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INSECT STUDIES AT KAKENAUWE AND LAMBUSANGO IN 2001
Introduction
One method of characterising the level of disturbance to forests may be the impact that such disturbance has on the invertebrate fauna. Because of the diversity of the insect fauna, two large groups namely the Coleoptera (beetles) and Diptera (true-flies) are being studied. Both of these groups are highly diverse in this habitat and it might be expected that the maximum diversity would be found in areas where the forest has been undisturbed by either human or natural means. The forests in the study area are subjected to the following;
Logging
Other human disturbance such as clearance, cultivation and exploitation of other natural resources
natural disturbance such as tree falls
Areas of pristine undisturbed forest were selected along with disturbed forest. Certain studies (eg. New and Collins, 1991) have indicated how incredibly rich and diverse the insect faunas are in the forests of Sulawesi (and Indonesia as a whole). The objectives of this study are to compare the diversity of these two insect groups from the canopy to the ground layer in forest with different levels of disturbance. The information gathered will be used to determine insect diversity, to identify areasof importance for invertebrates and to provide input into management plans.
A second study was also undertaken on the butterflies present within the disturbed and undisturbed forest sites. The study concentrated on comparisons between the two forest sites and between canopy and ground level faunas. A small amount of additional material was also collected to supplement the larger scale butterfly survey carried out in 2000 which recorded 175 species including over 30 of which a number are endemic to Sulawesi.
Additional invertebrate work was carried out on moths, termites and other groups partly to provide baseline data and partly as a prelude to undertaking more work in future years.
Objectives
To compare the fauna between disturbed and undisturbed forest.
To relate any differences to disturbance whether natural or man made.
To suggest how impacts may be reduced and provide recommendations for habitat improvement.
To provide recommendations for input into management plans.
Methods
Four Malaise traps were placed within two study grids. Two of these were suspended within the canopy whilst the other two were placed at ground level. Two sets of yellow water traps were also placed at 100 metre intervals along transects within the grids. Material was also collected by timed sweep netting within and outside the grid.
Butterfly bait traps were placed within kakenauwe (disturbed forest) and Lambusanga (undisturbed forest) reserves. These were placed along transectswithin the canopy and at scrub level within the sample grids. the butterflies attracted to these traps were checked and recorded on a daily basis. the specimens captured were scanned into a computer and a photosuite built up of the species present as an aid to identification.
Termites were sampled at constant distances within 20m2 plots located within the grids. A small number of moths were sampled using Heath portable light trap and also a lantern and sheet.
Initial Results
The results of this work will be analysed by specialists in the various taxonomic groups in the UK when the samples have ben forwarded from Bogor museum and sorted into separate taxonomic groups. the contents of the Malaise traps suspended in the canopy are much less than those in the ground based Malaise traps, although this is in keeping with previous studies. The water trap samples proved disappointing although they still attracted a range of smaller insects. The disappointing catches in these traps is probably due to the absence of flowers in the forest (water traps work by attracting flower visiting specialists). It is anticipated that the material collected will contain a number of species new to science.
The butterfly traps were affected by macaques taking the banana bait from the bait traps, tearing the netting in some cases to get at the bait.
Publications
A paper entitled ' Observations on the Diptera fauna of the Kakenauwe and Lambusanga Forest Reserve Areas' will be prepared by Andy Godfrey for submission by March 2002.