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Funding Information: This work was funded by Portuguese National Funding through FCT - Fundação para a Ciência e Tecnologia, I. P., through project LA/P/0083/2020 (LA LARSyS - MARETEC) and project LA/P/0069/2020 granted to the Associate Laboratory ARNET. The present work was supported by the Marine and Environmental Sciences Centre (MARE) which is financed by national funds from FCT/MCTES (UIDB/04292/2020) Joana M. Neves was supported by a PhD fellowship (UI/BD/150954/2021) from FCT. This work was supported by Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (JCC, FAPERJ- E26/201.286/2014) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (JCC, CNPq- 307117/2014–6) and Santander Bank staff mobility funding through Swansea University, UK. Studies in Costa Rica were funded by the Vicerrectoría de Investigación at the Universidad de Costa Rica. The funders took no part in the design of the study, in the collection, analysis, and interpretation of data, and in writing the manuscript. Publisher Copyright: Copyright © 2022 Vieira, Lobo-Arteaga, Santos, Leitão-Silva, Veronez, Neves, Nogueira, Creed, Bertelli, Samper-Villarreal and Pettersen. Seagrasses are declining globally, in large part due to increased anthropogenic coastal nutrient loads that enhance smothering by macroalgae, attenuate light, and are toxic when in excessive concentrations of inorganic nitrogen and phosphorus. However, as sanitation is improved many seagrass meadows have been observed to recover, with a few studies suggesting that they may even benefit from mild anthropogenic nutrient additions. Monitoring seagrass demography and health has faced difficulties in establishing the adequate variables and metrics. Such uncertainty in the methods has caused uncertainty of the significance of results presented and compromised extrapolations to other seasons, areas, or species. One solution has come from within the plant self-thinning theories. During the 1980s, an interspecific boundary line (IBL) was determined as the upper limit of the combination of plant density and above-ground biomass for any stand on Earth, setting their maximum possible efficiency in space occupation. Recently, two meta-analyses to determine specific IBLs for algae and for seagrasses have been performed. The recently updated seagrass dataset comprises 5,052 observations from 78 studies on 18 species. These IBLs opened new perspectives for monitoring: the observed distance of a stand to the respective IBL (i.e., each stand’s relative efficiency of space occupation) was demonstrated to be a valuable indicator of a population’s health. Thus, this metric can be used to determine the impact of nutrients and pollutants on algae and seagrass populations. Furthermore, because the IBLs are common to all species, they may be used to compare all species from any location worldwide. This novel approach showed that Halodule wrightii, Halodule beaudettei, Halophila baillonii, Zostera marina, and Zostera noltei meadows benefit from anthropogenic additions of nitrogen and phosphorus, as long as these additions are moderate. In fact, the healthier Z. noltei meadows in Portugal (and among the healthiest meadows worldwide) were the ones exposed to effluents from wastewater treatment plants (WWTP) and a food factory. We conclude that those effluents are providing water with enough quality and that their optimal management should coordinate the technological solutions of the WWTP with the natural potential of seagrass meadows as water purifiers and biomass producers. publishersversion published

The scleractinian corals Tubastraea coccinea Lesson, 1829 and T. tagusensis Wells, 1982 have invaded reefs along Brazil's coastline. Over the period 2011–2017 a standard, fast, easily repeatable semi-quantitative method was used to produce maps of distribution and a site (n = 77) specific Relative Abundance Index (RAI) to determine range expansion at Cabo Frio, an upwelling region. Invaded sites doubled from six to 12 over the period (one per year) and mean abundance increased tenfold from 0.2 to 2.6 RAI and 0.22 to 1.8 RAI (T. coccinea and T. tagusensis respectively). Site specific oceanographic conditions (temperature, salinity and water transparency) and distance from currently invaded sites (a proxy for propagule pressure) were chosen and used as determinants of invasion success in order to model the expansion. Model results compared favourably with empirical measurements and the simple, regional, and spatially explicit model predicted future range expansion under 10 and 20 year scenarios.

