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- The Azorean edible abalone Haliotis tuberculata, an alternative heavy metal-free marine resource?Publication . Torres, Paulo; Rodrigues, Armindo; Prestes, Afonso L.; Neto, Ana I.; Álvaro, Nuno V.; Martins, Gustavo M.Abalones are considered a delicacy and exploited for food worldwide. In many places, overfishing has led to the decimation of wild stocks and many are now reared in aquaculture systems. In the Azores, there is no tradition of eating abalones and Haliotis tuberculata stocks are still virtually untouched. However, as tourism in the islands grows and the stocks of other shellfish diminish, there is an increasing pressure to find alternative edible resources, leading to a rising interest in abalones. According to previous studies performed in the region, other edible species, including the local highly appreciated limpets and the giant barnacle, present high concentration levels of some heavy metals, which has been attributed to the volcanic origin of the islands. Here we analysed the metal content in the edible tissue of Haliotis tuberculata from São Miguel Island, Azores. The potential human health risks due to its consumption was assessed by estimating the average daily intake (EDI) and target hazard quotient (THQ) of metals. Similarly to other organisms in the Azores, abalones have higher than normal levels of some heavy metals, particularly cadmium, reflecting a local natural source that should be closely monitored from a public health point of view.
- Gastropods with different development modes respond differently to habitat fragmentationPublication . Cacabelos, Eva; Neto, Ana I.; Martins, Gustavo M.The role of the human-made structures in coastal ecosystems can determine the spatial distribution or patterns of spatial abundances of marine organisms. To contribute to the understanding of linkages between different components of habitats (i.e. natural and artificial structures), we explored the role of type of larval development (planktotrophic vs. non-planktotrophic) on patterns of spatial variation of gastropods on rocky shores, elucidating the possible responsibility of habitat fragmentation on their distribution. Obtained results suggest that habitat fragmentation affects differently the patterns of variability of species with different types of larval development. Namely, fragmentation caused by artificial structures mostly influence variability of species with non-planktotrophic development. Moreover, although abundance of the species with non-planktotrophic development varied at small spatial scales, suggesting that processes operating at this scale are likely the main drivers of their distribution, changes in species variability were not associated with differences in species abundance among habitats.
- Predicting the ecological impact of a recent range expansion in the structure of intertidal biofilmsPublication . Martins, Gustavo M.; Prestes, Afonso L.; Faria, Joao; Neto, Ana I.Predicting the consequences of recent changes in species distributional ranges is paramount. The trochid Phorcus sauciatus has recently colonised the Azores and is the only intertidal trochid in these islands. In this study we used experimental mesocosms to examine whether its addition to the remainder of the intertidal assemblage of grazers composed of littorinids and patellids affects the structure of epilithic biofilms growing on experimental plates. We also examined if its presence can compensate the loss of patellid limpets to simulate areas where these are chronically harvested. Results showed that when the native assemblage of grazers (littorinids and patellids) are present, the addition of P. sauciatus had little influence on the overall structure of epilithic biofilms. However, when patellids were absent, and in contrast to expectations, biofilm standing stock on experimental plates decreased significantly. Results suggest that patellids may negatively affect the foraging activities of P. sauciatus via interference competition and are further discussed in face of ecological knowledge of these organisms.
- Macaronesia as a Fruitful Arena for Ecology, Evolution, and Conservation BiologyPublication . Florencio, Margarita; Patiño, Jairo; Nogué, Sandra; Traveset, Anna; Borges, Paulo A. V.; Schaefer, Hanno; Amorim, Isabel R.; Arnedo, Miquel A.; Ávila, Sérgio P.; Cardoso, Pedro; Nascimento, Lea; Fernández-Palacios, José María; Gabriel, Sofia I.; Gil, Artur José Freire; Gonçalves, Vitor; Haroun, Ricardo J.; Illera, Juan Carlos; López-Darias, Marta; Martínez, Alejandro; Martins, Gustavo M.; Neto, Ana I.; Nogales, Manuel; Oromí, Pedro; Rando, Juan Carlos; Raposeiro, Pedro M.; Rigal, François; Romeiras, Maria M.; Silva, Luís; Valido, Alfredo; Vanderpoorten, Alain; Vasconcelos, Raquel; Santos, Ana M. C.Research in Macaronesia has led to substantial advances in ecology, evolution and conservation biology. We review the scientific developments achieved in this region, and outline promising research avenues enhancing conservation. Some of these discoveries indicate that the Macaronesian flora and fauna are composed of rather young lineages, not Tertiary relicts, predominantly of European origin. Macaronesia also seems to be an important source region for back-colonisation of continental fringe regions on both sides of the Atlantic. This group of archipelagos (Azores, Madeira, Selvagens, Canary Islands, and Cabo Verde) has been crucial to learn about the particularities of macroecological patterns and interaction networks on islands, providing evidence for the development of the General Dynamic Model of oceanic island biogeography and subsequent updates. However, in addition to exceptionally high richness of endemic species, Macaronesia is also home to a growing number of threatened species, along with invasive alien plants and animals. Several innovative conservation and management actions are in place to protect its biodiversity from these and other drivers of global change. The Macaronesian Islands are a well-suited field of study for island ecology and evolution research, mostly due to its special geological layout with 40 islands grouped within five archipelagos differing in geological age, climate and isolation. A large amount of data is now available for several groups of organisms on and around many of these islands. However, continued efforts should be made toward compiling new information on their biodiversity, to pursue various fruitful research avenues and develop appropriate conservation management tools.
