Project : USDA ARS

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Research Project: Restoration and Conservation of Great Basin Ecosystems

Location: Range and Meadow Forage Management Research

2021 Annual Report

Objectives
The long-term objective of this project is to develop practices and strategies to restore and conserve Great Basin rangelands. Specifically, during the next five years we will focus on the following objectives: Objective 1 (Restoration): Develop practices and strategies for restoring perennial livestock forages and ecosystem function on degraded and fire-prone Great Basin rangelands using combinations of grazing management, vegetation treatments, seed enhancements, and traditional restoration techniques. Subobjective 1A: Develop seed enhancement technologies for overcoming barriers to rangeland seeding success. (Davies, Boyd, Copeland) Subobjective 1B: Determine appropriate seed mixes for use after wildfires to limit exotic annual grass invasion and restore productivity. (Davies, Boyd, Copeland) Subobjective 1C: Develop and evaluate management practices for controlling juniper encroachment of sagebrush steppe plant communities. (Bates, Davies) Subobjective 1D: Determine post-treatment change in vegetation composition and structure over a 30 year time horizon in cut compared with burned juniper-encroached sagebrush steppe. (Boyd, Bates, Davies) Objective 2 (Conservation): Develop practices and strategies (including decision-support tools) to maintain and enhance livestock forage production and other ecosystem services in rangelands across different site characteristics, climate conditions, and management systems. Subobjective 2A: Evaluate grazing management as a tool to decrease wildfire risk, behavior, and severity. (Davies, Bates, Boyd, Copeland) Subobjective 2B: Evaluate post-fire grazing management effects on herbaceous productivity and sage-grouse habitat. (Bates, Davies) Subobjective 2C: Determine the influence of site attributes and climate variation on long-term productivity and diversity of sagebrush steppe. (Bates, Davies, Copeland) Subobjective 2D: Develop a science-based framework for management planning. (Boyd, Bates, Davies) Subobjective 2E: Use precision management technologies (global positioning of livestock, virtual fencing, remote sensing of landscape and others) to enhance livestock producer capability for optimum management of pastures and rangelands, balancing production and ecosystem services.

Approach
Objective 1: Hypotheses: 1) Incorporating seeds into activated carbon pellets will protect seeded vegetation from pre-emergent herbicides, 2) Seeds treated with abscisic acid will have delayed germination and increased seedling density relative to non-coated seeds, 3) Coating and imbibing treatments will produce similar seedling densities, 4) The effects of abscisic acid treatment will be dependent on level of coating; based on previous lab work we hypothesize that intermediate levels of treatment will produce highest seedling densities, 5) Drill seeding a mixture of native and introduced bunchgrasses after wildfire in sagebrush steppe will reduce exotic annual grass invasion compared to seeding native bunchgrasses, seeding introduced bunchgrasses, and not seeding, 6) Burning juniper-encroached sagebrush steppe will increase desirable herbaceous production, 7) Herbaceous vegetation productivity and abundance will be greater when juniper is controlled with either fall broadcast burning treatment or clear-cut/slash burning treatment compared to untreated woodlands, 8) Clear-cut/slash burning of encroaching junipers will produce more favorable habitat characteristics for sage-grouse compared to fall broadcast burning, 9) Juniper cover and density will increase at a faster rate in cut vs. burned western juniper plant communities, 10) Cover and density of mountain big sagebrush will decrease in association with burning but will recover to levels in cut treatments within 30 years, 11) Rate of increase in density and cover of large perennial bunchgrasses will be faster in burned vs. cut treatments, and 12) exotic annual grasses will initially increase more in the burned compared to the cut treatment. Objective 2:Hypotheses: 1) moderate livestock grazing compared to grazing exclusion will reduce fine fuel continuity, height, total biomass, and accumulation of residual biomass on perennial grass crowns and 2) decrease fire-induced mortality of perennial grasses and thereby reduce post-fire exotic annual grass invasion, 3) increasing grazing pressure will reduce fuels and thereby decrease fire ignition potential and propagation, 4) Long-term heavy rotational grazing after fire will decrease herbaceous productivity, sage-grouse dietary forbs, and horizontal screening cover compared to light, moderate, and no grazing treatments, and 5) No grazing and light grazing will have greater herbaceous productivity, sage-grouse dietary forbs, and horizontal screening cover than moderate grazing. Experimental approaches and research procedures: We will use a combination of grow room studies and small and large replicated field studies to answer these research questions. Many of these field studies will be long-term studies. If initial research plan is unsuccessful, we will revise our grow room and field studies to address the reasons why our initial research plan was unsuccessful or replicate the original experiment if it was unsuccessful because of an act of nature.

Progress Report
In support of Objective 1, scientists in Burns, Oregon, collected data on grow room and field experiments designed to test the effectiveness of activated carbon pellets and seed coatings at protecting seeds from pre-emergent herbicide damage. The researchers prepared peer-reviewed manuscripts on the effects of activated carbon pellets and seed coatings on seeded species. Data was collected on field plots designed to evaluate coating and imbibing seeds with abscisic acid to delay germination. The researchers and support staff collected data on experiments evaluating drill seeding native compared to non-native grasses after wildfire and investigated the effects of burning juniper on herbaceous production. A peer-reviewed manuscript on the effects of seeding native compared to introduced bunchgrasses after wildfire in sagebrush steppe communities was prepared. In addition, manuscripts were prepared on the effects of juniper treatments on plant community characteristics. In support of Objective 2, the researchers continued to collect data on experiments designed to evaluate grazing management as a tool to decrease wildfire probability, behavior, and severity. Peer-reviewed manuscripts on the effects of pre-fire grazing on post-fire community recovery were prepared. The researchers continue to apply treatments and collect data on the effects of grazing after fire in sagebrush steppe communities. A peer-review manuscript on the effects of fall-winter grazing after wildfire in sagebrush steppe communities was also prepared. The scientists are continuing to develop management-oriented materials to guide rangeland management based on ecological threats and the influence of management and non-management factors on plant community change.

Accomplishments
1. Modeling wildfire probability in the Great Basin. ARS scientists at Burns, Oregon, worked with the Rangeland Analysis Platform (RAP) team at the University of Montana to create a model that predicts probability of large wildfires in the Great Basin region as a function of antecedent fuel (primarily perennial grass) accumulation and precipitation. RAP represents a computer-derived estimate of vegetation cover and biomass (shrub, perennial herbaceous, and annual herbaceous) based on satellite-derived imagery (Landsat) dating back to the late 1980’s. The model explains 70% of the variation in yearly acres burned in the Great Basin from 1988 to present, and model predictions are available on April 1 of each year, allowing sufficient time for local and regional fire managers to conduct fuels treatments and pre-position suppression equipment prior to the onset of the fire season. The National Interagency Fire Center requested a meeting with the ARS team to discuss implications of the model for preemptive fire management actions in the Great Basin region. This is the first fuel-driven, spatially explicit, and preemptive (i.e. available before the fire season) model to be accurate enough for broad management utility in predicting wildfire occurrence in rangelands.

U.S. DEPARTMENT OF AGRICULTURE

Range and Meadow Forage Management Research: Burns, OR