IADIZA   20886
INSTITUTO ARGENTINO DE INVESTIGACIONES DE LAS ZONAS ARIDAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Environmental factors affecting lentic mollusk distribution in northern Mendoza Province.
Autor/es:
MASI C.I.; CIOCCO, N. F.
Lugar:
La Punta, San Luis, Argentina
Reunión:
Congreso; XXVII Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2009
Institución organizadora:
Sociedad Biológica de Cuyo
Resumen:
Although studies on distributional ecology of freshwater mollusks have recently been initiated in Centre-West Argentina, extensive zones remain unexplored. The aim was to examine the factors affecting malacofauna distribution in lentic waters from Mendoza River basin (MRb). The study was conducted in summer/09 at 25 sites from high Andean wetlands to lowlands. Mollusks were counted to species and a series of environmental parameters were measured. Multivariate Analyses were used to ordinate sites based on environmental variables and to explore the relationships between measured variables and mollusk assemblages. In all, means and ranges of conductivity (CD), water temperature (WT), oxygen saturation, pH, vegetation cover (VC), depth and proportion of fine grain in sediment were 1414.4 (232-5950)mS.cm-1, 17.8 (5.1-32.2)oC, 70.9 (28.5-92)%, 7.8 (6.96-9.64), 54.9 (25-78)%, 15.1 (3.5-37)cm and 53.8 (10-90)%, respectively.  Mollusks were present on 15 sites outside of all 25 environments sampled. Lymnaea viator, Physa acuta, Heleobia hatcheri, Heleobia sp., Biomphalaria peregrina, Pomacea canaliculata, Chilina mendozana and Pisidium chiquitanum were identified. Highest species richness and relative abundance of mollusks matched with moderate levels of CD and WT and high values of VC as those of the low middle reach of MRb. Cold and moderately vegetated high Andean waters had no mollusks. Harder, warmer and poorly vegetated waters of lowlands generally represented critical conditions for the development of mollusk populations.