Tropical marine ecosystems are biologically diverse and economically invaluable. However, they are severely threatened from impacts associated with climate change coupled with localized and regional stressors, such as pollution and overfishing. Non-native species (sometimes referred to as ‘alien’ species) are another major threat facing these ecosystems, although rarely discussed and overshadowed by the other stressors mentioned above. NNS can be introduced accidentally (for example via shipping activities) and/or sometimes intentionally (for aquaculture or by hobbyists). Understanding the extent of the impacts NNS have on native flora and fauna often remains challenging, along with ascertaining when the species in question actually became ‘invasive’. Here we review the status of this threat across key tropical marine ecosystems such as coral reefs, algae meadows, mangroves, and seagrass beds. We aim to provide a baseline of where invasive NNS can be found, when they are thought to have been introduced and what impact they are thought to be having on the native ecosystems they now inhabit. In the appended material we provide a comprehensive list of NNS covering key groups such as macroalgae, sponges, seagrasses and mangroves, anthozoans, bryozoans, ascidians, fishes, and crustaceans.

Voluntary participation of citizens scientists has become a valuable tool for scientific research, but rarely applied for detection of non-native species in marine environments. This study was conducted in the Rio de Janeiro state, southeastern Brazil, at sites used for the SCUBA diving. The awareness activity was directed at dive centres before dives, addressing themes such as marine biodiversity, rocky reefs, biological invasions and citizen science. After the briefing, divers were invited to record occurrences of the invasive Tubastraea spp. on a wet note slate that were left under the responsibility of the dive centers, usually visible on the boat. This study showed a high level (100%) of credibility for data provided by volunteers, new records (N = 39) for the invasive species that had not previously been mentioned in published articles, and that the approach used is efficient in its spatial and temporal aspects. The successful development of citizen-based monitoring programs depends on the approximation of the academic community and the commitment of dive operators. The diver plays a critical role within this process, providing valuable information, which can be used to confirm the engagement of common citizens and also to track the spread of non-native marine species.

Tubastraea coccinea Lesson, 1830 and T. tagusensis Wells 1982 are azooxanthellate corals non-native to Brazil and introduced through fouling on oil platforms, the primary vector. They first invaded the tropical rocky reefs at Ilha Grande Bay (southwest Atlantic Ocean), during the early 1990s. Currently, at some Brazilian locations these species occupy 80% of the benthos of the shallow subtidal. They cause economic and environmental impacts by fouling shipping and modifying native communities. This study provides observations of an additional mechanism of secondary dispersal by T. coccinea and T. tagusensis that were seen attached to floating wood debris and marine litter, which are highly abundant in the region. Such rafting corals have been found adjacent to invaded reefs and stranded on beaches. These observations indicate that transport by rafting over long distances may be another mechanism of range expansion and secondary introduction of these invasive species within the region.

Seagrasses, marine flowering plants, provide a wide range of ecosystem services, defined here as natural processes and components that directly or indirectly benefit human needs. Recent research has shown that there are still many gaps in our comprehension of seagrass ecosystem service provision. Furthermore, there seems to be little public knowledge of seagrasses in general and the benefits they provide. This begs the questions: how do we move forward with the information we have? What other information do we need and what actions do we need to take in order to improve the situation and appreciation for seagrass? Based on the outcomes from an international expert knowledge eliciting workshop, three key areas to advance seagrass ecosystem service research were identified: 1) Variability of ecosystem services within seagrass meadows and among different meadows; 2) Seagrass ecosystem services in relation to, and their connection with, other coastal habitats; and 3) Improvement in the communication of seagrass ecosystem services to the public. Here we present ways forward to advance seagrass ecosystem service research in order to raise the profile of seagrass globally, as a means to establish more effective conservation and restoration of these important coastal habitats around the world.

Non-indigenous species (NIS) can cause substantial change in ecosystems and as marine invasives they can become a major threat to coastal and subtidal habitats. In September 2017 previously unknown and apparently NIS soft corals were detected on a shallow subtidal tropical rocky reef at Ilha Grande Bay, southeast Brazil. The present study aims to identify the species, quantify their distribution, abundance, and their interactions with native species. The most abundant NIS belonged to the recently described genus Sansibia (family Xeniidae) and the less common species was identified as Clavularia cf. viridis (family Clavulariidae). They were found along 170 m of shoreline at all depths where hard substrate was available. Sansibia sp. dominated deeper communities, associated positively with some macroalgal and negatively with the zoantharian Palythoa caribaeorum, which probably provided greater biotic resistance to invasion. Both species are of Indo-Pacific origin and typical of those ornamentals found in the aquarium trade.

