Coexistencia del coral formador de arrecifes Cladocora caespitosa y la macroalga formadora de dosel Treptacantha ballesterosii: descripción de un nuevo hábitat mediterráneo

Shallow Mediterranean rocky environments are usually dominated by macroalgae, but the stony colonial zooxan­thellate coral Cladocora caespitosa is able to build extensive banks in some particular areas. Although zooxanthellate corals and benthic macroalgae are expected to compete for light and space when overlapping in the same habitat, there is previous evidence that C. Caespitosa and Mediterranean macroalgae do not suffer from competitive exclusion when living together. Here we characterize a new and unique Mediterranean habitat where the reef-building coral C. Caespitosa and erect seaweeds of the order Fucales (Cystoseira s.l.) coexist. In this new habitat C. Caespitosa reaches 34% cover and densities of Cystoseira s.l. (mainly Treptacantha ballesterosii) are much higher than values reported from other sites. Interestingly, abundances of T. Ballesterosii and C. Caespitosa show a positive relationship, suggesting that some kind of facilitation mechanism is taking place. These findings challenge the theory of competitive exclusion between corals and macroalgae and launch a wide array of possible open discussions on coral-macroalgae interactions.Los ambientes rocosos someros del Mediterráneo están habitualmente dominados por macroalgas, no obstante, el coral colonial zooxantelado Cladocora caespitosa es capaz de formar bancos extensos en algunos lugares. Aunque es prede­cible que los corales con zooxantelas y las algas bentónicas compitan por la luz y el espacio cuando coinciden en el mismo hábitat, hay evidencias previas de que C. Caespitosa y las algas mediterráneas no se excluyen competitivamente cuando viven juntas. En este trabajo se caracteriza un nuevo y único hábitat mediterráneo donde el coral formador de arrecifes C. caespi­tosa y algas erectas del orden Fucales (Cystoseira s.l.) coexisten. En este hábitat nuevo C. Caespitosa alcanza coberturas del 34% y las densidades de Cystoseira s.l. (principalmente de Treptacantha ballesterosii) son mucho mayores que los valores encontrados en otros lugares. Remarcablemente, las abundancias de T. Ballesterosii y C. Caespitosa muestran una relación positiva, sugiriendo que existe algún tipo de mecanismo de facilitación. Este hallazgo pone en jaque la teoría de exclusión competitiva entre corales y macroalgas, a la vez que puede iniciar un amplio abanico de discusiones en las interacciones entre corales y macroalgas

Importance of life history traits for vulnerability to climate change: implications for macroalgal restoration

Fucalean algae are dominant canopy-forming species that create extensive and highly productive ecosystems in the intertidal and subtidal rocky shores of temperate seas. Regrettably, these marine forests are in decline due to various human drivers, with the Mediterranean Sea one of the most threatened areas. To design appropriate restoration strategies adapted to cope with the unavoidable change in future climate conditions, the response to climate change of the candidate species must be considered. It is important to assess how the specific life history traits of the foundational species may determine environmental requirements, and thus responses to future climate change. This knowledge will allow us to predict the potential winners and losers among the species potentially inhabiting the same areas in a future context of global climate change, providing important information to fine-tune future restoration interventions. The aim of this study was to evaluate the response of two canopy-forming species inhabiting similar upper subtidal zones but with different life history traits to a combination of anomalous high temperatures and increased UV radiation. One of the species (Ericaria crinita) was perennial, slightly exposed rocky shores and dwelling in areas where extreme temperatures can be frequent; while the other (Ericaria mediterranea) a semi-perennial species that dwells in wave-exposed zones, with seawater temperatures buffered by the high hydrodynamism. Our results show that the effects of temperature and radiation are species- (mediated by the species life history traits) and life-stage specific. High temperatures strongly affected the adults of both species, especially E. mediterranea. The germlings in addition to being very susceptible to high temperatures, were also vulnerable to UV radiation, exacerbating the impacts of temperature, especially on E. crinita recruits. Interestingly, vulnerability to climate-driven impacts was determined by the specific life history traits, with i) the species dwelling in open areas the most sensitive to warming and, ii) the perennial species the most vulnerable to UV radiation. Last, we discuss how these species-specific responses to climate-driven impacts may be key in terms of species that could foster the resistance and resilience of marine ecosystems to future climate impacts

