Changes of Benthic Macrofaunal Composition on a Tidal Flat of Río Gallegos Estuary, Argentina

Z. I. Lizarralde1, S. Pittaluga1, M. Perroni1
1Instituto de Ciencias del Ambiente, Sustentabilidad y Recursos Naturales (ICASUR), Unidad Académica Río Gallegos, Universidad Nacional de la Patagonia Austral, Río Gallegos, Argentina

Tóm tắt

This work analyzed the variation in composition and abundance of benthic assemblages in an intertidal environment of the Río Gallegos estuary, Argentina (51°35′ S - 69° 01′ W). The macrofauna was sampled in a tidal flat adjacent to the city in late summer of 2006 and 2013 (March). In total 27 macrofauna taxa were identified; the most abundant species were Darina solenoides (44%) in 2006 and Fabricinuda sp. (89%) in 2013. Biogenic structures composed of aggregates of polychaete (Fabricinuda sp.) tubes and sediment were observed for the first time in December 2006; they are spherical or of irregular shape, 1 to 3 m2 in area, and up to 50 cm in height. In 2013 benthic composition was compared between biogenic aggregates (“patch”) and the area outside them (“non-patch”). Species richness and total abundance of individuals were higher in the patch. The associated benthos was different; Fabricinuda sp. was dominant in the patch (107,780.7 indiv.m-2, SD = 44,772.6), and Kinbergonuphis dorsalis (2139 indiv.m-2, SD = 840) and Notocirrus lorum (1830 indiv.m-2, SD = 516.4) in the non-patch. In 2013, four taxa that were not found in 2006 were recorded only in the patch samples, two bivalves (Sphenia hatcheri and Malletia cumingii) and two polychaetes (Fabricinuda sp. and Ophioglycera eximia). Polychaete aggregations have produced changes in number and abundance of benthic species at the lowest level of the tidal flat.

Tài liệu tham khảo

Clarke KR, Gorley RN (2001) PRIMER v5: User Manual/Tutorial. PRIMER-E, Plymouth

Elias R, Rivero MS, Palacios JR, Vallarino EA (2006). Sewage-induced disturbance on Polychaetes inhabiting intertidal mussel beds of Brachidontes rodriguezii off Mar del Plata (Southwestern Atlantic, Argentina). In: Sarda R, San Martin G, Lopez E, Martin D, George D (eds) Scientific Advances on Polychaete Research. Sci Mar 70(3):187–196

Holt TJ, Rees EI, Hawkins SJ, Seed R (1998) Biogenic reefs. In: An overview of dynamic and sensitivity characteristics for conservation management of marine SACs. Scottish Association for Marine Science (UK Marine SACs Project), Oban

INDEC (2010) Censos Nacionales de Población, Hogares y Viviendas. Resultados definitivos, Argentina http://www.censo2010.indec.gov.ar

Lizarralde ZI, Pittaluga S (2011) Distribution and temporal variability of the benthic fauna in a tidal flat of the Rio Gallegos estuary, Patagonia, Argentina. Thalassas 27(1):9–20

Mazé RA, Laborda AJ, Luis E (1990) Macrofauna intermareal de sustrato arenoso en la Ría de El Barquero (Lugo, NO de España): Estructura de la comunidad. Zonación. Cah Biol Mar 31:47–64

Perillo GME, Ripley MD, Piccolo MC, Dyer KR (1996) The formation of tidal creeks in a salt marsh: new evidence from the Loyola Bay salt marsh, Rio Gallegos, Estuary, Argentina. Mangrove Salt Marshes 1:37–46

Schwindt E, Iribarne OO (1998) Reef of Ficopomatus enigmaticus (Polychaeta, Serpulidae) in the Mar Chiquita CoastaI Lagoon, Argentina. Boll Soc Hist Nat Balears 41:35–40

Zar JH (1999) Biostatistical analysis, fourth edn. Prentice-Hall Press, Englewood Cliffs