PARENT SESSION
Poster Session #18: Remote Sensing and GIS.
Tuesday, August 7, 2001. Presentation from 3:30 PM to 5:00 PM. Exhibition Hall
97
Assessment of habitat availability for Boltonia decurrens, a threatened floodplain species, using a GIS.
Mettler, Paige1, Smith, Marian2, Middleton, Beth1, 1 2
ABSTRACT- The decline of the federally threatened species, Boltonia decurrens (Torrey and Gray) Wood (Asteraceae) is due to hydrologic changes in the Illinois River and its associated floodplain. Boltonia decurrens is a fugitive, floodplain species that colonizes regularly flooded sites along the Illinois River and its confluence with the Mississippi River, but is primarily restricted to the Illinois River Valley. The proliferation of agriculture in the Illinois River watershed has greatly reduced habitat availability for B. decurrens, creating disjunct populations. We used a geographic information system to assess current habitat availability for B. decurrens. We downloaded the following data for 5 Illinois counties from the Illinois Department of Natural Resources Geospatial Data Clearinghouse; county boundary, floodzones, National Wetland Inventory Classification and streams. Each county was mapped individually using the geoprocessing tool in ArcView. Query builder was used to isolate areas where NWI classifications recorded at current B. decurrens populations intersected with the river flood zone. This information was used to identify suitable habitat and calculate the area of this habitat remaining for B. decurrens within each county.
KEY WORDS: Boltonia decurrens, threatened, Illinois River, NWI