Ground-dwelling ant diversity in Maliau Basin, Borneo: Evaluation of hand-sorting methods to estimate ant diversity

Abstract

The ground-dwelling ant fauna in tropical forests remains the “final frontier” in the study of Formicidae biodiversity. This is mainly due to a lack of convenient sampling methods for the inventory of ants in soil. In the present study, employing the hand-sorting of small soil cores, we carried out the first survey of ground-dwelling ants in Maliau Basin Conservation Area, in Sabah, Borneo, to compare disturbed and undisturbed forest ant communities and to evaluate the sampling method’s performance in assessing species richness and characterizing community structure of the ant fauna. For this purpose we set a 5 m long and 1 m wide transect, consisting of five 1-m2 sections, in disturbed and undisturbed forest plots in the area, and compared the sampling results of hand-sorting between the two plots. A total of 50 ant species, in 28 genera and eight subfamilies, were collected in the two plots, of which 32 species in 20 genera were collected from the undisturbed plot and 24 species in 18 genera from the disturbed plot. According to estimates of expected species richness, the hand-sorting of soil cores allowed for the collection of 66.7 to 80.0% of the ant species expected in the undisturbed plot, and 83.3 to 88.9% in the disturbed plot. Besides lower species richness, the ant community in the disturbed plot had lower species evenness and a different species composition in comparison to undisturbed plot, which may be related with environmental changes in the plot, due to open canopy. These results indicate that hand-sorting of small soil cores is a method that could provide reliable information, not only to estimate species richness at a site, but also to evaluate differences in community structure between sites.