Loading...
10 results
Search Results
Now showing 1 - 10 of 10
- Environmental representativity in marine protected area networks over large and partly unexplored seascapesPublication . Stratoudakis, Yorgos; Hilário, Ana; Ribeiro, Cláudia; Abecasis, David; Gonçalves, Emanuel J.; Andrade, Francisco; Carreira, Gilberto P.; Gonçalves, Jorge Manuel Santos; Freitas, Luis; Pinheiro, Luis Menezes; Batista, Marisa I.; Henriques, Miguel; Oliveira, Paulo B.; Oliveira, Paulo; Afonso, Pedro; Arriegas, Pedro Ivo; Henriques, SofiaConverting assemblages of marine protected areas (MPAs) into functional MPA networks requires political will, multidisciplinary information, coordinated action and time. We developed a new framework to assist planning environmental representativity in a network across the marine space of Portugal, responding to a political commitment to protect 14% of its area by 2020. An aggregate conservation value was estimated for each of the 27 habitats identified, from intertidal waters to the deep sea. This value was based on expert-judgment scoring for environmental properties and features relevant for conservation, chosen to reflect the strategic objectives of the network, thus providing an objective link between conservation commitments and habitat representativity in space. Additionally, habitats' vulnerability to existing anthropogenic pressures and sensitivity to climate change were also scored. The area coverage of each habitat in Portugal and within existing MPAs (regionally and nationally) was assigned to a scale of five orders of magnitude (from < 0.01% to >10%) to assess rarity and existing representation. Aggregate conservation value per habitat was negatively correlated with area coverage, positively correlated with vulnerability and was not correlated with sensitivity. The proposed framework offers a multi-dimensional support tool for MPA network development, in particular regarding the prioritization of new habitats to protect, when the goal is to achieve specific targets while ensuring representativity across large areas and complex habitat mosaics. It requires less information and computation effort in comparison to more quantitative approaches, while still providing an objective instrument to scrutinize progress on the implementation of politically set conservation targets.
- Effect of Depth across a Latitudinal Gradient in the Structure of Rhodolith Seabeds and Associated Biota across the Eastern Atlantic OceanPublication . Pérez-Peris, Inés; Navarro-Mayoral, Sandra; de Esteban, Marcial Cosme; Tuya, Fernando; Peña, Viviana; Barbara, Ignacio; Neves, Pedro; Ribeiro, Cláudia; Abreu, Antonio; Grall, Jacques; Espino, Fernando; Bosch, Nestor Echedey; Haroun, Ricardo; Otero-Ferrer, FranciscoRhodolith seabeds are 'ecosystem engineers' composed of free-living calcareous red macroalgae, which create extensive marine habitats. This study addressed how depth influenced the structure (size and morphology) of rhodoliths and the abundance of associated floral and faunal epibionts across the Eastern Atlantic Ocean. Sampling was carried out at two sites within five regions (Brittany, Galicia, Madeira, Gran Canaria, and Principe Island), from temperate to tropical, covering a latitudinal gradient of 47 degrees, in three depth strata (shallow, intermediate and deep), according to the rhodolith bathymetrical range in each region. Depth typically affected the rhodolith size at all regions; the largest nodules were found in the intermediate and deep strata, while rhodolith sphericity was larger at the shallow depth strata. Higher biomasses of attached macroalgae (epiphytes) were observed at depths where rhodoliths were larger. The abundance of epifauna was variable across regions and depth strata. In general, the occurrence, structure, and abundance of the associated biota across rhodolith habitats were affected by depth, with local variability (i.e., sites within regions) often displaying a more significant influence than the regional (large-scale) variation. Overall, this study showed that the rhodolith morphology and associated epibionts (flora and fauna) were mostly affected by depth, irrespective of latitude.
