Distribuição e abundância do coral invasor Tubastraea spp.

Abstract

The invasive coral species, Tubastraea tagusensis and T. coccinea were accidentally introduced into Brazil by oil platforms. The rapid growth and reproductive stage, competition against native species, chemical defenses against natural predators and competitors and ample use of different substrates contribute to the success and expansion of Tubastraea spp. on the Brazilian coast. This study had two aims: 1) investigate a methodology that results in more efficient and cost-effective monitoring of the Tubastraea spp. invaders on the Brazilian coast, 2) map the geographical distribution, characterize the populations and study the effect of corals insertion in the community on the northern coast of São Paulo (LNSP). The first aim evaluated four methods by comparing the visual census method and three other methods that use photography and filming. The visual census method proved to be more efficient in achieving the results compared with other methods, primarily to identification of smaller organisms; however, time in the field and costs were higher. The second aim used the visual method to study the effect of insertion of coral invaders into the community. Also, a semi-quantitative monitoring of spatial scale to characterize the spatial distribution of coral invaders was carried out; transects with squares were used to estimate the density of Tubastraea spp. along the depth gradient, and transects and graduated arcs employed to estimate the occurrence of colonies at different inclinations of the substrate, in LNSP. The invader corals are increasing their distribution, causing several impacts on native communities and species. T. tagusensis is actually found dominating several rocky shores, with a higher density deeper and in a vertical and negative substrates slopes in LNSP. Eradication and/or control of the invasive corals are recommended on the Brazilian coast, especially where populations are isolated or are still small.