Florida Coastal Everglades LTER

Where Research and Management Meet

The quantity and quality of water in the Florida Everglades have been grossly affected by human alterations and are now the subject of a major restoration initiative. A primary challenge for managers of the Everglades Restoration Project is to predict how various restoration options will affect the aquatic plants and animals that live there. A challenge for scientists is to understand and communicate how knowledge of these plants and animals will help show that the restoration is working. To accomplish this, managers and scientists study the linkage between aquatic communities and the environmental factors that are likely to be sensitive to the restoration project.

• For more than 22 years, Everglades National Park and Florida International University biologists have collected data on fish at three sites representative of different hydroperiods, which is the length of time during the year when a site is inundated with water (Loftus and Eklund 1994). During this study two major events have occurred. Without this long-term research, the connections between and the relevance of these events would not be evident.
• 1) In 1985 one of the three marsh sites (the 'intermediate' site in the figure) switched from a site that dried up most years, to one that dried up much less often (top figure). The other two sites were unaffected by this management change, or "references."
• 2) In 1989 and 1990, a system-wide drought occurred that obscured differences in hydroperiod among the sites (Trexler et al. 2001). Long-term climate records suggest that south Florida experiences similar dry conditions roughly every 10 years.

There was a multi-year lag before the effects of the hydrological manipulation emerged, during which time the drought occurred. This lag occurred because it took several generations for the effects to be manifest in some of the fish species.
The hydrological manipulation ultimately lead to a change in fish density at the manipulated site ('intermediate'), making it more like the long-hydroperiod reference than it was in the early 1980s (bottom figure). This result is consistent with the goals of the management experiment. Results like these demonstrate that the aquatic communities will respond in the desired direction as the Everglades Restoration Project proceeds. They also illustrate the usefulness of long-term ecological studies.