Proceedings brand creation for a prescribed fire culture – utilizing key social media parameters. Lars Coleman*1, J. Kelly Hoffman1, Thomas McDaniel1, R. Patrick Bixler2, Urs P. Kreuter1, Morgan Russell3

Native plant species are not generally known to be weeds. Many even question whether native species can be invasive in the full extent of the definition. However, there are many native species in rangeland ecosystems that decrease habitat availability and forage quality and increase wildfire intensity. Many of these native species are woody, secondary succession species. A primary reason for native species becoming weedy is because of effective fire suppression strategies following European settlement of the western U.S. Suppressing historical wildfires has many times led to native woody species dominance of mixed plant ecosystems. In many cases, sites invaded by native woody species cross a threshold to a woody plant dominated state that is irreversible without significant management inputs. Across the Great Plains, native weedy species have become dominant in areas where wildfire frequency has decreased and led many grasslands to now be dominated by woodlands. Alternatively, in Great Basin ecosystems, historical fire suppression has led to dense woodland forests with low forage availability at high elevations and a buildup of fine fuel at low elevations, which increases fire intensity and spread. High intensity wildfire is particularly devastating to low elevation bunchgrasses and shrub species that keep their growing points above ground. Adding fuel to these wildfires is the increased dominance and spread of invasive annual grasses that decrease forage quality and wildlife habitat and both increase wildfire frequency and are increased by wildfire occurrence. Restoring structure and function these ecosystems can take a considerable amount of money and management efforts, many times with low success rates. A greater understanding of these rangeland ecosystems currently invaded by native weedy species and those that have been devastated by historical mismanagement should lead to better management strategies for restoring ecological structure and function to these vulnerable rangelands. 

20,000 YEARS OF PINYON AND JUNIPER WOODLAND HISTORY: CONCERNS FOR THE FUTURE. Rick Miller*; Oregon State University, Corvallis, OR

ABSTRACT

Semi-arid woodlands have expanded and contracted across the Great Basin and Colorado Plateau throughout the Pleistocene and Holocene.  Large scale expansions typically occurred during mild-moist climate conditions and contractions during the transition from mild-moist to dry.  There is strong evidence that both tree infill into existing stands and expansion were slowly increasing prior to Eurasian settlement.  However, expansion and infill rapidly accelerated during settlement in the late 1800s, peaking in the early 1900s.  Causes attributed to woodland expansion and infill since the late 1800s have been widely debated, and are most frequently attributed climate, livestock grazing, altered fire regimes, and/or changes in atmospheric CO2.  There is considerable evidence that climate has been a primary driver of woodland expansion, contraction, and infill over the past tens of thousands of years and was likely a major factor during the persistent wet period throughout the West in the early 1900s.  However, the effects of climate on woodland dynamics since Eurasian settlement cannot be separated from anthropogenic factors such as altered fire regimes, grazing, and elevated CO2 levels.  There is also considerable debate as to the proportion of woodland expansion versus regeneration, and old-growth or persistent woodlands versus recently converted sagebrush-steppe and savannas.  This in part can be attributed to regional differences in disturbance regimes and ecological site characteristics, which can lead to regional biases when interpreting woodland dynamics across the Great Basin and Colorado Plateau.  Managing these woodlands takes careful consideration of the ecological site components, potential and current vegetation, and the resilience and resistance to invasive annuals for the site of interest.  Introduced invasives are a considerable threat in replacing both recently encroached and persistent (old-growth) woodlands throughout the West and can be linked to warming climate, fire, and elevated CO2.

HISTORY OF SAGEBRUSH MANAGEMENT: FROM WEED TO KEYSTONE SPECIES

Shortly after the introduction of livestock into sagebrush rangelands, it was recognized that sagebrush competed with forage species.  This led to many efforts to control this “weed” to increase herbaceous vegetation for livestock.  Sagebrush was mechanically and chemically controlled as well as prescribed burned to reduce its abundance.  Sagebrush control was often coupled with seeding non-native forage grasses.  This led to millions of acres of sagebrush rangeland being converted to non-native grasslands.  However, as management focus shifted from livestock production to ecosystem services and the value of wildlife became recognized, scientists and land managers started to recognize the importance of sagebrush.  Efforts to reduce sagebrush became less common.  Following conservation concerns for sagebrush obligate wildlife species, increases in exotic annual grass, and increases in large fires in sagebrush rangelands, sagebrush conservation became a high priority.  This resulted in increased efforts to restore sagebrush after wildfires as well as increased pressure to protect sagebrush communities.  This also included efforts to control pinyon-juniper encroachment of sagebrush rangelands.  Many of these efforts to conserve and restore sagebrush rangelands have been quite valuable; however, they are limited in scale.  This is a cautionary tale of what is now considered a weed may be a keystone species in the future.

