Long-term responses of the endemic reef-builder Cladocora caespitosa to Mediterranean warming

Recurrent climate-induced mass-mortalities have been recorded in the Mediterranean Sea over the past 15 years. Cladocora caespitosa, the sole zooxanthellate scleractinian reef-builder in the Mediterranean, is among the organisms affected by these episodes. Extensive bioconstructions of this endemic coral are very rare at the present time and are threatened by several stressors. In this study, we assessed the long-term response of this temperate coral to warming sea-water in the Columbretes Islands (NW Mediterranean) and described, for the first time, the relationship between recurrent mortality events and local sea surface temperature (SST) regimes in the Mediterranean Sea. A water temperature series spanning more than 20 years showed a summer warming trend of 0.06°C per year and an increased frequency of positive thermal anomalies. Mortality resulted from tissue necrosis without massive zooxanthellae loss and during the 11-year study, necrosis was recorded during nine summers separated into two mortality periods (2003-2006 and 2008-2012). The highest necrosis rates were registered during the first mortality period, after the exceptionally hot summer of 2003. Although necrosis and temperature were significantly associated, the variability in necrosis rates during summers with similar thermal anomalies pointed to other acting factors. In this sense, our results showed that these differences were more closely related to the interannual temperature context and delayed thermal stress after extreme summers, rather than to acclimatisation and adaption processes

Proposta per a un pla de zonificació dels usos en l'àmbit marí del Parc Natural del Montgrí, les Illes Medes i el Baix Ter

L’objectiu d’aquest projecte és desenvolupar un pla de zonificació del usos comercials i turístics a la costa del Montgrí compresa dins el Parc Natural del Montgrí, les Illes Medes i el Baix Ter. Aquesta proposta es farà tenint en compte la extensió i distribució dels diferents hàbitats presents a la zona i la seva distribució en base a la cartografia bionòmica desenvolupada l’any 12012 (Hereu et al., 2010; Hereu i Quintana, 2012), la seva importància en el manteniment de la biodiversitats i la seva sensibilitat als diferents usos i possibles pertorbacions en base a les evidències científiques, així com tenint en compte els actuals usos que s’hi fan, amb l’objectiu de prioritzar la conservació fent-la compatible amb els usos que s’hi donen. Aquesta proposta es farà de utilitzant mètodes de decisió objectius en funció de la informació disponible, mitjançant l’ús de sistemes d’informació geogràfica (SIG) i programes analítics de distribució espacial (MARXAN)

Diagnosi sobre l’efecte del submarinisme en les comunitats bentòniques de la Reserva Marina de les Illes Medes

Memòria tècnica. Generalitat de Catalunya. Departament de Territori i Sostenibilitat. Direcció General de Polítiques Ambientals.La normativa específica dels usos i activitats de l’àrea protegida de les Illes Medes, estan regulats pel Pla Rector d’Usos i Gestió recollit aprovat el 2008 (en el Decret 222/2008, d'11 de novembre, pel qual s'aprova el Pla rector d'ús i gestió de l'Àrea Protegida de les Illes Medes), i que recentment ha estat modificat en els seus annexes 1 i 6 (ORDRE AAM/112/2015, de 30 d'abril). En aquesta nova normativa es regula el nombre de submarinistes que poden accedir a les diferents zones de busseig (Taula 1) segons el grau de fragilitat de les comunitats en les que s’hi desenvolupa aquesta activitat. Aquesta normativa preveu que aquest nombre pugui anar canviant al llarg del temps en funció de la informació que es vagi obtenint sobre l’estat de conservació de les comunitats i l’impacte del submarinisme sobre els fons

Avaluació de la població de Corall (Corallium rubrum) de les Illes Medes. Exercici 2003

Podeu consultar l'Informe complet a: http://hdl.handle.net/2445/2367

Editorial: Biogenic Reefs at Risk: Facing Globally Widespread Local Threats and Their Interaction With Climate Change

