Home Archived October 29, 2018
(i)
USGS Home
SOFIA Home

Alligator Ecology, Modeling, and Monitoring to Complement MAP

Metadata also available as - [Questions & Answers] - [Parseable text] - [XML]

Metadata:


Identification_Information:
Citation:
Citation_Information:
Originator:
Kenneth G. Rice

Frank J. Mazzotti; H. Franklin Percival; Daniel Slone; Laura Brandt

Publication_Date: 2003-2006
Title: Alligator Ecology, Modeling, and Monitoring to Complement MAP
Geospatial_Data_Presentation_Form: project
Online_Linkage: <https://sofia.usgs.gov/projects/index.php?project_url=gator_eco>
Description:
Abstract:
This project will accomplish several tasks with a combination of field data collection, GIS mapping, and computer simulation. Our main objectives are designed to answer questions critical to restoration success and to provide the tools necessary for evaluation:

1. Develop monitoring methods necessary for evaluation of restoration success in alligator populations. 2. Understand the effects of decompartmentalization and other CERP (Comprehensive Everglades Restoration Plan) projects on restoration of alligator populations. 3. Identify and quantify the extent of aquatic refugia maintained by alligators throughout the system and develop relationships necessary to predict restoration of refugia. 4. Validate and update ecological models for use in prediction of the effects of restoration.

Purpose:
Many important questions concerning the effects of Everglades restoration on alligator populations remain unanswered such as the impacts of decompartmentalization, the role of alligator holes as aquatic refugia, and the effects of hydrology on population growth and condition. Further, the methods for monitoring and evaluating restoration success are not clear or have not been adapted for use during CERP. Also, we need to continue to update and validate restoration tools such as population models for use in alternative selection, performance measure development, and prediction. This project will directly address the questions outlined above, develop monitoring methods, and validate restoration tools for use in CERP. All project tasks have been requested by management agencies in South Florida (NPS, USFWS), listed as critical CERP priority research needs (see USGS Ecological Modeling Workshop at <https://sofia.usgs.gov/publications/infosheets/ecoworkshop/>), and/or highlighted as science objectives for CESI
Supplemental_Information:
This study has become part of a larger study funded by science questions identified by the NPS (Critical Ecosysstem Studies Initiative -CESI) and USACE (CERP Monitoring and Assessment Plan - MAP).

In 2008 this project became a companion study to CERP MAP "Alligators"

Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20021001
Ending_Date: 2008
Currentness_Reference: ground condition
Status:
Progress: In Work
Maintenance_and_Update_Frequency: As needed
Spatial_Domain:
Description_of_Geographic_Extent:
Loxahatchee National Wildlife Refuge, Water Conservation Areas 2 & 3, Everglades NP, Gulf of Mexico estuaries
Bounding_Coordinates:
West_Bounding_Coordinate: -81.5
East_Bounding_Coordinate: -80.25
North_Bounding_Coordinate: 26.75
South_Bounding_Coordinate: 25
Keywords:
Theme:
Theme_Keyword_Thesaurus: none
Theme_Keyword: alligators
Theme_Keyword: biology
Theme_Keyword: ecology
Theme_Keyword: monitoring
Theme:
Theme_Keyword_Thesaurus: ISO 19115 Topic Category
Theme_Keyword: biota
Theme_Keyword: environment
Theme_Keyword: inlandWaters
Theme_Keyword: 002
Theme_Keyword: 007
Theme_Keyword: 012
Place:
Place_Keyword_Thesaurus:
Department of Commerce, 1995, Countries, Dependencies, Areas of Special Sovereignty, and Their Principal Administrative Divisions, Federal Information Processing Standard (FIPS) 10-4, Washington, DC, National Institute of Standards and Technology
Place_Keyword: United States
Place_Keyword: US
Place:
Place_Keyword_Thesaurus:
U.S. Department of Commerce, 1987, Codes for the identification of the States, the District of Columbia and the outlying areas of the United States, and associated areas (Federal Information Processing Standard 5-2): Washington, DC, NIST
Place_Keyword: Florida
Place_Keyword: FL
Place:
Place_Keyword_Thesaurus:
Department of Commerce, 1990, Counties and Equivalent Entities of the United States, Its Possessions, and Associated Areas, FIPS 6-3, Washington, DC, National Institute of Standards and Technology
Place_Keyword: Broward County
Place_Keyword: Collier County
Place_Keyword: Miami-Dade County
Place_Keyword: Monroe County
Place_Keyword: Palm Beach County
Place:
Place_Keyword_Thesaurus: none
Place_Keyword: Central Everglades
Place_Keyword: Greater Lake Okeechobee
Place_Keyword: SW Big Cypress
Place_Keyword: WCA2
Place_Keyword: Water Conservation Area 2
Place_Keyword: WCA3
Place_Keyword: Water Conservation Area 3
Place:
Place_Keyword_Thesaurus: USGS Geographic Names Information System
Place_Keyword: Everglades National Park
Place_Keyword: Loxahatchee National Wildlife Refuge
Taxonomy:
Keywords/Taxon:
Taxonomic_Keyword_Thesaurus: none
Taxonomic_Keywords: animals
Taxonomic_System:
Classification_System/Authority:
Classification_System_Citation:
Citation_Information:
Originator:
U.S. Department of Agriculture - Agricultural Research Service (ARS)

