Benthic macrofauna alteration due to deposition of invasive coral Tubastraea spp. (Anthozoa, Scleractinia) on unconsolidated substrates

Abstract

Biological invasions are considered one of the main threats to global biodiversity and ecosystem functioning. In the oceans, generate impacts on benthic and pelagic marine communities, and consequently on the marine landscapes. In the mid-1980s, the coral species Tubastraea coccinea and Tubastraea tagusensis were accidentally introduced to the Brazilian coast, probably embedded in oil and gas platforms. Currently, such species are registered in most Brazilian coastal zones, including several protected areas. Commonly known as sun-corals, these species have several characteristics that give them high dispersal potential and, thus, have been systematically recorded, altering the marine landscape and affecting the functioning of invaded ecosystems. In Buzios Island, north coast of the State of São Paulo - where these species settled in high densities covering in some points almost 100% of the consolidated substrate - numerous changes in the benthic infralittoral community were measured. In addition, significant changes were observed in the unconsolidated substrate adjacent to the high concentration of these invaders. Adult colonies of Tubastraea are naturally coming off the vertical substrate and settling on adjacent sandy sediments, becoming a substrate for other species in a process known as "invasion meltdown". As a result, several changes in the sandy landscape have been occurring and are likely to have significant consequences for the benthic communities of these unconsolidated bottoms as well as for the pelagic organisms that use them. Thus, through periodic sampling and manipulative in situ experiments, this interdisciplinary project aims to evaluate changes in benthic macrofauna communities resulting from the deposition of Tubastraea colonies in unconsolidated sediments. (AU)