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University of Kentucky

Articles 1 - 18 of 18

Full-Text Articles in Ecology and Evolutionary Biology

Residual Spatial Autocorrelation In Macroecological And Biogeographical Modeling: A Review, Guetchine Gaspard Jan 2021

Residual Spatial Autocorrelation In Macroecological And Biogeographical Modeling: A Review, Guetchine Gaspard

Theses and Dissertations--Geography

Macroecological and biogeographical modelers have predicted the distribution of species across space relying on the relationship between biotic processes and environmental variables. Such a method employs data associated, for instance, with species abundance or presence/absence, climate, geomorphology, and soils. Statistical analyses found in previous studies have highlighted the importance of accounting for the effects of spatial autocorrelation (SAC), which indicates a level of dependence between pairs of nearby observations. A consensus has existed that residual spatial autocorrelation (rSAC) can substantially impact modeling processes and inferences. However, more emphasis should be put on identifying the sources of rSAC and the degree …

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Nitrogen Fertilizer Suppresses Mineralization Of Soil Organic Matter In Maize Agroecosystems, Navreet K. Mahal, William R. Osterholz, Fernando E. Miguez, Hanna J. Poffenbarger, John E. Sawyer, Daniel C. Olk, Sotirios V. Archontoulis, Michael J. Castellano Mar 2019

Nitrogen Fertilizer Suppresses Mineralization Of Soil Organic Matter In Maize Agroecosystems, Navreet K. Mahal, William R. Osterholz, Fernando E. Miguez, Hanna J. Poffenbarger, John E. Sawyer, Daniel C. Olk, Sotirios V. Archontoulis, Michael J. Castellano

Plant and Soil Sciences Faculty Publications

The possibility that N fertilizer increases soil organic matter (SOM) mineralization and, as a result, reduces SOM stocks has led to a great debate about the long-term sustainability of maize-based agroecosystems as well as the best method to estimate fertilizer N use efficiency (FNUE). Much of this debate is because synthetic N fertilizer can positively or negatively affect SOM mineralization via several direct and indirect pathways. Here, we test a series of hypotheses to determine the direction, magnitude, and mechanism of N fertilizer effect on SOM mineralization and discuss the implications for methods to estimate FNUE. We measured the effect …

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Nutrient Addition And Drought Interact To Change The Structure And Decrease The Functional Diversity Of A Mediterranean Grassland, Carla Nogueira, Alice Nunes, Miguel N. Bugalho, Cristina Branquinho, Rebecca L. Mcculley, Maria Conceição Caldeira Oct 2018

Nutrient Addition And Drought Interact To Change The Structure And Decrease The Functional Diversity Of A Mediterranean Grassland, Carla Nogueira, Alice Nunes, Miguel N. Bugalho, Cristina Branquinho, Rebecca L. Mcculley, Maria Conceição Caldeira

Plant and Soil Sciences Faculty Publications

Anthropogenic activities are increasing nutrient availability and altering precipitation regimes. This may lead to critical changes in grasslands functioning. This is particularly important for grasslands in the Mediterranean Basin that have evolved in nutrient poor soils, and where more frequent and prolonged droughts are projected to occur. However, there is limited knowledge regarding the interacting effects of multiple nutrient inputs and rainfall variability on the plant functional structure and diversity of Mediterranean grasslands. We conducted a nutrient addition experiment in a Mediterranean grassland during four contrasting precipitation years. We established four treatments that varied in the number of added nutrients, …

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Lake Regionalization And Diatom Metacommunity Structuring In Tropical South America, Xavier Benito, Sherilyn C. Fritz, Miriam Steinitz-Kannan, Maria I. Vélez, Michael M. Mcglue Aug 2018

Lake Regionalization And Diatom Metacommunity Structuring In Tropical South America, Xavier Benito, Sherilyn C. Fritz, Miriam Steinitz-Kannan, Maria I. Vélez, Michael M. Mcglue

Earth and Environmental Sciences Faculty Publications

Lakes and their topological distribution across Earth's surface impose ecological and evolutionary constraints on aquatic metacommunities. In this study, we group similar lake ecosystems as metacommunity units influencing diatom community structure. We assembled a database of 195 lakes from the tropical Andes and adjacent lowlands (8°N–30°S and 58–79°W) with associated environmental predictors to examine diatom metacommunity patterns at two different levels: taxon and functional (deconstructed species matrix by ecological guilds). We also derived spatial variables that inherently assessed the relative role of dispersal. Using complementary multivariate statistical techniques (principal component analysis, cluster analysis, nonmetric multidimensional scaling, Procrustes, variance partitioning), we …