U.S. Department of Agriculture - Natural Resources Conservation Service (NRCS) Department of the Interior - U.S. Geological Survey Department of Commerce - National Oceanic and Atmospheric Administration (NOAA) Environmental Protection Agency (EPA) Smithsonian Institution - National Museum of Natural History (NMNH)

Publication_Date: 2000
Title: Integrated Taxonomic Information System (ITIS)
Geospatial_Data_Presentation_Form: Database
Other_Citation_Details:
Retrieved from the Integrated Taxonomic Information System on-line database, <http://www.itis.gov>.
Online_Linkage: <http://www.itis.gov>
Taxonomic_Procedures:
A number of biological attributes (relative density, relative body condition, nesting effort, and nesting success) are measured and standardized methods for monitoring have been developed.
Taxonomic_Completeness:
Established survey routes of estuarine rivers and freshwater canals and marshes extending from the mangrove fringe of Everglades National Park north to Arthur R. Marshall National Wildlife Refuge will continue to be performed at night by skiff, canoe, jon boat, airboat, and truck. Night light surveys are a well-established, cost effective method for gathering the required information (Bayliss 1987, Woodward and Moore 1990). Alligator locations will continue to be recorded using GPS and field maps, and sizes of alligators will be estimated whenever possible. Environmental data including habitat type, air and water temperature, salinity, wind and wave action, and spot water levels will be recorded. Regional hydrologic data will be obtained from the SFWMD and the USGS through EDEN.

To determine demographic structure (size class and sex) structure semi-annual capture surveys will be performed using the same vehicles and locations described above. Alligators will be captured by hand, noose, dart, or tongs. Total length, snout-vent length, tail girth, and weight will be measured, and sex determined. In addition the relative condition of alligators will be determined by doing a condition factor analysis (Leslie 1997, also see CESI project Compilation of America Alligator Data Sets in South Florida for Restoration Needs completed in FY02 for specific body condition methods).

At this time, we have performed simulations using all of the available data sets (calibration 1979-95, 1995 and 2050 base 1965-95, and the restoration scenario D13-R 1965-95). We have also devised a validation regimen that will allow us to check the accuracy of the predicted output from the calibration data set by comparing nighttime spotlighting surveys along geo-referenced trails with a virtual survey performed along the same paths through the simulation output. Tests indicate that the model has a close fit to actual survey counts.

General_Taxonomic_Coverage: American Alligators are described to the species level
Taxonomic_Classification:
Taxon_Rank_Name: Kingdom
Taxon_Rank_Value: Animalia
Applicable_Common_Name: animals
Taxonomic_Classification:
Taxon_Rank_Name: Phylum
Taxon_Rank_Value: Chordata
Applicable_Common_Name: chordates
Taxonomic_Classification:
Taxon_Rank_Name: Subphylum
Taxon_Rank_Value: Vertebrata
Applicable_Common_Name: vertebrates
Taxonomic_Classification:
Taxon_Rank_Name: Class
Taxon_Rank_Value: Reptilia
Applicable_Common_Name: reptiles
Taxonomic_Classification:
Taxon_Rank_Name: Order
Taxon_Rank_Value: Crocodilia
Applicable_Common_Name: alligators
Applicable_Common_Name: crocodiles
Applicable_Common_Name: caimans
Taxonomic_Classification:
Taxon_Rank_Name: Family
Taxon_Rank_Value: Alligatoridae
Applicable_Common_Name: alligators
Taxonomic_Classification:
Taxon_Rank_Name: Genus
Taxon_Rank_Value: Alligator
Applicable_Common_Name: alligators
Taxonomic_Classification:
Taxon_Rank_Name: Species
Taxon_Rank_Value: Alligator mississippiensis
Applicable_Common_Name: American alligator
Applicable_Common_Name: Florida alligator
Access_Constraints: none
Use_Constraints: none
Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Kenneth G. Rice
Contact_Organization: U.S. Geological Survey
Contact_Address:
Address_Type: mailing address
Address: 7920 NW 71st Street
City: Gainesville
State_or_Province: FL
Postal_Code: 32653
Country: USA
Contact_Voice_Telephone: 352 264-3544
Contact_Facsimile_Telephone: 352 378-4956
Contact_Electronic_Mail_Address: krice@usgs.gov
Browse_Graphic:
Browse_Graphic_File_Name: <http://pubs.usgs.gov/fs/2004/3105/images/fig1.gif>
Browse_Graphic_File_Description: Alligator survey routes in the Everglades
Browse_Graphic_File_Type: GIF
Data_Set_Credit:
Project personnel include Chris Bugbee, Brian Jeffery, Wellington Guzman, and Mike Rochford
Cross_Reference:
Citation_Information:
Originator:
Woodward, A. R.

