Plant Sciences Commons^™

A Systematic And Biogeographic Study Of Trillium (Melanthiaceae), Jayne A. Lampley

Doctoral Dissertations

Trillium (Melanthiaceae, Parideae) has a disjunct distribution occurring in eastern and western North America, and eastern Asia. Past studies have examined the phylogeny and historical biogeography of Melanthiaceae and Parideae, however these studies either did not fully examine these aspects within Trillium or did not employ sufficiently broad taxonomic or character sampling to clarify relationships among taxa. The first phylogenetic analysis presented in this study provides a resolved phylogeny for Trillium s.l. and Paris s.l. by using a dataset of 70 plastid coding genes and by sampling broadly from Trillium s.s., Pseudotrillium, Trillidium, Paris s.s., Daiswa, and Kinugasa. The results …

American Burying Beetle, Plant Richness, And Soil Property Responses To Collapse Of Juniperus Virginiana Woodlands With Fire, Alison Ludwig

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Grasslands are declining in the Great Plains due to land use changes, woody plant encroachment, and loss of historic fire cycles. Prescribed burn associations have utilized prescribed fire to collapse invading woodlands and allow the restoration of grasslands. This fire is considered “extreme” because it is capable of changing the structure and function of an ecosystem. Our study site is the Loess Canyons Experimental Landscape, a long-term, ecoregion-scale experiment to apply prescribed fire across the region to restore grasslands. The Nebraska Natural Legacy Project established the Loess Canyons ecoregion as a Biologically-Unique Landscape in 2005 with the state’s wildlife action …

How Do Cover Crops Change Soil Health In A No-Till System?, Aysha Kirsten Tapp Ross

Electronic Theses and Dissertations

Nutrient levels and aggregation measurements are currently the most accurate means to measure soil health. It has been suggested that bacterial and fungal communities may prove to be a more accurate measure of soil health. In this study soil microbe communities and nutrient levels were compared in rye cover cropped soils to measure for differences between treatments. Effects between the microbial communities and environmental measurements were also measured within those treatments to test for correlations between soil health measures and microbial communities. The plots were put in a biennial corn (Zea mays L.) and soybean (Glycine max …

Opposing Community Assembly Patterns For Dominant And Nondominant Plant Species In Herbaceous Ecosystems Globally, Carlos Alberto Arnillas, Elizabeth T. Borer, Eric W. Seabloom, Juan Alberti, Selene Baez, Jonathan D. Bakker, Elizabeth H. Boughton, Yvonne M. Buckley, Miguel Nuno Bugalho, Ian Donohue, John Dwyer, Jennifer Firn, Riley Gridzak, Nicole Hagenah, Yann Hautier, Aveliina Helm, Anke Jentsch, Johannes M. H. Knops, Kimberly J. Komatsu, Lauri Laanisto, Rebecca L. Mcculley

Plant and Soil Sciences Faculty Publications

Biotic and abiotic factors interact with dominant plants—the locally most frequent or with the largest coverage—and nondominant plants differently, partially because dominant plants modify the environment where nondominant plants grow. For instance, if dominant plants compete strongly, they will deplete most resources, forcing nondominant plants into a narrower niche space. Conversely, if dominant plants are constrained by the environment, they might not exhaust available resources but instead may ameliorate environmental stressors that usually limit nondominants. Hence, the nature of interactions among nondominant species could be modified by dominant species. Furthermore, these differences could translate into a disparity in the phylogenetic …

Comparing Allelochemicals Of ​English Ivy And Native Georgia Plants​, Rebecca Senft

Symposium of Student Scholars

English Ivy (Hedera helix L.) is a common invasive plant causing biodiversity losses across the southeast and parts of the northwestern US. The mechanisms by which Ivy invades native ecosystems are not well understood but may include allelopathy, a process through which one species produces biochemicals that disrupt competitors. These biochemicals are often produced and exuded by roots into soil, making them difficult to isolate. This study used a soil-less hydroponic system and gas-chromatography mass spectroscopy to examine differences in the chemicals produced by roots of native Georgia plants and English Ivy. Our results suggest there are differences in the …

