Diet, Activity Patterns, and Ranging Ecology of the Bale Monkey (Chlorocebus djamdjamensis) in Odobullu Forest, Ethiopia

Abstract

Bale monkeys (Chlorocebus djamdjamensis) are little-known primates endemic to the forests of the Bale Massif and Hagere Selam regions of Ethiopia. From August 2007 to May 2008, we conducted the first ever study of the species' behavior and ecology, focusing in particular on its diet, activity patterns, and ranging ecology in the Odobullu Forest. We studied 2 neighboring groups (group A: 55-60 members; group B: 46-50 members) and conducted behavioral scan samples on the first 2-5 individuals sighted at 15-min intervals. Feeding accounted for 65.7% of the activity budget, followed by moving (14.4%), resting (10.7%), social (7.1%), and other behaviors (2.4%). Overall diet during the study was dominated by young leaves (80.2%), though subjects also ate fruits (9.6%), flowers (3.1%), animal prey (2.3%), shoots (1.5%), stems (1.4%), mature leaves (1.1%), and roots (0.9%). Bale monkeys consumed only 11 plant species; of these, the top 5 species accounted for 94.3% of their diet. The top food item, bamboo (Arundinaria alpina), was responsible for a remarkable 76.7% of their diet, with most (95.2%) of the bamboo consumption consisting of young leaves. Mean daily path length for the study Int groups was 928 m and mean (100% minimum convex polygon) home range size was 15.2 ha. Though we are cautious in drawing conclusions from only 2 groups, the larger group traveled further per day and occupied a larger home range, patterns suggesting scramble competition may be occurring in Bale monkey groups at Odobullu. The dietary specialization of Bale monkeys on bamboo makes them unique among Chlorocebus spp. and suggests an intriguing ecological convergence with the golden monkeys (Cercopithecus mitis kandti) of Uganda and bamboo lemurs (Hapalemur spp.) of Madagascar. Their narrow ecological niche, limited geographic distribution, and bamboo harvesting by local people for commercial purposes place Bale monkeys at risk of extinction. To ensure the long-term survival of Bale monkeys, appropriate management action should be taken to conserve the species and the bamboo forests upon which it depends.Keywords activity budget . bamboo . feeding ecology . home range . quantitative natural history . scramble competition

Nonhuman Primates

“…were previously listed in the genus Cercopithecus; however, genetic studies have separated them from Cercopithecus and reclassified them as genus Chlorocebus (Groves, 2001(Groves, , 2005Mekonnen et al, 2010aMekonnen et al, , 2010bPerelman et al, 2011;Tosi et al, 2002;Xing et al, 2007). were previously listed in the genus Cercopithecus; however, genetic studies have separated them from Cercopithecus and reclassified them as genus Chlorocebus (Groves, 2001(Groves, , 2005Mekonnen et al, 2010aMekonnen et al, , 2010bPerelman et al, 2011;Tosi et al, 2002;Xing et al, 2007).…”

Size variation facilitates population divergence but does not explain it all: an example study from a widespread African monkey

“…The bamboo forest habitat of Cercopithecus a. djamdjamensis in the Bale Mountains (an area of high endemism and vegetation diversity) is highly unusual compared to those of other vervets (Butynski et al, 2008;Mekonnen et al, 2010). Fossil pollen records from the late Pleistocene and early Holocene indicate a complex history of vegetative change in the region, which alternated between glacial conditions, Afroalpine vegetation and woody vegetation, with the flora responding to shifts in moisture availability (Umera et al, 2007).…”

Mitochondrial Diversity and Distribution of African Green Monkeys (Chlorocebus Gray, 1870)

“…1) [Kingdon, 1997; Lernould, 1988]. Previously, African green monkeys have been subsumed into the aethiops group of the genus Cercopithecus [Dandelot, 1971; Grubb et al, 2003; Hill, 1966; Napier, 1981; Schwarz, 1926], but based on recent morphological and genetic studies, they are now separated from Cercopithecus and placed within the genus Chlorocebus as sister taxon to the other ground dwelling members ( Erythrocebus, Allochrocebus ) of the Cercopithecini [Groves, 2001, 2005; Mekonnen et al, 2010a, 2010bb; Perelman et al, 2011; Tosi et al, 2002; Xing et al, 2007; but see Grubb et al 2003 for a different opinion]. Due to their wide distribution and phenotypic diversity, 22 taxa have been described with most of them now being recognized as synonyms [Dandelot, 1971; Groves, 2001; Hill, 1966; Napier, 1981; Schwarz, 1926].…”