Moore, C. T.

Publication_Date: 1990
Title: Statewide alligator surveys: Final report
Geospatial_Data_Presentation_Form: publication
Publication_Information:
Publication_Place: Tallahassee, FL
Publisher:
Bureau of Wildlife Research, Florida Game and Freshwater Fish Commission
Cross_Reference:
Citation_Information:
Originator:
Campbell, Mark R.

Mazzotti, Frank J.

Publication_Date: 2001
Title:
Mapping Everglades Alligator Holes Using Color Infrared Aerial Photography
Geospatial_Data_Presentation_Form: publication
Series_Information:
Series_Name: Florida Scientist
Issue_Identification: v. 64, issue 2, p. 148-158
Publication_Information:
Publication_Place: Orlando, FL
Publisher: Florida Academy of Sciences
Cross_Reference:
Citation_Information:
Originator:
Mazzotti, Frank J.

Brandt, Laura A.

Publication_Date: 1994
Title:
Ecology of the American alligator in a seasonally fluctuating environment
Geospatial_Data_Presentation_Form: publication
Publication_Information:
Publication_Place: Delray Beach, FL
Publisher: St. Lucie Press
Other_Citation_Details:
in Everglades: the ecosystem and its restoration

Steven M. Davis and John C. Ogden, editors

Cross_Reference:
Citation_Information:
Originator:
Palmer, Mark R.

Gross, Louis; Rice, Kenneth G.

Publication_Date: 1998
Title:
ATLSS American Alligator Production Index Model Basic Model Description
Geospatial_Data_Presentation_Form: publication
Publication_Information:
Publication_Place: Knoxville, TN
Publisher:
The Institute for Environmental Modeling, University of Tennessee, Knoxville
Other_Citation_Details: accessed as of 8/18/2010
Online_Linkage: <http://atlss.org/gator_mod.html>
Cross_Reference:
Citation_Information:
Originator:
Rice, K. G.

Mazzotti, F. J.; Brandt, L. A.

Publication_Date: 2003
Title:
Status of the American Alligator (Alligator mississippiensis) in Southern Florida and its Role in Measuring Restoration Success in the Everglades
Geospatial_Data_Presentation_Form: publication
Publication_Information:
Publication_Place: Melbourne, FL
Publisher: Krieger Publishers
Other_Citation_Details:
in Status and Conservation of Florida Amphibians and Reptiles

W. E. Meshaka and K. J. Babbitt, editors

Cross_Reference:
Citation_Information:
Originator:
Slone, D. H.

Rice, K. G.; Allen, J. C.

Publication_Date: 2003
Title:
Model evaluates influence of Everglades restoration plan on alligator populations (Florida)
Geospatial_Data_Presentation_Form: publication
Series_Information:
Series_Name: Ecological Restoration
Issue_Identification: V. 21, n. 2
Publication_Information:
Publication_Place: Madison, WI
Publisher: University of Wisconsin Press
Cross_Reference:
Citation_Information:
Originator:
Zweig, C. L.

Mazzotti, F. J.; Brandt, L. A.; Rice, K. G.

Publication_Date: 2003
Title:
Evaluation of field measurements of the American alligator for use in porphometric studies
Geospatial_Data_Presentation_Form: publication
Series_Information:
Series_Name: Herpetological Review
Issue_Identification: V. 34, n. 1
Publication_Information:
Publication_Place: Laclede, MO
Publisher: Society for the Study of Amphibians and Reptiles
Cross_Reference:
Citation_Information:
Originator: Bayliss, P.
Publication_Date: 1987
Title:
Survey methods and monitoring within crocodile management programmes
Geospatial_Data_Presentation_Form: publication
Publication_Information:
Publication_Place: Chipping Norton, NSW, Australia
Publisher: Surrey Beatty and Sons
Other_Citation_Details:
in Wildlife Management: Crocodiles and Alligators

Webb, G. J. W., S. C. Manolis, and P. J. Whitehead (eds)

