Diversity of aquatic and riparian macrophytes in oxbow streams of the upper Bengawan Solo River, Central Java, Indonesia

Rahmawati D, Zahrani D, Naafi DA, Putri DS, Safira RN, Dewangga A, Setyawan AD. 2025. Diversity of aquatic and riparian macrophytes in oxbow streams of the upper Bengawan Solo River, Central Java, Indonesia. Intl J Bonorowo Wetlands 15: 28-39. Oxbow streams represent dynamic transitional habitats that support diverse aquatic and riparian plant communities. This study investigates the diversity and ecological structure of aquatic and riparian macrophytes in three oxbow streams of the upper Bengawan Solo River, Central Java, Indonesia. A total of 45 species representing 25 families were identified, dominated by amphibious and riparian life forms. Species richness and life form composition varied across sites, reflecting differences in hydrology and habitat heterogeneity. Diversity indices showed the highest richness and evenness in Sidowarno, while Kadokan exhibited lower richness but relatively balanced species distribution. The Importance Value Index (IVI) revealed site-specific dominance by taxa such as Ipomoea aquatica, Commelina diffusa, and Marsilea crenata. Several of these structurally dominant species, including Eichhornia crassipes and Colocasia esculenta, are also recognized as bioaccumulators of heavy metals, highlighting their functional relevance for phytoremediation. Moderate inter-site similarity values (Jaccard index 0.45-0.58) suggest that each oxbow supports a partially distinct macrophyte community. These findings underscore the importance of conserving multiple oxbow units as complementary reservoirs of biodiversity and ecological function in tropical river-floodplain systems.