Thesis (M.Sc.)--Chulalongkorn University, 2008

The species diversity and abundance of ants in three different land use types: a mixed deciduous forest, a commercial teak plantation, and a durian orchard, were studied to determine and compare the ant species diversity and abundance in these areas. Five sampling methods: handling capture over constant time, sugar-protein bait trap, pitfall trap, leaf litter sifting, and soil sifting, were conducted in these land use types monthly from September 2007 to September 2008. The species richness of ants in the overall area was 62 identified-species and 67 morpho-species, belonging to 49 genera in nine subfamilies. The Shannon-Wiener’s species diversity index indicated that the diversity was the highest in the mixed deciduous forest (2.387), followed by the durian orchard (1.997) and lastly the teak plantation (1.463). The Sorensen’s similarity coefficient was highest at 65.5% between the forest and the teak plantation, at 45.5% between the teak plantation and the durian orchard, and lowest at 39.7% between the forest and the durian orchard, indicating that both ant species diversity and species composition were distinctly varied by these three different land use types. Besides different land use types, the environmental fluctuation due to seasonal effects could lead to the variation in ant diversity. Therefore, the species diversity of ant between seasons in each study site was compared. In the forest, the Shannon-Wiener’s species diversity index in dry season (2.520) was higher than in the wet season (2.213), whereas in the other two sites, the diversity in the wet season was higher than in the dry season. The Sorensen’s similarity coefficient in the species composition between wet and dry seasons was highest in the durian orchard (80.5%), which had high soil moisture due to irrigation through out the year, whereas those in other two habitats were lower (67.2% and 64.7% in the teak plantation and the forest, respectively). This pattern of ant diversity indicated that the human management could affect to the variation pattern in species composition of ant between seasons in these areas. The abundance of important ant species (selected from the first 4 highest abundance in the forest) in the study sites and the correlation between their abundance and the physical factors were determined. The abundances of many important ant species were very low in the two anthropogenic habitats whereas, some species was high in these habitats. From the four important ant species, the abundance of three species correlated with the physical factors in the forest, whereas only one species correlated with physical factors in the other two anthropogenic habitats. Due to the water irrigation, the highest soil moisture content was found in the durian orchard in all year round. The measured physical factors confirmed the difference in the study areas due to the land use management. This showed the difference in abundance of ant in the difference land use types that might be due to the human practice that affect to the physical factors in each habitat. Therefore, the information from this study demonstrates the negative effect of land use management on the ant community in nature. Moreover, the combination of five collecting methods provides the complementarily reliable data of ant diversity for evaluating the effects of land use types.