Declines in populations of and reproductive success of wood storks and
other wading birds have occurred in the Florida Everglades over the p
ast several decades. These declines have been concurrent with major ch
anges in the Everglades' landscape characteristics. Among the plausibl
e hypotheses that relate to landscape change are the following: (1) ge
neral loss of habitat; (2) heavy loss of specific habitat, namely, sho
rt-hydroperiod wetlands that provide high prey availability early in t
he breeding season; and (3) an increase in frequency of major drying o
ut of the central slough areas, which can affect prey availability lat
e in the breeding season. These three hypotheses were compared using a
n individual-based model of wood stork (Mycteria americana) reproducti
on. This model simulated the behavior and energetics of each individua
l wood stork in a breeding colony on 15-min time intervals. Changes in
water depth and prey availability occurred on daily time steps. Simul
ation results showed a threshold response in reproductive success to r
eduction of wetland heterogeneity. Model comparisons in which (1) only
short-hydroperiod wetlands were removed and (2) wetlands of both long
and short hydroperiods were removed showed that, for the same loss of
total area, the specific habitat removal caused a much greater reduct
ion in wood stork reproduction, indicating hypothesis 2 may be a more
likely explanation than hypothesis 1. Reduction of initial prey availa
bility in the central slough areas (simulating frequent drying; hypoth
esis 3) reduced fledging success by an average of more than 90% in the
model.