Soft-bottom crustacean assemblages in Mediterranean marine caves: the cave of Cerro Gordo (Granada, Spain) as case study

Abstract

Although marine caves are priority conservation areas according to the Directive 92/43/CEE of the European Community, there is a lack of studies dealing with their soft bottom communities. For a case study, we selected the Cerro Gordo cave at 15 m depth. Three different zones were defined: a semi-dark 25-m long entrance area, a dark inter mediate area of 35 m, and the final zone at 90 m from the entrance. Sediment samples were taken from these zones as well as from outside the cave (control) by SCUBA diving. Six rectangular cores of 10 9 250 cm2 were collected in each site for macrofaunal study, and three more replicates were taken to analyze physico-chemical parameters. The granulometry showed a clear gradient from medium sands outside the cave to silt and clay in the inner zone. Measure ments of the crustacean assemblages showed that the number of species and abundance were significantly higher outside the cave (30–40 species,[4,000 ind m-2 ) than inside (5–10 species,\1,000 ind m-2 ). Multivariate analyses showed a clear difference in species composition between outside and inside the cave. Caprellids, tanaids, cumaceans, and deca pods were only found outside the cave, while gammarids and isopods were present both outside and inside the cave. The gammarid Siphonoecetes sabatieri and the tanaid Apseudes latreilli were the dominant species outside the cave, while the gammarids Harpinia pectinata, Harpinia crenulata, and Harpinia ala were dominant inside. The present study represents an increase in depth range and geographic distribution for Kupellonura mediterranea and Monocul odes packardi. This is the first description of soft-bottom crustacean communities from submarine caves of south ern Spain.