Cooperative Research Units
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Linking Exposure to Sub-lethal Stressors to Individual Vital Rates and Population Abundance


September 2016 - September 2021


1. Sample across a gradient of wetlands with differing levels of brine contamination in the Prairie Pothole region of the Williston Basin (Montana and North Dakota). The contamination index (CI), which measures the ratio of chloride to specific conductance in water (Reiten and Tischmak 1993), is a well-established measure of brine intrusion in the region. (Note: This component is already being done by B. Hossack and others.)

2. Estimate abundance and community richness of amphibian larvae in reference wetlands and wetlands impacted by energy development in the Williston Basin of North Dakota and Montana. This will be done using ≥2 capture sessions with unbaited minnow traps. For tiger salamanders, we will batch-mark larvae based on capture session and estimate abundance with capture-mark-recapture methods. For frog larvae that are less amenable to marking, we will use N-mixture models to estimate abundance. Community richness will be estimated using the pooled dataset.


Current Staff

Federal Staff: 101

Masters Students: 239

Phd Students: 154

Post Docs: 55

University Staff: 241

5 Year Summary

Students graduated: 695

Scientific Publications: 1962

Presentations: 4417



  • Mike MitchellCo-Principal Investigator
  • Creagh BruenerCo-Principal Investigator

Funding Agencies

  • USDI - Geological Survey


Cooperative Research Units Program Headquarters Cooperators

  1. U.S. Geological Survey