Life Sciences Commons^™

Plant-Soil Feedbacks Help Explain Biodiversity-Productivity Relationships, Leslie E. Forero, Andrew Kulmatiski, Josephine Grenzer, Jeanette M. Norton

Wildland Resources Student Research

Species-rich plant communities can produce twice as much aboveground biomass as monocultures, but the mechanisms remain unresolved. We tested whether plant-soil feedbacks (PSFs) can help explain these biodiversity-productivity relationships. Using a 16-species, factorial field experiment we found that plants created soils that changed subsequent plant growth by 27% and that this effect increased over time. When incorporated into simulation models, these PSFs improved predictions of plant community growth and explained 14% of overyielding. Here we show quantitative, field-based evidence that diversity maintains productivity by suppressing plant disease. Though this effect alone was modest, it helps constrain the role of factors, …

Tree Establishment On Post-Mining Waste Soils: Species, Density, And Mixture Effects, Degi Harja Asmara, Suzanne Allaire, Meine Van Noordwijk, Damase P. Khasa

Aspen Bibliography

Tree establishment to restore degraded boreal post-mining lands is challenged by low soil productivity, a harsh microclimate, and potentially high contaminant levels. The use of mixed vegetation can facilitate the microclimate but increase competition for soil resources. A statistical accounting of plant–plant interactions and adaptation to multispecies conditions is hard to achieve in field experiments; trials under controlled conditions can distinguish effects of planting density and species interactions in the early stages of plant establishment. A greenhouse trial was established in containers (“mesocosms”) with waste rock or fine tailings from gold mines. Pregerminated (1-week-old) seedlings (Alnus viridis subsp. crispa …

Spatial And Temporal Variation Of Epigaeic Beetle Assemblages (Coleoptera, Carabidae, Staphylinidae) In Aspen-Dominated Mixedwood Forests Across North-Central Alberta, H. E. James Hammond, Sergio García-Tejero, Greg R. Pohl, David W. Langor, John R. Spence

Aspen Bibliography

Epigaeic beetle assemblages were surveyed using continuous pitfall trapping during the summers of 1992 and 1993 in six widely geographically distributed locations in Alberta’s aspen-mixedwood forests prior to initial forest harvest. Species composition and turnover (β-diversity) were evaluated on several spatial scales ranging from Natural Regions (distance between samples 120–420 km) to pitfall traps (40–60 m). A total of 19,885 ground beetles (Carabidae) representing 40 species and 12,669 rove beetles (non-Aleocharinae Staphylinidae) representing 78 species was collected. Beetle catch, species richness, and diversity differed significantly among the six locations, as did the identity of dominant species. Beetle species composition differed …

Recreation Effects On Wildlife: A Review Of Potential Quantitative Thresholds, Jeremy S. Dertien, Courtney L. Larson, Sarah E. Reed

All Publications

Outdoor recreation is increasingly recognised for its deleterious effects on wildlife individuals and populations. However, planners and natural resource managers lack robust scientific recommendations for the design of recreation infrastructure and management of recreation activities. We reviewed 38 years of research on the effect of non-consumptive recreation on wildlife to attempt to identify effect thresholds or the point at which recreation begins to exhibit behavioural or physiological change to wildlife. We found that 53 of 330 articles identified a quantitative threshold. The majority of threshold articles focused on bird or mammal species and measured the distance to people or to …

Splitting The Difference: Heterogeneous Soil Moisture Availability Affects Aboveground And Belowground Reserve And Mass Allocation In Trembling Aspen, Ashley T. Hart, Morgane Merlin, Erin Wiley, Simon M. Landhäusser

Aspen Bibliography

When exploring the impact of resource availability on perennial plants, artificial treatments often apply conditions homogeneously across space and time, even though this rarely reflects conditions in natural systems. To investigate the effects of spatially heterogeneous soil moisture on morphological and physiological responses, trembling aspen (Populus tremuloides) saplings were used in a split-pot experiment. Following the division of the root systems, saplings were established for a full year and then subjected to either heterogeneous (portion of the root system exposed to non-lethal drought) or homogeneous (whole root system exposed to non-lethal drought or well-watered) treatments. Above- and belowground …

