Factors Affecting Wading Bird Prey Concentrations in the Everglades During the Dry Season

One factor that potentially controls the distribution and density of wading bird
prey within open-water marsh habitats during seasonal drying events is the amount of
available aquatic habitat, which is partly a function of the amount of microtopographic
relief at a given location. To determine how microtopographic relief affects prey
concentrations during dry-downs a simulation model was developed and run using
empirical microtopographic data collected from the Everglades. The simulation suggests
that those locations within the marsh with higher levels of microtopographic relief
concentrate prey earlier during the dry-down period and potentially to greater densities
overall. In addition, a model selection analysis was performed on field data to determine
which set of factors displayed the greatest effects upon prey concentrations during drydown
events. When examining the best selected a priori model it appears that the
amount of available aquatic habitat, water depth, and macrophyte density have the
strongest affects upon concentrations of prey during a seasonal drying event.