Exploring factors influencing expansion of invasive Bullfrogs and persistence of native Northern Leopard Frogs in northeastern Colorado (South Platte Basin)

Warner College of Natural Resources

Fish, Wildlife, and Conservation Biology



(Boulder, Logan, Morgan, Weld, Yuma)

Primary Topic:

Natural Resources and Sustainability

Other Topics:

No additional topic areas, only my selection from previous question

Lead Mentor:  

Larissa Bailey


Internship Overview:

The intern will help collect data in cooperation with Colorado Parks and Wildlife aquatic technician(s) and the CSU graduate student leading the project. They will gain field expertise using multiple amphibian detection methods including visual encounter surveys, dip netting, acoustic recording units and environmental DNA (eDNA). They will also be trained in amphibian handling and disease sampling, i.e., swabbing for the invasive fungal pathogen Bd. The intern will engage with CPW personnel, CSU faculty, cooperating municipalities (e.g., Fort Collins Natural Areas, City of Longmont Natural Areas, etc.) and private landowners. They will have an opportunity to summarize their work and present findings to various stakeholder and interest groups including meetings with funding agencies (CPW), Colorado Partners in Amphibian and Reptile Conservation (COPARC), the Northern Leopard Frog Working Group, CSU undergraduate symposiums, and the Lower South Platte Children’s Water Festival, which occurs every September. The internship will be stationed in Fort Collins and involve daily travel to field sites with CPW/CSU crew members. Overnight trips will occur when sampling sites in Morgan, Logan, and Weld counties or when round trip driving time exceeds daily surveying time. These overnight trips will create opportunities for the intern to interact with Extension agents, landowners, and wildlife managers in eastern Colorado as well other areas. The intern will gain valuable career experience while contributing to research questions investigating the relative importance of habitat alteration, invasive species, and disease in determining Northern Leopard Frog distribution. This information will help predict potential future distributions of both native and invasive species, given anticipated climate change and human expansion. Additionally, expanding existing collaborative efforts among CPW, municipal open space programs, and private landowners in the northeast region will help prioritize areas for Bullfrog control and aquatic habitat management actions to benefit Northern Leopard Frog populations.

Goals, Scope and Objectives:

Fresh water ecosystems provide important goods and services that benefit human society, thereby making their conservation and management a global priority (Dodger 2005). Two main threats to these ecosystems are habitat alteration and invasive species. With climate change related drought threatening the persistence of aquatic habitat and invasive species degrading the quality of remaining habitat, there has never been a more important time to understand the effects of these combined threats. Amphibians are considered indicators of changes in aquatic ecosystem health, as evidenced by their dramatic world-wide declines during the Anthropocene. Northern Leopard Frogs (Lithobates pipiens) are historically one of the most widespread frogs in North America but have experienced dramatic reductions in their occupied range in recent decades. Specifically, Northern Leopard Frogs (NLFs) are adversely affected by drought-related habitat loss, disease caused by the invasive fungal pathogen Batrachochytrium dendrobatidis (Bd), and invasive predators (American Bullfrogs; Lithobates catesbeianus). These threats are likely contributors to dramatic population declines across much of the species range in the Intermountain West, notably east of the Continental Divide along the Front Range of Colorado, based on a species assessment conducted over a decade ago (Johnson 2011). This project investigates how habitat alteration, and invasive species (pathogen and predator) interact to influence current Northern Leopard Frog occurrence in the South Platte River Basin

With which stakeholder group(s) will the intern work?

Colorado Parks and Wildlife, private landowners and regional conservation groups associated with the Northern Leopard Frog Working Group

What student learning outcomes do you anticipate and what are the opportunities for professional development?

The selected intern will become proficient in amphibian field sampling techniques including acoustic recorder setup, environmental DNA collection, visual survey strategies, and amphibian handling protocols. The student will gain confidence working collaboratively with team members and independently while practicing data quality control. Additional opportunities for professional growth will include optional presentations to interested organizations (COPARC, CPW), private landowner communications, and outreach to the Extension community. Opportunities for future research within the context of this study are numerous and the student will be encouraged to develop their own research questions, if interested. The student will leave this position with a complete understanding of the scientific process, including data collection, data analysis, and presentation of results.
Scroll to Top