Cross_Reference:
Citation_Information:
Originator: Leslie, A. J.
Publication_Date: 1997
Title:
The ecology and physiology of the Nile crocodile, Crocodylus niloticus, in Lake St. Lucia, Kwazulu/Natal, South Africa
Geospatial_Data_Presentation_Form: publication
Publication_Information:
Publication_Place: Philadelphia, PA
Publisher: Drexel University
Other_Citation_Details: PhD dissertation

Data_Quality_Information:
Logical_Consistency_Report: not applicable
Completeness_Report: not available
Lineage:
Process_Step:
Process_Description:
Relative distribution, abundance, and demographic structure of the American alligator in relation to habitat, water levels, and salinities

The purpose of this project is to evaluate the relative distribution, abundance, and demographic structure of alligators in various habitats in relation to water levels and salinities. The relative distribution and abundance of alligators is a key indicator component of the conceptual ecosystem models for Big Cypress, marl prairie/rocky glades, ridge and slough, and mangrove transition zone ecosystems and has been identified as a performance measure in the CERP monitoring and assessment plan. Demographic data are needed for development of models to assess the potential impacts from operation of CERP projects.

During FY03, we will concentrate our work on:

1. Continued development of monitoring methods and correction factors for environmental conditions and sighting proportions. 2. Continued monitoring of South Florida’s alligator populations through night-light surveys on routes developed during FY02. Also, we will begin development of new survey routes based on the 2x2 mile cells developed for monitoring and evaluation of restoration success by RECOVER. 3. Continued alligator capture for comparison of condition through South Florida and through time.

After examining past survey data in Everglades National Park and evaluating the ability to detect change in an alligator population we believe it most effective to concentrate surveys to peak wet season and peak dry season replicate spotlight surveys along with capture surveys of alligators to assess the relative distribution, abundance, and demographic structure of the American alligator. Established survey routes of estuarine rivers and freshwater canals and marshes extending from the mangrove fringe of Everglades National Park north to Arthur R. Marshall National Wildlife Refuge will continue to be performed at night by skiff, canoe, jon boat, airboat, and truck. Alligator locations will continue to be recorded using GPS and field maps, and sizes of alligators will be estimated whenever possible. Environmental data including habitat type, air and water temperature, salinity, wind and wave action, and spot water levels will be recorded. Regional hydrologic data will be obtained from the SFWMD and the USGS.

To determine demographic structure (size class and sex) structure semi-annual capture surveys will be preformed using the same vehicles and locations described above. Alligators will be captured by hand, noose, dart, or tongs. Total length, snout-vent length, tail girth, and weight will be measured, and sex determined. In addition the relative condition of alligators will be determined by doing a condition factor analysis.

Process_Date: 2003
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Frank J. Mazzotti
Contact_Organization: University of Florida
Contact_Address:
Address_Type: mailing address
Address:
University of Florida, Fort Lauderdale Research and Education Center

3205 College Ave.

City: Davie
State_or_Province: FL
Postal_Code: 33314
Country: USA
Contact_Voice_Telephone: 954 577-6304
Contact_Electronic_Mail_Address: fjma@ufl.edu
Process_Step:
Process_Description:
Mapping and Characterizing Aquatic Refugia in Everglades National Park and Arthur R. Marshall Loxahatchee National Wildlife Refuge

Dry season refugia for aquatic animals, are assumed to be a critical component of the Everglades landscape (Craighead 1968, Mazzotti and Brandt 1994). They are an important attribute in the conceptual models being used to develop the monitoring and assessment plan for the Comprehensive Everglades Restoration Plan. The relationships among dry season refugia, aquatic fauna, wading birds, and alligators have been identified as a key uncertainty in the CERP monitoring and assessment plan. In addition, the distribution and occupancy of alligator holes has been identified as a performance measure for the marl prairie/rocky glades conceptual model. As important as aquatic refugia are imagined to be, their ecology has remained an almost completely unstudied phenomena.

The project began in FY02 in Loxahatchee NWR. We anticipate finishing the work in Loxahatchee in early FY03 and moving our work to Everglades National Park for completion during FY03.

The following subtasks have been designed to achieve the project objectives.

Mapping: Aquatic refugia will be located and mapped using a combination of aerial photography (supplied by Everglades National Park and/or Loxahatchee National Wildlife Refuge) and global position system (GPS) technology. Photographic imagery will be analyzed using a geographic information system (GIS). All GPS data will be managed using GIS.

Ecological characterization: The geography of aquatic refugia will be described using the map and GIS database completed above. Location of refugia can be categorized by position in central slough or peripheral wetland and by proximity to landscape features such as canals. Structure and function of aquatic refugia will be determined from field studies of selected holes.

