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THE
FACTORS INFLUENCING THE CROP RAIDING ACTIVITIES OF THE BUTON MACAQUE (MACACA
OCHREATA BRUNNESCENS) IN KAWELI,
BUTON ISLAND, SE SULAWESI
AIM
To quantify and assess the factors affecting raid frequency and duration, and observe the behavior of the monkeys prior to and during a raid. To compare the actual problem of crop raiding with the perceived problem, and to identify effective deterrents with aim to assist farmers to reduce the problem with minimal ecological impact.
OBJECTIVES
INTRODUCTION
The
village of Kaweli, as with many villiages on Buton, relies on agriculture for
food and trade, and areas of forest are cleared for this need.
Many troupes of which are found around Kaweli, and the majority of
troupes have farm land encroaching into their home range.
These farms produce a various crops with varying abundance, such as sweet
potato, banana, coconut, pineapple, and sugar cane.
This is a rich supply of food for a macaque troupe.
Crop
raiding by macaques, pigs and other species is a problem, both in physical
damage to farmland, and the economic problems of loss of crops.
Research into the crop raiding of other macaque species is widespread,
but the Buton macaque has never been studied in this capacity.
The perceived scale of the problem is being determined by Nancy Priston,
through a series of interviews with the people of Kaweli and surrounding
villiages. The three animals
regarded as the biggest pests are rats, pigs and monkeys.
Kaweli has no wet paddy fields, so the problem of rats is minimized, but
pigs and monkeys still pose a threat to the farmers, who employ a variety of
preventative measures, some resorting to trapping and poisoning as a last
resort.
The
majority of farms are poorly defended by structural defences, as fences provide
little security from monkeys, and are easily broken by a determined pig, and
traps are difficult to maintain and often ineffective against monkeys, who
quickly learn to avoid them. Human presence at the farms varies greatly, and
this may have significant effects on the frequency and duration of raids,
however this may be insignificant compared to other factors such as distance
from the forest, crop availability, or presence of dogs.
Assessment of these factors and
the affect they have may allow the farmers to re-assess their defences and
reduce the problem without relying on harmful measures such as poisoning.
METHODS
Seven
farms were observed at five sites, as at two sites two farms could be observed
simultaneously. The farms were
chosen due to differences in crops grown, abundance, distance from the forest,
and percentage of farm bordered by forest.
Cooperation of the farmers was essential and choice of farms limited by
this. The farms were observed from the same observation point from 0630 until
1630 on a rotational basis to ensure each of the farms received the same amount
of observation. Observation times were chosen to coincide with the general daily
activity of the macaques, who rise at sunrise (0600) and return to their
sleeping trees at approx 1630-1700. Observers
spent one week with the previous observer to ensure inter observer reliability,
and then staggered farm rotation to maximize observation time.
1&2
Husnya
3
La Tole
4
Musrifa
5
La Sahili
6&7
La Ruhini
The
following observations were made when appropriate whilst attending each farm:
·
Human activity
was recorded as age/sex class location and behaviour, noting whenever the
situation changed to the nearest second.
·
The presence of
dogs and their behavior was also noted to the nearest second.
·
Noises such as
shouting, crying, and barking were recorded as well as noises from chainsaws
in or near the farm.
·
2 minute
behavioural scans noting age/sex class, location and behaviour of monkeys
outside the perimeter of the farm.
·
The duration of a
raid
·
2 minute
behavioural scans noting age/sex class, location and behaviour of monkeys
during a raid.
·
The number of
active raiding and non-raiding monkeys
·
Crop data,
availability and changes throughout the course of study were recorded
·
GPS data of the
perimeter of the farm and observation points were recorded
· Interviews were conducted and transcribed by Nancy Priston.
INITIAL RESULTS
The results suggest a strong correlation between raid frequency and distance from the forest, further statistical analysis is required to determine if the level of human activity directly affects this. Human activity does, however, seem to have an effect upon raid duration and, therefore, the quantities of crop taken by the monkeys. Due to time constraints little data analysis has been completed, and further conclusions about the relationship between specific human activity, crop availability, and the crop raiding behaviour of the macaques; will become available in time. Other conclusions, such as behaviour variations during and before raids, food preferences, and effectiveness of trapping and poisoning, will also be drawn from future analysis of the data and interviews.
A dissertation entitled The
Factors Influencing The Crop Raiding Activities Of The Buton Macaque (Macaca
ochreata brunnescens) In Kaweli,
Buton Island, S. E. Sulawesi will be produced by Ben Valsler, University Of
Aberystwyth by May 2003.