Behavioral Ecology of the Patas Monkey (Erythrocebus patas) and Conservation Challenges in Alatish National Park, Northwest Ethiopia
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Date
2015-06
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Addis Ababa University
Abstract
The results of both qualitative and quantitative investigations on the behavioral ecology of the
patas monkey (Erythrocebus patas) and conservation challenges at Alatish National Park are
presented in this dissertation. The study aimed at the behavioral responses of patas monkeys to
their seasonal lowland habitats and evaluating the taxonomic status of the patas monkeys found
in Ethiopia as well as the conservation threats the park faces. The field study was carried out
from November 2011 to April 2013 in two wet seasons and two dry seasons. Behavioral data
were collected through 15 minutes scanning samples of 10 hours and 30 minutes field
observations a day, particularly on feeding, activity time budget and ranging patterns.
Morphological features of all age groups and sexes were also noted during both wet and dry
seasons. Seasonality in feeding behavior was tested through Schoener’s dietary niche overlap
index and Levins' dietary niche breadth index. Effects of seasonal changes on activity time
budgets were statistically tested by MANOVA; ecological factors that determine activity time
budget were statistically analyzed by MANCOVA. Daily range length and home range size were
estimated using OpenJump toolbox (MOVEAN), and statistically tested by t-test and Wilcoxon
test. Kernel density (95%), MCP (95%), and grid cell home range estimation methods were also
used to estimate home range sizes. Conservation threats were studied through field observations
and Landsat Satellite Imagery Analysis. Erythrocebus patas found in Ethiopia have some
distinctive morphological features compared with E. p. pyrrhonotus. The adult males face is fully
black without a white spot on their nose. Adult females also have a white frontal band. Food
items such as gum (39%), fruits and flower buds (32.7%), Acacia pod (0.6%), crop seed (8.1%),
herb stem pith (3.5%), corm/tuber (14.8%), and insect (1.3%) contributed to their annual diet
composition. Patas show dietary switching in response to seasonal changes. The diet similarity
between wet season and dry seasons was only 15.5%. Dietary niche breadth of patas was also
narrow during dry seasonal. Moreover, this study found that within their daylight activity time
budget, Patas monkeys spent 16.71% feeding, 22.75% moving, 11.26% social activity, 32.03%
resting, 14.93 % vigilance and 2.33% other activity. The results of multivariate analysis reveal
that season has a statistically significant effect on activity time budget, Wilks’ λ = 0.21, F =
17.14, df = (6, 27), p < 0.001, η2 = 0.79. Analyses on the effect of ecological factors in activity
time budget also show that food availability or dietary niche breadth, temperature, ectoparasite
infestation and predation risks significantly determine seasonal changes in activity time budgets.
Patas monkeys respond to seasonal environmental changes in their ranging behavior. Day
journey lengths varied between wet and dry seasons (t= - 8.4, df = 28, p< 0.001) with long
(1,512.8m (±466.18) daily travel length during the dry season. Home range size of the wet
season was 36.19651 hectares (±15.5196), whereas in the dry season it was 105.29439 hectares
(±104.7916). Wildlife dwelling in the Park have been affected by habitat degradation caused by
human induced fire and dry season water and food resource scarcity. The land cover change
analysis found that woodland cover of the Park is highly altered. Finally, based on morphological
features and feeding behavior, the study suggests that patas monkey in Northwest Ethiopia is
distinct enough from E. P. pyrrhonotus and warrant designation as a new and distinct subspecies.
Key words: Erythrocebus patas, feeding, activity time, ranging behavior, Alatish National Park,
conservation challenge
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Keywords
Erythrocebus Patas, Feeding, Activity Time, Ranging Behavior, Alatish National Park, Conservation Challenge