Evaluating Changes In Visible To Short-Wave Infrared Spectral Reflectance Of Arctic Mosses In Response To Experimental Drying To Find The Best Predictors Of Moisture Content, Steven L. Unger

FIU Electronic Theses and Dissertations

Mosses are a dominant understory component in the Arctic and because of sparse canopy cover, contribute to spectral signals used in remote sensing estimates of various ecologically important characteristics such as productivity, phenology, and vegetation mapping. However, little is known about their contributions to community level spectra or how moisture content influences those spectral signals. Unlike vascular plants, mosses cannot actively regulate moisture content and are highly susceptible to desiccation. Previous research has shown that moss reflectance is sensitive to tissue moisture content. Here, a lab-controlled drying experiment was conducted to identify the best spectral predictors of moisture content of …

Sampling Bias Exaggerates A Textbook Example Of A Trophic Cascade, Elaine M. Brice, Eric J. Larsen, Daniel R. Macnulty

Aspen Bibliography

Understanding trophic cascades in terrestrial wildlife communities is a major challenge because these systems are difficult to sample properly. We show how a tradition of non-random sampling has confounded this understanding in a textbook system (Yellowstone National Park) where carnivore [Canis lupus (wolf)] recovery is associated with a trophic cascade involving changes in herbivore [Cervus canadensis (elk)] behaviour and density that promote plant regeneration. Long-term data indicate a practice of sampling only the tallest young plants overestimated regeneration of overstory aspen (Populus tremuloides) by a factor of 4–7 compared to random sampling because it favoured plants taller than the preferred …

Functional Strategies Of Tree Fine-Roots In Relation To The Soil Environment And Microbiome: Variaiton In Root Morphology, Tissue Chemistry And Physiology, James Aaron Hogan

FIU Electronic Theses and Dissertations

Tree root systems have evolved multidimensional functioning, specializing in water and nutrient acquisition via different strategies. Root functional strategies vary among tree species and are adapted to the abiotic and biotic soil environment. This dissertation explores how three facets of root system functional strategies – morphology and chemistry, biotic associations with fungi, and respiration rates – vary within and among tree species along environmental gradients. Chapter one examines how root system morphology varies with forest succession and soil environment in a tropical forest of Hainan, China, finding that root systems had larger diameters and fewer root tips in the younger …

Study Of The Vegetation Cover Along The Coastal Area Of Al Rayyan-Mayfa Hadramout-Yemen, Khaled Saleh Bawahadi, Salah Adellah Ben Fraijan, Abdulkarim Saber Ali

Hadhramout University Journal of Natural & Applied Sciences

A survey was conducted along the coast dividing it into several segments and a distance estimated at .1.121 km from region to region where Sheher Reedah district is the study area characterized with solid earth nature and dry weather. Therefore the vegetation in the study area is weak and most of the plant species are saline, 95 vegetable types have been identified as belonging to 90 genus and comprise 40 species. The results showed that vegetation more prevalent species Aerva javanica with 100% ،37.2% density as for the frequency of plant desert palms Digera muricata ،Agave sislana ،Jatropha spinosa are …

Center For Grassland Studies, November 2021

Center for Grassland Studies: Newsletters

Contents

Ranchers’ Preferences for Payment for Ecosystem Services Programs in Nebraska by Kyle Martens

Center for Grassland Studies Policy Advisory Committee

Director's Column by Walt Schacht (Interim Director)

Fall Army Worms Reared Their Ugly Heads and Wings in Nebraska in 2021by Roch Gaussoin

Dalbey-Halleck Open House by Margo McKendree

Internships – Let’s Get More Students on the Land! by Shelly Kelly

Jim Gerrish Insightful and Relatable for Grazing Livestock (GLS) Club Members

Long-Term Vs. Short-Term Plant Responses To Warming And Nitrogen Addition In A Temperate Old Field, Breanna Craig

