Weed Science Commons^™

Challenges And Opportunities For Revegetation In Areas Dominated By Invasive Annual Grasses, B. A. Mealor, J. A. Crose

IGC Proceedings (1997-2023)

Invasive annual grasses (IAG) are a primary ecological threat to sustainability and ecological integrity of rangelands in the western U.S. While availability of effective tools to control IAG is increasing, ensuring compatibility of control practices with other management practices, such as seeding desirable species, is a critical information need. We summarize a series of studies investigating influences of timing, seeding depth, species selection, and planting timing with various herbicides in sites dominated by invasive annual grasses.

Invasion Ecology And Response To Fire Of The Nonnative Fern Lygodium Microphyllum In The South Florida Everglades, Nicole Sebesta

FIU Electronic Theses and Dissertations

Lygodium microphyllum (Old World Climbing Fern (OWCF)) is a climbing fern native to tropical and subtropical regions of Australia, Asia, and Africa. First introduced to Florida as an ornamental in the 1960s, the fern has become a serious invasive in numerous Florida habitats, severely degrading native herbaceous and woody vegetation and altering fire behavior. One area with the greatest increase in OWCF cover is the sawgrass marsh of southern Everglades National Park (ENP), where prescribed fire is used for both maintenance of sawgrass marshes and management of OWCF infestations. However, the efficacy of OWCF control using fire in this habitat …

Salvinia Molesta: An Assessment Of The Effects And Methods Of Eradication, Arti Lal

Master's Projects and Capstones

Salvinia molesta is an invasive aquatic fern. It is now the second worse aquatic invader in the world. Since the 1930s, it has invaded most tropical and some temperate countries. S. molesta plants grow vegetatively and can increase in size rapidly. S. molesta can form thick mats of up to 1-meter-thick. There are a number of ways these thick mats negatively affect the environment: 1) reduce light to benthic organisms, 2) reduce oxygen in the water column for other organisms, 3) accumulate as organic matter at the bottom of the water column, 4) decrease nutrients for other organisms, and 5) …

The Effects Of Fire On Spore Viability Of Lygodium Microphyllum (Old World Climbing Fern), Nicole Sebesta

FIU Electronic Theses and Dissertations

Lygodium microphyllum, native to the Old World tropics, has invaded central and southern Florida, destroying native habitats, reducing biodiversity and altering fire regimes. Prescribed fire, one of several methods used to manage L. microphyllum infestations, reduces fern biomass over large areas, but its effects on spore viability are unknown. To provide tools to evaluate whether fire-dispersed spores are viable, this research determined how heat affects spore viability. Spores were exposed to temperatures of 50°C to 300°C for durations of 5 seconds to 1 hour, then allowed to germinate on agar in petri plates. Percent germination was assayed after two …

Exploring The Seed Bank Dynamics Of Red Brome: Longevity, Density, And Relationship To Fire, Benjamin S. Jurand

UNLV Theses, Dissertations, Professional Papers, and Capstones

This research explores several untested aspects of the seed bank characteristics of red brome (Bromus rubens), an invasive annual grass in southwestern United States arid lands. Red brome is a formidable competitor to native plant species, both annual and perennial alike, and produces many seeds that germinate easily. The stalks of red brome contribute continuous-cover fuel loads that facilitate wildfires destructive to mature native Mojave Desert plant communities. This makes it a priority species for land managers, particularly when dealing with recovery after fire.

This project addressed questions related to the longevity of red brome seeds in soil seed banks …

Native And European Haplotypes Of Phragmites Australis (Common Reed) In The Central Platte River, Nebraska, Diane L. Larson, Susan M. Galatowitsch, Jennifer L. Larson

Great Plains Research: A Journal of Natural and Social Sciences

Phragmites australis (common reed) is known to have occurred along the Platte River historically, but recent rapid increases in both distribution and density have begun to impact habitat for migrating sandhill cranes and nesting piping plovers and least terns. Invasiveness in Phragmites has been associated with the incursion of a European genotype (haplotype M) in other areas; determining the genotype of Phragmites along the central Platte River has implications for proper management of the river system. In 2008 we sampled Phragmites patches along the central Platte River from Lexington to Chapman, NE, stratified by bridge segments, to determine the current …

Assessing Invasive Plant Species As Threats In Mojave Desert Parks, Sara L. Mcpherson, Donovan J. Craig, Scott R. Abella