Chloroplast Genomes In Populus (Salicaceae): Comparisons From An Intensively Sampled Genus Reveal Dynamic Patterns Of Evolution, Jiawei Zhou, Shuo Zhang, Jie Wang, Hongmei Shen, Bin Ai, Wei Gao, Cuijun Zhang, Qili Fei, Daojun Yuan, Zhiqiang Wu, Luke R. Tembrock, Sen Li, Cuiha Gu, Xuezhu Liao

Aspen Bibliography

The chloroplast is one of two organelles containing a separate genome that codes for essential and distinct cellular functions such as photosynthesis. Given the importance of chloroplasts in plant metabolism, the genomic architecture and gene content have been strongly conserved through long periods of time and as such are useful molecular tools for evolutionary inferences. At present, complete chloroplast genomes from over 4000 species have been deposited into publicly accessible databases. Despite the large number of complete chloroplast genomes, comprehensive analyses regarding genome architecture and gene content have not been conducted for many lineages with complete species sampling. In this …

Interactive Effects Of Soil And Browsing On Big Sagebrush: Implications For Restoration Success, Kyle Nehring

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Heterogeneity in landscape conditions (e.g., soil types) precludes a “one size fits all” management strategy across large landscapes. New management approaches that explicitly account for heterogeneous landscapes (and the variable conditions therein) will be required to maintain habitat quality. In particular, we require an improved mechanistic understanding of how the outcomes of conservation and restoration actions are contingent upon a) contextual abiotic factors (e.g., moisture availability mediated by soils and precipitation) and b) their interactions with biotic factors (e.g., browsing wildlife).

We propose to answer fundamental questions about how big sagebrush (Artemisia tridentata), the foundational species for sagebrush …

Greater Sage-Grouse And Community Responses To Strategies To Mitigate Environmental Resistance In An Anthropogenic Altered Sagebrush Landscape, Justin R. Small

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Sagebrush (Artemisia spp.) ecosystems are diverse habitats found throughout western North America. Anthropogenic disturbances has resulted in the loss of over half of the sagebrush ecosystems impacting sagebrush obligate species such as sage-grouse (Centrocercus spp.). Federal, state, and private land managers have implemented landscape scale mechanical pinyon (Pinus spp.) and juniper (Juniperus spp.; conifer) removal projects in an effort to restore functioning sagebrush communities to benefit sage-grouse. However, few studies have investigated the potential for using large-scale conifer treatments to mitigate factors impeding sage-grouse seasonal movements and space-use in anthropogenic altered landscapes.

To address this management need, I …

Environmental Racism In A Growing City: Investigating Demographic Shifts In Salt Lake City's Polluted Neighborhoods, Emma Nathel Jones

Undergraduate Honors Capstone Projects

Studies investigating the spatial distribution of environmental hazards have repeatedly demonstrated the existence of environmental racism -- the disproportionate impact of environmental hazards on communities of color. We aim to contribute to research on environmental racism by asking how relationships between race and hazard exposure change over time. Our study area, Salt Lake City (SLC), UT, USA is one of the largest cities in the intermountain west and is expected to see continued population growth. SLC was 99% white from 1860-1950. 2019 census estimates indicate that SLC is becoming more racially diverse with 35.6% of the population identifying as racial …

Taphonomy Of Late Jurassic (Tithonian) Morrison Formation Apatosaurus Sp. Vertebrae Found Associated With Teeth From Allosaurus Sp. And Ceratosaurus Sp., And Body Size Extrapolation From The Associated Theropod Teeth., Greg C. Agyan

