Environmental Dynamics in Salinas Grandes, Catamarca, Argentina

MARCOS S. KARLIN, OMAR A. BACHMEIER, ANTONIO DALMASSO, JOSE M. SAYAGO ET ROBERTO SERENO

ARID LAND RESEARCH AND MANAGEMENT

TAYLOR & FRANCIS INC

Lugar: Londres; Año: 2011 vol. - p. 328 - 350

1532-4982

Saline systems are open systems where energy and matter fluxes produce modifications in the ecosystem, especially in plant communities, defined by species abundance and plant cover. Based on these changes, it is possible to define vectors that show the tendencies of such communities to reach mature or stationary states, and their modifications by natural or anthropic disturbances. Salinity and topsoil depth dominate the system dynamics. The decrease in soil salinity and the increase in the sandy topsoil horizon would allow installation of new plant populations, a higher biodiversity, ecological resilience and productive potentiality. Plant and soil surveys were conducted, establishing several relationships among the studied variables. Lyapunov coefficients (L) were calculated as the Euclidean distance of each site from a reference condition, used as exergy of the system. These values were correlated with the electrical conductivity data. The presence of soluble salts in the soils generates adverse conditions for unadapted species, reducing the total amount of biomass of a plant community, and therefore its exergy. When L decreases in time, it is expected that the system goes towards a steady state. If the contrary occurs, the equilibrium is unstable and become less resilient. While primary succession evolves, minimum rangeland requirements increase, depending on the dynamics of the system. According to the relationship between climate, plant cover and erosive processes, dunes development would increase total biomass and biodiversity. Anthropic degradation, through fire, deforestation and overgrazing, can produce retrogression of primary or secondary successions, through erosive processes and salinization.