Mapping Groundwater-Dependent Vegetation Zones: Application of GIS and Multicriteria Analysis with Field Validation

Wetlands with shallow water tables allow the development of groundwater-dependent vegetation, which is fundamental to the functioning and conservation of these ecosystems. Despite their importance, only 8% of the wetland area in Chile is protected. The lack of specific research on regions such as the center-south of the country hinders the protection and effective management of these ecosystems. This study presents an economical and practical methodology for mapping phreatophytic vegetation zones in a wetland in south-central Chile, using geographic information systems (GIS) and field validation. Through a literature review, five predictor parameters of the relationship between groundwater and vegetation in wetlands were selected. Using a multi-criteria analysis based on these five selected parameters, a map was generated to identify areas of high influence of groundwater on vegetation, which allowed the definition of ten zones to identify the type of vegetation and validate the methodology. The results indicated that 100% of the selected areas presented conditions of soil moisture and phreatophytic vegetation. Fourteen species were identified, of which nine are phreatophytes, corroborating that the parameters selected for mapping are indicators of areas where the existing vegetation depends on groundwater. It was demonstrated that the applied methodology offers a solid and accessible tool to map and identify the relationship between groundwater and vegetation in wetlands, generating valuable information that provides visibility to these ecosystems for better management and conservation.