A study on tree diversity in lowland, sub-montane and upper montane forest formations along the Hapugastenna nature trail in the Peak Wilderness sanctuary

Abstract

Hapugastcnna nature trail is one of sixth access way to peak "Sri-pada" that running through PeakWilderness sanctuary. It starts at the middle way of southern boundary of the sanctuary betweenRathganga and Waleboda and runs North-Western direction.

This study examined the tree diversity in different forest formations along the trail. Twelve plots(each 5 x 100 m) were laid in lowland (6), sub-montane (4) and upper montane (4) forest formations.respectively. Altitudinal range oflowland plots were below 1000 m, sub-montane plots were between1000 -1550 m and montane plots were above 1550 m. All tree species over 10 ern dbh were selectedfor the study. Important value index (IV!) and Shanon's diversity index were calculated. IVI wascalculated for each family, genera and species separately.

Recorded number of total individuals was 592 belong to 90 species, 55 genera and 26 families. Itincludes 58 endemic species with 3 endemic genera (Loxococcus -1 sp., Shumaeheria - 1 sp.,Stemonoporus= 6 sp.). A total of 58 (250 individuals), 32 (174 individuals) and 29 (168 individuals) treespecies were identified from lowland, sub-montane and upper montane forest formations, respectively.Identified species distributed in 3 forest formations as follows, lowland 43, upper montane 13, submontaneII, lowland and sub-montane 8, lowland and upper montane 2, sub-montane and uppermontane 8, all three formations 5. There were 35 endemic tree species in lowland (60.3 %) ,22 (68.7%) in sub-montane and 17 (60.7 %) in upper montane forest formations.

According to the [VI values, in the lowland forest formation Dipterocarpaceae was the dominant family,Myristica was the dominant genus and Myristica daetyloides was the dominant species. In the submontaneand montane forest formations Palaquium rubiginosum was the dominant species

The diversity index (Shannon's) was calculated for each plot and three different forest formations.These results were analyzed using analysis of variance. It showed that there were significant differencesbetween lowland - montane lowland - sub montane formations. Same result showed for evenness anddominance.