A biological mechanism for enhanced wading bird foraging patches in seasonally-pulsed wetlands

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.