Action Sheet

  • Location :
    Florida, United States
  • Species status :
  • Period :
    October 2010 - December 2012


Field operator

Evaluating Effects of Ecosystem Restoration on Crocodiles and Alligators in the Florida Everglades

The Florida Everglades is the only place in the world where both alligators and crocodiles live. The American crocodile (Crocodylus acutus) is a federally threatened species that continues to be challenged by expanding coastal development in south Florida. The American alligator (Alligator mississippiensis) once occupied all wetland habitats in south Florida but has been negatively affected by canal construction, drainage, and saltwater intrusion. Both crocodiles and alligators are critical in the Everglades food web as top predators. Alligators are ecosystem engineers that create wet and dry conditions in the wetlands (holes, trails, nests), providing habitat for plants and animals that otherwise would not be able to survive. The crocodile is a flagship species in Everglades estuaries, meaning it represents the ecological importance of restoring freshwater flow.

The Everglades is the stage for the largest and most complex ecosystem restoration ever undertaken. As the Comprehensive Everglades Restoration Plan (CERP) proceeds, crocodiles and alligators have been identified as a key indicator to track ecological responses to restoration. By restoring hydrology and salinity patterns to more natural conditions, CERP is expected to improve the health and abundance of alligators, crocodiles, and their habitats.

Field operator

University Florida

Department of Wildlife Ecology and Conservation, Fort Lauderdale Research and Education Center

Contact :

Dr. Frank Mazzotti – Associate Professor of Wildlife Ecology – Department of Wildlife Ecology and Conservation – Ford Lauderdale Research and Education Center

Missions :

  • Conservation planning
  • Endangered species
  • Invasive species
  • Human dimensions of wildlife
  • Landscape ecology
  • Environmental education

Further information on the website


Correlations between biological responses of crocodilians and environmental conditions contribute to an understanding of species’ status and trends over time as indicators of ecosystem responses to environmental changes. The purpose of this project is to evaluate the effects of ecosystem restoration in the Florida Everglades on the American crocodile and the American alligator.

Objectives are as follows:

  • Determine extent and magnitude of impacts of ecosystem restoration on crocodiles, alligators, and their habitats in Florida
  • Determine patterns of movement of American crocodiles and American alligators in response to ecosystem restoration
  • Develop an interactive web and social-media based outreach program to involve the general public and students worldwide


Launch of Interactive Crocodile and Alligator Tracking Map

As part of our ongoing monitoring program, we are outfitting American crocodiles and American alligators with telemetry units that provide daily locations and transmit them to the Argos satellite. We download these location data into a geographic information system to create the interactive map below. Over the course of this project we will add environmental information, such as water levels and salinity, so users can track the movements of animals in relation to environmental conditions. The Comprehensive Everglades Restoration Plan is expected to improve hydrological conditions and salinity to more natural conditions, which will benefit alligators, crocodiles, and their habitats. Over time, this spatial analysis will help us better understand how crocodiles and alligators are responding to Everglades restoration.


- In January, 2013 -

Capture of a new 4 meters long crocodile

The crocodile, captured and marked by the team of the University of Florida, was exactly 4,11 meters long, which is about 5 cm less than the biggest ever caught in the Everglades. This nice catch is very encouraging for the life expectancy of the Everglades crocodiles.

Researcher of the University of Florida next to the captured crocodile © University of Florida

- In September, 2012 -

Modest hatching of the nests in the Everglades

In its last newsletter (n°14), the The Explorers Foundation told you about disturbances in American crocodile hatching in the Everglades. Now it’s time to make the assessment on the global hatching period. Last summer, the research team of the University of Florida found and marked approximately 330 hatchlings. On the 95 confirmed nests, only 55 hatched successfully. The rest of the nests failed due to particularly bad weather conditions such as Isaac storm which made the eggs inundated.

Bouquet of American crocodile hatchlings (© University of Florida)

- In August, 2012 -

Disturbance in American crocodile hatching

Like every year, the American crocodile hatching season is underway during summer. Starting in July, University of Florida researchers began to check all known crocodile nests. The hatching rate seems to be higher on elevated human-made canal bank than on natural beaches. This may be the result of an elevated water table (after a very wet spring and early summer) and evaporative cooling effects which affect low elevation nests.

Hatching of a nest saved from the water level elevation (© University of Florida)

- In June, 2012 -

Four new crocodiles equipped

The team of the Crocodile project from the University of Florida recently equipped four new females with satellite transmitters. You can follow their movements of Irene, Gwen, Charlotte and Giana on the interactive map:

Irene with her new transmitter (© University of Florida)

- In April, 2012 -

Good catch in the Everglades!

During last month, the field team of the University of Florida caught 2 of the 5 biggest crocodiles identified since the beginning of the project in 1978! The biggest one was almost 4 meters long.  It is heartening to see that these large, older animals are still present and contributing to the gene pool since the severe cold spell in 2010 killed a large number of crocodiles.

