Weed Science Commons^™

Rejuvra's Effect On Soil Seed Banks, Blake J. Roeslein, Bryan Endress, Abby Mcmurtry, Akasha Faist

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Invasive annual grasses are a major driver of grassland degradation globally. In perennial grasslands, invasion can heavily impact biodiversity, including potential changes to the soil seed banks. Seed banks, the living seeds stored in the upper soil column, play an important role in healthy systems, or can harbor invasive species. To reduce negative invasion outcomes, whether in the seed bank, or aboveground vegetation, pre-emergent herbicides are a commonly used tool for land managers. Pre-emergent herbicides work by targeting seeds as they germinate and begin emerging from the soil. Thus, our study asks 1) how does pre-emergent herbicide influence germination and …

Exploring The Impact Of Invasive On Grassland Diversity: A Study In Montana, Ella Gaffney

Undergraduate Theses, Professional Papers, and Capstone Artifacts

For the capstone project with the University of Montana Davidson Honors College, I investigated the diversity index of grassland and rangeland plots across the state of Montana. My study, conducted from June to August 2023, includes data collected by my team. The purpose of this research project was testing the hypothesis that the diversity index decreases in plots containing invasive grass species.

During the summer of 2023, the Spatial Analysis Lab surveyed over 1000 plots in rangelands and grasslands across the state of Montana to locate an invasive grass, Ventenata dubia. Data collected includes species identification, ocular estimates of …

Impact Of Arbuscular Mycorrhizal Fungi On Conyza Canadensis Drought Responses And Possible Mechanisms, Kian G.M. Speck, Ylva Lekberg, Anna Sala

Undergraduate Theses, Professional Papers, and Capstone Artifacts

• Arbuscular mycorrhizal fungi (AMF) are important plant mutualists that can facilitate plant responses to various environmental stressors, such as drought. A plant that may benefit from AMF-induced drought tolerance is Conyza canadensis due to its ability to thrive in dry conditions and its high colonization rate. However, no studies have researched C. canadensis in this context and the exact mechanisms of AMF-induced drought tolerance are still unknown.
• To better understand if and how AMF facilitate drought response in C. canadensis, we conducted a greenhouse experiment comparing the response of mycorrhizal and non-mycorrhizal plants to three watering levels. We measured …

Collaborative Conservation And Backcountry Weed Control: A Case Study Of The Great Burn Proposed Wilderness, Christopher James Prange

Graduate Student Theses, Dissertations, & Professional Papers

Noxious weeds have become a management priority on public lands in the United States. Managing invasive weed populations in natural areas with complex ecosystems presents issues that need a systems-wide approach over long temporal and spatial scales. This broad-scale problem increasingly demands collaborative efforts. While collaborative conservation has become a tool in natural resource management during the 21^st century, it is less commonly applied in weed control in backcountry wilderness areas. Programs that have been initiated are understudied. Accordingly, this research was conducted through semi-structured interviews to gather perspectives of weed professionals involved in a collaborative backcountry weed program …

Managing Forest Disturbances: Effects On Mule Deer And Plant Communities In Montana's Northern Forests, Teagan Ann Hayes

Graduate Student Theses, Dissertations, & Professional Papers

Mule deer (Odocoileus hemionus) are frequently the focus of population and habitat management in the western United States. Land and wildlife managers use disturbance to reset forests to earlier successional stages and improve the quality and quantity of forage available to mule deer. However, the effects of management practices on nutrition and selection vary widely, so the implementation of management practices raises ecological as well as management-related concerns. This work investigated how disturbance from wildfire, prescribed fire, and timber harvest influences the spatial and temporal distribution of nutritional resources in mule deer summer range, and therefore, how the …

Drivers And Feedbacks Of The Fire-Grazing Interaction In The Northern Great Plains, Jacob E. Powell

Graduate Student Theses, Dissertations, & Professional Papers

The fire-grazing interaction is well studied in mesic grasslands worldwide, but research is lacking in semiarid systems. In addition, the fire-grazing interaction reduces the invasion of exotic forage species in mesic grasslands by increasing the scale of grazing selection and may be a tool to control invasive plants in other grasslands. We examined the principal drivers and feedbacks of the fire-grazing interaction on the strength of cattle grazing selection, forage quantity and quality, and vegetation structure and composition in two pastures in northeast Montana at The Nature Conservancy’s Matador Ranch. We also determined the influence of time since fire, within …

Does Timing Of Herbicide Use Influence Rates Of Germination Or Seedling Biomass Of Native Plants Used For Restoration?, Christine Mcmanamen

Graduate Student Theses, Dissertations, & Professional Papers

Invasive plants can negatively impact native grasslands by changing their species composition, productivity, and function. Managers commonly use herbicides as a control method; however, this practice can lead to secondary invasion by other non-native invasive plants, unless measures are taken to promote natives. Because of this, managers often seed native plants after spraying herbicides. There is evidence, however, that chemical control of invasive plants may reduce the effectiveness of subsequent seed-addition treatments, but there is currently little quantitative information on optimal timing between spraying and seeding or on variation in herbicide sensitivity among native plants commonly used in seed mixes. …