Document: HOJ-3-63-20

Do levees affect soil microbial activity in a large river floodplain ecosystem?

KANG, H.* and E.H.STANLEY

University of Wisconsin, Madison, WI 53706, USA. ¹

Abstract:
Recent years have witnessed increased concerns about floodplains due to their importance in water quality amelioration, high biodiversity, and the extensive modification of these systems. One such modification is construction of levees, whose long-term effects on floodplain ecosystems have rarely been studied. We measured soil microbial activities (dehydrogenase, and extracellular enzyme activities), soil properties (organic matter, pH, ions, and soil texture), biological attributes (coarse woody debris and litter accumulation) and tree species composition in a Wisconsin River floodplain where levees were constructed more than 100 years ago. Higher amounts of litter and organic matter were observed outside the levee compared to areas inside the levee. Further, significantly higher microbial activities (dehydrogenase, -glucosidase, phosphatase) per organic matter were found in the soils inside of the levee. These changes were attributed to modified hydrology, which caused differences in water availability, tree species composition (e.g., higher number of oaks outside the levee), and/or soil properties (e.g., soil texture). These results suggest that modification of the hydrological regime by levees alter not only the structure of plant communities but also the functional attributes of floodplain ecosystems.

Keywords: soil enzyme, hydrology, MUF, Silver maple

This abstract is being presented at: 8:15 AM in session:
Oral Session #71: Soil Microbial Biomass and Soil Respiration.