Seagrass ecosystems in Pujada bay, Davao Oriental, Philippines: evaluating the impact of anthropogenic pressures on species richness.

Abstract

This study investigates the biodiversity of seagrass ecosystems in Pujada Bay, Davao Oriental,Philippines, with a particular focus on evaluating the impact of anthropogenic pressures on speciesrichness and composition. Seagrass communities from three sites with varying disturbance levelswere compared: heavily populated Taganilao, moderately populated Lawigan, and uninhabited Pujada Island. Aerial surveys, transect-quadrat sampling, and environmental measurements(dissolved oxygen (DO), pH, salinity, temperature) were used to assess species distribution, shootdensity, and abundance. Results showed that Pujada Island had the highest species richness and a balanced community structure, while Taganilao, impacted by pollution and reclamation, had lowerdiversity and was dominated by the resilientThalassia hemprichii. Kruskal-Wallis tests confirmedsignificant differences in abundance, especially between Taganilao and Pujada Island (p = 0.000273). Canonical Correspondence Analysis highlighted temperature and DO as key drivers of species distribution. The study underscores the urgent need for conservation measures to mitigatehuman impacts and protect seagrass ecosystems in Pujada Bay.