Biodiversity loss in a Mediterranean ecosystem due to an extreme warming event unveils the role of an engineering gorgonian species

Stochastic perturbations can trigger major ecosystem shifts. Marine systems have been severely affected in recent years by mass mortality events related to positive thermal anomalies. Although the immediate effects in the species demography affected by mortality events are well known, information on the mid- to long-term effects at the community level is much less documented. Here, we show how an extreme warming event replaces a structurally complex habitat, dominated by long-lived species, by a simplified habitat (lower species diversity and richness) dominated by turf-forming species. On the basis of a study involving the experimental manipulation of the presence of the gorgonian Paramuricea clavata, we observed that its presence mitigated the effects of warming by maintaining the original assemblage dominated by macroinvertebrates and delaying the proliferation and spread of the invasive alga Caulerpa cylindracea. However, due to the increase of sediment and turf-forming species after the mortality event we hypothesize a further degradation of the whole assemblage as both factors decrease the recruitment of P.clavata, decrease the survival of encrusting coralligenous-dwelling macroinvertebrates and facilitate the spreading of C. cylindracea

A Roadmap for the Restoration of Mediterranean Macroalgal Forests

Canopy-forming macroalgae play a crucial role in coastal primary production and nutrient cycling, providing food, shelter, nurseries, and habitat for many vertebrate and invertebrate species. However, macroalgal forests are in decline in various places and natural recovery is almost impossible when populations become locally extinct. Hence, active restoration emerges as the most promising strategy to rebuild disappeared forests. In this regard, significant efforts have been made by several EU institutions to research new restoration tools for shallow and mesophotic reef habitats (e.g., MERCES EU project, AFRIMED, and ROCPOP-life) and effective techniques have subsequently been proposed to promote self-sustaining populations. Recent research indicates that macroalgal forest recovery requires a broad spectrum of measures, ranging from mitigating human impacts to restoring the most degraded populations and habitats, and that the viability of large restoration actions is compromised by ongoing human pressures (e.g., pollution, overgrazing, and climate change). We propose a roadmap for Mediterranean macroalgal restoration to assist researchers and stakeholders in decision-making, considering the most effective methods in terms of cost and costeffectiveness, and taking background environmental conditions and potential threats into account. Last, the challenges currently faced by the restoration of rocky coastal ecosystems under changing climate conditions are also discussed

The role of grazers in early-life stages of Cystoseira sensu lato can be crucial in the restoration of marine forests

Grazing is one of the most important biological factors controlling the abundance of early-life stages of fucoids and one of the major issues when restoring marine forests. Benthic macroinvertebrates (e.g., sea urchins) and fish shape and regulate benthic macroalgal communities from polar to tropical regions and can be responsible for regime shifts leading to the predominance of turfs and/or barren grounds. However, other herbivores (i.e., mesograzers) could also significantly participate in the grazing, especially on early-life stages, hampering the persistence and capacity of Cystoseira sensu lato populations to recover after major disturbances and being a cause of failure of restoration actions. We performed experiments in the field and in mesocosm in order to investigate the herbivory pressure and the effects of different grazers on recruits of Cystoseira compressa. The results highlight that non-strict herbivorous invertebrates, such as Clibanarius erythropus, Cerithium vulgatum, and Idotea balthica, graze on recruits of Cystoseira s.l. spp., with I. balthica showing the highest consumption rate. We concluded that biotic factors such as herbivory, which affect key life stages, can be crucial for the conservation of Cystoseira s.l. forests and need to be better understood and considered on a case-by-case basis when planning restoration actions

