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Collaborative Research: Seed-fungal interactions: uncovering functional specificity and primary symbionts as key drivers of tropical tree recruitment
No full textEffect of thermodynamic parameters and intrinsic properties on crystallization kinetics and physical properties of fats
No full textCAREER: End-to-End Active Region-based Heliospheric Forecasting System using Multi-spacecraft Data and Machine Learning
No full textCollaborative Research: RAPID: Fault rupture and spring sampling of the 2023 Kahramanmaras, Turkey, earthquake sequence ruptures
No full textNear-Earth Object (NEO) Surveyor Introduction “NEOS”
No full textNEOS - Near-Earth Object Surveyor (NEOS) - Its Mission - Its Importance - How it’s built - What you will see today Where piece parts were made Where it will be assembled Where it will be teste
Sexual and Vegetative Recruitment of Trembling Aspen Following a High-Severity Boreal Wildfire
No full textBackground High-severity fire is rare in trembling aspen-dominated forests of the boreal region. The post-fire recruitment strategy of aspen, by either vegetative suckering or sexually (i.e., by seed), has considerable implications for subsequent forest structure, genetic diversity, and ecological resilience to shifting climatic and disturbance regimes. In this study, we take advantage of the unique opportunity provided by the Chuckegg Creek Wildfire Fire (310,000 ha) in northern Alberta, Canada, which burned at high severity through aspen stands before and after spring green-up, to document how phenology, fire severity, and stand characteristics affect recruitment one year following the fire.
Results We found sites were dominated either by high-density patches of seedlings or a fairly uniform density of suckers, with few sites occupied by both. Sites dominated by seedlings burned predominantly after green-up. Using boosted regression trees, we found that surface fire severity best predicted both aspen seedling and sucker density at sites. Seedlings were favoured at sites that burned at high surface severity and after spring green-up, whereas suckering density was highest at sites that burned at moderate-high surface severity before green-up.
Conclusion Our research highlights the influence of surface fire severity and phenology on aspen recruitment. High fire severity, particularly after aspen green-up, reduced suckering while promoting seedling recruitment. Aspen seed‑ lings filled the recruitment gap caused by this lowered, suckering response, providing an alternate route for aspen forest adaptive capacity after high-severity surface fire
Evaluating Use of Multiple Hydrologic Storage Indicators to Enhance Streamflow Forecasting
No full textAccurate seasonal streamflow forecasts are essential for managing water resources in the western United States, where much of the water supply depends on snow accumulation and melt. Water managers, farmers, and communities rely on these forecasts to plan for water use, prepare for droughts, and protect the environment. However, traditional forecasting methods often do not fully use all the available information about how water is stored in the landscape, such as in snowpacks, soil moisture, and groundwater. This can limit the accuracy of predictions and make water management more difficult.
This study aimed to improve streamflow forecasts by explicitly including multiple hydrologic storage indicators, namely, snow water equivalent (SWE), January baseflow, and soil moisture, within forecasting models for watersheds in two important basins: the Upper Colorado River Basin and the Great Salt Lake Basin. January baseflow, the streamflow that occurs during winter when there are limited water inputs, has been suggested as an indicator of groundwater storage. By testing various combinations of these indicators, the research showed that including them improves forecast accuracy, especially in the mountainous headwater areas where natural hydrologic processes remain largely undisturbed. Among the indicators tested, soil moisture was consistently the best at incrementally improving current National Weather Service seasonal water supply forecasts, highlighting its crucial role in these regions. Soil moisture also proved to be a key predictor, often providing the largest gains in forecast skill when added by itself to the official Colorado Basin River Forecast Center Most Probable forecast. This highlights the important role of antecedent soil moisture conditions in determining how much rainfall and snowmelt actually reaches rivers and streams, especially during the spring runoff season.
