by
Freshwater flow is the subject of great interest concerning Everglades restoration. The effects of restoring freshwater flow to the system are suggested to not only increase flow, but also increase nutrient inputs to downstream communities. Tree islands are ecologically important communities in the Southern Everglades, and this area is currently receiving canal water delivery as part of hydrologic restoration. Local nutrient cycling and forest dynamics of the islands are key to understanding the relationship between wetland management and tree island function.
To investigate this relationship, I quantified
cocoplum (Chrysobalanus icaco) productivity, vegetation structure,
nutrient utilization and soil dynamics of the seasonal swamp tree
islands. I utilized an experimental design with "flow" (islands
experience both flow and nutrient effects of canal water delivery),
"walled" (experimentally, islands experience reduced flow and
nutrient effects), and "no flow" (islands have greatly reduced flow
and nutrient effects) treatments.
In the “flow” treatment group, there were significantly higher water levels and marsh flow rates in the wet season, but in the “no flow” treatment group, there were higher soil redox potentials, standing litter and cocoplum twig production rates. Tree islands in the Southern Everglades efficiently utilized both phosphorus and nitrogen as indicated by several nutrient indices, but showed more clear support for efficient P use. When compared with both temperate and tropical forested wetlands, the tree island communities were among the most efficient forested wetland communities. This study should be continued to determine the long-term effects of increased freshwater flow on tree islands in the Southern Everglades.
Date: November
26, 2001 Department: Biological Sciences
Time: 10:00 AM Major
Professor: Dr. Daniel Childers
Place: WC 130