Local-scale climatic refugia offer sanctuary for a habitat-forming species during a marine heatwave

En prens

A Roadmap for the Restoration of Mediterranean Macroalgal Forests

Este artículo contiene 14 páginas, 3 figuras, 1 tabla.Canopy-forming macroalgae play a crucial role in coastal primary production and nutrient cycling, providing food, shelter, nurseries, and habitat for many vertebrate and invertebrate species. However, macroalgal forests are in decline in various places and natural recovery is almost impossible when populations become locally extinct. Hence, active restoration emerges as the most promising strategy to rebuild disappeared forests. In this regard, significant efforts have been made by several EU institutions to research new restoration tools for shallow and mesophotic reef habitats (e.g., MERCES EU project, AFRIMED, and ROCPOP-life) and effective techniques have subsequently been proposed to promote self-sustaining populations. Recent research indicates that macroalgal forest recovery requires a broad spectrum of measures, ranging from mitigating human impacts to restoring the most degraded populations and habitats, and that the viability of large restoration actions is compromised by ongoing human pressures (e.g., pollution, overgrazing, and climate change). We propose a roadmap for Mediterranean macroalgal restoration to assist researchers and stakeholders in decision-making, considering the most effective methods in terms of cost and costeffectiveness, and taking background environmental conditions and potential threats into account. Last, the challenges currently faced by the restoration of rocky coastal ecosystems under changing climate conditions are also discussed.This work was supported by the CSIC Library will cover 25% of the APC. AFRIMED. European Maritime and Fisheries Fund EMFF (Grant/Award No. EASME/EMFF/2017/1.2.1.12/S4/01/SI2.789059), MERCES, Horizon 2020 Framework Programme (Grant/Award No. 689518), FoRestA, Spanish Ministry of Science and Innovation (Grant/Award No. PID2020-112985GB-I00), Generalitat de Catalunya (Grant/Award No. 2017 SGR 1521), Universitat de Girona, Ph.D. Grant to JV (Award No. IFUdG-2016), and the Fundación tatiana Pérez de Guzman el Bueno Ph.D. Grant to CG.With the institutional support of the ‘Severo OchoaCentre of Excellence’ accreditation (CEX2019-000928-S).Peer reviewe

Scientific monitoring program of the Research Station “Jaume Ferrer”: Temporal evolution of the cover of potentially invasive alien algae

4 págs, 1 fig.[EN] We analyze the changes in the percentage of cover of five species of introduced marine algae during more than a decade in different marine habitats around the island of Menorca. Acrothamnion preissii is abundant in the rhizomes of Posidonia oceanica but its cover has been decreasing during the last ten years. Womersleyella setacea shows persistent high abundances in coralligenous outcrops and sciaphilic algal communities. Asparagopsis taxiformis has colonized almost all habitats but its cover has been low during all the study period, never displaying an invasive behavior. Lophocladia lallemandii has also colonized almost all kind of habitats but it has never reached high coverages during the study period. Finally, Caulerpa cylindracea, a very ubiquitous species, has shown strong interannual cover variability, but it is not currently performing as an invasive species.[ES] En este trabajo se analizan los cambios en el porcentaje de cobertura de cinco especies de algas introducidas desde hace más de una década en distintos hábitats marinos de la isla de Menorca. Acrothamnion preissii es abundante en hábitats de Posidonia oceanica pero su cobertura ha ido disminuyendo a lo largo de los últimos diez años. Womersleyella setacea continua siendo muy abundante en los hábitats de coralígeno y de algas esciáfilas. Asparagopsis taxiformis ha colonizado casi todos los hábitats pero ha presentado una cobertura muy baja durante todo el periodo de estudio sin presentar nunca un carácter invasor. Lophocladia lallemandii llegó a colonizar casi todos los hábitats pero nunca tuvo una cobertura importante. Finalmente, Caulerpa cylindracea, muy ubicua, ha sufrido variaciones interanuales en su cobertura pero actualmente tampoco presenta un carácter invasor.Las actividades de Seguimiento científico de la Estación de Investigación "Jaume Ferrer" están cofinanciadas por la Dirección General de Políticas Universitarias e Investigación del Gobierno de Baleares y el Centro Oceanográfico de Baleares (IEO-CSIC). Queremos hacer llegar nuestro agradecimiento a la Dirección General de Pesca y al Parque Natural de s’Albufera des Grau, para facilitarnos las autorizaciones pertinentes que nos han permitido realizar los trabajos en los espacios marinos protegidos de Menorca. También a Joan Moranta por su ayuda en los primeros muestreos.Peer reviewe

