MACRÓFITAS DE LA CUENCA DEL RÍO ELQUI, ZONA SEMIÁRIDA DE CHILE.

Background and aims: The Elqui river basin is located north of the Coquimbo Region, in the semiarid zone of Chile. This body of water is particularly important due to the economic activities it supports and its high environmental vulnerability. The objective of this study was to determine the diversity and floristic composition of macrophytes of the Elqui river basin. M&M: Twenty sampling stations with plots of 1 m2 were distributed in the three sub-basins that make up the study area. Inside each plot, all plant species were recorded along with their respective abundances. In addition, in each station some environmental variables were measured, which were analyzed together with the biological data. Results: A total of 51 macrophyte species and one alga were identified, with dominance of native elements with emergent habit. Statistical analyses indicate moderate differences regarding the floristic composition of the three sub-basins compared; these are mainly concentrated in the Turbio river. The analysis of the environmental data indicates that the variables that most influence the composition of species in the study area are: altitude, total suspended solids, redox potential and water depth. Discussion: Studies on macrophytes at the hydrographic basin level are practically null in Chile. This type of information increases knowledge on biodiversity and allows a more efficient management of continental aquatic systems. [ABSTRACT FROM AUTHOR]