NATIVE SHRUB CONTROL AND ESTABLISHMENT OF MIXED-SPECIES SEEDINGS ON EIGHT ECOLOGICAL SITES IN UTAH.

Brush control is often necessary to reduce overabundant shrub species and enhance herbaceous understory conditions. However, simply removing shrubs rarely leads to long-term benefits, especially when understory conditions express low resilience. Results can also vary widely depending on target shrub species and site-specific conditions. To clarify this variability, we established large-scale (200-700 acre) studies and applied herbicide to reduce density of big sagebrush, rubber rabbitbrush, broom snakeweed, and black greasewood at different ecological sites in Utah. In addition, we established replicated small-plot studies to evaluate how various herbicide products impact shrub density and plant establishment of old and new herbaceous species varieties. After five years, sagebrush reduction was much higher (75%) and native herbaceous cover increased to a greater extent on shallow-soil sites compared to deep- soil sites. Over the same timeframe, black greasewood and rubber rabbitbrush rapidly re-sprouted, even though initial mortality was noted after treatment. Heavy livestock grazing greatly weakened understory perennial grasses at rabbitbrush sites, and likely enhanced rapid shrub recovery. In contrast, broom snakeweed was reduced by 25% relative to control areas, and understory vegetation responded through simultaneous reductions in redstem filaree and increases in downy brome relative to control areas. Plant establishment of seeded species did not vary between old and new varieties, but species showed large differences in establishment across sites. Our talk will explore both within-site and among-site variability in vegetation dynamics to reach an understanding of the interactive effects soil pre-treatment conditions, shrub reduction, and herbaceous response. 

USING NATIVE WEEDS FOR RESTORATION: CAN NATIVE ANNUALS HELP, RATHER THAN HURT, RESTORATION EFFORTS?

In the Great Basin, native annual plants occupy a niche similar to the niche exploited by invasive annuals, increasing in abundance after soil disturbances and wildlife. In arid systems, some native annual species have been shown to compete effectively with weeds. Native annuals are also an important component of wildlife habitat, and provide resources for many species. Despite their ecological importance, native annuals have rarely been used in restoration and habitat improvement projects in the Great Basin, and their potential for propagation has not been investigated. Seed source development for restoration and wildlife habitat improvement has focused on native perennials, and great strides have been made for those species. Similar work has not been attempted for annual species, despite preliminary results that suggest that annual species can play important roles in occupying disturbed habitats and reducing the fecundity of annual weeds. Here, we present evidence from field and greenhouse trials indicating that native annuals can compete effectively with invasive annual plants, as well as results from seed increase trials of wild-collected populations. While native annuals are, by definition, short-lived additions to any restoration project, their ability to quickly increase from seed and persist in the seed bank during unfavorable periods makes them a unique contributor to current restoration mixes, which typically focus on perennial species that may be slow to reproduce and are vulnerable to drought or other disturbances. Incorporating native annuals into restoration projects may allow for increased restoration success, and developing effective methods for seed increase will allow the seeding of larger-scale trials in invaded and degraded habitats. 

SOCIO-ECOLOGICAL TRANSFORMATION OF THE GREAT PLAINS THROUGH JUNIPERUS INVASION

Many ecological studies and observations indicate that the increased dominance of woody plants on Great Plains grasslands is a major threat to agriculture and conservation of grassland ecosystems. It is generally agreed that the dominant driver of invasion is fire suppression and altered fire regimes, while restoration is often discussed in terms of thresholds. With Juniperus invasion in the Great Plains, models predict that conversion of grassland to woodland can happen as quickly as 25-45 years and have identified thresholds for associated tree size and herbaceous biomass (fine fuel) that are related to fire frequency, fire intensity and other fuel-load altering processes. Our ecological understanding of the conversion process has progressed over the past several decades because of sound ecological studies, but patterns predicted by models are often incomplete in the privately owned landscapes of the Southern Great Plains. Sociological drivers exist that explain these patterns and are influenced by many social entities that range in scale from the federal government to the individual land owner. The traditional network of government agencies, such as USDA-NRCS and University Cooperative Extension Services, combined with the development of land-owner cooperatives, user groups and the Great Plains Fire Science Exchange has limited the invasion of these fire-sensitive trees in many places. Socio-ecological relationships among government agencies, land-owners and these new emergent organizations have managed to develop approaches to overcome thresholds and barriers predicted by the ecological models. 

FIRE AND BROWSING EFFECTS ON WOODY ENCROACHED GRASSLANDS.

