Amphibian Populations in Wetlands of the Des Moines Lobe in Central Iowa



Principal Investigator:     Clay L. Pierce

Student Investigator:      Jennifer Swanson

Collaborators:                  Erin Muths, Mark Vandever, Kelly Smalling (U.S. Geological Survey)

Duration:                          January 1, 2015 to August 31, 2017

Funding Source(s):         U.S. Geological Survey

Goals and Objectives:

  • Determine amphibian occupancy rates in Iowa Prairie Pothole Region wetlands
  • Correlate wetland habitat characteristics with amphibian species presence or absence
  • Document post-breeding movement patterns of northern leopard frogs on Conservation Reserve Enhancement Program wetlands
  • Assess the effect of surrounding land use practices as they contribute to chemical exposure and concentrations in northern leopard frogs



Amphibian populations have been experiencing declines in both the United States as well as globally. Recent research indicates that even species previously considered to have stable populations may be experiencing background rates of decline that have gone unnoticed or underestimated. Altough several factors have been identified as contributing to amphibian population losses, habitat loss and risks associated with landuse change, such as environmental contamination, have been acknowleged one of the top threats to amphibians. In the state of Iowa, much of the historic land cover has been converted from a mosiac of wetlands and prairies to agricultural production. In order to preserve amphibian species in these areas it is vital to understand the relationship between amphibian presence, movement, and  and habitat characteristics such as landscape use. Previous work has shown that wetlands in agricultural landscapes can support amphibian populations, but understanding how individuals use these habitats at several spatial scales is important to promote the health and diversity of amphibian species.

A graduate student, Jennifer Swanson, has completed two seasons of field work between April and August in 2015 and 2016. Seventy-two northern leopard frogs were radio tracked in two Conservation Reserve Enhancement Program wetlands. After tracking was completed, 30 of the frogs were euthanized and their bodies analyzed for pesticide content.  Twenty-seven wetlands in northern Iowa were surveyed for all amphibian species seven times each over the two field seasons of this study.


Future Plans:

Jennifer will defend her thesis in June, 2017.

01/01/2015 to 08/30/2017