First Survey of Land Snails in Mount Hamiguitan: Biodiversity and Environmental Insights from a UNESCO World Heritage and ASEAN Heritage Park in the Philippines.

Mount Hamiguitan, a UNESCO World Heritage Site and a biodiversity hotspot in the Philippines, supports diverse and unique ecosystems. This study presents the first comprehensive assessment of land snail diversity across five vegetation types: agro-ecosystem, dipterocarp forest, montane forest, mossy forest, and mossy-pygmy forest. A total of 96 individuals, representing 20 species from 6 families, were recorded. The mossy forest exhibited the highest diversity (1-D = 0.85, H' = 2.03), while the agro-ecosystem and mossy-pygmy forest had lower diversity, attributed to habitat disturbance and extreme environmental conditions. Canonical Correspondence Analysis (CCA) revealed that environmental factors, including leaf litter depth, relative humidity, soil pH, and temperature, influenced land snail distributions. Axis 1 (31.85% constrained inertia) showed a gradient favoring generalist species (Tanychlamys sp.) in disturbed, warmer habitats and specialist species (Hemiplecta sp.) in cooler, humid environments. Axis 2 (30.91%) emphasized humidity and leaf litter depth, associating montane forests and species like Trochomorpha sp. 2 with high moisture conditions. The Bray-Curtis similarity index revealed distinct ecological compositions among vegetation types. The agro-ecosystem formed a separate cluster with low species diversity and specialized communities. The mossy-pygmy forest shared similarities with the mossy forest, both characterized by high humidity and dense vegetation. A strong similarity was observed between the dipterocarp and montane forests, suggesting similar environmental conditions and overlapping species. This study underscores the vital ecological role of the mossy forest as a biodiversity refuge and provides critical data for conservation strategies aimed at preserving Mount Hamiguitan's unique ecosystems. It also advocates for targeted conservation efforts to mitigate human disturbances and enhance ecological resilience in this globally significant hotspot.