Analysis of spatial patterns: With the emergence of GIS the ability to analyze spatial patterns of ecological resources has advanced significantly. State-of-the-art spatial statistics will be used to analyze the data obtained from the mapping activity.

The methods described below have proven cost effective for mapping aquatic refugia at high resolution over a large area and has been used to map alligator holes in Water Conservation Areas 2 and 3 (Campbell and Mazzotti 2001). It is important that these data be collected now, prior to major changes, so that the influences of CERP projects can be evaluated.

Alligator holes will be mapped using color infra-red (CIR) aerial photography. CIR photography will be obtained from Everglades National Park or Loxahatchee National Wildlife Refuge. Selected photographs will be professionally scanned at one meter resolution and the digital images stored on CD-ROM. Photographic prints (contact prints) of the original film also will be made.

Potential alligator holes will be located on the contact prints using a light table and magnifying lens. The alligator holes found on each image will be plotted on a 9x9 inch clear acetate overlay with a permanent marker. For each image the location of the two to four ground control points also will be plotted on the overlay. Ground control for the photos will be plotted on a clear overlay, and included with the original data set.

All image overlays will be assembled and potential alligator holes mapped. Then a second, continuous transparent overlay will be placed over the mosaiced overlays, and all alligator holes and control points retraced onto a final single sheet. The large overly will be photographically reduced and scanned into the computer using a standard flatbed scanner.

The digital image, with potential alligator holes and ground control, will be imported into an image processing software, and the coordinates (Universal Transverse Mercator ) for the ground control entered into the computer. The digital image will then be reprocessed by the software producing a complete spatially referenced image.

The spatially referenced image will then be imported into GIS software after conversion to raster image format. A point layer for the GIS then will be digitized on screen and a database for the individual points with their locations can be developed.

Other layers of information for the GIS will be created in the same manner from the photographic contact prints. These include the study area boundary, canals and levees, major airboat trails, minor airboat and buggy trails, and islands. The GIS system also will include information obtained from other sources. These data layers include the Florida Landcover vegetation layer, developed form landsat satellite imagery by the Florida Cooperative Fish and Wildlife research Unit, University of Florida, and vegetation information from other sources.

Field measurements to describe alligator holes will include structure (size, shape, substrate, and vegetation) and function (hydrology, wildlife use, and water quality).

Alligator holes will be located in the field using a GPS receiver and printed field maps of the hole from the digital imagery. At each alligator hole field measurements will proceed in the following order:

1. Photo of the alligator hole. 2. Dissolved oxygen, conductivity, pH and temperature (air and water) of the pond will be measured. 3. Wildlife sightings, including tracks, scats, alligator trails, footprints, and tail drags will be recorded throughout the survey. 4. Surrounding vegetation will be recorded onto the color infra-red field-maps. 5. Transects will be established across both the length and width the alligator hole. Transects will extend into the marsh matrix. Depth of water will be recorded with a round fiberglass measuring pole at half meter intervals. Muck depth will be measured by sinking a thin fiberglass baton down to the limestone bedrock and noting the difference on the measuring pole. Vegetation or open water will be recorded at each point.

Based on these field observation alligator holes will be separated into the following descriptive classes: origin, status, size, shape, depth, muck, and island. A description of each of these categories follows:

1. origin: natural = created by alligators; artificial = created by humans 2. status: active = inhabited by alligators; inactive = no alligators present, or signs of alligators 3. size: area of the alligator pond; small = < 20 square meters; medium = 20 - 40 square meters; large = > 40 square meters 4. shape: shape of the alligator pond; circular = width ? half the length; oval = width < half the length; irregular = any non-elliptical shape 5. depth: shallow = < 15 cm average water depth; medium = 15 - 30 cm average water depth; deep = >30 cm average water depth 6. muck: shallow = < 30 cm average muck depth; medium = 30 - 60 cm average muck depth; deep = >60 cm average muck depth 7. island: yes = an island is within 20 meters of the alligator pond; no = an island is not within 20 meters of the alligator pond

The spatial patterns of aquatic refugia will be analyzed for all located refugia and for refugia of different type and characteristics as identified in the ecological characterization above. It will be determined if holes are distributed randomly, uniformly, or clumped. In addition, the scale of the pattern will be identified. A combination of indicies of spatial patterning such as: nearest neighbor distances, Pielou’s index of dispersion, Clark and Evens’ nearest neighbor, and Ripley’s K will be used for this task. Pielou’s index and the Clark and Evens’ index are used to determine if the holes are randomly distributed, uniformly distributed, or clumped. Ripley’s K is used to examine the scale of clumping. Density maps that illustrate the concentration of holes will be produced for each area. Distance from canals or other significant features will be calculated for each hole and these data along with available data on vegetation, hydrology, topology, etc. will be used to explore the relationships between hole location and type and physical and ecological landscape features.