- Population density, reproduction cycle and nutritional value of Sphaerechinus granularis (Echinodermata: Echinoidea) in an oceanic insular ecosystemPublication . Lourenço, Sílvia; José, Ricardo; Neves, Pedro A.; Góis, André; Cordeiro, Nereida; Andrade, Carlos; Ribeiro, CláudiaSea urchins play an important role in island coastal ecosystems as keystone species and as potential resources for harvesting and aquaculture. In Southern Europe, the most valuable and harvested species is the European purple sea urchin Paracentrotus lividus, but there is a growing interest to explore other edible species like the blunt sea urchin Sphaerechinus granularis. The echinoderms biodiversity of Madeira archipelago was previously described, but their local habitat, population densities and size distribution, important to establish their harvest and aquaculture potential, are poorly known. The present study aimed to evaluate S. granularis population in the oligotrophic and narrow insular shelf of Madeira archipelago, mainly regarding its habitat, densities, reproduction season and roe marketable characteristics. Sphaerechinus granularis was found in low densities (0.01 ind./m(2)) from shallow to deep reefs (5-30 m). The highest densities occurred in shallow waters and breakwaters in association to encrusting algae, turf and erect brown macroalgae. Here, the low primary productivity ecosystem influenced the long reproductive season of the local population. This population showed a relatively high gonadosomatic index (maximum GI of 8), high gonad weight (5.00-12.19 g) with high proportion of bright yellow and orange gonads (37.5-60%) between February and November. Additionally, the high level of total carotenoids, the high PUFA (particularly EPA) content, and the ratio n-6/n-3 close to one support the high nutritional value of S. granularis roe. The trend of incremental GI between September and November and the increasing content of PUFA in autumn suggests this could be the preferential harvesting season. This information is key to evaluate a sustainable exploitation of this living marine resource.
- Rhodolith physiology across the atlantic: towards a better mechanistic understanding of Intra- and interspecific differencesPublication . Schubert, Nadine; Peña, Viviana; Salazar, Vinícius W.; Horta, Paulo A.; Neves, Pedro; Ribeiro, Cláudia; Otero-Ferrer, Francisco; Tuya, Fernando; Espino, Fernando; Schoenrock, Kathryn; Hofmann, Laurie C.; Le Gall, Line; Santos, Rui; Silva, JoãoCoralline algae are important components in a large variety of ecosystems. Among them, rhodoliths are a group of free-living coralline red algae that cover extensive coastal areas, from tropical to polar regions. In contrast to other ecosystem engineers, limited research efforts preclude our understanding of their physiology, underlying mechanisms, drivers and potential differences related to species under varying environments. In this study, we investigated the photosynthetic and calcification mechanisms of six Atlantic rhodolith species from different latitudes, as well as intra-specific differences in one species from four locations. Laboratory incubations under varying light levels provided simultaneous photosynthesis- and calcification-irradiance curves, allowing the assessment of inter- and intra-specific differences on the coupling between these two processes. Stable isotope analysis and specific inhibitor experiments were performed to characterize and compare carbon-concentrating mechanisms (CCMs), as well as the involvement of specific ion-transporters for calcification. Our findings showed significant differences in rhodolith physiological mechanisms that were partially driven by local environmental conditions (light, temperature). High variability was found in the coupling between photosynthesis and calcification, in CCM-strategies, and in the importance of specific ion transporters and enzymes involved in calcification. While calcification was strongly correlated with photosynthesis in all species, the strength of this link was species-specific. Calcification was also found to be reliant on hotosynthesis- and light-independent processes. The latter showed a high plasticity in their expression among species, also influenced by the local environment. Overall, our findings demonstrate that (1) rhodolith calcification is a biologically-controlled process and (2) the mechanisms associated with photosynthesis and calcification display a large variability among species, suggesting potential differences not only in their individual, but also community responses to environmental changes, such as climate change.
