INVESTIGADORES
PALOMO Maria Gabriela
congresos y reuniones científicas
Título:
Geographic patterns of abundance and length distribution of the limpet Siphonaria lessoni in the Southwest Atlantic.
Autor/es:
SORIA S. A; TESO V.; PALOMO M. G.
Lugar:
Mar del Plata
Reunión:
Congreso; CERF 2012: The Changing Coastal and Estuarine Environment: A Comparative Approach; 2012
Institución organizadora:
CERF
Resumen:
The abundance
center hypothesis assumes that the species have abundant populations in the
center of their distribution, where individual success is greater due to the
optimal physical and biotic conditions. In turn, individuals from more abundant
populations have smaller lengths due to intraspecific competition. The main
objectives of this study were to test the abundance center hypothesis of Siphonaria lessoni and the hypothesis of
the relationship between abundance and length. Siphonaria lessoni (Gastopoda: Siphonariidae) is distributed from
southern Brazil (27°35'S, 48°32'W) to Tierra del Fuego (54º48'S, 68°19'W).
Eight samples were carried out in the middle intertidal collecting all
individuals of S. lessoni into quadrants
of 25 x 25 cm. The sites were: La
Pedrera (Uruguay), Mar del Plata, Quequén, Espigón, Lobería, Playas Doradas,
Pirámides, Puerto Madryn and Playa Larga (Argentina). The individuals collected were counted and measured in
the laboratory. The relationship between abundance and distribution of populations
of S. lessoni showed an irregular
pattern. The organism length decreases significantly in relation to the
increasing density (y=-2.68x+41.62, R²=0,864). The distribution and abundance
of a species can be determined by a single factor, as postulated by the
abundance center hypothesis, or by multiple factors interacting in complex ways
in space and time. The abundance of S.lessoni
along the coast could be affected by small environmental changes such as
proximity to outfall, degree of exposure in the harbor, association with mussel
community and residence on cliff area. In places with abundant populations of S. lessoni note that the average length
of individuals is lower, showing other example of intraspecific competition.
The abundance center hypothesis was tested in the intertidal limpet Lottia gigantea in North America, even
though our proposal is to consider a model with multiple factors in a future
study.