Process_Date: 2005
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Frank J. Mazzotti
Contact_Organization: University of Florida
Contact_Address:
Address_Type: mailing address
Address:
University of Florida, Fort Lauderdale Research and Education Center

3205 College Ave.

City: Davie
State_or_Province: FL
Postal_Code: 33314
Country: USA
Contact_Voice_Telephone: 954 577-6304
Contact_Electronic_Mail_Address: fjma@ufl.edu
Process_Step:
Process_Description:
Population-Based Simulation Modelng of American Alligator Populations in Support of CERP

An alligator population model is currently in the calibration phase for use in evaluating CERP restoration alternatives and developing performance measures. The model will require periodic updates, further calibration, and validation as new data becomes available. This data is being collected during monitoring of the alligator throughout South Florida.

Work to be done during FY2003:

The core model component is a 3-D matrix that records the density of each stage of alligator in each 500x500m spatial location (500m pixel size based on the mean adult female home range size). This structure is manipulated in its entirety with 3-D matrix operations, and interacts with survival and condition 3-D matrices, each in turn calculated for each time step based on water level, crowding, etc. Alligators either survive and grow to the next stage of development (SD), survive but not grow (SND), or die. The proportion of each stage that falls into the three categories depends on water levels and alligator condition throughout the year, and the density of adult alligators at each spatial location:

Adult female alligators produce offspring at each spatial location, depending on water levels during the nesting period, habitat type, and the age and condition of the female over the previous season. The nesting potential of each cell is predicted by the ATLSS American Alligator Production Index which incorporates local habitat data and hydrological dynamics to predict the probability of producing nests and offspring successfully in each cell, if a healthy female is present.

To disperse alligators, we use a discrete spatial convolution method . This is similar to a 'blur filter' used by many image-processing computer programs, and is a process that takes the contents of a cell and redistributes it according to a dispersal kernel). The dispersal kernels are sized according to average dispersal distance of each alligator stage. The subadult stage is most mobile, while adults and hatchlings are more sedentary.

Output of the model is a 3-D alligator density matrix, with space (x and y) along two axes, and the stage classes along the third axis. Also included are a 'running average' of the historical health and survival rates of each stage in each cell. This construct is easily summed for total alligator population, or subsampled to check for corroboration with field data. Instantaneous densities, and local rates-of-change can be calculated from this model.

We will concentrate our work on: 1. Developing 'virtual' night-light and nesting survey routes that correspond with NPS SRF, USFWS alligator monitoring. This will allow calibration and validation of the current model and checks on future model modifications. 2. Further modification of the model to incorporate new monitoring data. 3. Providing model runs and interpretation for CERP projects.

Process_Date: 2005
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Kenneth G. Rice
Contact_Organization: U.S. Geological Survey
Contact_Address:
Address_Type: mailing address
Address: 7920 NW 71st Street
City: Gainesville
State_or_Province: FL
Postal_Code: 32653
Country: USA
Contact_Voice_Telephone: 352 264-3544
Contact_Facsimile_Telephone: 352 378-4956
Contact_Electronic_Mail_Address: krice@usgs.gov
Process_Step:
Process_Description:
Work planned for FY 2004 includes:

1. Relative distribution, abundance, and demographic structure of the American alligator in relation to habitat, water levels, and salinities:

a. Continue monitoring of alligator populations throughout the Greater Everglades. b. Complete estimates of correction factors for environmental conditions and detection probabilities. c. Continue monitoring of alligator condition throughout the Greater Everglades. d. Provide data essential for validation of the ATLSS alligator population model.

To determine demographic structure (size class and sex) semi-annual capture surveys will continue to be performed using the skiffs, jon boats, airboats, and trucks at night along estuarine rivers and freshwater canals and marshes extending fromt he mangrove fringe of Everglades National Park north to Arthur R. Marshall National Wildlife Refuge. Alligators will be captured by hand, noose, dart, or tongs. Total length, snout-vent length, tail girth, and weight will be measured, and sex determined. In addition the relative condition of alligators will be determined by doing a condition factor analysis.

2. Mapping and Characterizing Aquatic Refugia in Everglades National Park and Arthur R. Marshall Loxahatchee National Wildlife Refuge

Mapping: Aquatic refugia in Everglades National Park will be located and mapped using a combination of aerial photography (supplied by Everglades National Park and/or Loxahatchee National Wildlife Refuge) and global position system (GPS) technology. Photographic imagery will be analyzed using a geographic information system (GIS). All GPS data will be managed using GIS.

