An evaluation of peat loss from an Everglades tree island, Florida, USA

Abstract

The tree islands of the Everglades are considered to be biodiversity “hotspots”, where the majority of terrestrial species of the Everglades are found. Drainage for agricultural and urban development in the early 1900s has had a severe impact, converting many of them into “ghost tree islands” which have lost most of their woody vegetation and much of their altitude (elevation). A survey conducted in 1973 on one of the prominent ghost tree islands, named “Dineen Island”, provides insights into the past. We compared the results of the 1973 survey with those of a survey conducted in 2009, in order to examine changes in Dineen Island that had taken place over 36 years and to provide information about general trends in the Everglades. Peat loss at Dineen Island was roughly 4 mm yr-1. This subsidence, as a consequence of peat loss, has been accompanied by losses in nitrogen and phosphorus of 234 and 2.5 metric tons (4.5 and 0.05 metric tons per hectare), respectively. As many of the Everglades tree islands have been lost from the landscape due to historical water management practices, quantifying nutrient losses from this ecosystem may be useful in helping to predict non-anthropogenic nutrient biogeochemistry shifts in Everglades oligotrophy.

Keywords

• carbon
• ghost tree island
• nitrogen
• peatland
• phosphorus
• restoration