Sun corals Tubastraea spp. from the Indo-Pacific have invaded hard grounds in the Caribbean, Gulf of Mexico, Brazil and Canary Islands where they cause significant ecological and economic damage to native systems, industry and society. In Brazil the National Plan for the Prevention, Control and Monitoring of the Sun Coral requires that sun corals are reduced to acceptable levels in nature and eradicated from vectors. Here we tested the efficiency of manual removal as a management tool at three sites along 260 km of Brazil's coastline with different oceanographic conditions (Ilha Grande, Rio de Janeiro and Cabo Frio). Four treatments were applied to shorelines undergoing management: (a) community removal (the whole benthic community scraped and stripped to bare rock), (b) sun coral single removal (c) sun coral repeated removal at 2 mo revisit) and (d) control areas naturally devoid of Tubastraea spp. Benthic communities were sampled over time using cover estimated from underwater photographs and larvae quantified in plankton trawls during management. The act of manual removal had no significant effect on sun coral larval abundance. The repeated removal method reduced cover at all sites to zero but a single removal was sufficient at sites with low densities of sun coral. The treatment effects varied systematically between sites, depending on local propagule pressure and invasion history. Manual removal is efficient and readily available and should be implemented in synergy with other methods to slow the spread of invaders, promote ecosystem recovery and allow time for the development of additional tools.

Phase shift phenomena are becoming increasingly common. However, they are also opportunities to better understand how communities are structured. In Southwest Atlantic coral reefs, a shift to the zoanthid Palythoa cf. variabilis dominance has been described. To test if competition drove this process, we carried out a manipulative experiment with three coral species. To estimate the natural frequency of encounters we assess the relationship between the proportion of encounters and this zoanthids coverage. The contact causes necrosis in 78% of coral colonies (6.47 ± SD 7.92 cm(2)) in 118 days. We found a logarithmic relationship between the proportion of these encounters and the cover of P. cf. variabilis, where 5.5% coverage of this zoanthid is enough to put 50% of coral colonies in contact, increasing their partial mortality. We demonstrate that zoanthid coverage increase followed by coral mortality increase will reduce coral cover and that competition drives the phase shift process.

The acidification of samples for the simultaneous measurement of stable carbon (δ13C) and nitrogen (δ15N) isotopes represents an important methodological question still not clarified because the removal of calcium carbonate (CaCO3) from samples may affect the outcome of the stable-isotope analysis. We investigated the effect of acidification on samples of 25 different taxa of benthic marine organisms from a rocky shore, to determine whether acidification affects the isotopic values of δ13C and δ15N. After washing with distilled water and drying, each sample was divided into two parts; one part was acidified by adding 1M HCl with a pipette, until no more CO2 was released, whereas the other part was retained as a non-acidified sample. Organisms with little CaCO3 showed no difference in carbon isotopic signatures after acidification, from those in the non-acidified part. Some organisms with a high CaCO3 content did show differences in carbon isotopic signatures after acidification. The nitrogen isotopic signature presented a significant difference; however, to what extent this difference is biologically important is discussed. Avoiding sampling parts containing a high concentration of carbonate is an efficient way to circumvent this problem. Acidification of samples as a pre-treatment for isotopic analysis is not useful for marine organisms without calcareous structures and is necessary only when the sampled parts contain significant amounts of carbonate.

Seagrasses are subjected to intense levels of anthropogenic disturbance as a result of the shallow nearshore waters they inhabit. Some seagrasses are known to have dynamic growth patterns, enabling them to colonize unstable shallow environments and adapt to a range of disturbances. This can result in high levels of variability in morphological and physiological attributes. The seagrass Halodule wrightii is known to be a fast-growing pioneering species with a large geographic range. The present study examines Halodule wrightii in a region under intense anthropogenic stress in order to determine what are the main environmental drivers affecting the morphology, physiology and status of these habitats. Parameters of plant morphology, physiology and status were measured either at the meadow scale (e.g. biochemistry) or at a higher frequency shoot scale (e.g. shoot width). We assigned an impact assessment index to a series of seagrass sites over a gradient of anthropogenic disturbance and found this to be explanatory of a number of the seagrass parameters measured including epiphyte cover, stable isotope δ15N and ETRmax however, it did not clearly explain shoot density, a commonly used bioindicator of environmental stress. At the shoot scale, Principal Component Analysis identified epiphyte and leaf width to have the strongest association. At the meadow scale this was shoot density, dry weight and Ek, albeit with the most impacted sites showing highest shoot density. Stable isotope (δ15N) and leaf length were most significant in explaining the variation between sites and impact category, providing a direct link between anthropogenic sources of nutrients to seagrass meadow density.