Ecological characterization: Location of refugia can be categorized by position in central slough or peripheral wetland and by proximity to landscape features such as canals. Structure and function of aquatic refugia will be determined from field studies of selected holes.

Analysis of spatial patterns: State-of-the-art spatial statistics will be used to analyze the data.

3. Population-Based Simulation Modeling of American Alligator Populations in Support of CERP

a. Continue refining the alligator model, to continue with validation as new data are released, and to actively seek out and gather data from any new scenarios that are developed in 2003. b. Simulate these hydrologic scenarios and provide results to project planners. c. Develop an intuitive graphical user interface for the model and release it to CERP managers.

At this time, we have performed simulations using all of the available data sets (calibration 1979-95, 1995 and 2050 base 1965-95, and the restoration scenario D13-R 1965-95). We have also devised a validation regimen that will allow us to check the accuracy of the predicted output from the calibration data set by comparing nighttime spotlighting surveys along georeferenced trails with a virtual survey performed along the same paths through the simulation output. Preliminary tests indicate that the model has a close fit to actual survey counts. The calibration data have only been released through 1995, which is approximately the same time that comprehensive spotlight surveys were started, so we have a very limited overlap from which to draw validation data. In the near future, these data should be released through 2002, at which time we will be able to run a more comprehensive set of comparisons. In addition, new project scenarios have been proposed, and when the water management simulation data is released, there will be a need for alligator population responses to those projects.

Process_Date: 2005
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Kenneth G. Rice
Contact_Organization: U.S. Geological Survey
Contact_Address:
Address_Type: mailing address
Address: 7920 NW 71st Street
City: Gainesville
State_or_Province: FL
Postal_Code: 32653
Country: USA
Contact_Voice_Telephone: 352 264-3544
Contact_Facsimile_Telephone: 352 378-4956
Contact_Electronic_Mail_Address: krice@usgs.gov
Process_Step:
Process_Description:
Relative distribution, abundance, and demographic structure of the American alligator in relation to habitat, water levels, and salinities.

Work planned for 2008 includes:

1. Continued development of monitoring methods and correction factors for environmental conditions and sighting proportions during alligator survey. 2. Continue monitoring of alligator population density, body condition, and size distribution throughout the Greater Everglades and further develop relationships to hydrologic condition including interaction with the Everglades Depth Estimation Network (EDEN) funded by ACOE and USGS-PES. 3. Continue monitoring of American crocodile juvenile growth and hatchling survival throughout south Florida. 4. Complete research on detection probabilities of alligators during night-light survey including double-observer surveys, distance sampling, and radio-telemetry of submergence rates. This has resulted in 1 MS Thesis completed, 1 MS Thesis to be completed in FY08, as well as several publications. 5. Continue development of a monitoring program of alligator hole occupancy throughout the Everglades system. 6. Begin new radio-telemetry project investigating movement patterns and habitat use of subadult animals to provide paramater estimates to models. This objective was not initiated in FY07 as proposed due to problems with securing final transmitters. 7. Provide data essential for validation of the ATLSS alligator population model. 8. Perform trend analyses of night counts and body condition on routes throughout the Everglades on an annual basis for the MAP assessment update.

Process_Date: Not complete
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Kenneth G. Rice
Contact_Organization: U.S. Geological Survey
Contact_Address:
Address_Type: mailing address
Address: 7920 NW 71st Street
City: Gainesville
State_or_Province: FL
Postal_Code: 32653
Country: USA
Contact_Voice_Telephone: 352 264-3544
Contact_Facsimile_Telephone: 352 378-4956
Contact_Electronic_Mail_Address: krice@usgs.gov
Process_Step:
Process_Description:
Population-Based Simulation Modeling of American Alligator Populations in Support of CERP

Work plannded for 2008 includes:

1. Continue validation and updating of models using "virtual" night-light and nesting survey routes that correspond with NPS SRF, USFWS, and our previous alligator monitoring. 2. Continue updates to the ATLSS alligator production index with new relationships developed using ENP nesting data. 3. Continue refining the alligator model, to continue with validation as new data are released, and to actively seek out and gather data from any new scenarios that are developed. 4. Simulate these hydrologic scenarios and provide results to CERP project planners and managers.

At this time, we have performed simulations using all of the available data sets (calibration 1979-95, 1995 and 2050 base 1965-95, and the restoration scenario D13-R 1965-95). We have also devised a validation regimen that will allow us to check the accuracy of the predicted output from the calibration data set by comparing nighttime spotlighting surveys along geo-referenced trails with a virtual survey performed along the same paths through the simulation output. Tests indicate that the model has a close fit to actual survey counts.