This research is important because more reliable streamflow forecasts help water managers make better decisions about reservoir operations, irrigation, and drought planning. Communities can better prepare for water shortages or flooding, farmers can optimize irrigation, and environmental protections can be more effectively targeted. By providing a practical way to include multiple types of water storage information, this study offers a path toward improving water forecasts and supporting sustainable water management across the interior western United States, where every drop of water counts
Lagomorphs, Ungulates, and Predation: Exploring Interactions and Quantifying the Effect of Lagomorph Herbivory in Rangelands
No full textRangelands are expansive ecosystems that make up more than 30% of the total surface land area in the contiguous United States. In the west, they are typically categorized as shrublands, grasslands or deserts with low precipitation. The vegetation communities consist largely of grasses and forbs and are thus widely used for livestock grazing. Despite their barren appearance, rangelands are diverse ecosystems that are home to a wide breadth of species. The Henry Mountains, located in south central Utah, is one example of this system type. With their inspiring red-rock mesas and towering plateaus, this public land, managed by the Bureau of Land Management (BLM), is home to an array of diverse wildlife. Bison, mule deer, black-tailed jackrabbits and desert cottontails are some of the animals that graze alongside cattle, while coyotes prey on smaller mammals, like rodents, rabbits, and hares. There is a strong focus on livestock and larger game species in rangelands, so the impacts of smaller herbivores often go unrecognized. However, rabbits and hares have high metabolic needs and are preferential foragers, qualities that suggest they may have a greater impact on the plant community than generally thought. Understanding their role requires a greater understanding of their behaviors and the broader ecological context that shapes their populations. The BLM manages livestock and hunting permits. Moreover, coyotes and other predators are often controlled in rangelands through lethal, state-led measures that aim to reduce their population sizes. Predator control may provide an opportunity for rabbit and hare populations to increase, thereby increasing their potential effects on plant communities. Recognizing these dynamics is essential for the development of effective management practices that account for the full complexity of rangeland ecosystems. My research found that rabbits and hares reduced native forbs while promoting invasive forbs through selective foraging. I also validated that pellet counts were a reliable estimator of lagomorph abundance, and camera traps revealed a positive relationship between lagomorphs and coyotes. Together, these findings highlight the dual role of lagomorphs as influential herbivores and key prey species, underscoring their relevance in rangeland management and food web dynamics
Biocontrol of Canada Thistle (\u3ci\u3eCirsium arvense\u3c/i\u3e) With the Rust Fungus, \u3ci\u3ePuccinia punctiformis\u3c/i\u3e in the Intermountain West: Integrated Weed Management Compatibility and Characterization of Microbiome Associations
No full textCanada thistle (Cirsium arvense) is an invasive weed of major concern in both agricultural and native areas. It competes against native plants, reduces crop production and quality, and causes significant costs in management and damages. Canada thistle can survive and spread through seeds, but primarily does so through its extensive root system, which causes the greatest management difficulties. There are several control methods for this invasive weed, herbicides are perhaps the most common and effective, however, they have limitations and negative consequences. Herbicide use near waterways is restricted and there are growing concerns of the development of herbicide resistance. Biological control is an alternative method to herbicides, and the Canada thistle rust fungus (Puccinia punctiformis) is already naturally occurring with the plant and is highly host specific (i.e., it only infects the thistle). My dissertation aims to understand how the rust works within an integrated weed management (IWM) program, which combines multiple control methods, and to identify the microbial communities that live on and inside Canada thistle. The research explores how these microbes may affect the rust fungus’s effectiveness, and how we can use this knowledge to better control the weed. My second chapter includes two IWM experiments (Utah and Colorado) that were conducted to monitor ground coverage, Canada thistle stem density, and rust incidence during application of different control Canada thistle control methods. While I did observe that rust alone decreased thistle density, it was far less effective compared to herbicide treatments, and its impact when integrated with mowing or tillage varied. My third and fourth chapters show how the microbes associated with Canada thistle differed throughout two spore stages of the pathogen, in and on the plant, and between healthy and infected plants. I did this by characterizing the microbe communities and analyzing the microbe associations in these various states. Microbes of the leaf surface were more diverse than inside the plant. I also found that disease state (whether the plant was symptomatic or not) and time of year (early and late season) led to differences in microbe communities. Multiple microbes were identified as having significant associations with specific disease states and spore types. These associations could be exploited for control efforts, such as being selected for their relationship with the biocontrol agent and Canda thistle to increase biocontrol effectiveness. Further studies will enable us to determine how much these microbes will improve the rusts\u27 effectiveness and what role it will continue to have in an IWM program for improved management of Canada thistle
Multi-Agent Robotaxi Dispatch Coordination in a Real-World Simulation – Optimizing Rider Assignment, Rebalancing, and Charging Using Battery-Dependent Rewards and Welfare Maximization
No full textWe propose an approach to coordinate a robotaxi fleet for an autonomous ride-hail service. This is a service similar to a traditional ride-hailing service (Uber, Lyft), where customers request a ride and are then picked up in a car and dropped off in a new location; except, driverless vehicles called robotaxis are used to transport the customers.
Our approach teaches helpful coordination strategies to a robotaxi fleet while taking into account the individual battery level of the robotaxis. Each robotaxi acts as an individual agent in our simulation and can choose to pick up a rider, reposition to a new area, or charge. Consider a group of robotaxis that needs to decide which nearby rider would be most valuable for each vehicle to pick up. Our approach maximizes the benefit of the overall system rather than any individual robotaxi’s reward.
Charging autonomous robotaxis is often more difficult than charging standard electric vehicles (EVs), as they do not have drivers who can plug them in at publicly available EV chargers. Because of this, our work focuses on a scenario in which robotaxis must return to a central Operations Depot to charge. We incentivize robotaxis with a higher battery level to pick up riders and reposition farther away from the Operations Depot.
We develop a real-world simulation that utilizes data from the City of Chicago to simulate realistic timing for trip requests around the city. Our results show that using our learning strategies to coordinate robotaxi actions significantly increases the service rate and earning potential for an autonomous ride-hail service