FAUNA SEMUT TANAH PADA LAHAN GAMBUT YANG DIALIHGUNAKAN MENJADI KEBUN KELAPA SAWIT DAN HTI AKASIA SERTA PERANANNYA SEBAGAI PENGANGKUT GAMBUT

Abstract

Deforestation and conversion of peatlands into plantations have promoted the proliferation of ground dwelling ants (class Insecta, order Hymenoptera, family Formicidae) in peatland environments. The insects, which build belowground nests, potentially affect the physical characteristics of peat through pedoturbation activity. We conducted the present study to know the species assemblages of ground-nesting ants and to assess the significance of peat displacement made by the insects. Surveys were carried out in oil plam plantations and acacia plantations (“HTI”) in Bukit Batu area, Bengkalis District, Riau Province. Ants were directly sampled at the nest’s holes that occurred within sampling transects (4 locations/plantation type and 4 transects/location). In a total of 190 nests, we encountered 16 ants spesies belonging to five subfamilies (Dolichoderinae, Ectatomminae, Formicinae, Myrmicinae, and Ponerinae). There were 14 species found in oil palm plantations and seven species in acacia plantations. Most abundant nests in the former belonged to Pheidole sp1 (262.5 nests/ha), Odontoponera trasversa (212.5 nests/ha), Dolichoderus sp. (187.5 nests/ha) in oil palm plantations. In acacia plantation, Anoplolepis gracilipes (612.5 nests/ha), Paratrechina longicornis (212.5 nests/ha) had the most abundant nests. The overall nest density was 1250 nests/ha in oil palm plantations and 1125 nests/ha in acacia plantations. In oil palm plantations, ants soil species that carried out peat in the biggest total is Pheidole sp.1 (1101,8 kg/ha/year), Dolichoderus sp. (807.6 kg/ha/year) and Irydomyrmex sp. (677.1 kg/ha/year) and in acacia plantations Anoplolepis gracilipes (3688.8 kg/ha/year), Odontomachus sp.(1002.8 kg/ha/year), dan Paratrechina longicornis (698.1 kg/ha/year). Total of peat transport rate in oil palm plantations is 4.4 ton/ha/year and in acacia plantation (5.9 ton/ha/year)