The calibration data have only been provided in the format required for our models through 1995, which is approximately the same time that comprehensive spotlight surveys were started, so we have a very limited overlap from which to draw validation data. In the near future, these data should be released through 2002, at which time we will be able to run a more comprehensive set of comparisons. In addition, new project scenarios have been proposed, and when the water management simulation data is released, there will be a need for alligator population responses to those projects.

The core model component is a 3-D matrix that records the density of each stage of alligator in each 500x500m spatial location (500m pixel size based on the mean adult female home range size). This structure is manipulated in its entirety with 3-D matrix operations, and interacts with survival and condition 3-D matrices, each in turn calculated for each time step based on water level, crowding, etc. Alligators can survive and grow to the next stage of development (SD), survive but not grow (SND), or die. The proportion of each stage that falls into the three categories depends on water levels and alligator condition throughout the year, and the density of adult alligators at each spatial location. See the FY2008 workplan Task 2 for the formulas used in the calculations.

The ATLSS (Across Trophic Level System Simulation) project is a long-term, large-scale predictive model of the effects of planned restoration activities in the Florida Everglades on animal and plant species living there. For the last 3 years, we have been writing and implementing a module for ATLSS that simulates alligator populations in the Everglades. We have used this model and data from the South Florida Water Management District, the Florida GAP project, and ATLSS to describe the likely population densities that would occur across the Everglades landscape under various scenarios.

Process_Date: Not complete
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Kenneth G. Rice
Contact_Organization: U.S. Geological Survey
Contact_Address:
Address_Type: mailing address
Address: 7920 NW 71st Street
City: Gainesville
State_or_Province: FL
Postal_Code: 32653
Country: USA
Contact_Voice_Telephone: 352 264-3544
Contact_Facsimile_Telephone: 352 378-4956
Contact_Electronic_Mail_Address: krice@usgs.gov

Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Planar:
Grid_Coordinate_System:
Grid_Coordinate_System_Name: Universal Transverse Mercator
Universal_Transverse_Mercator:
UTM_Zone_Number: 17
Transverse_Mercator:
Scale_Factor_at_Central_Meridian: 0.9996
Longitude_of_Central_Meridian: -81
Latitude_of_Projection_Origin: 0
False_Easting: 500000
False_Northing: 0
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: Coordinate Pair
Coordinate_Representation:
Abscissa_Resolution: 0.01
Ordinate_Resolution: 0.01
Planar_Distance_Units: meters
Geodetic_Model:
Horizontal_Datum_Name: North American Datum of 1983
Ellipsoid_Name: Geodetic Reference System 80
Semi-major_Axis: 6378137
Denominator_of_Flattening_Ratio: 298.257

Distribution_Information:
Distributor:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Kenneth G. Rice
Contact_Organization: U.S. Geological Survey
Contact_Address:
Address_Type: mailing address
Address: 7920 NW 71st Street
City: Gainesville
State_or_Province: FL
Postal_Code: 32653
Country: USA
Contact_Voice_Telephone: 352 264-3544
Contact_Facsimile_Telephone: 352 378-4956
Contact_Electronic_Mail_Address: krice@usgs.gov
Resource_Description: American alligator data
Distribution_Liability: No warrantees are implied or explicit for the data
Standard_Order_Process:
Non-digital_Form: model support data
Fees: none
Ordering_Instructions:
Contact Kenneth G. Rice for information and data from this project.

Metadata_Reference_Information:
Metadata_Date: 20110504
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Heather Henkel
Contact_Organization: U.S. Geological Survey
Contact_Address:
Address_Type: mailing and physical address
Address: 600 Fourth Street South
City: St. Petersburg
State_or_Province: FL
Postal_Code: 33701
Country: USA
Contact_Voice_Telephone: 727 803-8747 ext 3028
Contact_Facsimile_Telephone: 727 803-2030
Contact_Electronic_Mail_Address: sofia-metadata@usgs.gov
Metadata_Standard_Name:
Content Standard for Digital Geospatial Metadata Part 1: Biological Data Profile
Metadata_Standard_Version: FGDC-STD-001.1-1999
Metadata_Access_Constraints: none
Metadata_Use_Constraints:
This metadata record may have been copied from the SOFIA website and may not be the most recent version. Please check <https://sofia.usgs.gov/metadata> to be sure you have the most recent version.

This page is <https://sofia.usgs.gov/metadata/sflwww/rice_alligators_04.html>

U.S. Department of the Interior, U.S. Geological Survey
Comments and suggestions? Contact: Heather Henkel - Webmaster
Generated by mp version 2.8.18 on Wed May 04 10:46:27 2011