Dynamics of Riparian Vegetation Structure in Logawa River: Ecological Impacts and Landscape Management

One of the riparian zone functions is to act as a buffer zone, playing crucial roles in economic and ecological aspects. The riparian area of the Logawa River is currently under anthropogenic pressure from sand mining activities, leading to habitat degradation. It is characterized by slopes >15% and high rainfall intensity and is prone to erosion. This research aimed to analyze the structure of riparian vegetation and its correlation with environmental parameters. Observations were conducted in July 2024 along the Logawa River, divided into the upstream, midstream, and downstream sections, with four stations in each section. Vegetation analysis was carried out using a purposive sampling method with plots measuring 20x20m (tree), 10x10 m (pole), and 1x1m (seedling), positioned parallel to the riverbank. Measured soil parameters included C-organic (%), N-total (%), P-total, and organic matter, while water parameters included pH, temperature, TDS, BOD, and COD. Riparian vegetation data were analyzed using alpha diversity indices, including the Shannon-Wiener index (H'), dominance index (D), and evenness index (e'). Further analysis was conducted using Redundancy Analysis (RDA) to explore the relationship between vegetation and habitat variation and Canonical Correspondence Analysis (CCA) to assess the correlation between vegetation presence and environmental parameters. The results showed that the H' ranged from 0.58 to 1.98, D ranged from 0.20 to 0.75, and e' from 0.30 to 1.00. RDA results indicate that Loc 5 in the midstream is closely associated with Swietenia macrophylla and Cocos nucifera. In contrast, Loc9 downstream is associated with Artocarpus heterophyllus and Mangifera indica, suggesting that these species are prevalent and commonly found in these areas. CCA results show that Paraserianthes falcataria is more strongly associated with higher levels of chemical oxygen demand and strongly correlates with the environmental gradient represented by N-total (%).