GIS technologies for aquatic macrophyte studies: I. Database development and changes in the aquatic environment

Geographic information system (GIS) and digital database technologies provide a link between landscape-scale ecological studies and resource management applications. A case study involves the development of an extensive GIS database for upper Lake Marion, South Carolina that includes macrophyte distributions for 1972–1988, bathymetry, sedimentation and water chemistry. This database was utilized to assess changes in the aquatic environment related to management practices such as herbicide applications for aquatic plant control. Although the herbicides were found to be very effective, spraying must be repeated annually to maintain open water areas clear of aquatic vegetation. Without herbicides macrophytes quickly reinvade and proceed in normal successional patterns to establish submergent and emergent aquatic plant beds. The PC-based procedures developed in this study can be utilized by local resource managers to assess the impact of management practices on the aquatic environment.