Research assistant riding a 4 meters crocodile! (Source : Université de Floride)

- In January, 2012 –

Public shows real interest to the American crocodile project

On January the 21st, the UF Fort Lauderdale Research & Education Center organised its second Open House. It was the opportunity for the American crocodile and Alligator project operators to share information about their research program with more than 200 community members. Their display included an airboat, crocodile and alligator catching equipment, crocodile and alligator skulls, videos of field researchers in action, the online crocodile/alligator tracking map, and numerous outreach publications. In addition to a focus on Florida’s native reptiles (e.g., crocodiles and alligators), American crocodile project operators presented the non-native invasive wildlife that competes with and preys on our native fauna. To this end they developed a “Native or Non-native Bingo” game and played it for the first time at the Open House: it was a hit!

- In December, 2011 –

Follow the movements of nine American crocodiles on the tracking maps of the The Explorers Foundation and of the University of Florida!

Online users can now follow the movements of nine American crocodiles, which have been equipped with satellite/VHF telemetry units, through their coastal habitats in the Everglades: (Click on “Actions”) and The map also provides a visual description of the areas in which the crocodiles may be observed. Currently, six of the crocodiles are in the Cape Sable area on the southwestern coast of the Everglades, and three are in the northern part of the Bay of Florida.

- In November, 2011 -

New Publication: The American Alligator, An Indicator Species for Everglades Restoration

University of Florida, in partnership with U.S. Fish & Wildlife Service, published a new two-page fact sheet summarizing the importance of the American alligator as an indicator species for Everglades restoration. The alligator is an indicator of ecosystem responses to Everglades restoration because it is sensitive to hydrology, salinity, and system productivity, all factors that are expected to change as a result of restoration. The alligator also serves as a potent communication tool because it is a species that is valued and understood by managers, policy makers, and the public. The fact sheet discusses the role of canals as unsuitable habitat for alligators, emphasizing that the UF research group must focus on monitoring alligator populations in natural wetland habitats to assess restoration effectiveness. The fact sheet can be downloaded in PDF form from

Everglades Crocodile and Alligator Research Exhibited at Regional Farm Expo

On October 18-20, the American crocodile program research team contributed to the University of Florida exhibit at “North America’s Premier Farm Show”—the Sunbelt Agricultural Expo in Moultrie, GA. This year’s theme was Florida: It’s a “Swamp” Thing, so most of the displays pertained to swamps and wetlands in Florida. Highlights of the team´s display included crocodile and gator skulls—the researchers were impressed with how many kids (more than the adults!) could easily tell the difference between the two. The UF team also guided people in using our interactive online crocodile tracking map (

- In October, 2011 –

American alligator capture surveys to monitor body condition

The Florida University researchers completed our alligator spotlight surveys in October and began catching alligators in three study areas of the Everglades. The research team captures and measures alligators to calculate their “body condition,” a ratio of body length to body volume. Body condition is of interest to researchers because of its potential for assessing how crocodilians are “coping” with their environment. Body condition can provide a measure of ecosystem condition and a measure of the quality and accessibility of prey species. Monitoring long-term trends in body condition of the alligator population can help to assess positive or negative responses of the ecosystem to restoration.

Photo: Jemeena Carrigan

American crocodile spotlight surveys

This month, with the end of crocodile hatching season, University of Florida researchers began their regular triannual spotlight surveys to monitor relative density of crocodile populations.

- In September, 2011 -

Beginning of the hatching season for the American crocodiles in the Everglades

American crocodile hatching season is in full swing along the coast of the Everglades and the Florida Keys. The University of Florida´s research team has been surveying the study area since spring. Nests are checked regularly to look for signs of activity. The locations of recently-hatched nests are recorded and rechecked at night to look for hatchlings. Hatchlings are captured, counted, measured and marked for future identification and growth monitoring. So far this summer approximately 75 nests and 800 hatchlings have been located, and the survey work continues.

Tracking the movements of American crocodiles in the Everglades.

In July, the University of Florida researchers attached satellite/VHF telemetry units to three more adult female American crocodiles. These animals ranged from 2.56m to 2.93m in total length. One of these females had already been captured 22 years ago, in 1989, when she was 84 cm long! These animals have been added to the interactive tracking map, which enables online users to follow the crocodiles´ movements over time as they move through the coastal habitats of the Everglades.

You can also track these animals on the Fonds de Dotation pour la Biodiversité´s (The Explorers Foundation) website –

- In August, 2011 -

Spring drought continues to delay the American alligator surveys in the south of Florida

The rainy season has arrived in south Florida! However, because of an unusually dry spring, the research team is still waiting for water levels to rise to enable them to access their study areas in the Everglades.

