Ecological Assessment of Physico-Chemical Variability in the Kuttanad Wetlands Using Integrated Statistical Tools

Abstract

The current research work examines the spatial and seasonal variability of physico-chemical water quality parameters in the Kuttanad wetlands of Kerala, India, using integrated univariate and multivariate statistical methods. Seasonal sampling was conducted form 24 sites within three ecologically distinct panchayats in Kuttand wetland such as Ala, Edathuva and Kainakari, during pre-monsoon, monsoon and post-monsoon seasons. Important water quality parameters including temperature, pH, dissolved oxygen (DO), nitrate, and phosphate were analysed. Descriptive statistics exposed significant seasonal fluctuations in nitrate and phosphate particularly monsoonal nitrate variation in Ala panchayat and persistent phosphate enrichment in Kainakari panchayat. Boxplot analysis highlighted location-based extremes and seasonal trends, while correlation analysis demonstrated strong inverse associations between nitrate and phosphate, and negative relationships between DO and both phosphate and pH. Two-way ANOVA indicated significant spatial influence on nitrate concentrations, with no significant seasonal effects. Principal Component Analysis (PCA) captured over 80% of the total variance in the first two components, distinguishing sites based on nutrient loading and oxygen-pH gradients. PCA separated Kainakari due to its phosphate enrichment and alkaline character, while Ala showed strong monsoonal nitrate variability. Discriminant Function Analysis (DFA) further confirmed distinct water quality clusters among the panchayats, with LD1 accounting for 99.5% of variance. These findings point out the spatial dominance over temporal variability in nutrient dynamics and the utility of integrated statistical tools for wetland water quality analysis. The study offers a healthy framework for future ecological monitoring and management strategies of all wetlands particularly the Ramsar wetlands of Kerala.