Suchergebnisse

The present study explores the amphipod assemblages of six marine caves on the Mediterranean coast of southern Spain. Replicate samples were taken both inside and outside each marine cave in order to characterize the amphipod fauna and the physicochemical properties of the sediment. As a result, 44 amphipods species were identified. The high number of species found in a relatively limited area highlighted the richness of the Alboran Sea fauna, which is mainly due to the mixture of species from different biogeographic areas. Harpinia genus was the dominant amphipod taxa inside marine caves and Perioculodes longimanus was also very abundant in the caverns. On the other hand, external communities were dominated by Siphonoecetes sabatieri, Metaphoxus fultoni and Photis longipes. There was a high degree of variability in both the internal and the external stations. Only the external station situated at low-medium depth showed a relatively homogeneous amphipod assemblage. The structure and behaviour of soft-bottom communities inside marine caves is difficult to predict because their environmental conditions depend on a particular combination of factors such as topography, depth and orientation. Therefore, no constant patterns were observed for species richness, Shannon diversity and abundance of amphipods in marine caves in comparison with open habitats. According to canonical correspondence analysis, sediment granulometry, organic matter and nitrogen concentration were the parameters that best explained the distribution of amphipods. Species were also classified by their tolerance to environmental pollution according to criteria followed by the Azti Marine Biotic Index and the BENTIX index. The great abundance of sensitive species at both the internal and external stations indicates the good ecological quality of the soft bottom studied. However, the suitability of biotic indices in marine caves should be tested in future studies. ; En el presente trabajo se estudia la fauna de anfípodos presente en el sustrato blando de seis cuevas submarinas de la costa Mediterránea del sur de España. Con el objetivo de caracterizar tanto la comunidad biótica como las características físico-químicas del sedimento, se tomaron muestras de sedimento a la salida y en el interior de las cuevas submarinas. Como resultado, se identificaron un total de cuarenta y cuatro especies de anfípodos diferentes. Este elevado número de especies encontrado en un área relativamente limitada pone de manifiesto la riqueza faunística del Mar de Alborán, la cual se atribuye principalmente a la mezcla de especies de diferentes áreas biogeográficas. El género Harpinia fue el taxón dominante en el interior de las cuevas, junto con Perioculodes longimanus. Por otro lado, la comunidad en las zonas externas estaba dominada por Siphonoecetes sabatieri, Metaphoxus fultoni y Photis longipes. Se observó un alto grado de variabilidad tanto en las estaciones internas como externas. Solo las estaciones externas situadas a profundidades bajas-medias mostraron una fauna relativamente homogénea. La estructura y el comportamiento de las comunidades que habitan los sustratos blandos en el interior de cuevas submarinas es difícil de predecir, ya que las condiciones ambientales dependen de sus particulares características en cuanto a topografía, profundidad y orientación. Por ello, no ha podido extraerse ningún patrón constante de la comparación de comunidades internas y externas para el número de especies, diversidad de Shannon o abundancia de anfípodos. La granulometría y los porcentajes de materia orgánica y nitrógeno en el sedimento fueron los parámetros que mejor explicaban la distribución de los anfípodos, de acuerdo con los resultados del análisis CCA. Las especies también fueron clasificadas en base a su tolerancia a la polución ambiental, siguiendo los criterios establecidos por los índices AMBI y BENTIX. La gran abundancia de especies sensibles refleja el buen estado ecológico de los sedimentos estudiados. Sin embargo, la aplicabilidad de los índices bióticos en cuevas submarinas debería ser testada en futuros estudios. ; Financial support for this work was provided by the Ministerio de Economía y Competitividad (Project CGL 2011-22474, internal reference 2011-707). It was cofinanced by FEDER funds of the European Union and by the Consejería de Economía, Innovación, Ciencia y Empleo, Junta de Andalucía (Project P11-RNM-7041).

Detection of new non-indigenous species is often delayed when taxa are taxonomically challenging, such as small-sized marine organisms. The present study highlights the relevance of scientific cooperation in the early detection of the invader amphipod Stenothoe georgiana. Originally described from North Carolina (USA), the species was recently found in Chile and the Western Mediterranean. Here, we provide the first record of the species in Macaronesia, Atlantic coasts of continental Europe, North Africa and Australia, and extend its known distribution along the Mediterranean coast. Just like other small crustaceans, shipping (both ballast water and recreational boating) and aquaculture are probably the main vectors of introduction and secondary spread for this amphipod species. This case of S. georgiana sheds light on the importance of promoting taxonomical knowledge, and building multidisciplinary networks of experts that ensure an effective diessemination of alien species information. We also encourage the implementation of standardized monitoring methodologies to facilitate early detection of small mobile invaders. ; Financial support for this study was provided by a predoctoral grant from the Spanish Government to GM-L (Reference FPU15/02223), and the Ministerio de Economía y Competitividad (Project CGL2017-82739-P) co-financed by the ERDF, European Union. MVL was supported by a postdoctoral contract Juan de la Cierva-Incorporacion (IJCI-2016-29329) of Ministerio de Ciencia, Innovacion y Universidades. Surveillance in the Azores was possible under ASMAS - M2.1.2/I/032/2011 project FEDER funds through the Operational Programme for Competitiveness Factors - COMPETE and by National Portuguese Funds through FCT - Foundation for Science and Technology under the UID/BIA/50027/2013 and POCI-01-0145-FEDER-006821.