age dependent survival rate, age of maturity, and other

factors.

 Information for the models in this study on the

 regional scale was obtained primarily by original work.

 Information at the biological community scale was obtained

 partially by original work and partially from previous

 studies. Information concerning the indicator species was

 obtained almost entirely from previous studies.

 Demographic material was largely hypothetical, but based on

 the best information available.



 Model of Water, Fish, and Wading Birds

 Figure 1 is a simple diagrammatic model of the

wetlands system of souLiiwest Florida that shows the

relationships between primary productivity, surface water

area, fish production, fish density, and breeding success

of wading birds. The model describes a connection between

the seasonal change in sunlight and rain and the timing of

biological events. In the model, fish production is a -

function of sunlight and total surface water area. Fish

density, as defined in this study, is total fish biomass

divided by surface water area. Both bird biomass and fish

kills are proportional to fish density rather than to

absolute fish biomass. Fish kills occur only when fish

density exceeds a certain threshold value. In the model

bird reproduction is dependent on the average weight of the

birds, which is total bird biomass divided by bird number.