Body size measurements and stomach contents of Alligator mississippiensis on Jekyll Island, Georgia

Human-driven land use change can fundamentally alter ecological
communities, especially the diversity and abundance of large-bodied
predators. Yet despite the important roles large-bodied predators play in
structuring communities through feeding, there have been only a few
investigations of how the feeding patterns of large-bodied predators
change in human-dominated landscapes. One group of large-bodied predators
that has been largely overlooked in the context of land use change is the
crocodilians. To help fill these gaps we studied the feeding patterns of
juvenile American alligators (Alligator mississippiensis) on neighboring
barrier islands on the southeast coast of Georgia, USA. Jekyll Island has
multiple golf courses and substantial amounts of human activity, while
Sapelo Island does not have any golf courses and a much smaller amount of
human activity. We found that juvenile alligator populations on both
islands ate the same types of prey but in vastly different quantities.
Sapelo Island alligators primarily consumed crustaceans while alligators
that lived on Jekyll Island’s golf courses ate mostly insects/arachnids.
Furthermore, the Jekyll Island alligators exhibited a much more generalist
feeding pattern (individuals mostly ate the same types of prey in the same
quantities) than the more specialized Sapelo Island alligators (diets were
more varied across individuals). The most likely explanation for our
results is that alligators living on golf courses have different habitat
use patterns and have access to different prey communities relative to
alligators in more natural habitats. Thus, land use change can strongly
alter the feeding patterns of large-bodied predators and, as a result, may
affect their body condition, exposure to human-made chemicals, and role
within ecological communities.