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Advancing The Understanding Of Environmental Transformations, Bioavailability And Effects Of Nanomaterials, An International Us Environmental Protection Agency—Uk Environmental Nanoscience Initiative Joint Program, Mitch M. Lasat, Kian Fan Chung, Jamie Lead, Steve Mcgrath, Richard J. Owen, Sophie Rocks, Jason M. Unrine, Junfeng Zhang Apr 2018

Advancing The Understanding Of Environmental Transformations, Bioavailability And Effects Of Nanomaterials, An International Us Environmental Protection Agency—Uk Environmental Nanoscience Initiative Joint Program, Mitch M. Lasat, Kian Fan Chung, Jamie Lead, Steve Mcgrath, Richard J. Owen, Sophie Rocks, Jason M. Unrine, Junfeng Zhang

Plant and Soil Sciences Faculty Publications

Nanotechnology has significant economic, health, and environmental benefits, including renewable energy and innovative environmental solutions. Manufactured nanoparticles have been incorporated into new materials and products because of their novel or enhanced properties. These very same properties also have prompted concerns about the potential environmental and human health hazard and risk posed by the manufactured nanomaterials. Appropriate risk management responses require the development of models capable of predicting the environmental and human health effects of the nanomaterials. Development of predictive models has been hampered by a lack of information concerning the environmental fate, behavior and effects of manufactured nanoparticles. The United …

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Herbivory And Eutrophication Mediate Grassland Plant Nutrient Responses Across A Global Climatic Gradient, T. Michael Anderson, Daniel M. Griffith, James B. Grace, Eric M. Lind, Peter B. Adler, Lori A. Biederman, Dana M. Blumenthal, Pedro Daleo, Jennifer Firn, Nicole Hagenah, W. Stanley Harpole, Andrew S. Macdougall, Rebecca L. Mcculley, Suzanne M. Prober, Anita C. Risch, Mahesh Sankaran, Martin Schütz, Eric W. Seabloom, Carly J. Stevens, Lauren L. Sullivan, Peter D. Wragg, Elizabeth T. Borer Apr 2018

Herbivory And Eutrophication Mediate Grassland Plant Nutrient Responses Across A Global Climatic Gradient, T. Michael Anderson, Daniel M. Griffith, James B. Grace, Eric M. Lind, Peter B. Adler, Lori A. Biederman, Dana M. Blumenthal, Pedro Daleo, Jennifer Firn, Nicole Hagenah, W. Stanley Harpole, Andrew S. Macdougall, Rebecca L. Mcculley, Suzanne M. Prober, Anita C. Risch, Mahesh Sankaran, Martin Schütz, Eric W. Seabloom, Carly J. Stevens, Lauren L. Sullivan, Peter D. Wragg, Elizabeth T. Borer

Plant and Soil Sciences Faculty Publications

Plant stoichiometry, the relative concentration of elements, is a key regulator of ecosystem functioning and is also being altered by human activities. In this paper we sought to understand the global drivers of plant stoichiometry and compare the relative contribution of climatic vs. anthropogenic effects. We addressed this goal by measuring plant elemental (C, N, P and K) responses to eutrophication and vertebrate herbivore exclusion at eighteen sites on six continents. Across sites, climate and atmospheric N deposition emerged as strong predictors of plot‐level tissue nutrients, mediated by biomass and plant chemistry. Within sites, fertilization increased total plant nutrient pools, …

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Cover Crops And Fertilization Alter Nitrogen Loss In Organic And Conventional Conservation Agriculture Systems, Rebecca E. Shelton, Krista L. Jacobsen, Rebecca L. Mcculley Jan 2018

Cover Crops And Fertilization Alter Nitrogen Loss In Organic And Conventional Conservation Agriculture Systems, Rebecca E. Shelton, Krista L. Jacobsen, Rebecca L. Mcculley

