Wading birds.

In tropical wetlands, breeding wading birds rely on concentrations of aquatic
fauna during the dry season to meet increased energetic demands. Wetland
microtopography increases aquatic fauna concentration levels. Crocodilians modify the
landscape creating deep-water refugia but their role as a mechanism for aquatic fauna
concentration is unknown. I sampled alligator (Alligator mississippiensis) abundance and
slough microtopography to examine correlation between the two measures. Despite
increased microtopography in high alligator use sloughs, the differences were not
significant. Using an in situ experimental approach, I quantified the magnitude, timing,
and spatial extent of aquatic fauna concentrations within simulated alligator depressions
and the surrounding marsh. Aquatic fauna density and biomass were greater within
simulated depressions, thus enhancing wading bird foraging habitat. Further
understanding the mechanisms creating microtopography, thus enhancing wading bird habitat, is critical to facilitate restoration and prevent declines of wading bird populations
in seasonally pulsed wetlands worldwide.

Avian reproductive success varies depending on environmental conditions,
degree of predation, location, and food availability. I examined food availability and
nesting habitat of wading birds in South Florida. Evaluating prey availability and prey
used by two small heron species demonstrated the ability for small herons to maintain
consistent diets through fluctuating environmental conditions, within and across different
wetland types. Small herons may be able to cope with environmental changes by altering
foraging locations and strategies. Regarding nesting habitat, man-made sites may
provide habitat comparable to natural sites, at least in the short-term. The nest’s position
can influence its susceptibility to increased temperatures and predators, particularly for.
Climatic conditions such as rainfall can also impact nesting success by altering foraging
conditions and fish behavior. Understanding the effects of hydrologic regimes on biota
can have practical applications since ecosystems around the world share similar problems with competing demands for resources, and there is a concern for how use can affect the
quality of the resource.