Effects of an Introduced Benthivorous Fish on Macroinvertabrates Diversity in a Semiarid Shallow Lake

The Cyrinus carpio Linnaeus, 1758 (common carp) is a widely introduced species for commercial purposes. However, its detrimental effects on lakes and reservoirs, such as a decrease in water quality, abundance and richness of macrophytes, and macroinvertebrate abundance, are also known. In this study, we investigated the effect of common carp introduction on the macroinvertebrate community in a shallow lake in the Brazilian semiarid region. The study in Panati lake took place between 2002 and 2008 with the introduction of common carp in 2004. Shallow lakes from Our results showed that after common carp introduction, there was a significant reduction in the richness and diversity of the macroinvertebrate community, as well as an increase in the dominance of certain groups, such as chironomids. The decrease in richness and diversity is likely a result of the decline in abundance of key dominant benthic groups and species, such as the gastropods Pomacea lineata (Spix, 1827), Biomphalaria straminea (Dunker, 1848), Aplexa marmorata (Guilding, 1828) and Plesiophysa ornata (Haas 1938), oligochaetes, and ostracods, as well as several insect families. This decline may also lead to increased variability (destabilizing effect) among gastropods, annelids, and crustaceans, as well as an increase in the variability of richness and diversity among benthic macroinvertebrate species