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

An Apatosaurus sp. locality from Dinosaur National Monument designated DNM-15 was excavated in 1985, and associated with two Allosaurus teeth and one Ceratosaurus tooth that were near one of the caudal vertebrae. The Ceratosaurus tooth was buried between an overlying rib and that same caudal vertebra. The caudal vertebrae of the DNM-15 Apatosaurus were intact and articulated, but the anterior skeleton was mostly absent, with a row of articulated sacral vertebrae in close association with a femur. Two other Allosaurus teeth were reported near the preserved ilium of the Apatosaurus, but they could not be located in the collections. …

Mechanisms Of Overyielding And Coexistence In Diverse Tallgrass Prairie Communities, Leslie E. Forero

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Plants compete for the same basic nutrient and water resources. According to the competitive exclusion principle, when a substantial overlap in resource pools exists, the best competitor for resources should drive all other species to extinction. The ability for plants to coexist in violation of the competitive exclusion principle is the “biodiversity paradox”. Coexistence is actually beneficial for plants: as species diversity increases, you typically see increases in plant biomass production (known as the biodiversity-productivity relationship). The mechanisms behind coexistence and the biodiversity-productivity relationship remain an ecological mystery. One hypothesis is that plants obtain water and nutrients from different places …

The Fate And Cycling Of Nitrogen, Phosphorous, And Trace Heavy Metals In Beaver-Altered Headwater Streams, Desneiges S. Murray

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Human land-use can increase the amount of non-point source (NPS) pollution in a stream, negatively affecting ecosystem health and beneficial services provided by an ecosystem. Unfortunately, NPS pollution remains high in many waterbodies. Beaver dams may be a passive, cost-effective strategy for removing NPS pollution in headwater streams because beaver dams slow stream flow and collect sediments. Impounded sediments can change how nutrients and pollutants are cycled in a stream through multiple pathways. In the first part of our study, we investigated whether beaver activity can reduce nitrogen, phosphorous and heavy metals from otherwise traveling downstream. Results suggest beaver ponds …

Bighorn Sheep Demographics Following Pneumonia Die-Off Events, Kylie Sinclair

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Bighorn sheep populations across the Intermountain West are subject to disease pressure from the respiratory bacteria Mycoplasma ovipneumoniae. Although the effects of M. ovipneumoniae-associated disease die-offs are well documented, less is known about the factors driving long-term differences in post-die-off population responses. While many herds experience years to decades in which recruitment is less than 20 lambs per 100 ewes, some herds’ lamb survival rates are able to rebound rapidly following die-off events. The reason why these herds recover quickly while others do not is currently unknown. Here, we assess the roles environmental, demographic, and pathogen-associated factors could …

Short- And Long-Term Mechanisms For Increasing Inputs Of Phosphorus In Mountain Waterbodies Of Northeastern Utah, Usa, Jessica Scholz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Phosphorus is an essential nutrient that allows life in water to flourish, but changes in phosphorus supplies are not well understood in remote watersheds. In mountain environments, remote watersheds contain critical high-quality water supplies and unique ecosystems, but excess phosphorus can diminish water quality by producing unfavorable aquatic species. Therefore, observed trends of increasing phosphorus concentrations in remote lakes and rivers in the US over the last two decades are a significant concern. Using the Uinta Mountains as a case study, we evaluated three different direct and indirect pathways for phosphorus increases in remote mountain watersheds that may explain observed …

Patterns Of Post-Fire Aspen Seedling Establishment, Growth, And Mortality In The Western United States, Mark Regier Kreider

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Sexual seedling establishment in aspen is increasingly recognized as an important natural regeneration pathway for the species in the western U.S. However, information on seedling abundance as well as factors influencing aspen sexual regeneration is limited and frequently anecdotal, due to historical assumptions of seedling rarity as well as difficulty identifying sexual seedlings from asexual aspen sucker regeneration. This thesis contributes to the field of aspen seedling ecology in three major ways. Chapter 1 utilizes historical aspen seedling occurrences in the western U.S. and a systematic field survey of 2018 fire footprints to explore patterns and test assumptions of aspen …

