A Method to Assess the Risk of Sun Coral Invasion in Marine Protected Areas.

The safest and most efficient method of avoiding costs and impacts associated with biological invasions is to prevent the introduction and establishment of non-native species. In Brazil, two invasive coral species have been causing ecological, economic and social impacts: Tubastraea coccinea and Tubastraea tagusensis. This work presents a protocol to analyze the risk of invasion in Marine Protected Areas (MPAs) in the State of Rio de Janeiro considering the main vector of these species on the Brazilian coast. This protocol takes five risk factors into account: environmental similarity between the donor area and the possible receiving area; available substrate for colonization; proximity to the donor region; proximity and quantity of oil platforms and drill ships that passed by the analyzed MPAs and proximity and quantity of oil platforms and drill ships that anchored near the MPAs. Results must be used by decision-makers for a better management of Marine Protected Areas. The protocol we present can be applied to analyze the relative risk of invasion throughout the Brazilian coast, in order to prioritize areas for early detection and monitoring of the presence of sun corals.

Abundance of the reef-building Petaloconchus varians (Gastropoda: Vermetidae) on intertidal rocky shores at Ilha Grande Bay, southeastern Brazil.

The reef-building vermetid Petaloconchus varians occurs in the western Atlantic Ocean, from the Caribbean Sea to the southern coast of Brazil. The present study evaluated the abundance of P. varians on intertidal rocky shores in Ilha Grande Bay (Rio de Janeiro State), and characterized their reefs, describing the species density, besides the weight and the belt width of the reefs. Petaloconchus varians reefs were recorded at 25 sites, with rocky shores exposed to different wave action (very sheltered, sheltered, semi-exposed and exposed) and slopes (10° to 46°). Clusters of individuals constructed large reefs along the middle intertidal zone, creating a wide belt (38 cm to 2 m). The density of P. varians and the weight of the reefs ranged from 620 to 2,559 ind.100 cm-2 and from 100 to 1,500 g.100 cm-2, respectively. Considering that the species was last reported from the area in the mid-20th century, the present study suggests that P. varians reefs are becoming dominant in the intertidal zone of rocky shores in Ilha Grande Bay. This is a contribution to knowledge of this ecosystem in Ilha Grande Bay, in view of local or global ecological changes.

Abundance of the reef-building Petaloconchus varians (Gastropoda: Vermetidae) on intertidal rocky shores at Ilha Grande Bay, southeastern Brazil

ABSTRACT The reef-building vermetid Petaloconchus varians occurs in the western Atlantic Ocean, from the Caribbean Sea to the southern coast of Brazil. The present study evaluated the abundance of P. varians on intertidal rocky shores in Ilha Grande Bay (Rio de Janeiro State), and characterized their reefs, describing the species density, besides the weight and the belt width of the reefs. Petaloconchus varians reefs were recorded at 25 sites, with rocky shores exposed to different wave action (very sheltered, sheltered, semi-exposed and exposed) and slopes (10° to 46°). Clusters of individuals constructed large reefs along the middle intertidal zone, creating a wide belt (38 cm to 2 m). The density of P. varians and the weight of the reefs ranged from 620 to 2,559 ind.100 cm-2 and from 100 to 1,500 g.100 cm-2, respectively. Considering that the species was last reported from the area in the mid-20th century, the present study suggests that P. varians reefs are becoming dominant in the intertidal zone of rocky shores in Ilha Grande Bay. This is a contribution to knowledge of this ecosystem in Ilha Grande Bay, in view of local or global ecological changes.

How much is too little to detect impacts? A case study of a nuclear power plant.

