Immediate ecological impacts of a prescribed fire on a cattail-dominated wetland in Florida Everglades
Miao, Shili; Edelstein, Chris; Carstenn, Susan; Gu, Binhe
published: Jan 1, 2009
ArtNo. ESP141017601005, Price: 29.00 €
The effects of fire on nutrient release in wetlands prior to, during and afterwards are notably rare. We initiated a long-term and large-scale ecosystem study, driven by a large restoration program, to assess ecological effects of repeated fires on a nutrient-enriched, cattail-dominated wetland in the Florida Everglades. Here, we report the immediate and short-term (30 days) impacts of the first prescribed fire focusing on a central question of whether the fire affected surface-and pore-water nutrient concentrations and forms. Specifically, we addressed several questions: 1) how fast could the impacts be detected, 2) what were the magnitude and duration of the impacts, and 3) were there any downstream effects detected and if so, how far downstream was the impact observed? The results showed that post-fire increases of average surface water total phosphorus (TP) concentrations over 10 days were 128%, 119%, and 135% for within burned plot, 25 m downstream, and 100 m downstream, respectively, relative to the upstream control (82 ± 11 μg L−1). A post-fire surface water pH peak (8.4) was observed as soon as 15 minutes after the fire reached within burned plot, and the increase in pH lasted at least three weeks. A significant increase (400%) in the daily peak dissolved oxygen was detected by the third week post-fire. Daily maximum water temperature increased 2-4 °C post-fire and this increase lasted the duration of the 30-day sampling period. Average periphyton TP concentrations from samples collected within burned plot were 3495 ± 320 mg kg−1 one month post-fire, but decreased to 1730 ± 219 mg kg−1 three months post-fire. Cattail seed germination decreased (41%) from pre- to post-fire, while seed germination of sawgrass and other species increased (97% and 12%, respectively). Overall, whether these short-term responses have sustained effects and how they will shape other entities of the ecosystem in the long-term are currently being investigated and will be assessed in the near future.