Horticulture Faculty Publications

Agroecosystem nitrogen (N) loss produces greenhouse gases, induces eutrophication, and is costly for farmers; therefore, conservation agricultural management practices aimed at reducing N loss are increasingly adopted. However, the ecosystem consequences of these practices have not been well-studied. We quantified N loss via leaching, NH3 volatilization, N2O emissions, and N retention in plant and soil pools of corn conservation agroecosystems in Kentucky, USA. Three systems were evaluated: (1) an unfertilized, organic system with cover crops hairy vetch (Vicia villosa), winter wheat (Triticum aestivum), or a mix of the two (bi-culture); (2) an organic …

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Local Loss And Spatial Homogenization Of Plant Diversity Reduce Ecosystem Multifunctionality, Yann Hautier, Forest Isbell, Elizabeth T. Borer, Eric W. Seabloom, W. Stanley Harpole, Eric M. Lind, Andrew S. Macdougall, Carly J. Stevens, Peter B. Adler, Juan Alberti, Jonathan D. Bakker, Lars A. Brudvig, Yvonne M. Buckley, Marc Cadotte, Maria C. Caldeira, Enrique J. Chaneton, Chengjin Chu, Pedro Daleo, Christopher R. Dickman, John M. Dwyer, Anu Eskelinen, Philip A Fay, Jennifer Firn, Nicole Hagenah, Helmut Hillebrand, Oscar Iribarne, Kevin P. Kirkman, Johannes M. H. Knops, Kimberly J. La Pierre, Rebecca L. Mcculley Jan 2018

Local Loss And Spatial Homogenization Of Plant Diversity Reduce Ecosystem Multifunctionality, Yann Hautier, Forest Isbell, Elizabeth T. Borer, Eric W. Seabloom, W. Stanley Harpole, Eric M. Lind, Andrew S. Macdougall, Carly J. Stevens, Peter B. Adler, Juan Alberti, Jonathan D. Bakker, Lars A. Brudvig, Yvonne M. Buckley, Marc Cadotte, Maria C. Caldeira, Enrique J. Chaneton, Chengjin Chu, Pedro Daleo, Christopher R. Dickman, John M. Dwyer, Anu Eskelinen, Philip A Fay, Jennifer Firn, Nicole Hagenah, Helmut Hillebrand, Oscar Iribarne, Kevin P. Kirkman, Johannes M. H. Knops, Kimberly J. La Pierre, Rebecca L. Mcculley

Plant and Soil Sciences Faculty Publications

Biodiversity is declining in many local communities while also becoming increasingly homogenized across space. Experiments show that local plant species loss reduces ecosystem functioning and services, but the role of spatial homogenization of community composition and the potential interaction between diversity at different scales in maintaining ecosystem functioning remains unclear, especially when many functions are considered (ecosystem multifunctionality). We present an analysis of eight ecosystem functions measured in 65 grasslands worldwide. We find that more diverse grasslands—those with both species-rich local communities (α-diversity) and large compositional differences among localities (β-diversity)—had higher levels of multifunctionality. Moreover, α- and β-diversity synergistically affected …

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Effects Of Climate Warming On Net Primary Productivity In China During 1961–2010, Fengxue Gu, Yuandong Zhang, Mei Huang, Bo Tao, Rui Guo, Changrong Yan Jul 2017

Effects Of Climate Warming On Net Primary Productivity In China During 1961–2010, Fengxue Gu, Yuandong Zhang, Mei Huang, Bo Tao, Rui Guo, Changrong Yan

Plant and Soil Sciences Faculty Publications

The response of ecosystems to different magnitudes of climate warming and corresponding precipitation changes during the last few decades may provide an important reference for predicting the magnitude and trajectory of net primary productivity (NPP) in the future. In this study, a process-based ecosystem model, Carbon Exchange between Vegetation, Soil and Atmosphere (CEVSA), was used to investigate the response of NPP to warming at both national and subregional scales during 1961–2010. The results suggest that a 1.3°C increase in temperature stimulated the positive changing trend in NPP at national scale during the past 50 years. Regardless of the magnitude of …

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Seedling Tolerance To Cotyledon Removal Varies With Seed Size: A Case Of Five Legume Species, Xiao Wen Hu, Rui Zhang, Yan Pei Wu, Carol C. Baskin Jun 2017

