, population structure, nutritive value
Description
Keywords
Behaviour, Band, Community Participation, Geladas, Guassa, Habitat Change, Detection, Land-Use/Land-Cover Changes, Population Structure, Nutritive Value