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Project Work Plan

Greater Everglades Science Program: Place-Based Studies

Project Work Plan FY 2003

A. GENERAL INFORMATION:

Project Title: Predicting effects of hydrologic restoration on manatees along the southwest coast of Florida
Project start date: 2000 Project end date: 2005
Project Funding: U. S. Geological Survey Place-Based Program
Principal Investigator: James P. Reid
Email address: Jim_Reid@usgs.gov
Phone: 352-372-2571 ext. 15 Fax: 352-374-8080
Mail address: Florida Caribbean Science Center, US Geological Survey, 412 NE 16th Ave., Room 250 Gainesville, FL 32601

Other Investigator(s): Dean E. Easton
Email address: Dean_Easton@usgs.gov
Phone: 352-372-2571 ext. 11 Fax: 352-374-8080
Mail address: Florida Caribbean Science Center, US Geological Survey, 412 NE 16th Ave., Room 250 Gainesville, FL 32601

Other Investigator(s): Bradley M. Stith
Email address: Bradley_Stith@usgs.gov
Phone: 352-372-2571 ext. 24 Fax: 352-374-8080
Mail address: Florida Caribbean Science Center, US Geological Survey, 412 NE 16th Ave., Room 250 Gainesville, FL 32601

Other Investigator(s): Susan M. Butler
Email address: Susan_Butler@usgs.gov
Phone: 352-372-2571 ext. 22 Fax: 352-374-8080
Mail address: Florida Caribbean Science Center, US Geological Survey, 412 NE 16th Ave., Room 250 Gainesville, FL 32601

Other Investigator(s): Lynn W. Lefebvre
Email address: Lynn_Lefebvre@usgs.gov
Phone: 352-372-2571 ext. 18 Fax: 352-374-8080
Mail address: Florida Caribbean Science Center, US Geological Survey, 412 NE 16th Ave., Room 250 Gainesville, FL 32601

Project Summary: This project focuses on West Indian manatee (Trichechus manatus latirostris) distribution, habitat use and movement patterns to address questions important to understanding the ecology of three estuarine communities in southwest Florida - submerged aquatic vegetation, mangroves, and brackish marshes. A large proportion of the southwest Florida manatee population occurs throughout the Everglades National Park (ENP) and north into the Ten Thousand Islands (TTI). Our on-going research in this area has shown that manatees make frequent movements up tidal creeks to obtain freshwater for drinking and to find thermal refugia during cold weather. Alteration of the freshwater and estuarine ecosystems associated with restoration of the Everglades and Southern Golden Gate Estates is likely to affect this manatee population. In addition, because manatees feed primarily on submerged aquatic vegetation (SAV) in estuarine and near-offshore areas, they are excellent barometers of the health of a range of communities. By providing baseline data on these communities, this research will be important to future monitoring of the effects of the South Florida hydrological restoration efforts. In so doing, this research addresses the most basic major issue i.e., "How will hydrological changes in quantity and quality of freshwater impact downstream aquatic habitats?" We hypothesize that manatee distribution, relative abundance, habitat use, and movement patterns will change because of altered water management regimes and resulting changes in near shore salinity. Aerial surveys (Task 1) and telemetry data from tagged manatees (Task 2) provide a valuable means of documenting the response of manatees to natural and human-induced fluctuations in freshwater inflow. This information, combined with water quality data obtained from monitoring stations, will be incorporated into the manatee ATLSS model (Task 3), which will be used to better understand and predict manatee response to different restoration scenarios.

Project Objectives and Strategy: The major objectives of the study are to determine relative abundance, distribution, movements, and habitat use of manatees associated with coastal waters and rivers, and to develop an individual-based ATLSS model to predict manatee response to changes in hydrology achieved by the Southern Golden Gate Estates (SGGE) project specifically, and more broadly by the Comprehensive Everglades Restoration Plan. Previous work focused on the TTI/SGGE restoration area; we propose to direct future efforts to tracking manatees using the southwest portion of ENP. Data for this project is collected via: strip-transect aerial surveys, satellite telemetry, and tracking of individuals using a specially-designed Global Positioning System (GPS) tag. Data will be used in developing the predictive manatee model (Task 3), which will integrate with the TIME model. We also anticipate integrating our data and model efforts with a proposed project entitled: "Integration of tidal-river bathymetric survey, hydrodynamic model, and manatee ATLSS model in southwest Everglades" (R. Schaffranek, P.I.).

