AUTHORS: Elizabeth M. Lang* – Department of Natural Resource Ecology and Management, Iowa State University
Dr. Stephen J. Dinsmore – Department of Natural Resource Ecology and Management, Iowa State University
Dr. Anna M. Tucker – U.S. Geological Survey, Iowa Cooperative Fish and Wildlife Research Unit, Iowa State University
Dr. Karen E. Kinkead – Iowa Department of Natural Resources
ABSTRACT: Blanding’s turtles (Emydoidea blandingii) are declining throughout their range due to habitat fragmentation, road mortality, and nest depredation. They have high adult and juvenile survival and varying hatchling survival and fecundity rates. In Iowa, there is little knowledge about current vital rates among Blanding’s populations, so land managers do not know which management actions will be most effective to reverse declines. Determining the outcomes of conservation is vital to land managers to plan efficiently and cost-effectively. To bridge this knowledge gap, we monitored six Blanding’s populations from June 2020 to August 2024. These projects offer preliminary vital rates that we used to model population viability under several management scenarios. We developed an age-based matrix model and conducted a literature review to parameterize the model. When using vital rates from published studies we modeled an Iowa population that is declining slowly (λ = 0.98). In Iowa, there is a concern about small, isolated populations, lower hatchling survival, and lower fecundity rates than those noted in other studies. We developed multiple scenarios representing these hypotheses for the Iowa population as well as potential management actions, including head starting, nest protection, and habitat improvement. We compare projected population sizes and growth rate with cost of implementation to aid managers with identifying the most cost-effective conservation strategy for this imperiled species.
