Native riparian forest cover was negatively associated with phosphorus concentrations, showing its contribution to nutrient regulation and water-quality management at the watershed scale.
Villarrica Lake is a glacial lake in southern Chile that has experienced increasing nutrient enrichment and eutrophication associated with anthropogenic pressures in its watershed. This study investigates the statistical association between nutrient concentrations in streams and riparian vegetation cover within the Villarrica Lake watershed. A monitoring network of 10 sites was established, with 12 campaigns conducted between 2024 and 2025. Total nitrogen, total phosphorus, and other water-quality parameters were measured. Native riparian forest cover was estimated using a national inventory of vegetation resources and land use cross-referenced with satellite imagery. Spearman rank correlations were used to assess the association between the percentage of native riparian forest cover and nutrient concentrations. Total phosphorus showed a statistically significant, negative correlation with native riparian forest cover (ρ = −0.673; p = 0.033), while total nitrogen did not show a statistically significant relationship, although it was also a negative association (ρ = −0.467; p = 0.174). Limitations associated with water quality data availability and the spatial accuracy of the land-cover data used to characterize riparian forest cover are discussed. These results provide evidence of an association between native riparian forest cover and nutrient concentrations, highlighting the potential contribution of riparian vegetation to nutrient regulation and water-quality management at the watershed scale.
Pablo is a senior environment consultant based in Chile. With more than 25 years of international experience, Pablo has been involved in a number of environment and social projects.