Potential Impacts and Major Products: The manatee model developed as part of this research will be a valuable component of the ongoing ATLSS modeling effort to judge and compare restoration scenarios. Model output will be useful to the U. S. Army Corps of Engineers, the South Florida Water Management District, and other agencies involved in implementation of the Comprehensive Everglades Restoration Plan. This project will also fill a significant void in our knowledge of manatee ecology, as there is very little existing information on manatee population biology and habitat use in southwestern Florida. Recent advances in tracking technology have made this project logistically feasible and cost-effective.

Products from this work include scientific publications, fact sheets, journals articles, and spatial databases. Linkages to other projects/databases include TIME model, ATLSS model, and the associated PBS projects: "Impacts of Hydrological Restoration on Three Estuarine Communities of the Southwest Florida Coast and on Associated Fauna" (Carol McIvor) (http://sofia.usgs.gov/projects/impacts_est/); "Southwest Florida Coastal and Wetland Systems Monitoring Project" (E. Patino) (http://sofia.usgs.gov/projects/sys_monitor/)

Additional information on "Predicting Effects of Hydrologic Restoration on Manatees along the Southwest Coast of Florida" is available on the Sofia website: http://sofia.usgs.gov/projects/manatees/

Collaborators: U.S. Fish and Wildlife Service - Ten Thousand Islands National Wildlife Refuge, the National Park Service - Everglades National Park, Big Cypress National Preserve, Florida Fish and Wildlife Conservation Commission - Florida Marine Research Institute, Rookery Bay National Estuarine Research Reserve, Mote Marine Laboratory, Marine Mammal Commission, and Cincinnati Zoo

Clients: U.S. Fish and Wildlife Service, U. S. Army Corps of Engineers, South Florida Water Management District, National Park Service - Everglades National Park.

B. WORK PLAN

Title of Task 1: Strip Transect Aerial Surveys To Determine Trends In Manatee Distribution And Abundance
Task Funding: PBS, FWS
Task Leaders: Dean E. Easton
Phone: 352-372-2571 ext. 11
Fax: 352-374-8080
Task Status (proposed or active): active
Task priority: High
Task Personnel: Dean Easton, Terry Doyle (FWS), Lynn Lefebvre

Task Summary and Objectives: The overall objective of this research is to determine if manatee density and distribution change as a result of hydrologic restoration efforts in southwest Florida. A pilot study was conducted on the use of strip-transect aerial surveys to estimate manatee population size in the Ten Thousand Islands region of southwest Florida. Six transect surveys were conducted during July-October 2000. We determined that this approach could provide a reasonable and statistically sound estimate of manatee population trend in the region. Funding for the first year of this project was provided by the FWS/USGS Resource Partnership Program. During FY01, we modified the flight paths to provide a better representation of habitat features within the transect strips. Eight surveys were conducted in July and August 2001. Population estimates for the area 99 + 27 (0 + S.E.) in 2000 (n=5 flights) and 126 + 19 in 2001 (8 flights). Terry J. Doyle, Ten Thousand Islands National Wildlife Refuge, was the primary observer in all surveys. Data from these surveys may also play a role in validating parameters in the individual-based models described in Task 3.

Work to be undertaken during the proposal year and a description of the methods and procedures: Eight surveys will be conducted during June, July, and August of 2002 and 2003. The survey design is similar to that described by Miller et al. (1998). We established 30 parallel transects, 1 km apart, with a survey strip width of approximately 250 m. Transects are oriented perpendicular to shore, between Cape Romano and the Turner River, and are designed to sample the area from inshore bays to the offshore side of outermost islands. Transect lengths range from 3.4 to 8.4 km; water area surveyed ranged from 0.79 to 1.53 km_ per transect. Manatee locations are plotted on topographic maps, and flight paths are recorded on a Trimble Basic Plus GPS. Surveys are conducted from a Cessna 172 at an altitude of 153 m, traveling at approximately 120-140 km per h. Perception bias, which occurs when some of the manatees visible within a strip transect are missed by an observer, is estimated by applying a Petersen mark-recapture model to counts made by two observers (Pollock and Kendall 1987, Marsh and Sinclair 1989). We are using TRENDS software to assess the potential for detecting statistically significant population trends (Gerrodette 1993). Based on preliminary results, we determined that a minimum of eight surveys per year for a minimum of 4 years is required to detect an annual rate of change of 10% per year. Further descriptions of methods and procedures can be seen at the following web site: http://www.fcsc.usgs.gov/posters/Manatee/Manatee_Aerial_Surveys/manatee_aerial_surveys.html (now http://cars.er.usgs.gov/posters/Manatee/Manatee_Aerial_Surveys/manatee_aerial_surveys.html)

Planned Outreach: Project presentations are planned for the 2003 GEER Conference; Project summary, annual report, and presentations for Sofia website; USGS Fact Sheet for manatee/restoration effort.