Scleractinian corals are key organisms in structuring reef habitats and coral cover is being lost due to local and global stressors caused and/or exacerbated by anthropogenic activities. Despite being hardly touched upon, studies of size-frequency distributions serve as snapshots of coral populations’ status and provide information on population decline or growth over time. In our study we have intermittently monitored two Brazilian scleractinians species, the endemic Mussismilia hispida and Siderastrea stellata, since 2000 in an important coral marginal reef site at Armação dos Búzios, Rio de Janeiro, Brazil. We measured length, width and arc of all colonies from both species found across transects at eleven sites. In total, over 5,000 colonies have been measured over the past 17 years. Although the frequency of small and medium colonies remained relatively constant, we observed a clear decline in the frequency of larger colonies (> 30 cm) for both species, particularly the most common S. stellata. Additionally, we have been monitoring colonies for bleaching in five of these sites throughout 2017 to assess health status. The relationship between observed bleaching prevalence/intensity and environmental variables (temperature, light availability and sedimentation) may elucidate how changes in local conditions influence coral health.

There is at present a ‘coral reef crisis’; one of the more drastic consequences of this is a phase shift, in which reef-building corals are replaced by non-reef building benthos such as macroalgae and soft corals. Previous studies have principally focused on the shift to macroalgae. Our goal was to investigate whether the dominance of the zoanthid Epizoanthus gabrieli on some reefs of Todos os Santos Bay, Brazil, represented a non-algal phase shift. In 2003, we identified a high cover of this species on two reefs (52% and 70%), but only in 2007 was it possible to confirm a reduction in coral cover. This dominance has persisted for over 9 years, characterizing a true phase shift. This loss of coral cover may be a result of anthropogenic disturbances within the bay; however, given the large number of human impacts, further studies are needed to identify specific causes of this shift. Although there are some reports of phase shift involving species pertaining to the Class Anthozoa, this is the first report of this phenomenon involving the order Zoanthidea.

We report on the temporal and spatial changes in populations of the invasive corals Tubastraea coccinea and Tubastraea tagusensis over an eleven year period at the Ilha Grande Bay, tropical southwest Atlantic. A semi-quantitative method was used to investigate the geographical distribution of the two congeners on subtidal rocky reefs along 350 km of coastline by applying a relative abundance index (RAI) to quantify change. Data were compared among 2000, 2004, 2010 and 2011. The indices showed a transition from rarity to dominance throughout the region as well as range expansion; in contrast at one site, where a pilot management initiative of manual control has been carried out, there was a reduction in abundance over time. Abundance values were compared to distance from possible points of introduction to pinpoint where the initial introduction occurred. The observed relationship between the possible points of entry and abundance of the two Tubastraea species was highly significant for the achorage and oil terminal whereas somewhat less so for the shipyard and port. The data obtained in this study are being used to plan further urgent management actions to control the biological invasion of the two Tubastraea species throughout the region, as well as being applied in modeling the range expansion into other regions.

The Cape Verde archipelago consists of 10 volcanic islands in the eastern Atlantic Ocean located 570 km off the coast of Western Africa. While the shallow benthic communities have been studied in some detail no seagrasses have been previously reported for the Republic of Cape Verde. The seagrass Halodule wrightii Ascherson was found and described at one location at Praia, Santiago Island. There it formed a number of patches (≈10) covering a total of ≈ 20 m2 at 1.4–1.6 m depth on fine sand soft bottoms. Some population characteristics are also reported. Two other sites with seagrass are also reported for the first time. The current record fills a knowledge gap regarding the distribution of seagrasses in the Tropical North Atlantic and it is expected that seagrasses will be found at other suitable sites within the archipelago.

