Regime shifts of the Río Cruces wetland ecosystem: current conditions, future uncertainties

Abstract

0 0 1 166 914 Universidad de Chile 7 2 1078 14.0 Normal 0 21 false false false ES JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:Tabla normal; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:Calibri; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-ansi-language:ES-CL; mso-fareast-language:EN-US;} During April-May 2004 the Rio Cruces wetland ecosystem, located in Valdivia (40oS), southern Chile, was described as shifting from a clear water regime, dominated by the introduced macrophyte Egeria densa , to turbid waters and absence of submerged macrophytes. We analyzed the trophic status and ecological regime of the wetland from November 2011 through January 2013. The trophic status was determined comparing values of selected variables (nutrients, chlorophyll-a and transparency) with OECD criteria. The ecological regime was determined comparing the same variables with the criteria proposed by Ibelings et al. (2007). We further compared the concentration of nutrients and suspended solids with previous measurements. Results show that current trophic status of the wetland is between eutrophic and hypereutrophic and its ecological regime intermediate, between clear and turbid waters. In this article we discuss the potential relationship between the watershed land use, the change in wetland’s trophic level and ecosystem regime and potential future conditions.