Amphipods from marine cave sediments of the southern Iberian Peninsula: diversity and ecological distribution

Carlos Navarro-Barranco,José Manuel Guerra-García,José Carlos García-Gómez,Luis Sánchez-Tocino

doi:10.3989/scimar.04043.28e

Abstract

Summary: 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.

Highlights

Marine caves support diverse and distinctive communities, often acting as biodiversity reservoirs for many marine groups (Riedl 1966, Gerovasileiou and Voutsiadou 2012)
This area is characterized by the abundance of cliffs composed of carbonate rocks, which allow the presence of many marine caves
Amphipod assemblages were greatly dominated by Siphonoecetes sabatieri de Rouville, 1894, which comprised 68% of all individuals

Summary

Introduction

Marine caves support diverse and distinctive communities, often acting as biodiversity reservoirs for many marine groups (Riedl 1966, Gerovasileiou and Voutsiadou 2012). In the last few years there has been an increase in the evidence of impact by human activities on cave communities, including alterations by scuba diving activities, coastal pollution and global warming (Chevaldonné and Lejeusne 2003, Di Franco et al 2010, Parravicini et al 2010, Guarnieri et al 2012). Owing to their high natural stability, these ecosystems show low resilience and a high vulnerability to disturbances (Vacelet et al 1994), so they are considered as priority conservation areas according to Directive 92/43/EEC of the European Community and there is an urgent need to understand their biodiversity and organization. Crustaceans (and mainly amphipods) are the dominant taxa in both abundance and number of individuals (NavarroBarranco et al 2012)

Objectives

Methods

Results

Discussion

Conclusion