Bark-stripping and food habits of blue monkeys in a forest plantation on mount Meru, Tanzania
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Date
1989-04
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Sokoine University of Agriculture
Abstract
Bark-stripping of Cupressus lusitanica (cypress) and
Pinus patula (pine) by blue monkeys (Cercopethicus mitis
kibonotensis) in Meru Forest Plantations has been a problem
since they were established in the early 1950s.
This study
was conducted in 1987 in the Sokoine University of Agriculture
Training Forest, a portion of the Meru Forest Plantations, to
determine the magnitude of bark-stripping in relation to the
food habits of blue monkeys.
The extent, intensity and effects of bark damage were
assessed in compartments with trees 3 to 14 years old, and
the pattern of debarking was monitored throughout the year.
On the average, 79.5 % cypress and 88.7% pine trees were
debarked.
Blue monkeys preferred dominant cypress trees to
intermediate trees.
In contrast, intermediate pine trees were
more damaged than dominant trees.
trees were least damaged.
In both species, suppressed
In all types of trees, the most
severe bark damage occurred at the middle and top of the tree
trunks.
Twisted bole was the most common defect developed by
damaged trees; 34% cypress and 38% pine trees were twisted at
the middle and top sections.
Bark-stripping was low in the
rain season and increased in the dry season peaking at 22% of
trees damaged in June and July.
• The food habits data were collected from the indigenous
forest at two sites within the plantation.
plant species were eaten by blue monkeys.
A total of 38
Fruits were theiv
most frequently consumed food item and averaged 76% of the
monthly feeding records.
Leaves were the next important food
item but they were inversely related to the feeding on fruits.
The other food items (flowers, shoots, petioles and bark) were
similarly inversely related to the feeding on fruits.
Bark
stripping was negatively correlated to the feeding on fruits,
and thus increased when the feeding on fruits declined.
Fruits of Ficus thonninqii were the prime item in the diet of
blue monkeys contributing 50 to 60% of the monthly feeding
records.
The amount of fruit on these trees in the area was
also inversely related to extent of bark damage in the
plantation.
The water and carbohydrate in the bark of cypress and
pine trees was determined to examine if they influenced the
bark-stripping.
These were poorly correlated to the monthly
debarking of both tree species.
Description
PhD Dissertation
Keywords
Blue monkeys, Forest plantation, Mount Meru, Bark-stripping, Food habits-blue monkeys, Tanzania