Impact of forest fragmentation on moths (Lepidoptera: Geometridae & Limacodidae) in Sabah, Malaysian Borneo

• Main Authors: Suzan Benedick, Lim, Robin Ah Hee, Nurul Farihah Osman, Nur lsnimah Dora Satung
• Format: Research Report
• Language: English
• Published: Universiti Malaysia Sabah
• Subjects: SD Forestry
• Online Access: https://eprints.ums.edu.my/id/eprint/24830/1/Impact%20Of%20Forest%20Fragmentation%20On%20Moths.pdf; https://eprints.ums.edu.my/id/eprint/24830/

This project aims to study moths assemblages in natural forest remnants and adjacent oil palm plantations in Sabah, Malaysia (Borneo). This study focused on moths (Order: Lepidoptera) from family of Limacodidae and Geometridae and they were surveyed from April 2011 to April 2013 at 16 sites comprising eight forests (four contiguous and four fragments) ranging from 125 ha to 25,000 ha and eight sites of oil palm plantation 500m away from the adjacent studied forests. All moths were collected by hands at a light trap run from 1830 to 2230 as these hours encompass the time of maximum activity for moths on rain-free nights and avoiding nine nights around the full moon phase, from waxing gibbous moon to full moon and finally waning gibbous moon. Trap consisted of a 2 x 2-m illuminated vertical white sheet, and the light source of 125-watt mercury-vapour (MV) lamps were powered by a portable generator and placed on the ground (~1 m) in a clearing for better light distribution and maximal catch. The study showed significant differences in assemblages of moths (Shannon's t0.05, 14=4.02, p<0.05; Simpson's t0.05, 14=3.98, p<0.05; and Margalef's t0.05, 14=3.844, p<0.05), which is higher in forests than oil palm plantation. Highest similarity species spillover was found in fragmented forest and its adjacent oil palm plantation (Sg. Sapi - Sapi 2; n=13), followed by Segaliud Lokan-Bimbingan 2; n=7. There was no significant correlation between contiguous and fragmented forest for all assemblages (p>0.05) indicating forest can sustain higher assemblages of moths than oil palm plantation, which may lead to dispersal of moths into adjacent oil palm landscape. Excluding geographical distribution, there were significant differences in sensitivity towards fragmentation and larval host plants specialization {p<0.05 in all cases). A principal component analysis (PCA) indicated clear discrimination and contributed to two predictor set of moths in the forest lar,dscape: a forest with a large number of trees, a dense canopy cover, increasing tree girth or larger tree and increasing well developed understorey plants and also a forest with high canopy cover. Overall the results from this study indicate that forest fragmentation and agricultural disturbance affects moths species diversity, which deserve greater attention in terms of conservation of forest moths in Borneo. However, despite its negative implication on diversity, oil palm plantation could potentially be improved on diversity for some taxa due to spillover and dispersal effect from adjacent forest. This study also found that fragmented forest harbours endemic species, and these shows there are conservation values of small and fragmented fragments within oil palm plantation. In addition, the plantation management, however, remains the major key player in improving the diversity within the oil palm landscapes.