INVESTIGADORES
SCHIARITI Agustin
congresos y reuniones científicas
Título:
The successful invasion of Rapana venosa in Argentina: interactions between environmental factors and food supply
Autor/es:
GIBERTO, D. A.; SCHIARITI, A.; BREMEC, C. S.
Lugar:
Mar del Plata
Reunión:
Conferencia; 2nd World Conference on Biological Invasions and Ecosystem Functioning; 2011
Resumen:
The fate of an exotic species when arrived to new ecosystems is
constrained by the interaction of environmental and ecological factors. This study reviews the present knowledge of oceanographic
and ecological settings that facilitated the invasion of the gastropod Rapana venosa (RV) in the region of the Río
de la Plata (RdP). First collections were made in 1999 and nowadays RV is
common in mixohaline waters of RdP (35,000 km2) but it is also
moving into adjacent marine waters. Propagule pressure is sustained by active
reproduction during spring and summer, with fecundity estimations around 80,000
eggs per individual. Invasions to new areas could be facilitated by a larval
planktonic phase transported by RdP current, which flows southwards along the
Argentine coast in spring-summer. The invasion success is also related to prey
availability and its ability to exploit different bivalve species. RV is
preying upon the clam Mactra isabelleana and
the mussel Mytilus platensis, species
with the higher biomass in the region. Furthermore, laboratory experiments proved
that RV is capable of feeding upon many other local bivalves. Low gastropod diversity,
mostly small species, characterized the RdP benthic communities, suggesting the
absence of strong competitors for RV adults. Regarding natural predators,
recent studies only reported the presence of egg-masses in few benthic fishes
and turtle diets. The interaction of suitable environmental conditions, low
diversity communities and abundant food supply facilitated the invasion of the
mixohaline ecosystem, and now it is undeniable that RV is fairly integrated
into benthic communities of the RdP.