KELIMPAHAN DAN BIOMASSA CACING TANAH DI BEBERAPA JENIS PENGGUNAAN LAHAN GAMBUT DI KAWASAN BUKIT BATU, RIAU

Abstract

Although peatlands possess the unsuitable environmental characteristics as habitats of earthworms, fundamental changes after deforestation and draination that have taken place following land cultivation after, has modified their harsh environment into friendlier one. This study has been carried out to test whether earthworms were present on peatlands, especially those which have been converted into different land-use types. The specific objectives of this study were to assess the presence, abundance and biomass of earthworms under such land-use types like natural forest, rubber plantation, industrial pulpwood plantation (HTI), oil palm plantation, homegardens, and newly cleared-natural forest. This study had been conducted from December 2010 – October 2011 in peatland of Bukit Batu area, Riau. Each type of land use was represented by four separate sampling locations and at each location one diagonal transect line of 100 m was drawn, which composed of 10 subplots measuring 25 cm x 25 cm x 10 cm with an interval of 10 m. At each location, at which the aboveground conditions (number of tree species, tree density, basal area of trees and litter abundance) and belowground (water table, peat water content, peat pH and C/N ratio) were recorded. Results showed that earthworms could be found in most land-use types, including peat swamp forest. There was significant difference on earthworm presence frequencies (P<0.05), abundance (P<0.05) and biomass (P>0.05) in most land-use types. Earthworm were found most abundant in largest abundance and biomass in homegardens and oil palm plantation. Earthworm's presence in peatland were affected by water table, peat water content, and peat pH. There was indication of invasion by an exotic earthworm species (Pontoscolex corethrurus).