- Dramatic changes in the structure of shallow-water marine benthic communities following the invasion by Rugulopteryx okamurae (Dictyotales, Ochrophyta) in Azores (NE Atlantic)Publication . Faria, João; Prestes, Afonso L.; Moreu, Ignacio; Cacabelos, Eva; Martins, Gustavo M.Biological invasions are considered one of the most important drivers of biodiversity loss. Here we use a before-after-control-impact (BACI) design to investigate the impact of Rugulopteryx okamurae on the structure of shallow-water marine benthic communities in São Miguel island, Azores. After its first appearance in 2019, R. okamurae has rapidly invaded much of the southern coast of the island, where it became the dominant algae. This was followed by significant changes in the structure of shallow-water marine benthic communities, with substantial losses of natural variability and species richness. Compared to before, there has been dramatic reductions in the abundances of articulated coralline algae, corticated algae and corticated foliose algae in invaded locations. These results highlight its highly invasive character, not seen with other, more well-known, invasive species. It remains to be investigated if its impacts persist throughout time and to quantify the functional consequences of such dramatic changes.
- Frondose and turf-dominated marine habitats support distinct trophic pathways: evidence from ¹⁵N and ¹³C stable isotope analysesPublication . Hipólito, Cláudia; Neto, Raul M. A.; Costa, Tarso; Dionísio, Maria Ana; Prestes, Afonso L.; Azevedo, José M. N.; Martins, Gustavo M.; Neto, Ana I.Marine vegetation plays an important structuring role, delivering key functions and services to coastal systems the extent of which depends on the foundation species and their architecture. In increasingly urbanised coastlines, turf-forming macroalgae are replacing frondose morphotypes. Trophic relationships within these systems can be studied through stable isotope analysis of the different food web compartments. In the present study, we investigated trophic pathways in two distinct macroalgal assemblages: one dominated by small brown frondose algae, and one dominated by low-lying turf-forming species. ¹⁵N and ¹³C isotopic signatures were determined for selected macroalgae and sedentary animals from distinct trophic levels, collected from two habitats on São Miguel Island (Azores, Portugal). In frondose habitats macroalgae appeared to make up the primary carbon source for the entire food web, whilst in turf-dominated habitats there was a decouple between macroalgae and higher trophic levels. Because canopy replacement by algal turf may affect the structure of the littoral food webs, coastal biodiversity conservation strategies should give priority to natural areas rich in canopy-forming algae.
- Ervilia castanea (Mollusca, Bivalvia) populations adversely affected at CO₂ seeps in the North AtlanticPublication . Martins, Marta; Silva, Marina Carreiro; Martins, Gustavo M.; Ramos, Joana B.; Viveiros, Fátima; Couto, Ruben P.; Parra, Hugo; Monteiro, João; Gallo, Francesca; Silva, Catarina; Teodósio, Alexandra; Guilini, Katja; Hall-Spencer, Jason M.; Leitão, Francisco; Chícharo, Luís; Range, PedroSites with naturally high CO₂ conditions provide unique opportunities to forecast the vulnerability of coastal ecosystems to ocean acidification, by studying the biological responses and potential adaptations to this increased environmental variability. In this study, we investigated the bivalve Ervilia castanea in coastal sandy sediments at reference sites and at volcanic CO₂ seeps off the Azores, where the pH of bottom waters ranged from average oceanic levels of 8.2, along gradients, down to 6.81, in carbonated seawater at the seeps. The bivalve population structure changed markedly at the seeps. Large individuals became less abundant as seawater CO₂ levels rose and were completely absent from the most acidified sites. In contrast, small bivalves were most abundant at the CO₂ seeps. We propose that larvae can settle and initially live in high abundances under elevated CO₂ levels, but that high rates of post-settlement dispersal and/or mortality occur. Ervilia castanea were susceptible to elevated CO₂ levels and these effects were consistently associated with lower food supplies. This raises concerns about the effects of ocean acidification on the brood stock of this species and other bivalve molluscs with similar life history traits.
- Limited effects of marine protected areas on the distribution of invasive species, despite positive effects on diversity in shallow-water marine communitiesPublication . Cacabelos, Eva; Martins, Gustavo M.; Faria, Joao; Prestes, Afonso L.; Costa, Tarso; Moreu Badia, Ignacio; Neto, Ana I.Marine protected areas (MPAs) can be an effective tool for the conservation and management of marine coastal habitats. MPAs have been shown to halt habitat degradation, enhance the biomass of exploited species and diversity in general. Yet, we still know little about its role in halting the spread of non-native species. In this study, we assessed the role of MPAs in the structure of shallow subtidal communities around Sao Miguel Island, in general, and particularly on distribution of the two species of genus Asparagopsis: A. armata and A. taxiformis. In the Azores, the former is a well-established invasive species, whereas the status of A. taxiformis is still questionable. Overall, there was a significant greater diversity in terms of both species richness and number of macroalgal functional groups within MPAs. However, when considering the relative abundance of the various macroalgal functional groups, or the assemblage as a whole (multivariate analysis), there was no significant difference between areas within and outside MPAs. The cover of A. taxiformis was significantly greater within MPAs but not its biomass, whereas no significant variation was observed for A. armata. Overall, results suggest that surveyed MPAs had a positive effect on the diversity of shallow-water macroalgal communities. However, they have a limited role on the distribution of both Asparagopsis spp. and negligible effects when considering the relative abundances of macroalgal functional groups.