American alligators (Alligator mississippiensis) have long been recognized as ecosystem engineers in seasonal environments across the southeastern United States due to their construction and maintenance of holes, nests, and trails. These structures provide habitat, refuge, and protection for an assemblage of other species and increase ecosystem heterogeneity. However, alligators are rarely recognized for their engineering via the construction and maintenance of extensive burrow systems. We conducted surveys across the landscape to determine burrow location within wetlands and relative to elevation and vegetation. We also analyzed timelapse video recordings of burrow entrances to document species use and took microhabitat measurements (temperature, depth, turbidity, and dissolved oxygen) at one-meter intervals across the length of the burrows.
Results/Conclusions
Thus far, 11 burrows have been located across the 7 wetlands surveyed, in addition to the 16 burrows previously identified on site. Burrows tended to be located on contours and were concentrated within the center or edge of the wetlands. Thirteen different taxa have been documented using alligator burrows for foraging and/or refuge. Finally, burrows documented exhibited significantly lower DO, lower temperature, and higher turbidity relative to the surrounding wetland. Our results indicate that alligator burrows may provide a distinct habitat relative to the corresponding wetland and may be an important resource for multiple species, particularly in times of drought, fire, or other disturbance. This may be a particularly important area for further research, as species continue move north due to rising temperatures and sea level. Alligators are a highly mobile species, thus their ability to dig burrows may facilitate the survival of American alligators as well as that of other species.
