Flock Size, Habitat Analysis, Diet Composition and Genetic Diversity of Ankober Serin (Serinus Ankoberensis) in Semien Mountains National Park and Guassa Community Conservation Area, Ethiopia
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Date
2017-06-03
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Addis Ababa University
Abstract
Ankober Serin (Serinus ankoberensis) is an endemic bird limited in its distribution to certain high
altitude ranges of Ethiopia. The present study was aimed to study the flock size, habitat disturbance, habitat
analysis, diet composition and genetic diversity of the species in Simien Mountains National Park (SMNP)
and Guassa Community Conservation Area (GCCA). Five flocking sites (ranging from 0.25–0.5 km2) were
identified in each study area. The level of habitat disturbance was categorized as low, medium and high.
Plant species diversity, composition, vegetation cover and height of Ankober Serin’s habitat were assessed
for habitat analysis in two accessible flocking sites per study area. Diet analysis using fecal droppings was
used to determine the diet composition of Ankober Serin in the two accessible flocking sites. The intra and
inter-population genetic diversity was determined from five microsatellite markers. Flock size difference
between wet and dry seasons for the combined data from both study areas was also significant (t (38) = 3.053,
α = .004). Similarly, there was significant difference of mean flock size among all the flocking sites (F9, 39
= 6.882 p=0.000). Level of disturbance was negatively correlated with flock size (r=-.876 at 0.01 level) in
both study areas. The flocking site with Festuca spp. and Helichrysum spp. dominated habitat in SMNP had
the highest flock size (96.7±34.7). There was no direct relationship between vegetation diversity and flock
size. Also, there was no significant correlation between flock size and proportion of herbs (r= -.019, p=
.885), bare ground (r= .030, p=.821) and shrubs (r= .006, p=.963). Vegetation heights of <30 cm constituted
highest proportions in all of the foraging grounds of the flocking sites. There was positive correlation
between flock size and vegetation heights of 31–60 cm (r= .624, p= 0.01) and > 60 cm (r= .577, p= 0.01)
within the same foraging grounds. During the dry seasons, seeds significantly predominated the diet of
Ankober Serin (F1, 6= 324 p=0.000) and (F1, 6= 2437.098 p=0.000) at GCCA and SMNP, respectively, while
leaves were dominant during the wet season (F1, 14= 219.842 p=0.000) and (F1, 6= 580. 246 p=0.000) at
GCCA and SMNP respectively. Three of the four molecular markers i.e., Cuμ28, Ase43 and Ase42 used in
the genetic analysis resulted in significant differences between the populations of SMNP and GCCA (p <
0.05). The presence of shared alleles indicated gene flow between the populations. In GCCA, markers Cu28
and Ase42 showed significant deviations from Hardy-Weinberg equilibrium and in SMNP, the markers
Ase42 and Ase43 showed significant deviations (p<0.05). The variations in flock size may be attributed to
the differences in the degree of disturbance and habitat size. The predominance of leaves during the wet
season could be due to scarcity of seeds during the season. The significant genetic differentiation among the
two populations might have resulted from the geographical separation of the two populations by barriers
such as mountains, valleys and extensive plains as well as the separation distance which is more than 360
km. The stepping-stone pattern of small migration distances might have favored the observed gene flow.
The deviations from Hardy-Weinberg equilibrium in both populations might have resulted from limited
population size and restricted gene flow between the populations of Ankober Serin.
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Keywords
Ankober Serin, Diet Composition, Flock Size, Genetic Diversity, Habitat Disturbance