The brittle star Ophiothela mirabilis has recently invaded and is expanding its range in the southwest Atlantic. Here we report a total of 29 novel host taxons/functional group (ten sponges, six cnidarians, five ascidians, four echinoderms, two algae, one bryozoan and a seahorse) used by O. mirabilis at different sites at Ilha Grande Bay, Brazil. The large number of species colonized by the ophiuroids suggests that they have become opportunistic and generalist in relation to their host species. The yellow-orange Brazilian lineage did not use camouflage reported in other studies, as they were highly visible and contrasted in color to many host species which suggests that they may possess some kind of predator deterrence. The high abundances of O. mirabilis registered here also suggest potential impacts to their hosts which need further study.

Many studies have assessed in unison specific biological attributes and certain environmental impacts but few studies have analyzed multiple biological variables and pressures from multiple sites at the same time. Our study's goal was to quantify the major potential human pressures in the shallow subtidal rocky reefs along a tropical Atlantic coast; propose a relative environmental pressure index and investigate the relationships between environmental pressures, the benthic community and coral population attributes. The analysis of human pressures suggests that one-third of sites were under high or very high proportional stress. Sites with high human pressure had lower live cover, higher percent of recent mortality and density of Siderastrea stellata. These relations were species specific. The coral species S. stellata seemed to be the best indicator of present environmental stress. These findings demonstrate the need to include multiple species and stressors in monitoring programs designed to contribute to coastal management initiatives.

We know little about animal communities in seagrass beds in the southeast Atlantic. The aim of the current study was to characterize and quantify the mollusk assemblages within these unique tropical seagrass habitats at a spatial scale fine enough to relate change in assemblage structure to gradients in exposure to air/depth. The study was carried out off Cabo Frio, Southeast Brazil. A 1250 m² area vegetated by the seagrass Halodule wrightii was defined (50 m parallel to the shoreline × 25 m distance from the shore margin). Twenty-six transects were established and the sampling carried out in order to characterize and to quantify the associated mollusk fauna. The mollusk assemblage presented overall density, density of key species and mean richness which increased systematically along the onshore-to-offshore gradient. Furthermore over the short spatial distance of the study the mollusk assemblage changed sufficiently for ordination to detect different assemblages.Há pouco conhecimento sobre a comunidade animal em bancos de fanerógamas marinhas no Atlântico sudeste. O presente estudo teve como objetivo caracterizar e quantificar assembléias de Mollusca nesses habitats únicos, utilizando uma escala espacial sensível suficiente para relacionar mudança na estrutura da assembléia aos gradientes em exposição ao ar/profundidade. O estudo foi realizado em Cabo Frio, no sudeste do Brasil. Delimitou-se uma área de vegetação de Halodule wrightii de 1250 m² (50 m paralelo ao costão × 25 m distância da orla). Foram estabelecidos 26 transectos e realizada a amostragem, de modo a caracterizar e quantificar a malacofauna. A assembléia apresentou uma densidade, densidade de espécies chaves e riqueza média que aumentou sistematicamente ao longo do gradiente orla-mar. Além disso, em escala espacial curta, a assembléia de Mollusca mudou suficientemente que, através de uma ordenação, se detectou diferenças entre assembléias.