Graduate Research Symposium (GCUA) (2010 - 2017)

The invasion and persistence of exotic plant species threatens the natural features that national parks are designed to protect. For example, park managers have witnessed an increase in the frequency, extent and intensity of fires along with a reduction in native species richness and diversity. Many park managers are familiar with a suite of highly invasive plants, but lack a comprehensive and systematic way of prioritizing invasive plant species based on potential threats to the parks’ resources. We have entered into a collaborative project with the National Park Service’s Inventory and Monitoring program to develop an invasive plant early detection …

Research Poster: Physiological Responses Of Two Invasive Annual Grasses, Cheatgrass And Red Brome, In The Great Basin, L. Hernandez, R. Nowak, L. Salto

2010 Annual Nevada NSF EPSCoR Climate Change Conference

Research poster

Trying To Beat The Brome: Understanding Establishment Thresholds And Choosing Competitive Native Species At Parashant National Monument, Scott R. Abella, E. Cayenne Engel

Public Policy and Leadership Faculty Publications

Desert fires fueled by exotic grasses like the omnipresent red brome (Bromus rubens) can be intense and cause widespread mortality of native vegetation. Native desert scrub communities such as those dominated by blackbrush (Coleogyne ramosissima) do not readily reestablish after fire (Abella 2009) and may even become more abundant in the post-burn landscape initiating a fire cycle that occurs at a greater frequency than the recovery time of the long-lived desert perennial community.

Native Species Interactions With Red Brome: Suggestions For Burn-Area Revegetation, Scott R. Abella

Public Policy and Leadership Faculty Publications

In deserts, native perennial plants often actually facilitate the establishment of exotic annual grasses. One of our focal areas of research is to identify native species for use in revegetation projects that reduce the establishment of exotic annual grasses, or at least do not strongly facilitate exotic species establishment. An initial research effort involving a competition experiment of red brome with native species and a correlational field study of brome distribution among native perennial plants is in press with the journal Invasive Plant Science and Management.

Heat And Smoke Effects On Red Brome Soil Seed Banks, Scott R. Abella, E. Cayenne Engel

Public Policy and Leadership Faculty Publications

Management of exotic plants that are annuals entails understanding and managing their soil seed banks. We completed a study of the influences of heat and liquid smoke on red brome (Bromus rubens) soil seed banks collected from Red Rock Canyon in southern Nevada as part of a collaborative fire effects monitoring effort with Bureau of Land Management - Las Vegas. We collected the samples from the 2005 Loop Fire, where we observed in a monitoring field study that exotic grasses such as red brome were relatively sparse in the first 2-3 years (which were during a dry period) following the …

Keeping Fountain Grass Out Of The Mojave Desert, Curt Deuser

Lake Mead Science Symposium

Fountain Grass (Pennisetum setaceum) is an escaped ornamental perennial bunchgrass from Africa that has invaded parts of Hawaii and the Sonoran Desert. It is adapted to fire and increases hazardous fuels causing wildfires in areas that may not have historically occurred. It was detected in the late 1990’s within the Mojave Desert at Joshua Tree NP and along the Colorado River corridor on the shores of Lake Mohave. The extent of these populations was limited and a rapid response was necessary to keep it from spreading out of control. If no action is taken then fountain grass would spread by …

Early Post-Fire Plant Establishment On A Mojave Desert Burn, Scott R. Abella, E. Cayenne Engel, Christina L. Lund, Jessica E. Spencer

Public Policy and Leadership Faculty Publications

Fire has become more extensive in recent decades in southwestern United States arid lands. Burned areas pose management challenges and opportunities, and increasing our understanding of post-fire plant colonization may assist management decision-making. We examined plant communities, soils, and soil seed banks two years after the 2005 Loop Fire, located in a creosote-blackbrush community in Red Rock Canyon National Conservation Area in southern Nevada’s Mojave Desert. Based on a spring sampling of 20, 0.01-ha plots, live + dead cover of the exotic annual Bromus rubens averaged nine times lower on the burn than on a paired unburned area. Perennial species …

Estimating Soil Seed Bank Characteristics In Ponderosa Pine Forests Using Vegetation And Forest-Floor Data, Scott R. Abella, Judith D. Springer

