Cooperative Fish and Wildlife Research Units Program: Florida
Education, Research and Technical Assistance for Managing Our Natural Resources

Florida Project

Southwestern and northwestern pond turtle viability analysis to support a species status assessment

January 2021 - July 2023


Participating Agencies

  • USGS National Grants Branch

Species status assessments (SSA) are the new framework that the US Fish and Wildlife Service uses to compile, organize, conduct scientific analyses to support species conservation decisions under the ESA. SSAs entail three primary components, an ecological needs description, a current status assessment, and a future status prediction. The ecological needs and current-status assessment often entail reviewing existing literature and some analysis of existing, available data, whereas the future status requires some form of a predictive model. For some species, population projections could be as simple as categorical condition tables, while more complicated models such as stochastic demographic matrix models could be used to simulate alternative future environmental conditions under multiple scenarios.

Western pond turtles were recently split into two species the southwestern pond turtle and the northwestern pond turtles. Both species have exhibited substantial population declines and range contractions in recent decades. The causes of the declines are varied but include habitat loss, the introduction of exotic plant and wildlife species, and disease. The USFWS was petitioned to list the species, and the Service needs to complete an SSA, including a future status assessment to address the petition and make a classification determination. Western pond turtles, especially the southwestern species, have been the subject of substantial monitoring and research effort in recent years, and substantial datasets might be available to the USFWS to build predictive models for the SSA. By estimating trends in recent decades or demographic rates from these available data and associating these parameters with environmental covariates, we propose establishing a defendable framework for predicting future status.

Our work will endeavor to support SSA development, focusing on predicting future status (i.e., future redundancy and resiliency). The specific methods for accomplishing this goal will depend on the types of data available to the SSA core team; however, in general, we envision a two-step process. First, we will work with the FWS and species experts to elicit conceptual models of the species population and ecological dynamics, and second, we will use the results of those elicitations to design projection models for the two species and implement scenarios. This approach largely follows our work with SSA core teams on various species, including Eastern Black Rail, Alligator Snapping Turtle, and Sonora Desert Tortoise. We will work with the SSA core team to design scenarios to simulate varied possible future conditions allowing us to incorporate uncertainty in future system states along with uncertainty and variation in population dynamics.

Our project objectives will focus on:
Develop a predictive population model for each species of pond turtle to assess the future status of the species with respect to resiliency and redundancy; incorporate multiple scenarios into the simulation model to assess the probable effects of continuing threats and emerging threats (e.g., climate change, etc.) on future status.

Research Publications Publication Date
Gregory KM, Darst C, Lantz S M, Powellson K , McGowan CP. 2024. Effects of drought, invasive species, and habitat loss on future extinction risk of two species of imperiled freshwater turtle, Climate Change Ecology. January 2024