Aquatic Macrophyte Community Composition as an Indicator of Habitat Conditions and Anthropogenic Disturbance in Tropical Wetlands

Tropical wetlands are highly sensitive to climatic and anthropogenic disturbances, and their macrophyte communities provide valuable information about environmental conditions and habitat structure. This study evaluated the relationship between aquatic macrophyte richness, community composition, and habitat vulnerability to climate change in aquatic ecosystems of the San Luis rural district, Barrancabermeja municipality (Santander, Colombia). Macrophyte communities were characterized at 47 monitoring sites distributed across six mesohabitats: floodplain depressions, swamp, wetland, artificial ponds, naturalized ponds, and stream riparian zones. A total of 63 species belonging to 30 families and 51 genera were recorded. Contrary to theoretical expectations, correlation analyses showed no significant relationship between macrophyte species richness and habitat vulnerability indices (Spearman ρ = −0.118, p = 0.428; Pearson r = −0.069, p = 0.646). However, species richness differed significantly among mesohabitats (Kruskal–Wallis, p < 0.05), indicating strong spatial heterogeneity in aquatic plant distribution. In addition, multivariate analyses using Principal Component Analysis (PCA) revealed that macrophyte community composition was strongly structured by local anthropogenic activities, including livestock farming, oil palm cultivation, and wastewater inputs. Floodplain depressions and artificial ponds were dominated by disturbance-tolerant and eutrophication-resistant species such as Urochloa plantaginea and Salvinia minima, reflecting higher levels of environmental pressure. These results demonstrate that macrophyte community composition, rather than species richness alone, is a more reliable indicator of habitat conditions and anthropogenic disturbance in tropical wetland systems. Overall, this study highlights that taxonomic richness is not a robust predictor of climate-related vulnerability in highly disturbed wetlands and emphasizes the importance of considering species composition and environmental context when assessing ecosystem conditions.