« Comparison of sampling techniques to estimate tree diversity and aboveground biomass in Sinharaja forest Sri Lanka | Home | Effects of carbofuran on survival and growth of Duttaphrynus melanostictus tadpoles »
Diversity and microhabitats of termites in a natural and a secondary forest in Hantane hills, Kandy District
By lakmali | March 4, 2010
I.I. Hemachandra, 1,2, J.P. Edirisinghe 1, W.A.I.P. Karunaratne 1, C.V.S. Gunatilleke3
Termites (Isoptera) are the most important decomposers in tropical rain forests and are vital in maintaining nitrogen and carbon cycles. They are sensitive to disturbances, especially to forest canopy losses and hence are one of the important bioindicator taxa. The documented termite fauna of Sri Lanka is represented by 58 species in 28 genera. Research studies on termites of forests are few in Sri Lanka. Objective of this study was to determine the species composition, diversity and microhabitats of termites in a selected natural and a secondary forest in the Hantane hills.
The Hantane range is a series of hills, about 432 ha with an elevation between 518-1110 m. During the British period Hantane land was opened up for coffee, tea and rubber plantations. The selected study sites included patches of natural forest at > 1000 m elevation and a secondary forest, comprising mixed species, at elevations between 700-1000 m. A belt transect (2×100 m) was laid in each site for sampling termites. Each transect was divided into 20 (2×5m) sections and each section was sampled by 2 persons for 30 min. The number of encounters with termites (hits) of a given species within a transect was taken as the relative abundance of that species within that transect. An encounter is the presence of a species in one transect section (5×2 m). Termite diversity was compared using Shannon Diversity Index. Termites were also collected randomly from several areas within the two forest types for species determination.
A total of 11 termite species were collected from the two forest types using both methods. They are: from the natural forest Ceylonitermellus hantanae (Holmgren) (soil-wood interface feeder), Dicuspiditermes incola (Wasmann) (soil feeder); and from the secondary forest Odontotermes ceylonicus (Wasmann), O. globicola (Wasmann), O. horni (Wasmann) (all fungus growers and feeders), Nasutitermes fletcheri (Holmgren & Holmgern) (soil-wood interface feeder) and 5 unidentified species of Odontotermes Holmgren ( fungus growers and feeders) . A lower species Diversity Index was obtained for natural forest (H= 0.683) compared to secondary forest (H=1.630). The composition of termites species showed a marked contrast with none of the species in the natural forest being represented in the secondary forest and vice versa. The most common species in the natural forest was the endemic C. hantanae and in the secondary forest, the unidentified Odontotermes sp. 2.
A significant observation in both forests was the absence of termite mounds as well as long runways along live trees that lead to arboreal nests. The two termite species recorded from natural forest are subterranean nest builders that inhabit soil. The termites of the secondary forest inhabit soil, leaf-litter and wooden material like, tree stumps, logs, fallen branches and twigs. Termites of the fungus growing genus Odontotermes was confined to the lower altitudes.
A distinct difference in termite species composition, diversity and microhabitats was recorded from the two forest types, suggesting that altitude and temperature, among other factors may be influential environmental variables for termites.
I.I. Hemachandra, 1,2, J.P. Edirisinghe 1, W.A.I.P. Karunaratne 1, C.V.S. Gunatilleke3
1Department of Zoology, Faculty of Science, University of Peradeniya, Sri Lanka2Postgraduate Institute of Science, University of Peradeniya, Sri Lanka3 Department of Botany, Faculty of Science, University of Peradeniya, Sri Lanka.
Topics: Biodiversity, sympoisum 2009 | No Comments »