Research and Publications
This paper describes Fires of Change, a collaborative art exhibit designed to communicate about the shifting fire regimes of the United States Southwest through the lens of multimedia art. The Southwest Fire Science Consortium and Landscape Conservation Initiative, both of which are boundary organizations that facilitate collaboration among managers and scientists to develop and apply actionable science, organized Fires of Change by convening scientists, managers, and artists in the co-production of science-based artwork. Surveys were conducted with Fires of Change exhibit visitors to assess the impacts of viewing the exhibit, as well as with exhibit creators to assess the effects of participating in the project.
Potential Operational Delineations (PODs) is a spatial wildfire planning framework that brings together operational fire responses and landscape management goals from Forest Planning documents. The PODs risk-based framework helps managers weigh a portfolio of landscape values, including human assets and natural resources, current conditions, responder safety, and likely fire outcomes to identify appropriate fire management objectives. Across the country, more than 30 National Forests have begun developing and implementing this planning framework with local partners complementing the Shared Stewardship efforts.
The greater sage-grouse (Centrocercus urophasianus; hereafter GRSG) has been a focus of scientific investigation and management action for the past two decades. The 2015 U.S. Fish and Wildlife Service listing determination of “not warranted” was in part due to a large-scale collaborative effort to develop strategies to conserve GRSG populations and their habitat and to reduce threats to both. New scientific information augments existing knowledge and can help inform updates or modifications to existing plans for managing GRSG and sagebrush ecosystems. However, the sheer number of scientific publications can be a challenge for managers tasked with evaluating and determining the need for potential updates to existing planning documents. To assist in this process, the U.S. Geological Survey (USGS) has reviewed and summarized the scientific literature published since January 1, 2015. The first GRSG literature summary was published early in 2018. Here we provide an update to that document by adding summaries of articles published between January 6, 2018 and October 2, 2019.
We observed that juniper canopy dieback was most severe (>60% canopy dieback) at hot, dry, low elevation sites, and was associated with drought-induced hydraulic damage. There was no evidence that biotic agents could be the primary drivers of this dieback, implicating the acute effects of drought as the main causal agent. The speed and scale of this drought-induced juniper dieback seems to be historically unprecedented in the region and foreshadows an uncertain future for piñon-juniper woodlands as the region continues to get warmer and drier.
Meta-analyses indicated that while P–J reduction caused significant positive overall effects on all shrub and herbaceous components (including invasive cheatgrass [Bromus tectorum] and exotic annual forbs), responses were contingent on treatment- and plant community-type combinations. Restoration seedings also had strong positive effects on understory vegetation by augmenting changes in perennial grass and perennial forb components, which similarly varied by plant community type. Collectively, our results identified specific situations where broad-scale efforts to reverse woodland encroachment substantially met short-term management goals of restoring valuable ecosystem services and where P–J reduction disposed certain plant community types to ecological risks, such as increasing the probability of native species displacement and stimulating an annual grass-fire cycle. Resource managers should carefully weigh these benefits and risks and incorporate additional, appropriate treatments and/or conservation measures for the unique preconditions of a given plant community in order to minimize exotic species responses and/or enhance desirable outcomes.
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In recent decades, many bumble bee species have declined due to changes in habitat, climate, and pressures from pathogens, pesticides, and introduced species. The western bumble bee (Bombus occidentalis), once common throughout western North America, is a species of concern and will be considered for listing by the U.S. Fish and Wildlife Service (USFWS) under the Endangered Species Act (ESA). We attempt to improve alignment of data collection and research with USFWS needs to consider redundancy, resiliency, and representation in the upcoming species status assessment. We reviewed existing data and literature on western bumble bee, highlighting information gaps and priority topics for research. Priorities include increased knowledge of trends, basic information on several life‐history stages, and improved understanding of the relative and interacting effects of stressors on population trends, especially the effects of pathogens, pesticides, climate change, and habitat loss. An understanding of how and where geographic range extent has changed for the two subspecies of western bumble bee is also needed.
The Interpreting Indicators of Rangeland Health (IIRH) protocol is designed for assessing ecosystem function on rangelands and woodlands. The protocol was developed by an interagency cadre of technical experts and has been in use by for two decades. The protocol is well accepted and is a valuable tool for communicating rangeland conditions with stakeholders. Technical Reference 1734-6 Version 4, which describes the IIRH protocol, was published in 2005.
