IADO   05364
INSTITUTO ARGENTINO DE OCEANOGRAFIA
Unidad Ejecutora - UE
artículos
Título:
Positive interactions of the smooth cordgrass Spartina alterniflora on the mud snail Heleobia australis, in South Western Atlantic salt marshes
Autor/es:
ALEJANDRO D CANEPUCCIA; MAURICIO ESCAPA; PEDRO DALEO; JUAN ALBERTI; FLORENCIA BOTTO; OSCAR IRIBARNE
Revista:
JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY
Editorial:
Elsevier
Referencias:
Año: 2007 vol. 353 p. 180 - 190
ISSN:
0022-0981
Resumen:
The role of positive interactions is
often crucial in communities with intense abiotic stress such as intertidal
environments. Grasses acting as ecosystem engineers, for example, may
ameliorate intertidal harsh physical conditions and modify the community
structure. The mud snails Heleobia australis d'Orbigny frequently inhabit the SWAtlantic marshes,
mainly associated to intertidal marsh plants (mainly the smooth cordgrass Spartina alterniflora Loisel) probably due to the plant
indirect effects. The purpose of this work was to investigate the magnitude of
these association and the processes that generate the pattern. Samples of the
snail abundance in six SW Atlantic coastal marshes show that H. australis is associated to coastal areas of low energy and low or none freshwater
input. This result is important because this species is being used as bioindicator
of coastal estuarine systems during the Holocene. Thus the paleontological interpretation
based on this species should be revised.Within the studied areas, snails are
associated to intertidalmarsh plants. However, stable isotope analysis shows
that neither plant nor their epiphytes are their main food sources. Field
experiments show that snails actively select areas with plants, although
tethering experiments show that plants do not provide shelter from predators. However,
plants do buffer physical stress factors such as temperature, which generate
important mortality outside plants covered areas. These positive interactions
have large effects on H. australis distributions in marsh communities;
increasing the habitats available for colonization and affecting their local
distribution.