Public Policy and Leadership Faculty Publications

Soil seed banks are important for vegetation management because they contain propagules of species that may be considered desirable or undesirable for site colonization after management and disturbance events. Knowledge of seed bank size and composition before planning management activities facilitates proactive management by providing early alerts of exotic species presence and of abilities of seed banks to promote colonization by desirable species. We developed models in ponderosa pine (Pinus ponderosa) forests in northern Arizona to estimate the size and richness of mineral soil seed banks using readily observable vegetation and forestfloor characteristics. Regression models using three or fewer predictors …

Plant Community Response To Fire: A Chronosequence Study, Scott R. Abella, E. Cayenne Engel

Public Policy and Leadership Faculty Publications

Fires are becoming more prevalent events across the landscape in the southwestern US. Over the next several decades the already arid southwest is predicted to become warmer and drier, with longer summers, and an increase of “extreme” weather events such as lightening inducing thunderstorms. While the “hotter and drier” forecast may indicate less abundant plant life, and thus less available biomass for fuel, exotic invasive plant species are becoming more dominant across the landscape with increases in human travel and commerce. Exotic species (particularly many of the invasive grasses) are adding fuel for the fires to burn when the annuals …

Exotic Annual Plant Invasions And Their Relationships To Roads And Native Perennial Species In The Mojave Desert, Southwestern Usa, Donovan J. Craig, Jill Pacovsky Craig, Scott R. Abella

Vegetation Monitoring Presentations

For the last five years, roadside monitoring for exotic invasive species has been a common practice for documenting distributions in Clark County, Nevada (Abella et al., in press). Yet, studies have shown that weed relationships to road corridors differ depending upon the natural system (Hansen and Clevenger, 2005). In the Mojave Desert, it is unknown whether exotic species are limited to or even predominant along roadsides.

Compounding this uncertainty, fertile islands under shrubs are known to enhance conditions for many annuals (Thompson et al., 2005). Thus, a site’s shrub composition could influence exotic invasive plant distributions.

Implications For Management Prioritization Of Exotic Annual Weed Monitoring Near Roadsides In The Eastern Mojave Desert, Usa, Donovan J. Craig, Jill E. Craig, Scott R. Abella, Public Lands Institute,

Vegetation Monitoring Presentations

Invasive exotic plants provide an unnatural conduit for fires in the Mojave Desert. For the last five years, roadside monitoring for exotic invasive species has been a common practice for documenting distributions in Clark County, Nevada (Abella et al., in press). Yet, studies have shown that weed relationships to road corridors differ depending upon the natural system (Hansen and Clevenger, 2005). In the Mojave Desert, it is unknown whether exotic species are limited to or even predominant along roadsides.

Compounding this uncertainty, fertile islands under shrubs are known to enhance conditions for many annuals (Thompson et al., 2005). Thus, a …

Management Techniques For The Control Of Sahara Mustard (Brassica Tournefortii) In The Mojave Desert, Dianne N. Bangle, Scott R. Abella, Public Lands Institute,

Vegetation Monitoring Presentations

In the southwestern United States, Brassica tournefortii(Sahara mustard) is a highly invasive plant that colonizes roadsides, beaches, sand dunes, and open desert threatening native annuals. Sahara mustard is believed to contribute to fuel loads in the Mojave Desert in areas where Schismussp. and Bromussp. occur. Sahara mustard may act as ladder fuel, thereby facilitating the spread of fire throughout the landscape. Manpower limitations and insufficient funding limits the abilities of managers to effectively control Sahara mustard. We tested seed germinability in Sahara mustard after fruiting plants were treated with either 2%, 5%, or 12% triclopyr. Sahara mustard seed pods were …

Response Of Sahara Mustard (Brassica Tournefortii) To Water Addition And Soil Disturbance, Alexis Suazo, Jessica E. Spencer, Scott R. Abella

Vegetation Monitoring Presentations

Invasive exotic species can have a significant impact on the structure, function, and diversity of ecological communities. Sahara mustard (Brassica tournefortii) is one of the top exotic invasive species spreading through the southwestern deserts of North America. In arid environments, it is well documented that species abundance is sensitive to rainfall (Beatly 1974, Ernest et al. 2000). In the Mojave Desert, winter precipitation can trigger massive germination events (Beatly 1974). As a winter annual, Sahara mustard may have a positive response to winter precipitation by germinating, growing, and reproducing before native annuals, monopolizing soil moisture and nutrients, and potentially changing …

Alien Invaders: Envisioning Exotic Species In Florida, Kevin Archer

All Faculty Scholarship for the School of Graduate Studies and Research

No abstract provided.