Several approaches have been proposed to assess impacts on natural assemblages. Ideally, the potentially impacted site and multiple reference sites are sampled through time, before and after the impact. Often, however, the lack of information regarding the potential overall impact, the lack of knowledge about the environment in many regions worldwide, budgets constraints and the increasing dimensions of human activities compromise the reliability of the impact assessment. We evaluated the impact, if any, and its extent of a nuclear power plant effluent on sessile epibiota assemblages using a suitable and feasible sampling design with no 'before' data and budget and logistic constraints. Assemblages were sampled at multiple times and at increasing distances from the point of the discharge of the effluent. There was a clear and localized effect of the power plant effluent (up to 100 m from the point of the discharge). However, depending on the time of the year, the impact reaches up to 600 m. We found a significantly lower richness of taxa in the Effluent site when compared to other sites. Furthermore, at all times, the variability of assemblages near the discharge was also smaller than in other sites. Although the sampling design used here (in particular the number of replicates) did not allow an unambiguously evaluation of the full extent of the impact in relation to its intensity and temporal variability, the multiple temporal and spatial scales used allowed the detection of some differences in the intensity of the impact, depending on the time of sampling. Our findings greatly contribute to increase the knowledge on the effects of multiple stressors caused by the effluent of a power plant and also have important implications for management strategies and conservation ecology, in general.

Bioinvasion in a Brazilian bay: filling gaps in the knowledge of southwestern Atlantic biota.

BACKGROUND: Biological invasions are a major cause of global species change. Nevertheless, knowledge about the distribution and ecology of introduced species is regionally biased, and many gaps in knowledge exist for most developing countries. METHODOLOGY/PRINCIPAL FINDINGS: To study the zoobenthos on the hard substratum of the Ilha Grande Bay, a survey was conducted on both natural and artificial substrata at three depths and seven sites. The species recorded were classified as native, cryptogenic or introduced. Multivariate analyses were conducted to assess the prevalence of introduced species in these communities and to compare the distribution of species on natural and artificial substrata of this bay to identify possible discrepancies in habitat use. Of the 61 species, 25 were cryptogenic, 10 were introduced and 26 were native. Similar numbers of introduced species were found on both natural and artificial substrata, though the community composition was significantly different between them. We also compared the species composition of the Ilha Grande Bay survey to other inventories taken around the world. The highest similarities were found between the Ilha Grande Bay inventory and the Atlantic coastal region (Tampa Bay, USA and the Gulf of Mexico), American Samoa and Pearl Harbor (USA) inventories. CONCLUSIONS/SIGNIFICANCE: This study presents the first published comprehensive list of hard substratum sessile marine invertebrate species in a Brazilian bay. The high percentage of cryptogenic species reveals gaps in both zoological records and information on introduced species for the Brazilian coast. The introduced species successfully colonized different sites in the Ilha Grande Bay, including both natural and artificial substrata. In addition, we find that artificial structures may not be good surrogates for natural rocky shores and may represent an ecological threat. Comparisons with other inventories suggest a history of broad-scale invasion, though more evidence is needed to support this conclusion.

The effect of low salinity on teredinids

Teredinids survival in low salinities was determined in aquaria. Panels previously immersed in Ponta de Leste, Ilha Grande Bay, Rio de Janeiro, were transferred to aquaria with salinities ranging from 5.0 to 15.0 Practical Salinity Unities (PSU). The waters of Ilha Grande Bay receive a large amount of wood from the marginal rainforest vegetation, being suitable for the development of teredinids. The coastal areas of the bay are subjected to wide salinity fluctuations due to strong and sudden tropical storms. Eleven different species of teredinids were found in the panels. The critical salinity concentration for the survival of the two most common species was 11.93 PSU for Lyrodus floridanus and 12.90 PSU for Teredo furcifera. The effect of time on the mortality of teredinids at low salinities is also discussed.

A sobrevivência de moluscos bivalves perfurantes de madeira da família Teredinidae foi avaliada a partir de sua manutenção em aquários de baixa salinidade. Painéis de madeira previamente imersos em Ponta de Leste, Baía da Ilha Grande, RJ, foram transferidos para aquários, contendo água do mar, cujas concentrações salinas variaram de 5,0 a 15,0 PSU. A Baía da Ilha Grande recebe uma grande quantidade de madeira da vegetação marginal de Mata Atlântica, o que torna o ambiente particularmente favorável ao desenvolvimento de teredinídeos. As áreas costeiras da baía estão sujeitas a grandes variações salinas decorrentes de tempestades tropicais que ocorrem súbita e intensamente. A salinidade crítica à sobrevivência das duas espécies mais comuns nos painéis foi de 11,93, para Lyrodus floridanus e 12,90 para Teredo furcifera. O efeito do tempo na mortalidade dos teredinídeos, quando sujeitos a baixas salinidades, foi discutido.