Figure 3 shows the long term mean monthly moisture

 relations in the vicinity of the study area (Royal Palm

 Ranger Station, in the Everglades near the Tamiami Trail,

 latitude 25000'N). The graph demonstrates an excess of

 rainfall over evaporation during the summer and early fall,

 but a moisture deficit, evaporation greater than rainfall,

 during the spring and summer. In south Florida, pan

 evaporation appears closely related to solar radiation,

 also shown in Figure 3. Transpiration, the loss of water

 through plants, changes seasonally. Transpiration rates

 for some plants, such as cypress, willow, and many marsh

 macrophytes are greatly reduced when the plants shed their

 leaves or die back in late fall, suspending photosynthesis

 during winter.



 The Study Region

 The study region can be roughly defined as the

noncoastal parts of Lee, Hendry, and Collier counties. It

also includes the seasonally drying marshes on the western

and northwestern shores of Lake Okeechobee and parts of

Charlotte and Glades counties (Figure 4). This area, which

lies between latitudes 250 47' and 270 07' N, comprises

numerous sloughs, marshes, cypress strands, wet prairies,

and ponds that are linked by flows of energy through the

movement of water and animals such as wading birds.

Although many of these wetlands are in their natural state,