Defensive chemistry may be used against consumers and competitors by invasive species as a strategy for colonization and perpetuation in a new area. There are relatively few studies of negative chemical interactions between scleratinian corals. This study characterizes the secondary metabolites in the invasive corals Tubastraea tagusensis and T. coccinea and relates these to an in situ experiment using a submersible apparatus with Sep-Paks® cartridges to trap substances released by T. tagusensis directly from the sea-water. Colonies of Tubastraea spp were collected in Ilha Grande Bay, RJ, extracted with methanol (MeOH), and the extracts washed with hexane, dichloromethane (DCM) and methanol, and analyzed by GC/MS. Methyl stearate and methyl palmitate were the major components of the hexane and hexane:MeOH fractions, while cholesterol was the most abundant in the DCM and DCM:MeOH fractions from Tubastraea spp. The organic material retained in Sep-Paks® cartridges was tentatively identified as hydrocarbons. There was a significant difference between treatments and controls for 1-hexadecene, n-hexadecane and n-eicosane contents. The production of defensive substances by the invasive corals may be a threat to the benthic communities of the region, which include endemic species.Substâncias químicas de defesa contra consumidores e competidores podem ser usadas por espécies invasoras marinhas como estratégia de colonização e perpetuação em novo ambiente. Entretanto, há poucos estudos experimentais que demonstrem as possíveis interações negativas entre corais escleractínios. Este trabalho tem como objetivo caracterizar os metabólitos secundários dos corais invasores Tubastraea tagusensis e T. coccinea; avaliar através da técnica de amostragem in situ quais são as substâncias de T. tagusensis liberadas na água do mar, com o auxílio de aparelho subaquático com colunas Sep-Paks®. Colônias dos corais invasores Tubastraea spp foram coletadas na Baía de Ilha Grande, RJ, e extraídas com MeOH. Os extratos foram submetidos à eluições com hexano, DCM e MeOH, e analisados por CG-EM. Estearato de metila e palmitato de metila foram as substâncias majoritárias das frações hexânicas e hexano: DCM, enquanto o colesterol foi a substância mais abundante das frações DCM e DCM:MeOH de Tubastraea spp. O material orgânico retido nas colunas Sep-Paks® foi identificado como hidrocarbonetos. Diferenças significativas entre controle e tratamento foram relacionadas a diferentes quantidades de 1-hexadeceno, n-hexadecano e n-eicosano. A produção de substâncias de defesas em Tubastraea spp permite especular sobre a ameaça que estes corais invasores representam para as comunidades bentônicas da Ilha Grande.

Seagrass meadows are among the most threatened ecosystems on earth, raising concerns about the equilibrium of coastal ecosystems and the sustainability of local fisheries. The present review evaluated the current status of the research on seagrasses and submerged aquatic vegetation (SAV) habitats off the coast of Brazil in terms of plant responses to environmental conditions, changes in distribution and abundance, and the possible role of climate change and variability. Despite an increase in the number of studies, the communication of the results is still relatively limited and is mainly addressed to a national or regional public; thus, South American seagrasses are rarely included or cited in global reviews and models. The scarcity of large-scale and long-term studies allowing the detection of changes in the structure, abundance and composition of seagrass habitats and associated species still hinders the investigation of such communities with respect to the potential effects of climate change. Seagrass meadows and SAV occur all along the Brazilian coast, with species distribution and abundance being strongly influenced by regional oceanography, coastal water masses, river runoff and coastal geomorphology. Based on these geomorphological, hydrological and ecological features, we characterised the distribution of seagrass habitats and abundances within the major coastal compartments. The current conservation status of Brazilian seagrasses and SAV is critical. The unsustainable exploitation and occupation of coastal areas and the multifold anthropogenic footprints left during the last 100 years led to the loss and degradation of shoreline habitats potentially suitable for seagrass occupation. Knowledge of the prevailing patterns and processes governing seagrass structure and functioning along the Brazilian coast is necessary for the global discussion on climate change. Our review is a first and much-needed step toward a more integrated and inclusive approach to understanding the diversity of coastal plant formations along the Southwestern Atlantic coast as well as a regional alert the projected or predicted effects of global changes on the goods and services provided by regional seagrasses and SAV. Resumo Pradarias de gramas marinhas e vegetação aquática submersa (VAS) estão entre os ecossistemas mais ameaçados do planeta, gerando preocupação sobre o equilíbrio dos ecossistemas costeiros e a sustentabilidade das pescarias. A presente revisão avaliou o estado do conhecimento sobre as pradarias marinhas e VAS do Brasil, considerando as respostas das plantas às condições ambientais, e o possível papel da geomorfologia costeira e variabilidade climática sobre a distribuição e abundância das populações. Apesar do crescente aumento no número de publicações, a comunicação dos resultados ainda é relativamente limitada e destina-se principalmente ao público nacional ou regional. Como resultado, as pradarias de gramas marinhas da América do Sul raramente são incluídas ou citadas em revisões e modelos globais. A escassez de estudos em larga escala e de longo prazo, permitindo a detecção de mudanças na estrutura, abundância e composição dos habitats e espécies associadas, limita a investigação das comunidades no que diz respeito aos efeitos potenciais das mudanças climáticas. Pradarias marinhas e VAS ocorrem ao longo de toda a costa brasileira, mas a distribuição e abundância das espécies são influenciadas pela oceanografia regional, massas de água costeiras, descarga de rios e geomorfologia costeira. Com base nas características oceanográficas, geomorfológicas, hidrológicas e ecológicas, o estudo discutiu a distribuição e abundância dos habitats vegetados pelas distintas regiões costeiras. O estado de conservação das pradarias marinhas e VAS no Brasil é extremamente crítico. A exploração insustentável e ocupação da zona costeira durante os últimos 100 anos conduziram à rápida degradação e perda de muitos dos habitats bentônicos marinhos e costeiros, outrora favoráveis para a ocupação da vegetação aquática. O conhecimento sobre os padrões e processos que regem a estrutura e o funcionamento destas populações e comunidades é fundamental para prever e compreender os efeitos das mudanças climáticas. A presente avaliação é um primeiro passo, necessário para uma abordagem mais integrada e inclusiva sobre a diversidade de formações vegetais costeiras ao longo do Atlântico Sudoeste, bem como um alerta regional a respeito dos efeitos previstos das mudanças climáticas das mudanças globais sobre os produtos e serviços ecossistêmicos prestados pelas pradarias marinhas.

