Effects of fire on the community composition and mercury concentrations of aquatic macroinvertebrates in the Okefenokee Swamp, Georgia

Fire can be an influential disturbance in many ecosystems, and the frequency of wildfire is predicted to increase due to global climate change. However, little is known about how fire affects wetlands, and even less about impacts on resident invertebrates. Fire could change invertebrate community composition towards assemblages dominated by disturbance adapted invertebrates with subsequent succession back to a pre-fire community structure. Fire may also release contaminants such as mercury from vegetative or sediment sinks making it available for uptake by biota, therefore increasing mercury concentrations in invertebrates. In June 2007 a major wildfire swept through the Okefenokee Swamp in southeast Georgia, burning most (75%) of the wetland area. With the existence of extensive pre-fire data sets on community structure and mercury levels of invertebrates from the Okefenokee, the fire presented an opportunity to rigorously assess impacts of wildfire on invertebrates. Post-fire collection of samples is occurring in September, December and May, 2007–2009. Sample sites include 13 burned and 8 non-burned (reference) sites. Comparisons of data among pre-fire, post-fire non-burned, and burned sites will permit assessment of wildfire effects on the community composition of invertebrates and mercury concentrations of select invertebrates (amphipods, crayfish, odonates) in the Okefenokee Swamp.