- A new signal of marine tropicalization in the Macaronesia region: first record of the mesophotic macroalga Avrainvillea canariensis A. Gepp & E.S. Gepp in the Madeira archipelagoPublication . Ribeiro, Cláudia; Neto, A.I.; Moreu, I.; Haroun, R.; Neves, PamelaMesophotic green algal meadows of Avrainvillea canariensis are firstly reported for Madeira island. This represents a northern expansion of the species by nearly 500 km turning the species a Macaronesian endemism. The meadows of A. canariensis were found in a sandy bottom in the South coast of the island of Madeira, inside the Marine Park of Cabo Girao, covering an estimated area of 50 m(2) at a depth range 25-30 m. The collected specimens reached about 12 cm in height and were found clustered, forming distinct patches. Since this type of subtidal surveys in soft bottoms are scant in Madeira, we cannot evaluate whether this is a recent colonization. Yet, this new record can be another clear sign of climate change effects in the madeiran benthic communities, a process previously documented in the Macaronesia region with the arrival and subsequent settlement of other warm water marine species.
- A baseline for prioritizing the conservation of the threatened seagrass Cymodocea nodosa in the oceanic archipelago of MadeiraPublication . Ribeiro, Cláudia; Neves, Pedro; Kaufmann, Manfred; Araújo, Ricardo; Riera, RodrigoSeagrasses are experiencing fragmentation and regression globally; thus, protection and recovery of meadows are a preservation priority. However, conservation actions must consider inherent regional conditions, since certain coastal areas are not suitable for the settlement of extensive meadows. Likewise, small oceanic archipelagos are not always able to fulfil the habitat requirements of seagrass habitats but can harbour small patches that in turn provide unique research opportunities. In this study, we focused on the seagrass Cymodocea nodosa in the archipelago of Madeira (NE Atlantic Ocean). Here we compile historical and contemporary records of this species along with characterization of associated communities (fish and invertebrates). A bionomic map with potentially suitable areas for the establishment and settlement of this species is also included. Lastly, we highlight coastal management and restoration actions and future research directions to preserve this species in Madeira Island.
- “Pink round stones”—rhodolith beds: an overlooked habitat in Madeira ArchipelagoPublication . Neves, Pedro A.; Silva, João; Peña, Viviana; Ribeiro, CláudiaDespite its worldwide distribution in sedimentary infralittoral and circalittoral bottoms, rhodolith beds have been the subject of fewer studies than other nearshore communities, like kelp forests and coral reefs. This is also the case in Madeira archipelago (Eastern Atlantic), where until recently our knowledge on rhodolith beds was limited to a few references to its occurrence and species composition. In the course of an ongoing habitat-mapping project developed in Madeira, observations revealed that rhodolith beds are more common and extensive than previously supposed. The habitat maps for these beds in Madeira archipelago here presented are the first ever produced for the region. They reveal a total of 46 rhodolith beds at eleven different locations spread across three islands (Madeira, Desertas and Porto Santo), with areas ranging from 776 to 101,081 m(2) and at depths between 12 and 35 m. Author's observations, as well as the results suggest that more rhodolith beds are likely to exist in the archipelago, particularly at greater depths and unexplored locations. The application of molecular systematic tools for the identification of rhodolith-forming species revealed the occurrence of four species belonging to the genera Lithothamnion and Phymatolithon. This latter genus is represented by a single species which is commonly found in rhodolith beds of the archipelago. Genetically, our results show similarities both with the rhodolith communities from the Canary islands and the Algarve (south of Portugal) and highlight the singularities of the archipelago's marine flora. The new array of data here presented is deemed essential for an effective management and conservation of these important and sensitive habitats.