All organisms have a set of ecological conditions (or niche) which they depend on to survive and establish in a given habitat. The ecological niche of a species limits its geographical distribution. In the particular case of non-indigenous species (NIS), the ecological requirements of the species impose boundaries on the potential distribution of the organism in the new receptor regions. This is a theoretical assumption implicit when Ecological Niche Models (ENMs) are used to assess the potential distribution of NIS. This assumption has been questioned, given that in some cases niche shift may occur during the process of invasion. We used ENMs to investigate whether the model fit with data from the native range of the coral Tubastraea coccinea Lesson, 1829 successfully predicts its invasion in the Atlantic. We also identified which factors best explain the distribution of this NIS. The broad native distributional range of T. coccinea predicted the invaded sites well, especially along the Brazilian coast, the Caribbean Sea and Gulf of Mexico. The occurrence of T. coccinea was positively related to calcite levels and negatively to eutrophy, but was rather unaffected to other variables that often limit other marine organisms, suggesting that this NIS has wide ecological limits, a trait typical of invasive species.

The cerith Cerithium atratum (Born 1778) is an abundant gastropod in the seagrass beds at Cabo Frio, Brazil. In order to estimate the ecological importance of cerith shells as a rare hard substratum in the seagrass bed, the abundances of C. atratum and of cerith shells occupied by hermit crabs were quantified. The mean densities of C. atratum and hermit crabs were 1887 and 100 individuals m−2, respectively, and these provided 0.5 m2 shell area m−2 available for epizoite colonization. The tube-forming polychaete Hydroides plateni (Kinberg 1867) and oyster Ostrea puelchana Orbigny, 1841 were the dominant visible epizoites on inhabited cerith shells. These epizoite populations were compared in order to investigate whether the temporal and spatial patterns in the epibiotic community were related to ecological and behavioral aspects of the occupant species (cerith or hermit crab). Larger cerith shells had a greater abundance of epizoites. Each epizoite showed a preference for a different occupant of the shells (the oyster for C. atratum and the polychaete for cerith shells occupied by hermit crabs). The oyster showed a seasonal pattern in abundance on C. atratum, being more common in fall (March–April). The distribution of the epizoites on the shells depended on the shell occupant species and was probably related to their different foraging activity –C. atratum ploughs half buried through the sediment, while the hermit crab crawls on the sediment surface. In both cases, the activity of the shell occupant was considered to be beneficial to the epizoites, as empty shells and shell fragments did not support a macroepifauna.

Extensive degradation of coral reefs makes it imperative to create functional models that demonstrate ecological processes which occur in alternative states that persist over time. These models provide important information that can help in decision making regarding management measures for both the prevention of further degradation and the recovery of these ecosystems. Development of these models requires identifying and testing the ecological processes that will impose the reduction of coral cover and, preferably, identifying the disturbance that triggers this phenomenon. For this reason, research programs are a useful tool which allows a focus on the production of information for modeling. It should start with survey investigations and tests of hypotheses concerning the cause of the reduction of coral cover. Subsequently, projects should be guided by the most probable hypotheses, focusing on one guild or functional group at a time until the "trigger" process which unleashed the disturbance is identified. Even if incomplete, these models already provide information for focusing management steps.