Diversity of gastropods (Animalia: Mollusca) in the upper Bengawan Solo River, Central Java, Indonesia: Native versus alien species

Abstract. Reza AD, Mahendra AS, Riadi AA, Aryanto AEP, Agustin HN, Dewangga A, Indrawan M, Dadiono MS, Setyawan AD. 2024. Diversity of gastropods (Animalia: Mollusca) in the upper Bengawan Solo River, Central Java, Indonesia: Native versus alien species. Intl J Bonorowo Wetlands 14: 83-95. Bengawan Solo River in Java Island, Indonesia, is important habitat for aquatic organisms, one of which is gastropods. However, there is indication of the presence of invasive alien gastropods in this river, which might pose threat to native species. This study aimed to identify the diversity of gastropod species in the upper Bengawan Solo River, Central Java, Indonesia and assess the presence of invasive species measured. Data collection was conducted in December 2023 at five stations representing varying habitat conditions. Data was collected using the transect plot method and analyzed by calculating the Shannon-Wiener index, Simpson's dominance index and density. The invasive status of species was determined based on literature studies. The study revealed 23 gastropod species from 9 families. There were 16 invasive species found, including Tarebia granifera, Sulcospira testudinaria, Faunus ater, Achatina immaculata, Pomacea canaliculata, Sermyla riquetii, Limicolaria flammea, Littorina littorea, Perpolita hammonis, Viviparus glacialis, Viviparus viviparus, Viviparus intertextus, Semisulcospira libertina, Brotia costula, Zebrina detrita, and Melanoides tuberculata. There were 7 native species found, namely Pila scutata, Pila ampullacea, Filopaludina javanica, Stenomelania punctata, Stenomelania denisoniensis, Cipangopaludina chinensis and Acavus phoenix. The level of diversity of gastropod species in the upper Bengawan Solo River was in the medium category while the dominance index was low, indicating that there was no dominant gastropod in the upper Bengawan Solo River. Some invasive gastropod species had high density compared to other species, implying a threat to the native ones. This finding warrants attention since the dominance of invasive alien species can affect the ecological system balance and lead to the loss of native species.