DEVELOPING A GIS DATABASE TO MONITOR PLANT POPULATION 
DYNAMICS IN THE FLOODPLAIN: A MODEL BASED ON BOLTONIA DECURRENS, A THREATENED SPECIES

Marian Smith, Randall Pearson, Elizabeth Esselman, and Kelly Victory

Southern Illinois University Edwardsville
 

Abstract

Boltonia decurrens (Torr. and Gray) Wood (Asteraceae), an endemic of the Illinois River floodplain, is on the federal list of threatened species. Populations vary annually in size and location, depending upon the timing and severity of annual floods. Our purpose was to develop a simple predictive model that could facilitate the selection of suitable sites for mitigation and increase the efficiency and efficacy of census efforts following a flood. A 90-km² area containing two known populations of B. decurrens was selected to determine the feasibility of utilizing Geographic Information System (GIS) technology and readily available data to create a model to predict current and potential sites. A database was established in ArcView 3.1. Soil series type, National Wetland Inventory (NWI) classifications, and distance to surface water were identified for both sites and used to define the environmental constraint criteria. Potential habitat was identified in 2.7% of the study site, reducing the search area by 97.3%. Study areas that met constraint criteria were identified and verified by site inspection. 

Site inspection of predicted areas confirmed that the model can be used to identify locations of suitable habitat. All previously known populations were correctly identified by the model, and of the 14 areas that met the three constraint criteria, 71% had populations of either B. decurrens or B. asteroides, a species with similar habitat requirements. Application of the model could reduce the cost of surveys and improve the accuracy of site selection for reintroduction of the species. The approach used in this study could be adapted for any species of concern, or for groups of organisms that share similar habitat requirements.