American crocodile nest and hatchling surveys underway in the Everglades

The University of Florida´s researchers are continuing to monitor American crocodile nests in the Everglades by boat, foot, and helicopter. In late June, they found the first crocodile hatchlings of the season on Cape Sable in Everglades National Park. The research team captures, counts and measures the hatchlings, marking them for future identification to monitor growth.

Crocodile conservation and ecotourism in Belize

Dr. Frank Mazzotti travelled to Belize to work on the University of Florida´s ecotourism-based research and monitoring project on Morelet’s crocodiles that is being carried out in the New River Lagoon and adjacent marshes. In collaboration with the Lamanai Outpost Lodge the university offers a “crocodile encounter,” an opportunity for guests to participate in and fund this research program. For guest safety and satisfaction the researchers focus on juvenile crocodiles, which are brought on board and weighed, measured, and marked with a Passive Integrated Transponder (PIT) tag if not previously marked. Guests are allowed to handle the crocodile and are given a knowledgeable lecture on crocodile ecology by the guides.

While in Belize, Dr. Mazzotti also met with Wildlife Officer Rasheda Garcia to discuss developing a comprehensive conservation plan for Belize’s other crocodile species, the American crocodile.

- In June 2011 -

American crocodile nesting surveys underway in the Everglades

Spring is crocodile breeding season in the Everglades and the research team of the University of Florida is conducting surveys by boat, foot, and helicopter to monitor crocodile nesting effort. This work is being funded by the Monitoring and Assessment Plan of the Comprehensive Everglades Restoration Plan. Today, there are more crocodiles and more nests in more locations than when monitoring began in the 1970s. These results led to the crocodile’s reclassification in 2007 from an “endangered” to a “threatened” species. However, there are continuing challenges to crocodile conservation in Florida as a result of coastal development and human intolerance.

Spring drought continues to delay American alligator surveys in south Florida

Because of an unusually dry spring in south Florida, water levels are still too low to permit airboat access in some of our study areas in the Everglades. Historically during drought years, waters start to rebound by mid-May so UF´s research team hopes that water levels will rise enough soon, so that the researcher will be able to proceed soon with their monitoring. Extreme dry periods can have potentially negative impacts on wildlife. Alligators move from the marsh into crowded canals where young alligators risk being eaten by adults. Hypersalinity in estuaries can inhibit nesting and reduce prey availability for American crocodiles.

Additional American crocodiles are being tracked on the interactive map of the University of Florida!

So far this month the University of Florida (UF) research team has outfitted two more American crocodiles with a satellite/VHF telemetry unit. The tracking unit provides daily locations and transmits them to the Argos satellite. The UF´s research team downloads the data into a geographic information system and presents it on our interactive tracking map (URL). The researchers will soon be outfitting four American alligators with similar tracking units. Over time, this spatial analysis will help them better understand how crocodiles and alligators are moving through the Everglades in relation to environmental conditions. This work is being funded by the Monitoring and Assessment Plan of the Comprehensive Everglades Restoration Plan.


- In May 2011 -

Social media for the Everglades !

The University of Florida´s outreach team established the American crocodile project’s social media presence on Facebook, Twitter and YouTube @TheCrocDocs, and has also recently updated its own website : These online venues will be key communication tools for disseminating information about the Lacoste-sponsored research project. The team also developed a sample “Google Maps” application showing locations of telemetered crocodiles, and is coordinating the transfer of these maps that you will able to find at the The Explorers Foundation website: The maps will eventually be augmented with information such as water depth and salinity, so Internet users can see how crocodiles and alligators travel in relation to environmental conditions.

Lacoste´s CEO joins the researchers of University of Florida during their fieldwork operations

On February 21st 2011, Professor Frank Mazzotti from the University of Florida, welcomed Lacostes CEO, Christophe Chenut and Olivier Chiabodo representing the The Explorers Foundation, to the Everglades National Park for the launch of the fourth project funded by the Fonds de Dotation pour la Biodiversité (The Explorers Foundation) in partnership collaboration with Lacoste. This project
expands the University of Florida’s ongoing research on Florida’s two crocodilian species by examining the patterns of the movements of telemetered alligators and crocodiles in relation to changing environmental conditions, and by developing an interactive, social-media-based outreach program.

Spring American alligator surveys the Greater Everglades

In February 2011, researchers from the University of Florida began spring surveys of American alligators for the eighth year of monitoring for the Comprehensive Everglades Restoration Plan. The team monitors relative abundance and body condition biannually, in the spring (dry season) and fall (wet season), and percent of alligator holes that are occupied in the spring. Relative abundance is measured as encounter rate (number of alligators per km) by nighttime spotlight surveys. At least 15 animals are captured within each area and measured in order to enable researchers to determine their body condition (size measured as length/weight ratio).

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