Research Projects

Sagebrush ecosystem recovery after wildfire & herbicide application

In 2020, the Mullen wildfire in the Medicine Bow-Routt National Forest in southeastern Wyoming burned approximately 176,000 acres (~71,224 hectares). In the summer of 2021 the herbicide indaziflam was applied to 10,903 acres (~ 4,412 hectares) to the sagebrush areas that were in a high-risk category for the invasion of cheatgrass. To understand the efficacy of the herbicide Rejuvra (indaziflam) and the effects of herbicide application on the soil microbial community and vegetation, we are monitoring the soil and vegetation.

Project objectives:

1) Compare soil microbial diversity & function post-fire treated with the herbicide indaziflam to untreated control areas,

2) Understand changes in and the recovery of soil microbial communities post-fire and how this is related to the recovery of aboveground vegetation.

 

Publications:

Tanner Hoffman, 2023. Belowground biodiversity following herbicide application post wildfire. MS thesis, University of Wyoming, Department of Ecosystem Science and Management.

Forest Restoration after wildfire

In July 2012, the high-severity Arapaho Fire burned ~40,000 ha in the Northern Laramie Mountains of Wyoming, including the University of Wyoming’s Rogers Research Site (RRS). To understand recovery of the ponderosa pine ecosystem, restoration treatment were established at RRS.

View of burned ponderosa pine forest at Rogers Research Station

 

Project objectives:  Understand how wildfire and subsequent post-fire managements strategies affect a) ponderosa pine seedling survival, fitness, and pine regeneration from seed, b) post-fire vegetation community composition and dynamics, including invasive species, c) soil biogeochemical properties and processes, and d) soil microbial community and associated processes.

Publications:

Winters, S. and L.T.A. van Diepen, 2023. Ponderosa pine introduction methods following a high-severity stand replacing fire to promote forest regeneration.  Fire Ecology 19:4. https://doi.org/10.1186/s42408-022-00152-5

Stephanie Winters, 2019. Linking soil ecology with the restoration of ponderosa pine forests following a high-severity wildfire in the Laramie Mountains of Wyoming. MS thesis, University of Wyoming, Department of Ecosystem Science and Management.


 

surviving green ponderosa pine seedling

 

Ponderosa pine seedlings were planted and seeded in the various restoration treatments, but two years after seedling planting, average seedling survival in the hand-planted treatment was extremely low and natural regeneration and regeneration from broad cast seeding was almost nonexistent.

Current research is focused on understand the role of mycorrhizal fungi in seedlings estblishment and growth.

 

Ponderosa pine seedlings grown in burned and control soils from RRS

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Bark Beetle

Project objective: Characterize soil nutrient status and cycling, soil microbial communities, and tree regeneration in coniferous forest after bark beetle infestation in the Medicine Bow Mountains in Wyoming.

Publications:

Boggs-Lynch, L., U. Norton, and L.T.A. van Diepen, 2021. Legacy of bark beetles (Dendroctonus spp.) on soil carbon and nitrogen cycling seven years after forest infestation. Forest Ecology and Management 489: 119064. https://doi.org/10.1016/j.foreco.2021.119064

Custer, G.F., W. Stump, and L.T.A. van Diepen, 2020. Structural and functional dynamics of soil microbes following spruce beetle infestation. Applied and Environmental Microbiology 86(3): e0198419. https://doi.org/10.1128/AEM.01984-19

 

Liana Boggs-Lynch, 2020. Legacy Effects of Bark Beetle on Biogeochemical Transformations, Microbial Communities, and Tree Regeneration One Decade Post-Infestation. PhD dissertation, University of Wyoming, Department of Plant Sciences.

Gordon Custer, 2018. Structural and functional dynamics of soil microbes following spruce beetle infestation. MS thesis, University of Wyoming, Department of Plant Sciences.

 

Invasive plants

Project objectives:

  1. Measure effects of invasive plants on soil microbial diversity.
  2. Test growth of native and invasive plants when grown in soils collected from areas with different infestation levels of cheatgrass (Bromus tectorum) through greenhouse experiments.
  3. Assess the impacts of invasive plant removal via herbicide application on soil microbial structure and function.
    • The control of Dalmatian Toadflax (Linaria dalmatica) at High Plains Research Center (Cheyenne, WY) using pre- and post-emergent herbicides.

 

Publications:

Custer, G.F., and L.T.A. van Diepen, 2020. Plant invasion has limited impact on soil microbial a-diversity : a meta-analysis. Diversity, 12, 112. https://doi.org/10.3390/d12030112

 

Sagebrush microbiomes

Project objective: Characterizing bulk and rhizosphere soil microbiomes in sagebrush communities along a climate gradient in Wyoming.

 

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sagebrush

 

 

 

 

Project was led by postdoctoral fellow Paul Ayayee as part of the Microbial Ecology Collaborative.

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