North American grasslands historically had a suite of large herbivores that not only grazed (i.e. bison) but also browsed (i.e. elk, pronghorn, deer). Elk in the tallgrass prairie were extirpated by the 1860’s and at the same time homesteading increased which decreased fire frequencies. The loss of these two drivers (browsing and fire) has coincided with the conversion of grassland to shrubland/woodland over the last 150 years in the tallgrass prairie. Woody expansion can be categorized in to two groups: non-resprouting species that can be killed with fire and resprouting species that cannot be killed with fire. Resprouting species require additional active management strategies to remove them from encroached grasslands. In this study we investigate community, stem density and physiological effects of continuous simulated browsing and prescribed fire on Cornus drummondii, a resprouting native woody species, in hopes to understand how a reintroduction of the historical drivers can potentially reverse woody expansion.

CAN WE SUSTAINABLY MANAGE MESQUITE, A FIRE-RESISTANT NATIVE INVASIVE SHRUB? Jim Ansley*; Oklahoma State University, Stillwater, OK

Much of the Southern Great Plains (USA) grasslands have become dominated by native invasive woody plants such as honey mesquite (Prosopis glandulosa) and juniper (Juniperus spp.) in the last 100 years.  Mesquite has increased due to enhanced seed distribution via livestock consumption and fecal deposition, reduced frequency and intensity of fire, and livestock overgrazing that has weakened grasses competing with emerging shrub seedlings.  This vegetation shift has become so pervasive that it threatens grass-dependent livestock production and grassland-dependent plant and wildlife species.  Concurrently, different wildlife species and different income sources such as recreational hunting for shrub-dependent wildlife have developed that further threaten the impetus for grassland restoration. This trajectory will continue without anthropogenic brush management intervention. Mesquite is difficult to control in part because it can resprout following treatments that only kill above ground tissue (i.e., top-kill), such as fire or mechanical shredding. Moreover, recent studies have shown that mesquite regrowth following top-kill is essentially independent of extreme drought.  Application of chemical spray treatments via aircraft offer the best potential regarding precision of application and effect, but costs are high relative to potential grazing income generated from these lands.  This paper will summarize these various concerns and point to possible management solutions that achieve agricultural production, recreation and ecological restoration goals.   

A MULTI-SCALE RESILIENCE-BASED FRAMEWORK FOR RESTORING AND CONSERVING WET MEADOWS AND RIPARIAN ECOSYSTEMS

Riparian and wet meadow ecosystems comprise small percentages of aridland landscapes, but provide critical resources for upland, riparian, and stream-dependent species and supply water to downstream users and communities. Many of these systems have been degraded by various anthropogenic activities and are further threatened by climate change. We are developing a strategic, multi-scale framework for assessing resource values and threats to riparian and meadow ecosystems using resilience science that is broadly applicable. The framework provides the capacity to (1) prioritize riparian ecosystems for management based on ecosystem characteristics and response to disturbance, and (2) determine effective management strategies based on ecosystem resilience and resource values. We define resilience of wet meadow and riparian ecosystems as the capacity to regain fundamental structure, processes, and functioning when stressors and disturbances alter geomorphic and hydrologic regimes and vegetation communities. The framework builds on our prior development of a hierarchical classification of watershed types and their relative resilience to disturbance and is based on watershed geology and hydrogeomorphic characteristics, riparian corridor and valley characteristics and valley segment and stream reach characteristics. Similarly, meadow types are classified based on watershed, valley segment, and reach-scale geomorphic and hydrologic characteristics, and relative resilience to disturbance.  We are identifying focal species, including Lahontan cutthroat trout and Greater sage-grouse, and evaluating their associations with watersheds with different hydrogeomorphic relationships and relative resilience. We also are identifying the key threats within the watershed and determining how they vary across the region. Databases, field guides, and other tools are being developed in collaboration with regional managers. The framework enables managers to use the best science available to focus management actions in locations where they will have the greatest benefits for restoring and maintaining wet meadows and riparian ecosystems and conserving the many species that they support.

UNDERSTANDING AND ASSESSING WATERSHED RESILIENCE TO DISTURBANCE. Jerry R. Miller*; Western Carolina University, Cullowhee, NC

Developing effective management strategies for wet meadow and riparian ecosystems begins with an understanding of watershed resilience to disturbance. Late Holocene geomorphic and stratigraphic data collected from upland watersheds in central Nevada reveal that natural and anthropogenic disturbances during the past several centuries have led to two primary types of geomorphic response: channel incision and channel avulsion. Both can have significant detrimental effects on wet meadow and riparian ecosystems by lowering groundwater levels and altering the distribution, composition, and diversity of the existing vegetation. Our earlier geomorphic and hydrologic investigations of more than 50 upland watersheds in the Great Basin demonstrated that these catchments respond differently to external perturbations, and are characterized by different degrees of resilience to these disturbances. The most sensitive (dynamic) systems are characterized by basin traits that (1) promote  rapid, high magnitude flood flows, (2) generate relatively fine-grained channel bed material and (3) have large quantities of highly mobile sediment. A hierarchical analysis of these and other watershed traits allowed for the classification of the basins into four primary groups of basin sensitivity/resilience. Work conducted during the past year is expanding the initial classification developed for central Nevada and applying it to other areas of the Great Basin. Ultimately, the ability to identify a basin’s sensitivity to disturbance provides land managers with a powerful tool for managing land use.  Moreover, the classification scheme provides insights into the potential success of restoration programs for channels characterized by different types of geomorphic processes and response rates.

