Grantee Research Project Results

2004 Progress Report: Evaluating Multiple Stressors in Loggerhead Sea Turtles: Developing A Two-Sex Spatially Explicit Model

EPA Grant Number: R829094
Title: Evaluating Multiple Stressors in Loggerhead Sea Turtles: Developing A Two-Sex Spatially Explicit Model
Investigators: Wyneken, Jeanette , Crowder, Larry B. , Snover, Melissa , Epperly, Sheryan
Current Investigators: Wyneken, Jeanette , Crowder, Larry B. , Epperly, Sheryan
Institution: Florida Atlantic University - Boca Raton , National Marine Fisheries Service , University of California - Santa Cruz , Duke University
Current Institution: Florida Atlantic University - Boca Raton , Duke University , National Marine Fisheries Service
EPA Project Officer: Packard, Benjamin H
Project Period: November 15, 2001 through November 14, 2004 (Extended to November 14, 2005)
Project Period Covered by this Report: November 15, 2003 through November 14, 2004
Project Amount: $349,421
RFA: Wildlife Risk Assessment (2001) RFA Text | Recipients Lists
Research Category: Aquatic Ecosystems , Biology/Life Sciences , Ecological Indicators/Assessment/Restoration

Objective:

The objective of this research project is to integrate the effects of multiple stressors into population models to evaluate and advance contemporary management options for species conservation. We study loggerhead sea turtles, a species for which we can integrate temporarily and spatially specific data on males and females into a two-sex model.

Progress Summary:

During the past year, we continued data collection on spatial and temporal differences in loggerhead turtle sex ratios, assessed predation risks in waters adjacent to index nesting beach sites, and worked to update our conceptual model to better reflect what we know about spatial differences in loggerhead turtle life histories. We just completed a spatially and temporally specific assessment of hatchling predation risks for the Florida subpopulation. Completion of posthatchling loggerhead growth data in Year 2 of the project enabled us to update the durations (temporal exposures) of environmental stressors in our model. To date, we are reevaluating whether male and female posthatchlings experience stressors differently.

Management alternatives frequently only address a particular life stage, sex, habitat or spatial location, so adding our results to assessments of the integrated population-level response and consideration of management trade-offs requires a new generation of population models. Our conceptual approach to wildlife risk assessment for loggerhead turtles now is under consideration as a foundation for examining leatherback turtles and may be extended to other migratory, long-lived species.

(A) Preparing To Track Hatchlings Offshore; and (B) Proportion of Hatchlings Predated During Early, Middle, and Late Subseasons at All Sampling Locations

Figure 1. (A) Preparing To Track Hatchlings Offshore; and (B) Proportion of Hatchlings Predated During Early, Middle, and Late Subseasons at All Sampling Locations

Future Activities:

The remaining activities include completing data transfer from beach managers who promised historical data quantifying daily hatchling production, as well as working with mark and recapture data to use in our model. We also will complete analyses of predation results and the second year of sex ratio data collection for the remaining Florida sites to modify estimates of male and female hatchling production (year 1 in the life history tables). We will update the conceptual model and apply the new data as appropriate.

Journal Articles:

No journal articles submitted with this report: View all 50 publications for this project

Supplemental Keywords:

animals, reptiles, population biology, habitat degradation, indicators, temperature dependent sex determination, matrix population models, mark-recapture, aquatic, marine sciences, Mid-Atlantic, zoology, toxics, sex, ecological effects,, RFA, Ecosystem Protection/Environmental Exposure & Risk, Scientific Discipline, Economic, Social, & Behavioral Science Research Program, Environmental Statistics, Ecological Indicators, Ecological Risk Assessment, Ecosystem Protection, Zoology, Ecosystem/Assessment/Indicators, exploratory research environmental biology, wildlife, Monitoring/Modeling, Ecological Effects - Environmental Exposure & Risk, Toxicology, Ecology and Ecosystems, multiple stressors, Wildlife Risk Assessment, loggerhead sea turtles, stressors, stress effects on wildlife populations, risk assessment, demographic data, two-sex spatially explicit model, population, sensitive population, wildlife populations, spatial demographic model, spatial distribution, ecological exposure, contaminants, predicting risk

Relevant Websites:

http://www.fau.edu/webcast/state/statewebcast.html Exit

Progress and Final Reports:

Original Abstract

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.