Range-Wide Migratory Connectivity Of Painted Buntings, Andrew J. Sharp

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Painted Bunting (Passerina cirus) is a small (~16g), short/medium-distance migratory songbird that is listed as a species of conservation concern by the US Fish and Wildlife Service. Painted Buntings breed in two distinct populations, one eastern population and one interior population, separated by a 500 km gap that stretches from Mississippi to Georgia. I analyzed tracking data from 112 Painted Buntings from 11 different breeding sites to explore how individuals from different breeding sites differ in wintering location (chapter 2) and migratory timing (chapter 3). Additionally, I examined differences in migratory behavior between male and females in …

Visitor Perceptions And Resource Conditions Of Campsites In Two Coastal Alaskan National Parks, Shannon T. Wesstrom

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Increasing visitation in parks and protected areas presents managers with the challenge of providing quality visitor experiences while mitigating ecological impacts from recreation. Successful management strategies often suggest determining desired conditions for visitor experiences and ecological conditions to establish thresholds. These thresholds can then be compared to existing conditions in order to determine if changes in management strategies should be made. By integrating visitor survey results with ecological assessments, this research is a unique coastal Alaskan regional analysis of the three components of a management framework: 1. Establishes visitor determined thresholds of acceptability for crowding and coastal resource conditions in …

An Eulerian Perspective On Spring Migration In Mule Deer, Tatum Del Bosco

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Many herbivores travel between low-elevation winter ranges and high-elevation summer sites. These seasonal movements allow them to avoid deep snow cover, ensure access to favorable habitat, and maximize food intake throughout the year. During the spring season, plants at lower elevations green up earlier at lower elevations than at higher elevations. It has been shown that individual animals will track this vegetation growth during their spring migration, which allows them to maximize forage intake coming out of the nutrient scarce winter. This phenomena has previously been studied by monitoring individual movement trajectories, but it is unknown how this pattern scales …

Trends In Us Crop Yields & Water Use, Britta L. Schumacher

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Over half the land in the US is dedicated to agriculture, with the vast majority of all cropland cultivated in corn, wheat, or soybean. Despite continuing advances in agricultural technologies, and consistent yield growth over the twentieth century, research suggests that environmental change is already impacting agricultural yield and future changes are sure to exacerbate challenges to agricultural production. It follows that the future of US agriculture depends on the evolution of the changing climate, the relationship between crop yields and the environment, on-farm management and adaptations, the ecosystems that support agriculture, the political and economic incentives that shape what …

Monitoring Populations And Movement Of Bobcats (Lynx Rufus) On The Eastern Slope Of The Sierra Nevada Mountains Of California, Michael Brown

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Monitoring the spatial ecology and population densities of carnivores is critical for effective management and conservation of these populations and the ecosystems in which they exist. However, effective monitoring of carnivore populations through estimates of space use, habitat selection and densities can be difficult due to their relatively low densities and wide ranging, elusive behaviors. Bobcats (Lynx rufus) are medium sized, top-level predators which are widely distributed across North America. Quantifying space use, habitat selection and developing effective population monitoring strategies for this species will have important implications for wildlife management.

My first objective was to use telemetry …

Invasive Plant Occurrence Across Agency Boundaries: Two Case Studies From California, Natalie Otto

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Non-native invasive species (NNIS) are a major concern confronting land managers in and surrounding protected areas such as national parks. These areas are managed by a variety of entities, all of which have different mandates, management priorities, and resources that are allocated to NNIS programs. These differences can result in ecological divergences at land boundaries and can create barriers to cooperative management. Through interviews and ecological data collection, this research addresses three topics; 1. It identifies disparities in NNIS and disturbance occurrence between jurisdictions and tests the strength of correlations between these variables; 2. It seeks to determine what role …

