The San Nicolas River Basin, a major tributary of Laguna de Bay, is confronted with episodes of ecological degradation, marked by sub-optimal water quality, heightened flood risks, and the proliferation of invasive fish species, namely, the janitor fish (Pterygoplichthys disjunctivus) and the iridescent pangasius catfish (Pangasianodon hypophthalmus). This environmental distress is primarily associated with persistent agricultural runoff and the vulnerability of open-access riparian zones to the "tragedy of the commons." To address such a dilemma, this study evaluated the geospatial and sociodemographic factors driving ecological shifts while identifying behavioral determinants that influence community engagement in riverbank conservation. Utilizing remote sensing via Google Earth Engine, the research analyzed land cover shifts from 2010 to 2020 alongside historical water quality assessments (2013–2024) and a social survey of riparian residents. The geospatial analysis revealed that annual crops heavily dominate the riparian buffer zone, accounting for 86.77% of the land by 2020. Concurrently, water quality data indicated consistent violations of dissolved oxygen and ammonia thresholds, fostering anoxic conditions that favor invasive species. Through a binary logistic regression analysis, the study found that community engagement in conservation is significantly predicted by the presence of tangible incentives (p < 0.001). Effective sustainable management requires shifting toward incentive-based frameworks, such as Payment for Ecosystem Services, to offset conservation opportunity costs. Policymakers should prioritize socio-economic stability, upgrade sewage infrastructure, and collaborate with civic organizations to cultivate pro-environmental social norms.
Trio et al. (Thu,) studied this question.