Electronic Thesis and Dissertation Repository

Climate warming and atmospheric nitrogen (N) deposition are expected to have strong effects on plant productivity in temperate ecosystems over the next century. However, short-term experiments may not adequately address their potential effects because of lags in changes in species composition. I added new plots to a pre-existing field experiment to compare the short-term (1-2 year; new plots) vs. long-term (14-15 year; old plots) effects of warming and N addition on plant productivity, relative species abundances, plant tissue N content, and litter decomposition. In 2020, N addition increased aboveground plant productivity most in old plots and only increased belowground biomass …

Rebecca Fillyaw Ms Thesis Data For Publication In The Journal Sustainability, Rebecca Fillyaw, Melinda Donnelly, Linda Walters

CEELAB Research Data

By combatting erosion and increasing habitat, mangrove living shorelines are an effective alternative to hard-armoring in tropical and subtropical areas. An experimental red mangrove living shoreline was deployed within Mosquito Lagoon, Florida, using a factorial design to test the impact of mangrove age, breakwater presence, and mangrove placement on mangrove survival within the first year of deployment. Mixed mangrove age treatments were included to identify if seedling (11-month-old) survival could be enhanced by the presence of transitional (23-month-old) and adult (35 to 47-month-old) mangroves. Environmental factors were monitored to detect possible causes of mangrove mortalities. Approximately half (50.6%) of mangroves …

A Phenological Analysis Of Páramo Vegetation Along An Altitudinal Gradient: The Influence Of Camelids On Andean Flora In The Páramo Of Chimborazo, Ecuador, Tessa Seifried

Independent Study Project (ISP) Collection

This study hopes to reveal the mechanisms behind camelid-plant interactions in the Chimborazo province of Ecuador, which is known for having a large population of domesticated alpacas (Vicugna pacos), along with wild vicuñas (Vicugna vicugna) that were reintroduced into the area 30 years ago. These camelid species, especially vicuñas, are understudied within Ecuador in regards to their effects on plant composition, diversity, and spatial phenology. To gain a better insight into this topic, three sites were chosen: a site inhabited by only vicuña, a site inhabited by only alpaca, and a site inhabited by both species. The vicuña site sat …

Against The Odds: Hybrid Zones Between Mangrove Killifish Species With Different Mating Systems, Waldir M. Berbel-Filho, Andrey Tatarenkov, George Pacheco, Helder M. V. Espírito-Santo, Mateus G. Lira, Carlos Garcia De Leaniz, John C. Avise, Sergio M. Q. Lima, Carlos M. Rodriguez Lopez, Sofia Consuegra

Horticulture Faculty Publications

Different mating systems are expected to affect the extent and direction of hybridization. Due to the different levels of sexual conflict, the weak inbreeder/strong outbreeder (WISO) hypothesis predicts that gametes from self-incompatible (SI) species should outcompete gametes from self-compatible (SC) ones. However, other factors such as timing of selfing and unilateral incompatibilities may also play a role on the direction of hybridization. In addition, differential mating opportunities provided by different mating systems are also expected to affect the direction of introgression in hybrid zones involving outcrossers and selfers. Here, we explored these hypotheses with a unique case of recent hybridization …

Global Population Divergence Of A Cosmopolian Desert Plant, Victor Ryan Alfaro

Biology ETDs

Genetic and phenotypic variation can have different patterns within a species if it has populations with contrasting histories. Populations can have discrete differences that are shaped by different evolutionary scenarios, but within each population, range, or region, traits and association with fitness can also be affected by both edaphic and landscape variation. For my dissertation, I surveyed and experimentally analyzed variation and adaptive potential in Sahara mustard (Brassica tournefortii), a desert annual that has endemic, invasive, and agricultural populations in Africa, Asia, and the Americas. Although my multi-trait analysis generated complex results, my findings can be applied to …

Growth–Defense Trade-Offs Shape Population Genetic Composition In An Iconic Forest Tree Species, Olivia L. Cope, Ken Keefover-Ring, Eric L. Kruger, Richard L. Lindroth

Aspen Bibliography

All organisms experience fundamental conflicts between divergent metabolic processes. In plants, a pivotal conflict occurs between allocation to growth, which accelerates resource acquisition, and to defense, which protects existing tissue against herbivory. Trade-offs between growth and defense traits are not universally observed, and a central prediction of plant evolutionary ecology is that context-dependence of these trade-offs contributes to the maintenance of intraspecific variation in defense [Züst and Agrawal, Annu. Rev. Plant Biol., 68, 513–534 (2017)]. This prediction has rarely been tested, however, and the evolutionary consequences of growth–defense trade-offs in different environments are poorly understood, especially in long-lived species …