Responses Of Pacific Fishers To Habitat Changes As A Result Of Forestry Practices In Southwestern Oregon, Tessa R. Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The fisher (Pekania pennanti) is a medium-sized carnivore found in mature forest stands across much of the northern United States. Although historically abundant in the west, fisher populations declined rapidly after fur trapping, extensive logging, and urban development reduced their numbers. Currently, biologists are concerned about the effects timber harvest practices have on fisher tolerance and adaptability when faced with changes to high-quality habitat stands. Tree removal and thinning of understory vegetation are frequently used to alleviate the spread of wildfires in previously dense forest stands with a potential for large-scale habitat loss; yet, a deficit of large …

Pando's Lessons: Restoration Of A Giant Aspen Clone, Paul C. Rogers, Jody Gale, Darren Mcavoy

Aspen Bibliography

A 106 acre (43 ha) aspen clone lives in the Fishlake National Forest in south-central Utah. Clones are comprised of multiple aspen stems, called ramets, which are genetically identical. This particular colony of ramets was named “Pando” (Latin for “I spread”) by researchers believing it to be the largest living organism by mass on earth. Recently, forest managers have noted a rapid dying of mature stems without recruitment of younger trees. This unsustainable situation has galvanized restoration efforts at Pando. Human interventions caused this imbalance; restoration will rely on protection, monitoring, and innovation. As a laboratory, this forest icon may …

Detection Of European Aspen (Populus Tremula L.) Based On An Unmanned Aerial Vehicle Approach In Boreal Forests, Anton Kuzmin, Lauri Korhonen, Sonja Kivinen, Pekka Hurskainen, Pasi Korpelainen, Topi Tanhuanpää, Matti Maltamo, Petteri Vihervaara, Timo Kumpula

Aspen Bibliography

European aspen (Populus tremula L.) is a keystone species for biodiversity of boreal forests. Large-diameter aspens maintain the diversity of hundreds of species, many of which are threatened in Fennoscandia. Due to a low economic value and relatively sparse and scattered occurrence of aspen in boreal forests, there is a lack of information of the spatial and temporal distribution of aspen, which hampers efficient planning and implementation of sustainable forest management practices and conservation efforts. Our objective was to assess identification of European aspen at the individual tree level in a southern boreal forest using high-resolution photogrammetric point cloud …

Prescribed Fire Alters Structure And Composition Of A Mid-Atlantic Oak Forest Up To Eight Years After Burning, Cody L. Dems, Alan H. Taylor, Erica A. H. Smithwick, Jesse K. Kreye, Margot W. Kaye

Aspen Bibliography

Background

Prescribed fire in Eastern deciduous forests has been understudied relative to other regions in the United States. In Pennsylvania, USA, prescribed fire use has increased more than five-fold since 2009, yet forest response has not been extensively studied. Due to variations in forest composition and the feedback between vegetation and fire, Pennsylvania deciduous forests may burn and respond differently than forests across the eastern US. We measured changes in forest structure and composition up to eight years after prescribed fire in a hardwood forest of the Ridge and Valley region of the Appalachian Mountains in central Pennsylvania.

Results

Within …

Possible Mechanisms Behind Impaired Glucose Metabolism In Niacin-Deficient Mice, Sierra Lopez

Student Research Symposium

Niacin, a component of vitamin B3, is necessary for the synthesis of nicotinamide adenine dinucleotide (NAD). NAD is an essential coenzyme in many biologic functions, including a number of metabolic processes that regulate glucose and fat homeostasis. Humans obtain niacin in its dietary form, common in meats, nuts, legumes and some leafy vegetables. While severe niacin deficiency, or pellagra, has been drastically reduced in the United States, some populations remain vulnerable to deficiency, particularly pregnant women, cancer patients, the elderly and alcoholics. Age-related NAD deficiency is emerging as being positively correlated with cognitive decline and impaired dermal repair.. At the …

Monitoring The Spatial Ecology Of Puma Concolor Along A Wildland-Urban Gradient, Natalie D'Souza, Tim Cromwell