Where Is More Important Than How in Coastal and Marine Ecosystems Restoration

Restoration is considered an effective strategy to accelerate the recovery of biological communities at local scale. However, the effects of restoration actions in the marine ecosystems are still unpredictable.We performed a global analysis of published literature to identify the factors increasing the probability of restoration success in coastal and marine systems. Our results confirm that the majority of active restoration initiatives are still concentrated in the northern hemisphere and that most of information gathered from restoration efforts derives from a relatively small subset of species. The analysis also indicates that many studies are still experimental in nature, covering small spatial and temporal scales. Despite the limits of assessing restoration effectiveness in absence of a standardized definition of success, the context (degree of human impact, ecosystem type, habitat) of where the restoration activity is undertaken is of greater relevance to a successful outcome than how (method) the restoration is carried out. Contrary to expectations, we found that restoration is not necessarily more successful closer to protected areas (PA) and in areas of moderate human impact. This result can be motivated by the limits in assessing the success of interventions and by the tendency of selecting areas in more obvious need of restoration, where the potential of actively restoring a degraded site is more evident. Restoration sites prioritization considering human uses and conservation status present in the region is of vital importance to obtain the intended outcomes and galvanize further actions

Effects of Natural and Anthropogenic Stressors on Fucalean Brown Seaweeds Across Different Spatial Scales in the Mediterranean Sea

Este artículo contiene 14 páginas, 8 figuras, 3 tablas.Algal habitat-forming forests composed of fucalean brown seaweeds (Cystoseira, Ericaria, and Gongolaria) have severely declined along the Mediterranean coasts, endangering the maintenance of essential ecosystem services. Numerous factors determine the loss of these assemblages and operate at different spatial scales, which must be identified to plan conservation and restoration actions. To explore the critical stressors (natural and anthropogenic) that may cause habitat degradation, we investigated (a) the patterns of variability of fucalean forests in percentage cover (abundance) at three spatial scales (location, forest, transect) by visual estimates and or photographic sampling to identify relevant spatial scales of variation, (b) the correlation between semi-quantitative anthropogenic stressors, individually or cumulatively (MA-LUSI index), including natural stressors (confinement, sea urchin grazing), and percentage cover of functional groups (perennial, semi-perennial) at forest spatial scale. The results showed that impacts from mariculture and urbanization seem to be the main stressors affecting habitat-forming species. In particular, while mariculture, urbanization, and cumulative anthropogenic stress negatively correlated with the percentage cover of perennial fucalean species, the same stressors were positively correlated with the percentage cover of the semi-perennial Cystoseira compressa and C. compressa subsp. pustulata. Our results indicate that human impacts can determine spatial patterns in these fragmented and heterogeneous marine habitats, thus stressing the need of carefully considering scale-dependent ecological processes to support conservation and restoration.This study was supported by the European Union’s EASME (Executive Agency for Small and Medium Enterprise) and EMFF (European Maritime and Fisheries fund) as part of the project AFRIMED, “Algal Forest Restoration in the Mediterranean Sea” (under grant agreement no. 789059), http:// afrimed-project.eu/.Peer reviewe