AMPHIBIAN DIVERSITY AS AN INDICATOR OF ECOSYSTEM MATURITY: COMPARATIVE STUDIES IN FIVE DIFFERENT ECOLOGICAL SERAL STAGES AT THE BELIPOLA ANALOG FOREST, SRI LANKA

Amphibians are valuable bioindicators of environmental health due to their sensitivity to habitat changes. This study explores amphibian diversity across five seral stages in the Belipola Arboretum, the first analog forest in Sri Lanka's Central Highlands. The seral stages, identified based on stratification and cover, represent early, mid, and late stages of ecological succession. A Visual Encounter Survey method was employed to estimate amphibian presence, resulting in the recording of 120 individuals from 13 species across four families. Data analysis, using SAS statistical tools, revealed that 85% of recorded species were endemic, and 46% were threatened (categorized as Critically Endangered, Endangered, or Vulnerable). Statistical analysis showed no significant differences in amphibian biodiversity between the first and second (p=0.1478), second and third (p=0.0678), third and fourth (p=0.2055), and fourth and fifth (p=0.0609) seral stages. However, significant differences were observed among other stages. The highest Shannon Wiener index was recorded in the fifth seral stage (1.82), followed by the fourth (1.31), third (0.98), second (0.49), and first (0.11) stages. These results indicate that amphibian biodiversity exhibits exponential growth after the second seral stage, with habitat quality improving as ecological succession progresses. The findings suggest that analog forestry, a method of ecosystem restoration that mimics natural forest structures, can enhance habitat quality and support biodiversity conservation. As seral succession advances, the quality of habitats for threatened amphibians improves, underscoring the importance of maintaining and restoring diverse ecosystems. This study supports the use of analog forestry as a viable approach to promoting ecological health and biodiversity in forested landscapes.