- Local benthic assemblages in shallow rocky reefs find refuge in a marine protected area at Madeira IslandPublication . Alves, F.; Canning-Clode, João; Ribeiro, Cláudia; Gestoso, Ignacio; Kaufmann, ManfredThe patterns of variability in the composition and structure of benthic communities along two depth strata (5 and 10m) and the presence of sea urchins in structuring the subtidal rocky reefs were quantified in a long-established coastal marine protected area (Garajau MPA) and in two size equivalent and contiguous impacted areas (one highly urbanized and other with high fishing pressure) at Madeira Island (northeast Atlantic). Results suggest i) the MPA could be acting as a refuge for local biodiversity, ii) communities from the highly fished area could be suffering an impoverishment of local biodiversity, and iii) communities from the highly urbanized area would be enriched by the establishment of opportunistic species. These findings support that the level of human-pressure likely plays an important role in the composition of benthic communities in this insular ecosystem, although this was more relevant at the shallower stratum where the key grazer Diadema africanum explained 65% of the variance of benthic assemblages. It is suggested that this MPA small dimension and proximity to human impacted areas are limiting the survival of predators of the D. africanum.
- Filling gaps in the Webbnesia marine diversity: the madeiran sponge faunaPublication . Santín, A.; Wirtz, Peter; Neves, Pedro António Nobre Soares Pinto das; Ribeiro, CláudiaDespite few pioneering works in the late XIX and early XX century, the poriferan fauna of Madeira has remained mostly unexplored until today, Madeira being one of the least studied eastern Atlantic archipelagos in terms of its sponge diversity. After a thorough analysis of both new material collected by SCUBA diving as well as a literature research, 140 sponge species are known to occur in the Madeira archipelago. From the 56 species identified by both collected material and pictures, approximately 60% (34 species) are new records for the Archipelago. These 34 new records were found associated with littoral rocky substrates and, to a lesser extent, caves, rhodolith beds and wrecks, within a depth range of 10-35 m depth. Our records also contain several Mediterranean species that have not been previously recorded in the North Atlantic, several North-east Atlantic species whose presence in Madeira marks their southernmost limit of occurrence, as well as elements from the subtropical West African fauna. Amongst the new additions to its sponge fauna there are the first records of Homomscleromorpha, with at least three Oscarella species noted, as well as a new species of Hemimycale (Demospongiae, Poecilosclerida). Yet, this is still an underestimation of Madeira's real sponge diversity.
- Positive species interactions structure rhodolith bed communities at a global scalePublication . Bulleri, Fabio; Schubert, Nadine; Hall‐Spencer, Jason M.; Basso, Daniela; Burdett, Heidi L.; Francini‐Filho, Ronaldo B.; Grall, Jacques; Horta, Paulo A.; Kamenos, Nicholas A.; Martin, Sophie; Nannini, Matteo; Neves, Pedro António Nobre Soares Pinto das; Olivé, Irene; Peña, Viviana; Ragazzola, Federica; Ribeiro, Cláudia; Rinde, Eli; Sissini, Marina; Tuya, Fernando; Silva, JoãoRhodolith beds are diverse and globally distributed habitats. Nonetheless, the role of rhodoliths in structuring the associated species community through a hierarchy of positive interactions is yet to be recognised. In this review, we provide evidence that rhodoliths can function as foundation species of multi-level facilitation cascades and, hence, are fundamental for the persistence of hierarchically structured communities within coastal oceans. Rhodoliths generate facilitation cascades by buffering physical stress, reducing consumer pressure and enhancing resource availability. Due to large variations in their shape, size and density, a single rhodolith bed can support multiple taxonomically distant and architecturally distinct habitat-forming species, such as primary producers, sponges or bivalves, thus encompassing a broad range of functional traits and providing a wealth of secondary microhabitat and food resources. In addition, rhodoliths are often mobile, and thus can redistribute associated species, potentially expanding the distribution of species with short-distance dispersal abilities. Key knowledge gaps we have identified include: the experimental assessment of the role of rhodoliths as basal facilitators; the length and temporal stability of facilitation cascades; variations in species interactions within cascades across environmental gradients; and the role of rhodolith beds as climate refugia. Addressing these research priorities will allow the development of evidence-based policy decisions and elevate rhodolith beds within marine conservation strategies.