Tuesday, November 14, 2006 - 8:00 AM

Microbial Biomass and Enzyme Activity during Decomposition of Five Plant Species in a Chronosequence of Restored Wetlands in the Everglades National Park.

Angelique M. Keppler and K. R. Reddy. Univ of Florida, 106 Newell Hall, Gainesville, FL 32611

The Hole-in-the-Donut (HID) region of the Everglades National Park (ENP) offers a unique opportunity to investigate microbial biomass and enzyme activity on decomposition during successional development of vegetation and soil formation.  In 1916, farming practices were employed in this region that altered approximately 4000 ha of natural wetland vegetation.  In 1975, farming ended and the HID was aggressively colonized by a non-native pest plant Schinus terebinthifolius. In 1989, the ENP employed a “scraping” method to remove and control Schinus.  This method involves the mechanical removal of existing Schinus and underlying rock-plowed rubble and substrate leaving behind bedrock with pockets of captured substrate material.  These pockets provide enough substrate for vegetation to develop on the scraped sites.  Yearly restoration sites began in 1997 and will continue to completion in 2010.  To investigate site differences in microbial biomass carbon (MBC) and nitrogen (MBN) and enzyme activity of b-glucosidase, aminopeptidase, and dehydrogenase on the decomposition of 5 different plant species, a year long litter bag decomposition study is currently underway.  Litter bags were collected after 6, 12, 24, and 52 weeks after being placed in the field and analyzed for mass loss, TC, TN, TP, MBC, MBN, and enzyme activity.  The MBC:N ratios, TC:TN:TP ratios of the litter material and the enzyme activities will be used to indicate nutrient limitation of microbial decomposers across restored sites (1989, 1997 and 2003) as well as a reference site and a non restored Schinus site. Initial analysis for microbial biomass of the soil in restored sites indicate difference for MBN of 526.4 mg kg-1 (Schinus), 490.4 mg kg-1 (reference), 517.1 mg kg-1 (1989), 616.7 mg kg-1 (1997), and 494 mg kg-1 (2003) and MBC of 3912.3 mg kg-1 (Schinus), 5758.9 mg kg-1 (reference), 5638 mg kg-1 (1989), 6576.8 mg kg-1 (1997), and 6479.4 mg kg-1 (2003).