Biogenic reefs are secondary marine substrates, also referred to as bioconstructions or bioherms, made by autogenic ecosystem engineers (sensu, Jones et al., 1994) that provide habitats for various species. Their ecological role goes far beyond simple physical effects because they can modulate many resources and interactions between species inhabiting the reefs. Marine bioconstructions involve a variety of fragile three-dimensional habitats, from shallow water coral reefs to mesophotic coralligenous concretions, hosting rich, and diverse benthic assemblages (Cocito, 2004; Ingrosso et al., 2018; Cerrano et al., 2019). Biogenic reefs can be found from the intertidal to the deep sea; some are ephemeral and last a few years, while others remain active for millennia. The main framework builders are able to form bioconstructions at different latitudes, from tropical to polar zones, and include films of cyanobacteria and diatoms, calcareous rhodophytes, sponges, hermatypic symbiotic and aposymbiotic corals, polychaetes as serpulids and sabellariids, mollusks like vermetids, oysters and mussels, and bryozoans

Effective dispersal and density-dependence in mesophotic macroalgal forests: Insights from the Mediterranean species Cystoseira zosteroides

Dispersal and recruitment are fundamental processes for population recovery following disturbances in sessile species. While both processes are well understood for many terrestrial species, they still remain poorly resolved for some macroalgal species. Here we experimentally investigated the effective dispersal and recruit survival of a mesophotic Mediterranean fucoid, Cystoseira zosteroides. In three isolated populations, four sets of settlement collectors were placed at increasing distances (from 0 to 10 m) and different orientations (North, South, East and West). We observed that effective dispersal was restricted to populations' vicinity, with an average of 6.43 m and not further than 13.33 m, following a Weibull distribution. During their first year of life, survival was up to 50%, but it was lower underneath the adult canopy, suggesting a negative density-dependence. To put our results in a broader context we compared the effective dispersal of other fucoid and kelp species reported in the literature, which confirmed the low dispersal ability of brown algae, in particular for fucoids, with an effective dispersal of few meters. Given the importance of recruitment for the persistence and recovery of populations after disturbances, these results underline the vulnerability of C. zosteroides and other fucoid species to escalating threats

Indicateurs espèces thermophobes: État des populations de la gorgone blanche Eunicella singularis dans le Parc national de Port-Cros.

Étude réalisée par l’Universitat de Barcelona, dans le cadre d’un Partenariat Scientifique avec le Parc National de Port-Cros Contrat n° : 13-030 - 83400 PCLes gorgones sont des composantes courantes des communautés coralligènes et elles jouent un rôle très important dans certains écosystèmes méditerranéens de fond dur car il s’agit d’espèces ingénieures qui modèlent l’habitat. Cependant, ces espèces sont parmi les plus menacées par le réchauffement climatique, mais des informations sur leur démographie et leur distribution, aspect crucial pour la conservation et la gestion durable, sont encore rares. Par conséquent, nous avons caractérisé les populations de Eunicella singularis dans le Parc national de Port-Cros tout en examinant leur distribution spatiale et en profondeur, ainsi que la structure de tailles de ces populations et l’affectation des perturbations. Cette espèce est présente principalement dans la partie sud des îles, sur des sites exposés à des courants et à une profondeur allant de 9,5 à 38 m, mais montrant une grande variabilité dans les limites de distribution supérieures et inférieures entre les sites. Les valeurs de la densité, la taille et la mortalité des populations étudiées ont été très semblables aux études précédentes menées dans d'autres endroits de la Méditerranée. La plupart des populations étudiées ont été dominées par des colonies de taille moyenne, ont montré une faible proportion de colonies fortement endommagées, et les colonies les plus blessées avaient des épibiontes, suggérant que la plupart d'entre elles n'ont pas été exposées à de fortes perturbations récentes. Dans un seul site, Le Petit Sarranier, les populations de E. singularis montrent un pourcentage élevé de la surface endommagée, principalement sans épibiose, ainsi que des colonies mortes et une forte dominance de petites colonies. Ça semble indiquer que cette population, celle de moindre profondeur parmi les populations examinées, est exposée à des perturbations naturelles. Nos résultats montrent que les populations les moins profondes (moins de 15 m) présentent des signaux de mortalité récente avec une forte proportion de blessures par rapport aux populations les plus profondes. Ainsi, il semble que la température de l’eau, avec une formation d'une thermocline saisonnière, pourrait être le principal facteur qui affecte les populations peu profondes de E. singularis dans le Parc national de Port-Cros, bien que d'autres facteurs que la température pourraient avoir un rôle important dans le façonnement des tendances observées. Cette étude a fourni une base pour de futures études sur cette espèce dans le Parc, ce qui sera essentiel pour améliorer notre compréhension de la dynamique de cette espèce sur des échelles de temps plus grandes et de leurs tendances futures dans le cadre du scénario global de changement environnemental

