Abstract
The seagrass Posidonia oceanica plays an important role as habitat for invertebrates. A correlative study was done in El Campello (SE Spain) to understand the relationships between assemblage structure of crustaceans and modification of P. oceanica structure caused by bottom trawling. We compared the changes of community structure of the most important groups of crustaceans, amphipods and decapods with changes of cover, density, detritus and rhizome fragments. Sampling was carried out in four control and four impact locations, along a gradient of degradation (17 m depth, August 1992). Multivariate analysis was used for community data (nm-MDS) and P. oceanica structure (PCA). Both groups showed a similar number of species. The amphipod community showed a clear pattern of community changes with significant differences between impact and control locations (global R = 0.298, p
Highlights
Mobile invertebrates are distributed in seagrass meadows according to plant attributes
The changes in community structure can be determined by different variables existent in seagrass meadows such as biomass, density, epiphytes or detritus, and the influence that these variables place on each species (Heck and Wetstone, 1977; Stoner, 1980; Lewis, 1984; Stoner and Lewis, 1985; Howard et al, 1989; Edgar, 1990; Berggren, 1993; Harlin et al, 1996)
The community was dominated by Thoralus cranchii (Leanch, 1817), FIG. 2. – multidimensional scaling (MDS) bi-dimensional representation of decapod assemblages
Summary
Mobile invertebrates are distributed in seagrass meadows according to plant attributes. Many manipulative and correlative studies have been developed during the last decades to better understand the processes which influence the relationships between spatial distribution of invertebrates and habitat structure (Fonseca et al, 1990; Edgar, 1990; Schneider and Mann, 1991). Invertebrate-seagrass relationships in the Posidonia oceanica system are not well known. Along the Mediterranean coast Posidonia oceanica develops meadows in shallow sandy bottoms (Buia and Mazzella, 1991), and is an important habitat for mobile invertebrates (Mazzella et al, 1989). The impact of trawling on P. oceanica produces a reduction of canopy cover and an increase of detritus by erosion, which has an important influence on the invertebrate community (Sánchez Jerez and Ramos Esplá, 1996)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
