Physicochemical Profile and Abundance of Freshwater Snails in Mt. Dula-Dula, Damit, Bayog, Zambonga Del Sur

Freshwater snails are crucial components of tropical stream ecosystems, serving as grazers, detritivores, and indicators of environmental change. However, their responses to water quality gradients in upland Philippine freshwater systems remain poorly documented. This study examined the physicochemical profile and snail assemblages across upstream, midstream, and downstream sections of Mt. Dula-Dula, Damit, Bayog, Zamboanga del Sur. Dissolved oxygen (DO), pH, total dissolved solids (TDS), and temperature were measured in situ, while freshwater snails were collected using 3 by 5 meter quadrats and identified morphologically. Species diversity was assessed using Simpson’s Diversity Index, and relationships between physicochemical parameters and snail abundance were evaluated using Pearson correlation. All measured water quality parameters met DENR Class C standards, indicating generally suitable conditions for freshwater biota. Three species were recorded: Melanoides tuberculata, Tarebia granifera, and Physella acuta, with M. tuberculata dominating all sites. Overall diversity was low (Simpson’s D = 0.13), reflecting community dominance by a single tolerant species. Pearson correlation analysis revealed negative associations between snail abundance and DO, pH, TDS, and temperature, although values remained within acceptable ecological thresholds. The strong dominance of M. tuberculata suggests high ecological plasticity and potential resilience to environmental variation. These findings provide baseline data on the snail communities of Mt. Dula-Dula and highlight the importance of continued biomonitoring to detect future environmental changes in upland freshwater ecosystems.