Integration Of Crop-Livestock Systems: An Opportunity To Protect Grasslands From Conversion To Cropland In The Us Great Plains, Alexander J. Smart, Daren Redfearn, Robert Mitchell, Tong Wang, Cody Zilverberg, Peter J. Bauman, Justin D. Derner, Julie Walker, Cody Wright

Native Plant Focused Publications

The Great Plains is a mixture of cropland and grassland mainly used for agricultural purposes, with grasslands under continual threat of conversion to cropland. Agriculturists are advocating for the integration of crop-livestock systems (ICLS) to recouple nutrient cycles, improve biodiversity, and increase resilience of agricultural operations. We address the benefits of ICLS in the Great Plains, contending that focus on improving soil health and financial stability of agricultural operations should reduce the conversion of grasslands to cropland. Using US Department of Agriculture National Agricultural Statistics Service Census of Agriculture survey data from the 1925−2017 category “cropland used only for pasture …

Managing Invasive Plants On Great Plains Grasslands: A Discussion Of Current Challenges, John F. Gaskin, Erin Espeland, Casey D. Johnson, Diane L. Larson, Jane M. Mangold, Rachel A. Mcgee, Chuck Milner, Shishir Paudel, Dean E. Pearson, Lora B. Perkins, Chadley W. Prosser, Justin B. Runyon, Sharlene E. Sing, Zachary A. Sylvain, Amy J. Symstad, Daniel R. Tekiela

Native Plant Focused Publications

The Great Plains of North America encompass approximately 1,300,000 km2 of land from Texas to Saskatchewan. The integrity of these lands is under continual assault by long-established and newly-arrived invasive plant species, which can threaten native species and diminish land values and ecological goods and services by degrading desired grassland resources. The Great Plains are a mixture of privately and publicly owned lands, which leads to a patchwork of varying management goals and strategies for controlling invasive plants. Continually updated knowledge is required for efficient and effective management of threats posed by changing environments and invasive plants. Here we discuss …

Center For Grassland Studies, September 2021

Center for Grassland Studies: Newsletters

Contents

Nebraska Grazing Conference Recap by Daren Redfearn

Center for Grassland Studies Policy Advisory Committee

Director's Column by Walt Schacht (Interim Director)

Land Use and Property Taxes by Jordan Johnson

Congratulations August 2021 Graduates

Wildfires are Changing the Future of Nebraska’s Woodland-Grassland Complexes by Amanda Hefner

PGA WORKS Scholarship Recipients Announced by PGA Reach

Grazing Livestock Systems Internships Provide Diverse Experience by Bryan Reiling

Jim Choquette Receives Lifetime Achievement Award

Is The Life History Flexibility Of Cold Desert Annuals Broad Enough To Cope With Predicted Climate Change? The Case Of Erodium Oxyrhinchum In Central Asia, Huiliang Liu, Yanfeng Chen, Lingwei Zhang, Jerry M. Baskin, Carol C. Baskin, Lan Zhang, Yan Liu, Daoyuan Zhang, Yuanming Zhang

Biology Faculty Publications

Interannual seasonal variability in precipitation may strongly affect the life history and growth of desert annual plants. We compared the effects of dry and wet springs and dry and wet autumns on growth and F2 seed dormancy of plants from spring (SG)- and autumn (AG)-germinated seeds of the cold desert annual Erodium oxyrhinchum. Vegetative and reproductive growth and F2 seed dormancy and germination were monitored from September 2016 to November 2020 in the sandy Gurbantunggut Desert in NW China in Central Asia. Dry autumns decreased the density of AG plants, and dry springs decreased the density of SG plants …

Interspersed Denuded Zone (Idz): How Patchy Leaf Litter Dynamics In A Buckthorn-Invaded Urban Woodland Can Affect Microarthropod Species Richness, Angela Stenberg

