INVASIVE PLANT COMMUNITIES IN MISSISSIPPI RIVER FLOODPLAIN FORESTS: A 
COMPARISON BETWEEN MATURE, REFORESTED, AND NATURALLY REGENERATING STANDS

Valerie A. Barko1,2, Loretta L. Battaglia3, and Dawn E. Henderson1
1Open Rivers and Wetlands Field Station, Missouri Department of Conservation, 
Jackson, MO 63755. 2John A. Logan College, 700 Logan College Rd., 
Carterville, IL 62918. 3Department of Plant Biology, Southern Illinois 
University, Carbondale, IL 62901.

Keywords: bottomland hardwoods, exotic species, floodplain, invasive species, 
restoration

Large tracts of bottomland hardwood forests within the south central and 
southeastern United States were cleared for agriculture, fuel wood, and 
timber during the last century, resulting in declines five times greater than 
for other hardwood forest types in the United States.  Many tracts of 
bottomland hardwood forests within the Mississippi River System that were not 
cleared have been degraded. Many restoration practices have focused on 
afforestation without clear objectives, long-term monitoring of success, or 
the effect of invasive non-native plant species.  In general, few studies 
have addressed the threat of  exotic plant species to restoration success.  
We hypothesized that disturbed but restored stands would have greater exotic 
richness than mature, closed stands.  We also expected that passively 
restored, naturally regenerating stands would harbor more exotics than 
actively reforested stands where canopy closure may be faster.  Our main 
objective was to investigate these relationships within bottomland hardwood 
stands of the Mississippi River Ecosystem bordering Missouri and Illinois. 
Across all forest types, a total of 34 exotic species composing five growth 
forms were identified.  Exotic plant communities within mature stands 
differed from those within reforested stands (R = 0.107, p = 0.033); no other 
differences among exotic communities were detected. Reforested sites also had 
greater exotic species richness, and exotic:native ratios than mature and 
natural regeneration stands.  Our findings suggest that reforested bottomland 
stands in this region are vulnerable to exotic plant invasion.  Multiple 
stand entries, as well as planting of herbaceous cover species, are common in 
active restorations in the region and may contribute to exotic species 
establishment and proliferation.  Considerations should be made in these 
stands to employ methods to reduce this risk by planting native cover crops 
and minimizing anthropogenic disturbances.    

(VAB): John A. Logan College, 700 Logan College RD., Carterville, IL 62918; 
Email: valeriebarko@jalc.edu; tele: 618-985-2828 x 8258; Fax: 618-985-9181; 
Presentation type: POSTER ONLY