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Alexandra K.. Urza

Alexandra Urza

Post-Doctoral Research Ecologist

920 Valley Road
Reno, NV 89512-2812
Contact Alexandra K.. Urza

Current Research

I am a Postdoctoral Research Ecologist with the Grassland, Shrubland, and Desert Ecosystems Science program of the Rocky Mountain Research Station. My research uses observational, experimental, and modeling approaches to study ecosystem responses to disturbance, plant-plant interactions, and plant community dynamics in the context of climate change and invasive species. Current research projects include environmental drivers of post-fire sagebrush establishment, within- and among-population variation in pinyon pine seedling drought tolerance, and distribution of invasive species in the western US.

Research Interests

I am interested in plant community responses to disturbance, effects of climate variability on seedling establishment, biotic interactions, drivers of species invasions, and the ecological effects of management treatments. Much of my work considers how these processes vary across the landscape in relation to environmental heterogeneity. I work primarily in cold desert shrublands and woodlands.

Past Research

My past research includes multi-scale drivers of vegetation dynamics at the woodland-shrubland interface in the Great Basin, climate effects on post-fire mixed conifer forest recovery in the Northern Rockies, and aspen responses to management efforts in Wyoming.

Why This Research is Important

Dryland ecosystems of the western US are facing many threats, including warming temperatures, increasing fire, and widespread invasions by non-native species. Anticipating ecosystem responses to environmental change, and designing appropriate management interventions, requires an understanding of the underlying ecological processes and how these vary across the landscape.


  • University of Nevada-Reno, Ph.D., Ecology, Evolution, and Conservation Biology, 2018
  • Colorado State University, M.S., Ecology, 2012
  • Reed College, B.A., International Policy Studies, 2006
  • Professional Experience

    Natural Resource Specialist, Bureau of Land Management, Cedarville, CA
    2012 to 2014

    Contracted Research Ecologist, US Geological Survey, Ft. Collins, CO
    2011 to 2012

    Featured Publications


    Urza, Alexandra K.; Weisberg, Peter J.; Chambers, Jeanne C.; Sullivan, Benjamin W., 2019. Shrub facilitation of tree establishment varies with ontogenetic stage across environmental gradients
    Prescribed fire operations in Underdown Canyon Demonstration Project.
    The use of prescribed fire to reduce expansion of pinyon and juniper to sagebrush ecosystems is a commonly used by managers but can have unwanted consequences. In this Joint Fire Sciences Program Demonstration Project, we show how seeding native species after prescribed fire can decrease invasion of nonnative annual grasses in sites with low resistance.
    There is widespread interest in understanding the effectiveness of fuel treatments in mitigating the trajectory of wildfire suppression costs and how their effectiveness and longevity can be extended over large areas and landscapes. To date, there have been several studies that used a modeling approach to evaluate fuel treatment effectiveness at the landscape scale. However, empirical studies at this scale are rare because landscape-scale fuel treatment strategies have not been fully implemented or wildfires have not burned through implemented landscape fuel treatments. A thorough evaluation of what is currently available in the literature and lessons learned from forest and rangeland managers has not yet been conducted.
    The concepts of ecological resilience and resistance to invasive annual grasses have been used to develop an understanding of sagebrush ecosystem response to disturbances like wildfire and management actions to reduce fuels and restore native ecosystems. A multi-scale framework that uses these concepts to prioritize areas for conservation and restoration at landscape scales and to determine effective management strategies at local scales has been developed by Chambers and her colleagues. Regional SageSTEP (Sagebrush Treatment Evaluation Project) data coupled with west-wide AIM (Assessment, Inventory and Monitoring) data provide a unique opportunity to refine the predictors of resilience and resistance and extend the existing multi-scale framework effort.