Diversity analysis and trophic structure of a recently invaded tropical rocky shore

When a nonnative species remains in an invaded community for some time, long-term effects on community diversity and ecosystem functioning are expected, as are changes in trophic interactions between species. The blue soft coral Latissimia ningalooensis, presumably of Indian Ocean origin, was first detected in the wild in the tropical southeast Atlantic in Brazil in 2017. This study provides the first information on the trophic relationship that has developed between L. ningalooensis and 29 other benthic marine species in a food web on shallow tropical rocky reefs which have been invaded. The difference in species composition of invaded areas and control areas was also assessed. L. ningalooensis showed δ¹⁵N values close to those of macroalgae, suggesting that its symbiosis with zooxanthellae represents an essential source of energy in addition to the suspension feeding. An apparently opportunist-generalist consumer, the arrow crab Stenorhynchus seticornis showed values of δ¹³C and δ¹⁵N aligned as a probable consumer of L. ningalooensis. The difference in species composition between invaded and control areas and an increase in the abundance of L. ningalooensis in shallow areas suggests that a mechanism exists which will allow its further expansion into more favorable locations, so we encourage management such as continuous monitoring of the invaded area and eradication.