Change in tropical rocky shore communities due to an alien coral invasion

Abstract

To determine how benthic, tropical, rocky shore communities were affected by the invasive coral species Tubastraea coccinea and T. tagusensis, 8 sites were studied during 2 yr on rocky shores in the southwest Atlantic Ocean (Brazil) by using both fixed and random sampling techniques. Overall, mean cover of T. tagusensis was 0.7% and T. coccinea was 0.4%, (the eleventh and sixteenth most abundant taxa, respectively, throughout the sites). Forty-two major space occupying taxa were registered. In fixed quadrats there was a 76.6% increase per year in density of Tubastraea spp. over the study period. For percent cover no significant difference in cover over time was detected for T. coccinea, but for T. tagusensis and overall (both species) cover increased significantly. The random quadrats data showed subtle differences from the fixed quadrats. There was an increase in density of Tubastraea spp. through time (67.8% per year over the study period). In random samples the density of T. coccinea increased during the study but that of T. tagusensis did not. The cover of both corals also increased over time. The sites where Tubastraea spp. were most abundant possessed higher diversity, evenness and richness of species. Sites where Tubastraea was present tended to group in ordination. The presence of Tubastraea in the communities caused a mean dissimilarity of 4.8% in the invaded communities. A strong positive relationship between invader cover and change in community structure was found, which suggested complete (100%) community dissimilarity at an invader cover of 45%. The negative effects are sufficient to disturb the native benthic communities throughout the tropical Atlantic Ocean.

Population expansion of a new invasive coral species, Tubastraea micranthus, in the northern Gulf of Mexico

“…Tubastraea spp. in Brazil are showing signs of expansion and disruption of native species (Lages et al 2011, Sampaio et al 2012. Populations of this species have nearly monopolized artificial hard-bottom substrata, such as offshore platforms.…”

Using the critical salinity (S crit) concept to predict invasion potential of the anemone Diadumene lineata in the Baltic Sea

“…So far nothing is known about the anemone's impact on ecosystems, but if high population densities, as observed in the Kiel Fjord become the rule, we would expect an impact on biochemical fluxes of the benthic ecosystem. For example, dense polyp mats could significantly influence the native benthic hard bottom communities, which are commonly dominated by blue mussels, by competition for space and food with other epibionts (Lages et al 2011). Furthermore, little is known about the food spectrum of the animals: D. lineata feeds mainly on small crustaceans (Williams 1972), but according to Baker et al (2004) the anemone might also prey on larvae of economically important taxa such as blue mussels and oysters.…”

Host species of the non-indigenous brittle star Ophiothela mirabilis (Echinodermata: Ophiuroidea): an invasive generalist in Brazil?

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