Seedling Tolerance To Cotyledon Removal Varies With Seed Size: A Case Of Five Legume Species, Xiao Wen Hu, Rui Zhang, Yan Pei Wu, Carol C. Baskin

Biology Faculty Publications

It is generally accepted that seedlings from large seeds are more tolerant to defoliation than those from small seeds due to the additional metabolic reserves present in the large seeds. However, information on the effects of amount of seed reserves (cotyledon removal) from seedlings resulting from large vs. small seeds on seedling growth and long-term survival in the field is limited. Five legume species with different sizes of seeds were sown in the field and none, one, or both cotyledons removed 7 days after seedling emergence. Seedling biomass, relative growth rate (RGR) and survival were determined at different time. Cotyledon …

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Divergence In Life History Traits Between Two Populations Of A Seed-Dimorphic Halophyte In Response To Soil Salinity, Fan Yang, Jerry M. Baskin, Carol C. Baskin, Xuejun Yang, Dechang Cao, Zhenying Huang Jun 2017

Divergence In Life History Traits Between Two Populations Of A Seed-Dimorphic Halophyte In Response To Soil Salinity, Fan Yang, Jerry M. Baskin, Carol C. Baskin, Xuejun Yang, Dechang Cao, Zhenying Huang

Biology Faculty Publications

Production of heteromorphic seeds is common in halophytes growing in arid environments with strong spatial and temporal heterogeneity. However, evidence for geographic variation (reflecting local adaptation) is almost nonexistent. Our primary aims were to compare the life history traits of two desert populations of this halophytic summer annual Suaeda corniculata subsp. mongolica and to investigate the phenotypic response of its plant and heteromorphic seeds to different levels of salt stress. Dimorphic seeds (F1) of the halophyte S. corniculata collected from two distant populations (F0) that differ in soil salinity were grown in a common environment under …

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Effect Of Seed Position On Parental Plant On Proportion Of Seeds Produced With Nondeep And Intermediate Physiological Dormancy, Juan J. Lu, Dun Y. Tan, Carol C. Baskin, Jerry M. Baskin Feb 2017

Effect Of Seed Position On Parental Plant On Proportion Of Seeds Produced With Nondeep And Intermediate Physiological Dormancy, Juan J. Lu, Dun Y. Tan, Carol C. Baskin, Jerry M. Baskin

Biology Faculty Publications

The position in which seeds develop on the parental plant can have an effect on dormancy-break and germination. We tested the hypothesis that the proportion of seeds with intermediate physiological dormancy (PD) produced in the proximal position on a raceme of Isatis violascens plants is higher than that produced in the distal position, and further that this difference is related to temperature during seed development. Plants were watered at 3-day intervals, and silicles and seeds from the proximal (early) and distal (late) positions of racemes on the same plants were collected separately and tested for germination. After 0 and 6 …

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Fluvial-Lacustrine Processes Shaping The Landforms Of The Distal Paraguay Fluvial Megafan, Edward Limin Lo Jan 2017

Fluvial-Lacustrine Processes Shaping The Landforms Of The Distal Paraguay Fluvial Megafan, Edward Limin Lo

Theses and Dissertations--Earth and Environmental Sciences

Tropical wetlands such as the Pantanal help regulate global biogeochemical cycles, but climate change is modifying these environments. Controls on environmental changes can potentially be assessed from ancient, well-dated lacustrine sedimentary records. An integrated field and laboratory approach was undertaken to study the limnogeology of Lake Uberaba in the northern Pantanal, and test whether the lake has preserved a reliable record of environmental change in its strata. This study was designed to understand how the basin accumulates sediment and to assess its sensitivity to hydroclimatic variability. The data showed that modern Lake Uberaba is a highly dynamic, freshwater fluvial-lacustrine basin. …

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Effects Of Epichloë Coenophiala−Tall Fescue Symbiosis On Plant-Microbe-Soil Interactions In A Temperate Pasture, Lindsey C. Slaughter Jan 2016

Effects Of Epichloë Coenophiala−Tall Fescue Symbiosis On Plant-Microbe-Soil Interactions In A Temperate Pasture, Lindsey C. Slaughter