GEOMORPHIC AND HYDROLOGIC CONTROLS ON EXTENT AND COMPOSITION OF RIPARIAN VEGETATION. Peter J. Weisberg*¹, Jeanne C. Chambers², Blake Engelhardt³, Anna Knight¹; ¹University of Nevada, Reno, Reno, NV, ²USDA Forest Service, Reno, NV, ³United States Forest Service, Bishop, CA

Riparian vegetation is structured by hydrogeomorphic processes operating along a nested hierarchy of scales including the watershed, riparian corridor, and stream reach. Yet most studies have focused on reach-scale channel characteristics with limited consideration of either the watershed geomorphic characteristics or longitudinal position along the stream network. We quantified the influences of watershed and reach-scale characteristics in structuring riparian vegetation in small mountain watersheds within the Great Basin. At the watershed scale, bedrock lithology and basin morphometry combined to influence vegetation extent and composition. Riparian extent  was positively related to intrusive bedrock and drainage density, and negatively related to percentage carbonate bedrock and relative stream power. Disturbance adapted riparian tree and shrub species were prevalent in small, rugged, and high-relief watersheds. In contrast, meadow vegetation was favored in large, low-gradient watersheds with alluvium, carbonate and metasedimentary rock types and large side-valley alluvial fans. Riparian vegetation was also strongly influenced by longitudinal position within the watershed. For example, riparian aspen forest was more prevalent in steep, high-elevation parts of the watershed with high stream gradients, riparian willow and shrub communities in middle elevations where valleys broaden, and river birch communities where canyons narrow and frequent flooding occurs. At the reach scale, vegetation structure was strongly related to channel and bank characteristics such as terrace height, particle size, stream slope and width/depth ratio. Results are generalized to develop process-based management guidelines specific to watersheds with different hydrologic and geomorphic characteristics and, thus, resilience to disturbance. By evaluating the plant community with respect to its geomorphic context, our work identifies riparian systems that have greatest susceptibility to ecological state transitions resulting from stream incision and decreases in water tables. Our restoration guidelines incorporate plant community indicators within the overall hydrogeomorphic context driving vegetation patterns and responses to disturbance.

GEOLOGIC AND GEOMORPHIC CONTROLS ON GROUNDWATER AND SURFACE WATER AT REACH TO WATERSHED SCALES
. Mark Lord*, Jerry R. Miller; Western Carolina University, Cullowhee, NC

ABSTRACT

Riparian and wet meadow ecosystems are a critical ecological and human resource throughout the Great Basin.  Understanding the controls on surface and subsurface water is an essential component in evaluating the resilience of stream and groundwater dependent ecosystems and determining effective management strategies. Our prior research on 56 riparian wet meadows in central Nevada indicates that meadows occur in groundwater discharge zones with high groundwater tables.  These types of areas occur where geologic conditions have created significant sediment deposits that include fine-grained materials, for example, areas upstream of side-valley alluvial fans.  Wet meadows require high groundwater tables and can form independently of streams, but they are threatened by stream erosion.  Stream incision lowers groundwater tables and new stream channels can cut through stratigraphic units essential to supporting high-water tables.  The degree of loss of wet meadows due to incision is controlled by site characteristics such as the direction of groundwater flow, stratigraphic complexity, and the interaction of stream and groundwater.  Because different types of wet meadow vegetation have different groundwater depth requirements, patterns of vegetation can be used effectively and efficiently to provide a preliminary assessment of the controls on meadow location and sensitivity to stream incision.  At larger, watershed scale, similar variables can be used to understand the distribution and hydrologic function of riparian and meadow ecosystems.  The presence of perennial streams and wide valleys with significant sediment accumulations generally correlate with basins with meadows and wide riparian zones.  Alternatively, basins with low permeability bedrock and little sediment accumulation tend to lack meadows and have streams that can produce high-magnitude floods.  The ability to characterize the hydrologic setting and controls on meadow ecosystems are fundamental to our ability to develop a framework to support effective watershed management.

PREDICTING STREAMFLOW SENSITIVITY TO CLIMATE IN A DATA-POOR REGION – A NEW TOOL FOR WATER MANAGERS IN THE GREAT BASIN.