Refinements and improvements identified through 12 years of experience with class participants and field office personnel applying the protocol as outlined in Version 4 are incorporated into Version 5 of the technical reference. Indicators and attributes used in previous versions of the technical reference are largely the same, and following instructions in Version 5 is not expected to result in differing attribute ratings as compared to assessments completed using Version 4 of TR 1734-6 assuming that the same reference information is used.
Two major questions facing fuels managers are: how long do masticated fuels persist, and how does the composition of masticated fuelbeds change over time? To evaluate these changes, we measured 25 masticated sites with a range of vegetation, species masticated and time since treatment (1–16 years) in the western US. Seven of the 25 sites were sampled nearly a decade earlier, providing a unique opportunity to document fuelbed changes. Woody fuel loading ranged from 12.1 to 91.9 Mg ha−1 across sites and was negatively related to time since treatment. At remeasured sites, woody fuel loads declined by 20%, with the greatest losses in 1- and 10-h woody fuels (69 and 33% reductions in mass respectively). Reductions were due to declines in number of particles and reduced specific gravity. Mastication treatments that generate greater proportions of smaller-diameter fuels may result in faster decomposition and potentially be more effective at mitigating fire hazard.
At three study sites in Utah, 45 sampling plots spanning a range of tree cover from 5% to 50% were masticated. We measured surface fuel load components three times over a 10‐yr period. We also measured tree cover, density, and height as indicators of treatment longevity. Changes in these variables were analyzed across the range of pre‐treatment tree cover using linear mixed effects modeling. We detected decreases in 1‐h down woody debris by 5–6 yr post‐treatment, and from 5–6 to 10 yr post‐treatment, but did not detect changes in 10‐h or 100 + 1000‐h down woody debris. By 10 yr post‐treatment, there was very little duff and tree litter left for all pre‐treatment tree cover values. Herbaceous fuels (all standing live and dead biomass) increased through 10 yr post‐treatment. At 10 yr post‐treatment, pinyon–juniper cover ranged 0–2.6%, and the majority of trees were <1 m in height. Given that 1‐h fuels were the only class of down woody debris that decreased, it may be beneficial to masticate woody fuels to the finest size possible. Decreases in 1‐h down woody debris and duff + litter fuels over time may have important implications for fire behavior and effects, but increases in herbaceous and shrub fuel loads should also be taken into account. At 10 yr post‐treatment, understory grasses and shrubs were not being outcompeted by trees, and average pinyon–juniper canopy cover was <1%. Therefore, tree regeneration was not sufficient to support a crown fire. In areas where sage‐grouse are a management concern, we recommend monitoring tree regeneration at mastication treatments at 10–15 yr post‐treatment.
Because the effects of tree reduction on vegetation can vary with the soil temperature/moisture regime, we also analyzed differences in soil climate variables between the mesic/aridic‐xeric and frigid/xeric regime classifications for our sites. Growing conditions during all seasons except spring were greatly limited by lack of available water, low temperatures, or both. Advanced tree expansion reduced wet days (total hours per 24 hr when hourly average soil water matric potential >−1.5 MPa), especially in early spring. Fire and mechanical tree reduction increased wet days and wet degree days (sum of hourly soil temperatures >0°C when soil is wet per 24 hr) compared with no treatment for most seasons. Burning resulted in higher soil temperatures than untreated or mechanically treated woodlands. Tree reduction at advanced expansion phases increased wet days in spring more than when implemented at earlier phases of expansion. Added wet days from tree reduction were negatively associated with October through June precipitation and vegetation cover, rather than time since treatment, with more wet days added on drier sites and years. The longer period of water availability in spring supports increased growth and cover of not only shrubs and perennial herbs, but also invasive weeds on warmer and drier sites, for many years after tree reduction. We found that sites classified as mesic/aridic‐xeric had warmer soil temperatures all seasons and were drier in spring and winter than sites classified as frigid/xeric. Land managers should consider reducing trees at earlier phases of expansion or consider revegetation when treating at advanced phases on these warmer and drier sites that lack perennial herb potential.