Impacts on coralligenous outcrop biodiversity by a dramatic coastal storm

Extreme events are rare, stochastic perturbations that can cause abrupt and dramatic ecological change within a short period of time relative to the lifespan of organisms. Studies over time provide exceptional opportunities to detect the effects of extreme climatic events and to measure their impacts by quantifying rates of change at population and community levels. In this study, we show how an extreme storm event affected the dynamics of benthic coralligenous outcrops in the NW Mediterranean Sea using data acquired before (2006-2008) and after the impact (2009-2010) at four different sites. Storms of comparable severity have been documented to occur occasionally within periods of 50 years in the Mediterranean Sea. We assessed the effects derived from the storm comparing changes in benthic community composition at sites exposed to and sheltered from this extreme event. The sites analyzed showed different damage from severe to negligible. The most exposed and impacted site experienced a major shift immediately after the storm, represented by changes in the species richness and beta diversity of benthic species. This site also showed higher compositional variability immediately after the storm and over the following year. The loss of cover of benthic species resulted between 22% and 58%. The damage across these species (e.g. calcareous algae, sponges, anthozoans, bryozoans, tunicates) was uneven, and those with fragile forms were the most impacted, showing cover losses up to 50 to 100%. Interestingly, small patches survived after the storm and began to grow slightly during the following year. In contrast, sheltered sites showed no significant changes in all the studied parameters, indicating no variations due to the storm. This study provides new insights into the responses to large and rare extreme events of Mediterranean communities with low dynamics and long-lived species, which are among the most threatened by the effects of global change

Experimental evidence of synergistic effects of warming and invasive algae on a temperate reef-builder coral

In the current global climate change scenario, stressors overlap in space and time, and knowledge on the effects of their interaction is highly needed to understand and predict the response and resilience of organisms. Corals, among many other benthic organisms, are affected by an increasing number of global change-related stressors including warming and invasive species. In this study, the cumulative effects between warming and invasive algae were experimentally assessed on the temperate reef-builder coral Cladocora caespitosa. We first investigated the potential local adaptation to thermal stress in two distant populations subjected to contrasting thermal and necrosis histories. No significant differences were found between populations. Colonies from both populations suffered no necrosis after long-term exposure to temperatures up to 29 °C. Second, we tested the effects of the interaction of both warming and the presence of invasive algae. The combined exposure triggered critical synergistic effects on photosynthetic efficiency and tissue necrosis. At the end of the experiment, over 90% of the colonies subjected to warming and invasive algae showed signs of necrosis. The results are of particular concern when considering the predicted increase of extreme climatic events and the spread of invasive species in the Mediterranean and other seas in the future

The yellow gorgonian Eunicella cavolini: demography and disturbance levels across the Mediterranean Sea

The yellow octocoral Eunicella cavolini is one of the most common gorgonians thriving in Mediterranean hard-bottom communities. However, information regarding its distribution and ecology in several parts of the Mediterranean is lacking, while population trends and conservation status remain largely unknown. We investigated 19 populations of E. cavolini over three representative geographic regions: the NW Mediterranean, CE Adriatic, and N Aegean. Focusing on the upper bathymetric range of the species (30 cm). The CE Adriatic displayed intermediate densities, with well-structured populations, and continuous recruitment. In the N Aegean, most populations presented low densities, high proportion of large colonies, but low number of small colonies, signifying limited recruitment. Disturbance levels, as a function of extent and type of injury, are discussed in relation to past or present human-induced threats. This work represents geographically the most wide ranging demographic study of a Mediterranean octocoral to date. The quantitative information obtained provides a basis for future monitoring at a Mediterranean scale