Association of the global invader Carcinus maenas to intertidal and shallow subtidal habitats of Patagonia.

BARON, PJ; FERNANDO HIDALGO; PACCOTTI, VANESA; POPOUL RAPOSO; GAVIO, MARÍA ANDREA; BAZTERRICA, M CIELO; DELLATORRE, F. G.; CARRASCO, MAURO

Mar del Plata

Conferencia; 2nd World Conference on Biological Invasions and Ecosistem Functioning; 2011

Grieta www.grieta.org.ar

Carcinus maenas is a NIS expanding its distribution along the coastlines of many world regions. The types of habitatoccupied by the species are diverse, both within and between native and invaded ranges of distribution, but presence andabundance seem to be influenced mainly by: 1) bottom structure, 2) degree of exposure to breaking waves, and 3) bioticinteractions with the native community. The aim of the present work is to report the range of distribution of C. maenas alongthe Atlantic coast of Patagonia, its expansion rate, patterns of relative abundance and habitats occupied. Surveys wereconducted in 2004-2011, covering the coastline of continent and islands from 43°49?S to 51°36?S. At each sampling location,crabs were trapped and hand collected. Also, geomorphological characteristics, topographic profile, dominating substratefacie and biotic coverage and level in the intertidal were recorded. Wave exposure indices were calculated for each site asfunction of the average wave fetch and average wind energy. The geographical range of distribution recorded for C. maenasin Patagonia extends 800 km from 44º30? to 47°. The species is present in a varied repertory of coastline forms, fromembayments to headlands, with contrasting geomorphological characteristics (e.g., intertidal sanstone bedrocks, gentleslope muddy bottoms covered by rocks and cobble). Highest relative abundances are found on the southern margins of SanJorge gulf. Range expansion during the last 5 years was only 50km. In contrast to other invaded regions, in Patagonia thespecies is adapted relatively high levels of wave exposure.