Title of Task 2: Radio Tracking Manatees to Assess the Impact of Hydrologic Changes in Southwest Florida
Task Funding: PBS
Task Leaders: James P. Reid
Phone: 352-372-2571 ext. 15
Fax: 352-374-8080
Task Status (proposed or active): active
Task priority: High
Task Personnel: Jim Reid, Susan Butler, Dean Easton, Skip Snow (ENP)

Task Summary and Objectives: The radio-tracking task provides data critical for documenting the pre-restoration use of habitat by manatees within the region affected by the SGGE restoration. These data are essential for validating parameters in the individual-based model described in task 3. During the initial phase of this study, three rehabilitated adult manatees were tagged and released in July 2000. Eight more manatees were captured and radio-tagged at Port of the Islands in February and March 2001. Two others tagged by Mote Marine Lab near Charlotte Harbor and moved into the Ten Thousand Islands during summer 2001. During January 2002, five more manatees were captured and radio-tagged at Port of the Islands, bringing the total number of manatees tagged and tracked in this study to 20 individuals. In addition to the Argos satellite-monitored tags, we have opportunistically attached a GPS tag to six manatees. Preliminary analysis of movement patterns suggest that manatees in this region rely on existing freshwater sources, usually traveling between offshore seagrass beds and these inshore freshwater sites every 3-5 days. Individual movements are linked to a network of seagrass beds, which is revealed by manatee locations during GPS tag deployments. Two of the males tracked in this study traveled to areas more than 100 km north of the Ten Thousand Islands. Most remained within the study area, however, providing the first detailed movement data collected across seasons from wild manatees in the region.

Work to be undertaken during the proposal year and a description of the methods and procedures: We have relied on two types of technologies to acquire geographic locations from tagged manatees. All tagged manatees are fitted with satellite-based Argos transmitters, which provide approximately four location fixes per 24-hour period, and have a serviceable battery life of six months. The GPS tag provides locations which are much more accurate than the Argos data (approx. 30 m vs. >150 m) every 15-30 minutes, but the battery life expectancy is much shorter (8 weeks vs. 6 months). In combination, the Argos data provides region-wide, long-term coverage suitable for revealing general patterns of habitat use, while the GPS data shows fine details of travel pathways and time spent in specific areas. Four newly developed Argos-linked GPS tags have been acquired which will be employed in FY03 and 04. This tag relays GPS locations as sensor data through the Argos satellite link, enabling detailed tracking data to be acquired remotely. Location data are formatted in SAS for error checking, analyses, and display in ArcView. Databases are correlated with temperature, salinity, and tidal data collected throughout the region.

Further descriptions of methods and procedures can be seen at the following web sites:
http://www.fcsc.usgs.gov/posters/Manatee/Radio_Tracking_Manatees/radio_tracking_manatees.html (now http://cars.er.usgs.gov/posters/Manatee/Radio_Tracking_Manatees/radio_tracking_manatees.html)

http://www.fcsc.usgs.gov/posters/Manatee/GPS_Tag_for_Sirenians/gps_tag_for_sirenians.html (now http://cars.er.usgs.gov/posters/Manatee/GPS_Tag_for_Sirenians/gps_tag_for_sirenians.html)

Field efforts planned for FY03 and FY04 include tagging manatees in the southern portion of ENP. Manatee movement and habitat use data collected from Whitewater Bay to Lostmans River will be integrated with PBS models and associated field projects in this region. Remote and field-based tracking has enabled documentation of manatee use patterns associated with near shore habitats. These findings are relevant for determination of submerged aquatic vegetation planned for the PBS project "Impacts of Hydrological Restoration on Three Estuarine Communities of the Southwest Florida Coast and on Associated Fauna" (Carol McIvor) (http://sofia.usgs.gov/projects/impacts_est/). Collaboration with this project is planned to establish baseline data on the patterns of distribution and abundance of submerged aquatic vegetation in the TTI and ENP.