DePaul Discoveries

Biodiversity loss may serve as a key diagnostic of the Anthropocene. An important driver of this loss is by means of invasive species. In this study of a forest preserve in Chicago, Illinois we examined Interspersed Denuded Zones (IDZs for short), which are areas of patchy leaf litter in invaded forests caused in this case by the rapid decomposition of litter from buckthorn (Rhamnus cathartica). We characterized the leaf litter mass in IDZs and enumerated litter-inhabiting microarthropod populations. We found that plots of high buckthorn density are associated with IDZs: there was significantly less leaf litter mass in …

Determining The Novel Pathogen Neodothiora Populina As The Causal Agent Of The Aspen Running Canker Disease In Alaska, Loretta M. Winton, Gerard C. Adams, Roger W. Ruess

Aspen Bibliography

Neodothiora populina Crous, G.C. Adams & Winton was determined to be a new pathogen of trembling aspen (Populus tremuloides) growing in Alaska, based on completion of Koch’s Postulates in replicated forest and growth chamber inoculation trials. The pathogen is responsible for severe damage and widespread rapid mortality of sapling to mature aspen (≥ 80 years) in the boreal forests of interior Alaska, due to large diffuse annual (1–2 years) cankers. Isolation of the pathogen was challenging, and identification based on cultural characters was difficult. Fruiting bodies were not found on wild diseased trees, but erumpent pycnidia were found …

Moderate Plant–Soil Feedbacks Have Small Effects On The Biodiversity–Productivity Relationship: A Field Experiment, Josephine Grenzer, Andrew Kulmatiski, Leslie Forero, Anne Ebeling, Nico Eisenhauer, Jeanette Norton

Wildland Resources Student Research

Plant–soil feedback (PSF) has gained attention as a mechanism promoting plant growth and coexistence. However, most PSF research has measured monoculture growth in greenhouse conditions. Translating PSFs into effects on plant growth in field communities remains an important frontier for PSF research. Using a 4-year, factorial field experiment in Jena, Germany, we measured the growth of nine grassland species on soils conditioned by each of the target species (i.e., 72 PSFs). Plant community models were parameterized with or without these PSF effects, and model predictions were compared to plant biomass production in diversity–productivity experiments. Plants created soils that changed subsequent …

Supplementing East Tennessee Landscapes For Pollinators With Native Perennials, Amani Khalil

Masters Theses

Tennessee, home to the Great Smoky Mountains, is a biodiversity hotspot for many plant and animal species, yet it receives relatively few conservation dollars (Jenkins et al., 2015). As a biodiversity hotspot, this region may be home to many endemic species, but little is known about the abundance or diversity of insect pollinators. In order to both estimate pollinator communities in East Tennessee and pollinator forage preferences for native Tennessee plants, we established four plots, comprised of three plant families across five common land use types. Over two field seasons we collected nearly 7,300 insect specimens with a total sampling …

Nematode Biodiversity In Lincoln, Nebraska's Tallgrass Prairie Corridor, Abigail Borgmeier

Department of Plant Pathology: Dissertations, Theses, and Student Research

The tallgrass prairie was once one of the most diverse grasslands on the planet, however over 95% has been converted to agriculture in the past 150 years. The remaining prairie is still host to a wide variety of plants, insects, mammals, and soil-dwelling microorganisms, creating an incredibly complex ecosystem. The first aim of this study is to compare three approaches for the measurement of nematode diversity within a 10-mile-long protected prairie habitat corridor near Lincoln, Nebraska. The methods are 1) a traditional morphological analysis of 150 nematodes per study site, 2) a metabarcoding analysis using the 18S genetic marker of …

Spatial Turnover Of Multiple Ecosystem Functions Is More Associated With Plant Than Soil Microbial Β-Diversity, Xin Jing, Case M. Prager, Elizabeth T. Borer, Nicholas J. Gotelli, Daniel S. Gruner, Jin-Sheng He, Kevin Kirkman, Andrew S. Macdougall, Rebecca L. Mcculley, Suzanne M. Prober, Eric W. Seabloom, Carly J. Stevens, Aimée T. Classen, Nathan J. Sanders

