Spatial and temporal variation of natural toxicity in cnidarians, bryozoans and tunicates in Mediterranean caves

Submarine caves are considered as a top priority\ud for conservation, but the effects of common pressures\ud are poorly known for these habitats. Here, we examined the\ud effect of recreational human visitation on a selection of\ud submarine caves in a Mediterranean Marine Protected Area\ud (403504000N; 81103900E) where diving activities are regulated.\ud Sampling was conducted in visited and not visited\ud caves to assess whether diving activities have a significant\ud effect on cave habitats, what are the components of biodiversity\ud most affected by this disturbance, and its potential\ud effects on spatial heterogeneity of benthic assemblages.\ud Results clearly showed that human visitation could significantly\ud affect spatial patterns of benthic assemblages.\ud Organisms with erect growth forms were significantly more\ud abundant and homogeneously distributed where diving\ud activities are forbidden. An increase in the small-scale\ud heterogeneity of assemblages and a decrease in their threedimensional\ud structure could be the ultimate consequences\ud of human visitation. The interaction between specific\ud stressors and the patterns of distribution of species and\ud assemblages can drive their spatial heterogeneity also in\ud unique habitats like marine caves, representing an early\ud warning for the development of appropriate management\ud measures

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Proximity to competitors changes secondary metabolites of non-indigenous cup corals, Tubastraea spp., in the southwest Atlantic

Lages

Fleury

Hovell

et al. 2012

Mar Biol

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Competition for space changes species' distributions and community organization on tropical rocky shores, and the presence of secondary metabolites in the tissues of non-indigenous species may aid them in establishing and expanding their range through negative competitive interactions. The aim of this study was to describe the range of chemical substances produced by the nonindigenous cup corals Tubastraea coccinea and T. tagusensis and to test whether they varied in the field when the corals were placed in proximity to two local competitors. Cholest-5-en-3b-ol and 9-octadecanoic acid were two common secondary metabolites found in the tissues of Tubastraea. In the competition interaction experiment, necrosis was detected on the tissues of the coral Mussismilia hispida, and this species induced variation in sterol, alkaloid, and fatty acid production in Tubastraea tissues. In contrast, a sponge overgrew Tubastraea colonies. These results indicate that chemical defense may contribute to the ability of these non-indigenous corals to invade native communities.

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Spatial and temporal variation of natural toxicity in cnidarians, bryozoans and tunicates in Mediterranean caves

Cited by 16 publications

References 35 publications

Watersipora subtorquata and the Possible Role of Its Associated Microbes: An Attempt to Explain the Extraordinary Invasion Success of This Marine Bryozoan Species

Watersipora subtorquata and the Possible Role of Its Associated Microbes: An Attempt to Explain the Extraordinary Invasion Success of This Marine Bryozoan Species

Increasing heterogeneity of sensitive assemblages as a consequence of human impact in submarine caves

Proximity to competitors changes secondary metabolites of non-indigenous cup corals, Tubastraea spp., in the southwest Atlantic

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