Planned Outreach: Detailed tracking and field data are required for Task 3, ATLSS manatee model integration. Data sharing is planned with Everglades National Park for resource management needs. Project presentations are planned for 2003 GEER Conference; Project summary, annual report, and presentations for Sofia website; USGS Fact Sheet for manatee/restoration effort.

Title of Task 3: Development of an Individual-based ATLSS Model for Manatees to Evaluate the Impact of Hydrologic Change in Estuaries of Southwestern Florida
Task Leaders: Bradley M. Stith
Phone: 352-372-2571 ext. 24
Fax: 352-374-8080
Task Status (proposed or active): active
Task priority: High
Task Personnel: Bradley M. Stith, Jim Reid, Dean Easton

Task Summary and Objectives: We are developing a spatially-explicit, individual-based ATLSS model for manatees to better understand how changes in hydrology associated with restoration of SGGE and the Everglades may affect the distribution and abundance of manatees. Telemetry data and aerial surveys have demonstrated that manatees make regular use of many of the tidal rivers and streams within the study area, primarily as a source of drinking water and as thermal refugia during cold weather. To date, all 20 manatees we have tracked show a similar pattern of regular movement between near shore seagrass beds and sources of freshwater up various rivers, creeks, and canals. Our task is to use the telemetry data and water quality information to explain the movement patterns of manatees, and to incorporate these insights into the individual-based manatee model to properly simulate these movements and the response of manatees to alterations in hydrology.

Work to be undertaken during the proposal year and a description of the methods and procedures: Work to be undertaken includes two major tasks: 1) analysis of manatee telemetry data obtained from Task 2 to support the development and parameterization of the individual-based model, and 2) development of the model in preparation to evaluate different restoration scenarios. The data analysis task involves using GIS techniques to analyze the telemetry data and characterize manatee behavior, including habitat use, movement patterns, time budget, and home range size. Salinity, water temperature, water depth, and other environmental data obtained from water quality monitoring stations in the study area likely are important factors influencing the behavior of manatees. We will develop software routines to embed water quality data into the telemetry data at the appropriate time intervals, and analyze these data with multivariate statistics to investigate the importance of various factors to manatee behavior.

Development of the individual-based manatee model will focus on adding several new behavioral components to the model. A major new component will simulate manatee behavior within a Monte Carlo Markov Chain framework to model the transition of manatees between different behavioral states (e.g. feeding, drinking). Telemetry data and field observations provide valuable information that will be used to develop transition matrices that determine how much time animals engage in specific types of behavior, and how frequently they shift from one behavior to another. Another component will simulate different movement speeds associated with different behavioral activities, using distributions developed from the telemetry data. A third component will establish the home ranges of individual animals during the simulation. These home ranges will reflect the observed distribution of home ranges, with constraints added that each animal will inherit part of its range from it's mother, and each home range will include freshwater and seagrass areas. A fourth component will simulate adaptive learning in manatees, with emphasis on how they respond to positive or negative reinforcement when they are searching for freshwater. Initially, a variety of simple animal learning models developed for laboratory maze studies will be evaluated within the model. Telemetry and salinity data from this region and elsewhere around the state will provide some insights into this issue, but additional telemetry data (especially GPS) likely will be needed to reduce the uncertainty associated with this issue. As additional data is collected, the model can be refined to incorporate new insights provided by the survey and telemetry data and the response of manatees to natural environmental fluctuations and human-induced alterations.

Further descriptions of methods and procedures can be seen at the following web sites:
www.fcsc.usgs.gov/posters/posters_pending_approval/Agent_Based_Manatee_Model/agent_based_manatee_model.html (now http://cars.er.usgs.gov/posters/Manatee/Agent_Based_Manatee_Model/agent_based_manatee_model.html)

www.fcsc.usgs.gov/posters/Manatee/Modeling_Manatee_Movements/modeling_manatee_movements.html (now http://cars.er.usgs.gov/posters/Manatee/Modeling_Manatee_Movements/modeling_manatee_movements.html)

Water quality data will be obtained from several sources, including the USGS PBS project "Southwest Florida Coastal and Wetland Systems Monitoring Project" (E. Patino) (http://sofia.usgs.gov/projects/sys_monitor/)

Planned Outreach: Project presentations are planned for the 2003 GEER Conference; project summary, annual report, and presentations for Sofia website; USGS Fact Sheet; article in Journal of Ecological Modeling.


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