Plant and Soil Sciences Faculty Publications

Biodiversity—both above- and belowground—influences multiple functions in terrestrial ecosystems. Yet, it is unclear whether differences in above- and belowground species composition (β-diversity) are associated with differences in multiple ecosystem functions (e.g., spatial turnover in ecosystem function). Here, we partitioned the contributions of above- and belowground β-diversity and abiotic factors (geographic distance, differences in environments) on the spatial turnover of multiple grassland ecosystem functions. We compiled a dataset of plant and soil microbial communities and six indicators of grassland ecosystem functions (i.e., plant aboveground live biomass, plant nitrogen [N], plant phosphorus [P], root biomass, soil total N, and soil extractable P) …

Effects Of Wetland Management And Associated Abiotic Factors On Rare Plant Communities Of Spring-Fed Arid Wetlands, Antonio Cantu De Leija

LSU Master's Theses

Spring-fed arid wetlands support high biological productivity and are hotspots for endemism and distribution of rare plants, making them areas of high conservation value. These systems are driven by complex interactions among groundwater discharge and the geomorphic and climatic features of the setting, which provide gradients of edaphic conditions, particularly soil moisture and salinity that influence the presence and abundance of rare plant communities. However, spring-fed arid wetlands are at particular risk of increases in salinity and drier hydrological regimes due to anthropogenic activities. Such alterations to abiotic conditions may jeopardize the distribution and abundance of rare plants by exceeding …

Zygomorphic Flowers May Reduce Extinction Rates By Allowing Angiosperms To Occur In Low Abundances, Maria Belen Alvestegui

Theses

The high species richness that angiosperm show has been extensively correlated with key floral innovations. Key floral traits contribute to species boundaries and the origin of new species. However, how these relate to extinction remains largely untested. Among the multiple theories that attribute diversification to floral innovations, the reduced extinction model predicts that floral specialization allows the persistence of small populations and avoids their loss. Bilateral symmetry (zygomorphy) is a trait that has evolved recurrently in angiosperms. It is a form of floral specialization that restricts pollination to fewer visitors and precisely places pollen to ensure more effective transmission of …

Availability And Structure Of Coarse Woody Debris In Hemiboreal Mature To Old-Growth Aspen Stands And Its Implications For Forest Carbon Pool, Silva Šēnhofa, Guntars Šnepsts, Kārlis Bičkovskis, Ieva Jaunslaviete, Līga Liepa, Inga Straupe, Āris Jansons

Aspen Bibliography

European aspen deadwood is extensively studied as a habitat for saproxylic species, while less is known of its dynamics and role in carbon sequestration. We studied unmanaged mature (41–60 years), moderately overmature (61–80 years), overmature (81–100 years), and old-growth (101–140 years) and managed mature and moderately overmature aspen stands on fertile mineral soils. In unmanaged stands, marginal mean CWD volume was from 67.3 ± 12.1 m³ ha⁻¹ in moderately overmature to 92.4 ± 5.1 m³ ha⁻¹ in old-growth stands, with corresponding marginal mean CWD carbon pool 8.2 ± 1.6 t ha⁻¹ and 12.5 ± 0.7 …

Coarse Woody Debris Decomposition Assessment Tool: Model Validation And Application, Zhaohua Dai, Carl C. Trettin, Andrew J. Burton, Martin F. Jurgensen, Deborah S. Page-Dumroese, Brian T. Forschler, Jonathan S. Schilling, Daniel L. Lindner

Aspen Bibliography

Coarse woody debris (CWD) is a significant component of the forest biomass pool; hence a model is warranted to predict CWD decomposition and its role in forest carbon (C) and nutrient cycling under varying management and climatic conditions. A process-based model, CWDDAT (Coarse Woody Debris Decomposition Assessment Tool) was calibrated and validated using data from the FACE (Free Air Carbon Dioxide Enrichment) Wood Decomposition Experiment utilizing pine (Pinus taeda), aspen (Populous tremuloides) and birch (Betula papyrifera) on nine Experimental Forests (EF) covering a range of climate, hydrology, and soil conditions across the continental USA. …