Theses and Dissertations--Plant and Soil Sciences

Plants interact in myriad ways with microorganisms to influence ecosystem processes such as nutrient cycling, which can regulate ecosystem response to global change. One important plant-microbe symbiosis occurs between cool-season grasses and asexual fungal Epichloë endophytes, such as tall fescue (Schedonorus arundinaceus) and Epichloë coenophiala. Because the common toxic strain of the endophyte (CTE) harms grazing livestock, non-livestock toxic endophyte (NTE) strains have been developed and are increasingly deployed in pastures. Little is known about how these symbioses impact other plant-microbe interactions and microbe-mediated soil processes in grassland ecosystems. I conducted three studies to determine how E. …

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Ecohydraulic Investigation Of Diatoms In A Bedrock-Controlled Stream, Alex M. Rittle Jan 2015

Ecohydraulic Investigation Of Diatoms In A Bedrock-Controlled Stream, Alex M. Rittle

Theses and Dissertations--Geography

Recent studies within the past decade or so have shown the importance of algae in geomorphic and hydrologic processes of lotic systems. However, the ecohydraulic role of algae in bedrock systems has largely been ignored. In addition, the utility of algae as indicators of channel dynamics have often been assumed by geomorphologists, but relatively few studies have examined this relationship. The purpose of this study was to determine whether algae, specifically diatoms, are useful indicators of channel geomorphological dynamics, and to examine if distinct habitats or biotopes typical in fluviokarst and bedrock systems provide unique habitat space for diatoms, and …

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Factors Influencing The Establishment And Survival Of Native Hardwood Tree Seedlings Of The Kentucky Inner Bluegrass Blue Ash-Oak Savanna-Woodland, James D. Shaffer Jan 2013

Factors Influencing The Establishment And Survival Of Native Hardwood Tree Seedlings Of The Kentucky Inner Bluegrass Blue Ash-Oak Savanna-Woodland, James D. Shaffer

Theses and Dissertations--Biology

Historically, the Kentucky Inner Bluegrass blue ash-oak savanna-woodland was the primary ecosystem of the Inner Bluegrass Region (IBR) of Kentucky. After European settlement, the majority (>99%) of Bluegrass savanna was converted to agricultural and urban land uses. Currently remnant savanna tree species are failing to recruit. Therefore, a long-term restoration ecology project researching competition and disturbance on seedling establishment, survival, and growth has been established at Griffith Woods (the largest remaining savanna in Kentucky) in Harrison Co., KY. Fourteen native hardwood tree species (a total of 6,168 seedlings) have been experimentally planted. Light, soil, surrounding vegetation, and herbivory, factors …

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Atlas Of Wetlands In The Principal Coal Surface Mining Region Of Western Kentucky, William J. Mitsch, Jan R. Taylor, Kimberly B. Benson, Paul L. Hill Jr. Jul 1983

Atlas Of Wetlands In The Principal Coal Surface Mining Region Of Western Kentucky, William J. Mitsch, Jan R. Taylor, Kimberly B. Benson, Paul L. Hill Jr.

KWRRI Research Reports

This atlas contains maps of wetlands and surface mining activity in the Western Kentucky Coal Field, and focuses on a 3960 km2 (1530 mi2) region where approximately 90 percent of surface mining in the Coal field occures. Some present and potential competition exists between surface coal mining and wetland protection. A wetland classification, based on the recent FWS classification, includes six types of palustrine systems and one each of riverine and laucstrine systems. Wetlands and surface mines are located on twenty-seven 7.5 minute USGS quadrangles that define the study region. A total of 460 km2 (177 …

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A Study Of Naturally Occurring Algicides Produced By Freshwater Algae, Denny O. Harris, Harry D. Caldwell Dec 1974

A Study Of Naturally Occurring Algicides Produced By Freshwater Algae, Denny O. Harris, Harry D. Caldwell

KWRRI Research Reports

The mode of action of the algicide produced by Pandorina morum was examined by exposing Volvox globator and isolates spinach chloroplasts to a partially purified algicide preparation. Oxygen evolution of Volvox, whole chloroplasts and broken chloroplasts (minus the Calvin cycle),was reduced indicating that the algicide inhibits the light reactions of photosynthesis. Oxygen evolution studies of other Volvocaceae confirmed the observation that Pandorina morum is not significantly influenced by its own inhibitor. Molecular weight approximation by gel filtration established that the inhibitor has a low molecular weight (probably below 100 mw). Field studies indicate that this algicide has tremendous potential as …

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