Macrobenthic Assemblages of Intertidal Flats in Southern Patagonia, Argentina

MARTIN, JUAN P.; LIZARRALDE, ZULMA I.; PITTALUGA, SUSANA; SAR, ALICIA M.; PERRONI, MARIO; TORRES, SANTIAGO

THALASSAS (SANTIAGO DE COMPOSTELA)

UNIV VIGO

Año: 2019 p. 1 - 17

0212-5919

The aim of this work was to characterize the macrobenthic community of intertidal flats in southern Patagonia, by identifying thefaunal assemblages and analyzing their relationship with the main environmental factors. The study was conducted in fourlocalities of southern Santa Cruz (Argentina): Bahía San Julián (49°18?S, 67°41?W) and the lower reaches of the estuaries ofRío Santa Cruz (50°05?S, 68°29?W), Río Coyle (50°58?S, 69°16?W) and Río Gallegos (51°37?S, 69°02?W). Surveys wereperformed in spring 2015 and summer 2016 at the upper, middle and lower intertidal levels. Four sediment samples werecollected per intertidal level at each locality in each sampling period with a corer (0.00785 m2)upto20cmindepth.Theorganisms were separated using a 0.5 mm mesh sieve for subsequent identification and quantification. To explore possible spatialvariations in the community, environmental and abundance data were analyzed using univariate and multivariate statistics.Intertidal level, substrate grain size and organic matter content were determinant factors of distribution of benthic assemblages.The Darina solenoides-Scolecolepides uncinatus-Eteone sculpta assemblage was characteristic of sand-mud substrates withdominance of silt-clay and greatest organic matter content of upper and middle intertidal. The D. solenoides-Ampelisca sp.assemblage was characteristic of the lower intertidal, with dominance of fine sand. The presence of saltmarshes was also a factordetermining benthic assemblages at the upper intertidal of the estuarine localities. This work provides useful information toimplement adequate management actions to protect the lower reaches of the Río Santa Cruz estuary.