An introduced polychaete in South America: ecologic affinities of Manayunkia speciosa (Polychaeta, Sabellidae) and the oligochaetes of Uruguay River, Argentina

ARMENDÁRIZ, L.; SPACCESI, F.; RODRIGUES CAPÍTULO, A.

Ecosystems. Book 1

Editorial Board

Lugar: Rijeka; Año: 2011; p. 73 - 94

The introduction of species is one of the processes which produce major alterations in the biodiversity of ecosystems. Even though it is not a problem caused only by human activity, the number of species involved and the frequency of their relocation has grown enormously as a result of the expansion of transportation and trade (Glasby & Timm, 2008; Penchaszadeh, 2005). The continental aquatic environments are highly susceptible to the accidental or deliberate introduction of exotic species. Besides, the natural connection of the basins and the dispersion capacity of the aquatic organisms together with the human activity determine the possibility of invasion of new species (Ciutti & Cappelletti, 2009). In these aquatic environments, the transfer of exotic species occurs through a wide variety of ways and means, for example, in maritime transportation, in the ballast water of ships (El Hadad et al., 2007). In South America, most of the coastal ecosystems between the Río de la Plata Estuary and central Patagonia have been modified due to the introduction of exotic organisms. From 31 identified cases, 6 have caused a considerable ecological impact (Orensanz et al., 2002). In this region, the introduction of crustaceans such as Balanus glandula Darwin, 1854 and B. amphitrite Darwin, 1854; mollusks, such as Crassostrea gigas (Thumberg, 1793), Corbicula fluminea (Müller, 1774), C. largillierti (Philippi, 1844), Limnoperna fortunei (Dunker, 1857), and Rapana venosa (Valenciennes, 1846), and polychaetes such as Ficopomatus enigmaticus (Fauvel, 1923) have been recorded in the last 40 years (Penchaszadeh, 2005). Recently, the presence of Manayunkia speciosa Leidy, 1858 (Armendáriz et al., 2011) has been registered in Uruguay River. M. speciosa is a small polychaete strictly from freshwater, first recorded in Schuylkill River (USA) in 1858. Some decades later its distribution extended through the whole Nearctic Region, being recorded in the eastern and western lotic systems of North America (Brehm, 1978; Hazel, 1966; Holmquist, 1967; Krecker, 1939; Leidy, 1883; Mackie & Qadri, 1971; Meehean, 1929; Spencer, 1976). A hundred and fifty years after its first record, it is found for the first time in the Neotropical Region, enlarging its limit distribution from the United States of America to Argentina. Although it could not be determined whether its introduction had been recently, it can be assumed that M. speciosa arrived at the Uruguay River through the ballast water of commercial ships (Armendáriz et al., 2011). In recent years, the studies on M. speciosa have been focused in some aspects of its population dynamics and in its role as intermediate host of Myxozoa parasites of Salmonidae (Bartholomew et al., 1997; Bartholomew et al., 2006; Stocking & Bartholomew, 2007). Due to the lack of information on the ecological requirements of M. speciosa together with the scarce knowledge on the annelid fauna of the Lower Uruguay River, we propose, in this chapter, to analyze the main ecological variables which could have determined the establishment of M. speciosa with the oligochaete annelids, forming the benthic assemblage of the Lower Uruguay River.