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Vegetation Cover and Composition in Environments Surrounding Uranium Mines in the Grand Canyon Ecosystem, Northern Arizona

Open-File Report 2025-1024
Prepared in cooperation with the Bureau of Land Management and U.S. Forest Service
By: , , and 
https://doi.org/10.3133/ofr20251024

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Abstract

Mining uranium from breccia-pipe deposits in the greater Grand Canyon region has occurred since the mid-1900s. However, possible ecosystem contamination with harmful levels of radionuclides may have occurred due to mining activities in the 21st century. In response, a 20-year Federal moratorium on new mining claims in the Grand Canyon watershed was initiated in 2012, to allow time to evaluate the potential effects of uranium exploration and mining on human health, wildlife, and water resources. This moratorium, nor the 2023 designation of the “Baaj Nwaavjo I’tah Kukveni–Ancestral Footprints of the Grand Canyon National Monument,” precludes operation or development of mining claims predating 2012.

Vegetation is a core ecosystem component that may be affected by uranium mining (for instance, through uptake and storage of radionuclides from the air or soil) or may act as a vector of exposure to wildlife, livestock, and humans (for instance, via their consumption of contaminated plant tissues). To provide baseline information about the plant communities associated with uranium mines in the Grand Canyon region, the U.S. Geological Survey surveyed an approximately 200-meter-wide buffer surrounding four breccia-pipe deposits, each in a unique stage of mine development, and at one reference area (a livestock water tank) that underwent ground disturbance but contains no mineral deposits. We sectioned the buffer zones into 0.65–4.52 hectare plots, within which we (1) inventoried all plant species, (2) measured percent cover of plant species, plant functional groups, and ground surface types (dark cyanobacteria, lichen, moss, bedrock, rock, embedded litter, duff, plant bases, and bare soil) using line-point intercept, and (3) measured length and frequency of gaps between perennial plant canopies using canopy gap intercept. We found that plant composition at the mines and the reference area differed from one another but were all characteristic of expected regional vegetation patterns. We provide this data summary as potential baseline information for future research and management efforts.

Suggested Citation

Mann, R.K., Duniway, M.C., and Hinck, J.E., 2026, Vegetation cover and composition in environments surrounding uranium mines in the Grand Canyon ecosystem, Northern Arizona: U.S. Geological Survey Open-File Report 2025–1024, 44 p., https://doi.org/10.3133/ofr20251024.

ISSN: 2331-1258 (online)

Study Area

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Methods
  • Results
  • Discussion
  • Summary
  • References Cited
  • Appendix 1. Plant Species Occurrence and Cover Within Plots of All Study Sites, Grand Canyon Area, Northern Arizona
  • Appendix 2. Correlations Between Vegetation and Surface Metrics in Environments Surrounding Uranium Mines in the Grand Canyon Ecosystem, Northern Arizona
Publication type Report
Publication Subtype USGS Numbered Series
Title Vegetation cover and composition in environments surrounding uranium mines in the Grand Canyon ecosystem, Northern Arizona
Series title Open-File Report
Series number 2025-1024
DOI 10.3133/ofr20251024
Publication Date January 27, 2026
Year Published 2026
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Southwest Biological Science Center
Description Report: vii, 44 p.; Data Release
Country United States
State Arizona
Other Geospatial Grand Canyon region
Online Only (Y/N) Y
Additional publication details