Mojave Desert Water Resources

Assessing Vegetation and Precipitation Indices to Aid Bighorn Sheep Habitat Monitoring and Management

Assessing Vegetation and Precipitation Indices to Aid Bighorn Sheep Habitat Monitoring and Management

Desert bighorn sheep (Ovis canadensis; BHS) habitat selection is influenced by the relationship between precipitation patterns and habitat vegetation availability. The ability to effectively measure habitat resource quality and availability, and understand mortality rates caused by disease and predation is needed to enhance BHS habitat management. We applied NASA Earth observations, paired with in situ measurements of population distribution, to help assess availability of suitable BHS habitat. Satellite images from NASA's Landsat 8 Operational Land Imager (OLI) and the Aqua and Terra Moderate Resolution Imaging Spectroradiometers (MODIS) were processed into monthly Normalized Difference Vegetation Index (NDVI) maps from 2013 to 2017. We plotted means and standard deviations to identify trends in forage quality and heterogeneity. We acquired precipitation accumulation measurements from the Parameter-elevation Relationship on Independent Slopes Model (PRISM) and the Global Precipitation Measurement (GPM) Integrated Multi-satellite Retrievals for GPM (IMERG) product and compared these precipitation variables to vegetation characteristics within habitat use polygons. Comparative analysis of vegetation indices and precipitation identified areas of perennial or seasonally green vegetation resources with vegetative growth related to persistent or burst precipitation patterns, respectively. The National Park Service and the California Department of Fish and Wildlife will use this information to better understand areas where BHS have steadily-available resources, and to continue the use of NASA Earth observations to aid in future management decisions.


Project Video:
Taking Drought by the Horns
Location
Virginia - Wise
Term
Spring 2018
Partner(s)
National Park Service, Mojave National Preserve
National Park Service, Biological Resources Division, Wildlife Health Branch
California Department of Fish and Wildlife, Wildlife Branch, Game Management
Oregon State University, Department of Fisheries and Wildlife
Sierra Nevada Bighorn Sheep Foundation
NASA Earth Observations
Landsat 8, OLI
Terra, MODIS
Aqua, MODIS
GPM, IMERG
Team
Jacob Ramthun (Project Lead)
Devon Burks
Mariah Heck
Advisor(s)
Joseph Spruce (Science Systems & Applications, Inc., Consultant)
Dr. L. DeWayne Cecil (NOAA National Centers for Environmental Information, Global Science & Technology, Inc.)
Dr. Anette Hollingshead (Global Science & Technology, Inc.)
Bob VanGundy (The University of Virginia's College at Wise)
Dr. Kenton Ross (NASA Langley Research Center)
Project Materials
Poster PDF

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