Student Research Symposium

The wildland-urban gradient is a hotspot for human-wildlife conflict, as resources and land-use are often shared between the two. As humans encroach more into wildlife lands, humans become ecological players in urban, as well as wildland, ecosystems. Expanding into wildlife habitat creates gradients of human disturbance that can negatively alter ecosystem dynamics. Many species must adapt to human-dominated environments, or else face extinction. Cache Valley, Utah, has a growing wildland-urban interface that borders the southern Bear River Range, an extension of the Wasatch Front, and is mostly contained within Cache National Forest. Cache County is the sixth-fastest growing county in …

Widespread Mortality Of Trembling Aspen (Populus Tremuloides) Throughout Interior Alaskan Boreal Forests Resulting From A Novel Canker Disease, Roger W. Ruess, Loretta M. Winton, Gerard C. Adams

Aspen Bibliography

Over the past several decades, growth declines and mortality of trembling aspen throughout western Canada and the United States have been linked to drought, often interacting with outbreaks of insects and fungal pathogens, resulting in a “sudden aspen decline” throughout much of aspen’s range. In 2015, we noticed an aggressive fungal canker causing widespread mortality of aspen throughout interior Alaska and initiated a study to quantify potential drivers for the incidence, virulence, and distribution of the disease. Stand-level infection rates among 88 study sites distributed across 6 Alaska ecoregions ranged from < 1 to 69%, with the proportion of trees with canker that were dead averaging 70% across all sites. The disease is most prevalent north of the Alaska Range within the Tanana Kuskokwim ecoregion. Modeling canker probability as a function of ecoregion, stand structure, landscape position, and climate revealed that smaller-diameter trees in older stands with greater aspen basal area have the highest canker incidence and mortality, while younger trees in younger stands appear virtually immune to the disease. Sites with higher summer vapor pressure deficits had significantly higher levels of canker infection and mortality. We believe the combined effects of this novel fungal canker pathogen, drought, and the persistent aspen leaf miner outbreak are triggering feedbacks between carbon starvation and hydraulic failure that are ultimately driving widespread mortality. Warmer early-season temperatures and prolonged late summer drought are leading to larger and more severe wildfires throughout interior Alaska that are favoring a shift from black spruce to forests dominated by Alaska paper birch and aspen. Widespread aspen mortality fostered by this rapidly spreading pathogen has significant implications for successional dynamics, ecosystem function, and feedbacks to disturbance regimes, particularly on sites too dry for Alaska paper birch.

Historic Declines In Growth Portend Trembling Aspen Death During A Contemporary Leaf Miner Outbreak In Alaska, Melissa A. Boyd, Logan T. Berner, Adrianna C. Foster, Scott J. Goetz, Brendan M. Rogers, Xanthe J. Walker, Michelle C. Mack

Aspen Bibliography

Climate change-driven droughts and insect outbreaks are becoming more frequent and widespread, increasing forest vulnerability to mortality. By addressing the impacts of climate and insects on tree growth preceding death, we can better understand tree mortality risk under a changing climate. Here, we used tree stature and interannual growth (basal area increment; BAI) to assess processes leading to trembling aspen (Populus tremuloides) survival or mortality during an unprecedented leaf miner (Phyllocnistis populiella) outbreak in boreal North America. We identified eight sites (22 plots) in the longest running forest monitoring network in Alaska, spanning ~350 km of …

Pando: Charismatic Megaflora And The Populus Paradox, Paul C. Rogers, Lance Oditt

Aspen Bibliography

Within the field of landscape ecology, the Pando aspen grove on the Fishlake National Forest of Utah is legendary—and it is in danger of dying from hotter, drier temperatures and other threats. Pando is one of the largest and oldest known still-living organisms on Earth. Quaking aspen are an important tree species in Greater Yellowstone and the Rocky Mountain West. Enjoy this essay written by a scientist who studies Pando and a photographer who celebrates this arboreal mega-being.