PLANT SPECIES DIVERSITY IN RELATION TO CARBON STOCKS AT JANGKOK WATERSHED, LOMBOK ISLAND

Abstract

The area around Jangkok watershed has changed, dividing it into some land use systems. This research aimed to study the effect of plant species diversity on C- stocks, and to analyse the characteristics of land use system s based on their similar ity . The observations were carried out on 18 plots representing six land use systems in Jangkok watershed (Lombok Island) i.e. primary forest (PF), disturbed forest (DF), Mahogany - woodlot (MW), candlenut - agroforestry (CA), multistrata - agroforestry (MA), and simple - agroforestry (SA). The species diversity level was measured using Shannon-Weiner diversity index , while C- stocks according to the method of RaCSA ( Rapid Carbon Stock Appraisal ) . Results showed that forest conversion to agricultural land use s reduced the number and density of the species , average w ood density and tree basal area . The PF represented the highest biodiversity index (3.46), while the other land uses were categorised in medium and low. Largest C-stock was found in PF and in (30 years old) of MW average d of 500 Mg ha - 1 , while the lowest was in S A of 68 Mg ha - 1 , while in other land uses wa s 219 Mg ha - 1 . The quantity of C- stock was not related to species diversity and its density , but closely related (p of tree (R 2 =0.84), basal area of all sizes tree (R 2 =0.86), and with the basal area of big trees ( diameter > 30 cm ) (R 2 =0.71). Based on the number and species density, agroforestry system ( MA and CA ) resembled the characteristics of natural forest ( DF and PF ) . /spanEN-GBspan style=