Resistance & Resilience
The Great Basin Fire Science Exchange and Nevada Partners for Conservation and Development co-hosted this workshop that addressed maintenance of intact sagebrush communities in the face of multiple ecological stressors.
Workshop presentations available in pdf format:
- Needs assessment synthesis and workshop intro – Génie MontBlanc, University of Nevada, Reno
- Vegetation resilience and the importance of the herbaceous understory –Jeanne Chambers, US Forest Service, Rocky Mountain Research Station
- Vegetation monitoring and issues of scale – Pat Shaver, USDA Natural Resource Conservation Service
- Defining an intact sagebrush community – Brad Schultz, University of Nevada Cooperative Extension
- Current status of ungulates in sagebrush systems and managing for healthy populations – Tony Wasley, Nevada Department of Wildlife
- Wildlife/habitat relationships within the intact sagebrush-grass continuum – Kent McAdoo, University of Nevada Cooperative Extension
- Managing habitats for sage-grouse: do we need a sagebrush management decision support tool? – Clinton McCarthy, USDA Forest Service
- Collaboration in restoration – Lee Turner, Nevada Partners for Conservation and Development, Nevada Department of Wildlife
- Go big or go home: planning and implementing vegetation management projects at a meaningful scale – Paul Briggs, Bureau of Land Management
- Development and use of forbs in restoration – Scott Jensen, USDA Forest Service
- Synergistic monitoring project results and management implications – John Swanson, University of Nevada, Reno
This webinar discusses a strategic approach developed by an interagency, Western Association of Fish and Wildlife Agencies working group for conservation of sagebrush ecosystems, Gunnison sage-grouse, and greater sage-grouse. It uses information on (1) factors that influence sagebrush ecosystem resilience to disturbance and resistance to nonnative invasive plants and (2) distribution and relative abundance of sage-grouse populations to address persistent ecosystem threats, such as nonnative invasive plants and wildfire, and anthropogenic threats, such as oil and gas development and agronomic conversion, and to develop effective management strategies.
Webinar was presented by Jeanne Chambers, US Forest Service – Rocky Mountain Research Station and hosted by the Great Northern, Southern Rockies, and Great Basin Landscape Conservation Cooperatives
View paper.
This study found that to retain the shrub, especially sagebrush, components on a site and increase ecosystem resilience and resistance through increases in tall grasses, treatment should occur at low to mid tree dominance index (TDI) using mechanical methods, such as cutting or mastication. Effects of fire and mechanical treatments implemented at different phases of tree dominance create different successional trajectories that could be incorporated into state-and-transition-models to guide management decisions.
View article.
This study evaluated nutrient availability and herbaceous recovery following various cutting and prescribed fire treatments in late succession western juniper woodlands on two sites in southeast Oregon from 2007 to 2012. Treatments were untreated controls, partial cutting followed by fall broadcast burning (SEP), cut and leave (CUT), and cut and burn in winter (JAN) and spring (APR). Soil inorganic N (NO3−, NH4+), phosphorus (H2PO4−), potassium (K+), and cover of herbaceous species were measured in three zones; interspace, litter mats around the tree canopy (canopy), and beneath felled trees (debris). Peak nutrient availability tended to occur within the first two years after treatment. The increases in N, P, and K were greatest in severely burned debris and canopy zones of the SEP and APR treatments. Invasive annual grass cover was positively correlated to soil inorganic N concentrations. Herbaceous composition at the cool, wet big sagebrush-Idaho fescue site was generally resistant to annual grasses after juniper treatments and native plants dominating post-treatment even in highly impacted debris and canopy zones of the SEP treatment. The warm dry big sagebrush-bluebunch wheatgrass site was less resistance and resilient, thus, exotic annual grasses were a major component of the understory especially when tree and slash burning was of high fire severity.
View paper.
This study found while understory perennial herbaceous plant cover remained low 1 and 2 yr post treatment, it increased by > 700% in all fuel-reduction treatment plots six growing seasons post treatment. Furthermore, while we observed minor increases in invasive annual grass, Bromus tectorum L. (cheatgrass), colonization in 2010 and 2011, there were substantial increases in B. tectorum cover by 2015. B. tectorum cover varied among treatments with the greatest cover in the unseeded mastication plot at nearly 30%. Seeding applications did not increase overall seed mix species cover but enhanced seed mix species richness and, thus, may have increased resistance to B. tectorum invasion in seeded treatment plots.
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Results show that loss of perennial herbaceous species, which can result from inappropriate livestock grazing, and loss of shrubs, which often results from fire, interact to affect key functional groups. The implications are that ecosystem resilience to disturbance in Cold Desert shrublands decreases when competition from perennial native grasses and forbs for available resources no longer prevents dominance by A. tridentata and other shrubs and/ or annual invasive grasses. Managing livestock grazing to maintain or increase perennial herbaceous species, especially deep-rooted grasses, which contribute to resilience along elevation gradients, can help prevent threshold crossings to undesirable states and retain critical ecosystem services following disturbances such as wildfire.
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In this paper, optimization models successfully identified areas with low conifer canopy cover, high resilience and resistance to wildfire and annual grass invasion, and high bird abundance to enhance sage-grouse habitat. The inclusion of mesic resources resulted in further prioritization of areas that were closer to such resources, but also identified potential pathways that connected breeding habitats to the late brood-rearing habitats associated with mesic areas. Areas identified by optimization models were largely consistent with and overlapped ongoing conifer removal efforts in the Warner Mountains of south-central Oregon. Land ownership of preferential areas selected by models varied with priority goals and followed general ownership patterns of the region, with public lands managed by the Bureau of Land Management and private lands being selected the most. The increased availability of landscape-level datasets and assessment tools in sagebrush ecosystems can reduce the time and cost of both planning and implementation of habitat projects involving conifer removal. Most importantly, incorporating these new datasets and tools can supplement expert-based knowledge to maximize benefits to sagebrush and sage-grouse conservation.
View article.
Collectively, the data analyzed in this study demonstrate that good condition ungrazed Wyoming big sagebrush plant communities exhibited resilience following fire and maintained a native-dominated mosaic of shrubs, bunchgrasses, and forbs. Further, unburned control plots were dominated by woody vegetation and exhibited losses in herbaceous understory, possibly indicating that they are outside of their natural fire return interval.
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In this study, researchers determined vegetation response to fuel reduction by tree mastication (shredding) or seeding and then shredding by measuring cover of shrub and herbaceous functional groups on shredded and adjacent untreated areas on 44 sites in Utah. Findings suggested that shredding or seeding and then shredding should facilitate wildfire suppression, increase resistance to weed dominance, and lead toward greater resilience to disturbance by increasing perennial herbaceous cover.
View handbook.
This handbook discusses concepts surrounding landscape and restoration ecology of sagebrush ecosystems and greater sage-grouse that habitat managers and restoration practitioners need to know to make informed decisions regarding where and how to restore specific areas, by providing:
- Descriptions of plant dynamics of sagebrush steppe ecosystems and their responses to major disturbances, fire, and defoliation.
- Introductions of the concepts of ecosystem resilience to disturbances and resistance to invasions of annual grasses within sagebrush steppe.
- Introductions to soils and ecological site information will provide insights into the specific plants that can be restored in a location.
- Descriptions of concepts of landscape ecology that aid decisions regarding habitat restoration.
- Overviews of restoration techniques for sage-grouse habitat restoration.
- Descriptions of the critical nature of monitoring for adaptive management of sagebrush steppe restoration at landscape- and project-specific levels.