Bale Mountains vervet

Taxonomy

The Bale monkey is a member of genus Chlorocebus, along with six sister species. All members of Chlorocebus were formerly considered to be part of Cercopithecus; the Bale monkey was formerly known as Cercopithecus djamdjamensis. It was originally described as a subspecies of the grivet (Chlorocebus aethiops).

A 2018 study found that the populations of Bale monkey living in fragmented forests were genetically distinct from populations in continuous forests. This is due to the fragmented forest populations' hybridization with the grivet (Chlorocebus aethiops) and the vervet monkey (Chlorocebus pygerythrus). The Bale monkey does not currently co-occur with either of these monkeys in the wild and so it is proposed that this hybridization occurred over a century ago.

Ecology

The Bale Mountains vervet monkey is a dietary specialist with African alpine bamboo (Yushania alpina) making up as much as 77% of its diet. This makes the species unique in the genus Chlorocebus as the other five species are dietary generalist species. The diets of Bale monkeys in continuous forests are made up of approximately 10 species of plants; however, populations in fragmented forests have considerably higher dietary diversity and consume up to five times more species. For those populations, bamboo makes up as little as 2% of their diet. It is unclear if this dietary flexibility is due to hybridization from grivet and vervet monkeys or if the species adapts in the absence of bamboo. This dietary flexibility makes the Bale monkey less dependent on its main food source than other dietary specialist species like the koala or giant panda. In areas where Bale monkeys and human settlements co-occur, the monkeys often raid crops for food which can spark retaliatory hunting.

Conservation status

The Bale monkey is currently rated vulnerable by the IUCN Red List and is listed on Appendix II of CITES. The main threats to the species are habitat loss and hunting. They could be threatened by hybridization with the grivet and the vervet monkey in the future.

The monkey feeds on bamboo and may thus be threatened by deforestation. Encroaching human populations have nearly extirpated the Bale monkey from the Sidamo Highlands. The monkey is persecuted for crop raiding and hunted by local people. It is protected in parts of its range by the Bale Mountains National Park; the proposed Harena-Kokosa National Forest Reserve would protect some populations.

References

References

1. {{MSW3 Groves
2. Butynski, T.M.. (2022). "''Chlorocebus djamdjamensis''".
3. (October 2010). "Population size and habitat preference of the Vulnerable Bale monkey Chlorocebus djamdjamensis in Odobullu Forest and its distribution across the Bale Mountains, Ethiopia". Oryx.
4. (2021-11-15). "Bale Monkey, Chlorocebus djamdjamensis {{!}} New England Primate Conservancy".
5. (2003). "Assessment of the diversity of African primates". International Journal of Primatology.
6. (2018). "Population genetic structure and evolutionary history of Bale monkeys (''Chlorocebus djamdjamensis'') in the southern Ethiopian Highlands". BMC Evolutionary Biology.
7. (2018). "Dietary flexibility of Bale monkeys (''Chlorocebus djamdjamensis'') in southern Ethiopia: effects of habitat degradation and life in fragments". BMC Ecology.