The Croc Docs
Alligator Holes: Alligators, Plants, and Other Animals
Good morning friends. I'd like to invite you to come along with me and my field crew as we take a trip into the only subtropical preserve in North America - The
Everglades. Everglades National Park is listed as an International Biosphere Reserve, Wetland of International Importance, World Heritage Site, and is actively
being studied by many scientists at various universities to aid in the recovery of an ecosystem that has been compromised by changes in hydrology, land development,
contamination, and exotic species invasion.
Today we will be studying an alligator hole in Everglades National Park. Be sure to bring along sunblock, a hat, a long-sleeved shirt, a lunch, and plenty of water. We will get very hot working all day in the middle of the marsh. You should also bring a rain jacket for the occassional storm that can pop up. We will be taking a helicopter to get out to our field site. We will need to get suited up and briefed by the pilot before take-off.
Is everyone ready? Let's go!
The view from the air of the Everglades landscape is breathtaking. The sawgrass marsh seems endless. It's mind-boggling to think that the land area protected by Everglades National Park constitutes only one-fifth of the historic Everglades ecosystem.
As we arrive at the hole, we fly overhead before we land to look for alligators and birds that might be using the hole. We also scan the area to find the best place for us to land and walk into the hole. Any alligator trails leading to nearby holes are also noted.
There are many different kinds of alligator holes on the landscape. One of the goals of our work is to describe the many different kinds. We record whether an alligator is present, whether we see alligator trails leading from the hole, whether satellite holes are present, and whether other animal species are present. We also describe the overall community in which the alligator hole resides (for example, sawgrass marsh, wet prairie, etc.)
After landing, we walk to the hole with our equipment and survey the area, taking pictures for documentation. We then lay out two perpendicular transects through the center of the alligator hole.
Each transect extends through the hole, past the ecotone, and into the surrounding marsh on all sides. Plants are identified to species and quantified along the entire length of each transect and water depth and peat/soil depth are measured at each meter interval.
Plants that are often seen around gator holes include: Salix caroliniana (Carolina willow), Pontederia cordata (pickerelweed), Panicum hemitomon (maidencane), Thalia geniculata (Alligator flag), Sagittaria lancifolia (lance-leaf arrowhead), Polygonum hydropiperoides (wild water-pepper), Nuphar advena (spatter-dock), Bacopa caroliniana (water-hyssops), Sarcostemma clausum (white twinevine), Utricularia spp. (bladderworts), Typha spp. (cattail) and Ludwigia repens (red ludwigia).
Alligator holes support a variety of animal life including snakes, birds, frogs, fish, and - of course - alligators.
The data that we have collected is now put into a database of other gator holes. This information will be analyzed to understand how differences in sizes and depths of gator holes and their associated plant species are arranged spatially across the landscape.
If you would like further information on this project please take a look at the research highlight: Mapping and Characterization of Alligator Holes in Everglades National Park.
Getting Ready to Visit an Alligator Hole
Today we will be studying an alligator hole in Everglades National Park. Be sure to bring along sunblock, a hat, a long-sleeved shirt, a lunch, and plenty of water. We will get very hot working all day in the middle of the marsh. You should also bring a rain jacket for the occassional storm that can pop up. We will be taking a helicopter to get out to our field site. We will need to get suited up and briefed by the pilot before take-off.
Is everyone ready? Let's go!
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In the Air
The view from the air of the Everglades landscape is breathtaking. The sawgrass marsh seems endless. It's mind-boggling to think that the land area protected by Everglades National Park constitutes only one-fifth of the historic Everglades ecosystem.
Flying Over the Alligator Hole
As we arrive at the hole, we fly overhead before we land to look for alligators and birds that might be using the hole. We also scan the area to find the best place for us to land and walk into the hole. Any alligator trails leading to nearby holes are also noted.
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Types of Holes
There are many different kinds of alligator holes on the landscape. One of the goals of our work is to describe the many different kinds. We record whether an alligator is present, whether we see alligator trails leading from the hole, whether satellite holes are present, and whether other animal species are present. We also describe the overall community in which the alligator hole resides (for example, sawgrass marsh, wet prairie, etc.)
On the Ground
After landing, we walk to the hole with our equipment and survey the area, taking pictures for documentation. We then lay out two perpendicular transects through the center of the alligator hole.
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Each transect extends through the hole, past the ecotone, and into the surrounding marsh on all sides. Plants are identified to species and quantified along the entire length of each transect and water depth and peat/soil depth are measured at each meter interval.
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 |
Plants
Plants that are often seen around gator holes include: Salix caroliniana (Carolina willow), Pontederia cordata (pickerelweed), Panicum hemitomon (maidencane), Thalia geniculata (Alligator flag), Sagittaria lancifolia (lance-leaf arrowhead), Polygonum hydropiperoides (wild water-pepper), Nuphar advena (spatter-dock), Bacopa caroliniana (water-hyssops), Sarcostemma clausum (white twinevine), Utricularia spp. (bladderworts), Typha spp. (cattail) and Ludwigia repens (red ludwigia).
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Animals
Alligator holes support a variety of animal life including snakes, birds, frogs, fish, and - of course - alligators.
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Back in the Office
The data that we have collected is now put into a database of other gator holes. This information will be analyzed to understand how differences in sizes and depths of gator holes and their associated plant species are arranged spatially across the landscape.
Further Information
If you would like further information on this project please take a look at the research highlight: Mapping and Characterization of Alligator Holes in Everglades National Park.
