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Articles 1501 - 1530 of 19752

Full-Text Articles in Ecology and Evolutionary Biology

Hindcasting Water Availability In Semi-Arid Systems, Nicholas E. Kolarik Aug 2024

Hindcasting Water Availability In Semi-Arid Systems, Nicholas E. Kolarik

Boise State University Theses and Dissertations

Dryland systems cover one third of the earth’s land surface and are becoming increasingly drier, but existing datasets do not capture all of the types of available water that sustain these systems. In semi-arid environments, small surface water bodies and areas of mesic vegetation (wetlands, wet meadows, riparian zones) function as critical water resources. However, the most commonly-used maps of water availability are derived from the Landsat time series or single date aerial photographs, and are either too coarse spatially or temporally to effectively monitor dynamics of available water. In Chapter 1, I produced a Sentinel Fusion (SF) water resources …


Ecological, Climatic, And Geomorphic Controls Of The Transport And Fate Of Co2 In Coastal Arctic Aquatic Ecosystems, Alina Spera Aug 2024

Ecological, Climatic, And Geomorphic Controls Of The Transport And Fate Of Co2 In Coastal Arctic Aquatic Ecosystems, Alina Spera

Open Access Theses & Dissertations

Due to the ecological and physical responses of arctic tundra to warming, organic carbon (C) stored in frozen permafrost soils is increasingly at risk of mineralization and export to aquatic systems, the coast, and atmosphere. Although many coastal aquatic systems in the Arctic are likely net sources of CO2 to the atmosphere, little is known about the drivers of inorganic C flux and how these systems contribute to regional C budgets. This dissertation addresses several lapses in our understanding of coastal inorganic C dynamics in arctic Alaska via three data chapters. In chapter 2, I examine seasonal and regional variability …


I’M A Forest, Not A Saltmarsh, Captain: Carbon And Sap Flow Dynamics In Coastal Forested Wetlands Of The Southeastern United States, Chris Shipway Aug 2024

I’M A Forest, Not A Saltmarsh, Captain: Carbon And Sap Flow Dynamics In Coastal Forested Wetlands Of The Southeastern United States, Chris Shipway

All Theses

Coastal forested wetlands are identified as some of the highest-priority ecosystems for climate change mitigation. Here, we present two studies conducted in these unique ecosystems.

The first assessed changes in aboveground vegetative C stocks along the estuarine-riverine gradients of the Winyah Bay in South Carolina and the Savannah River in Georgia, using a space-for-time substitution to increase understanding of the impacts to upper estuarine forested wetlands from relative sea level rise. Standing C stocks on the Savannah River averaged 183.6 Mg C ha-1, while sites on the Winyah system averaged 162.3 Mg C ha-1. The largest …


Unraveling Wetland Ecology: The Effect Of Abiotic Heterogeneity And Habitat Size On Wetland Plant Diversity In The Piedmont, Gregory T. Gilmore Aug 2024

Unraveling Wetland Ecology: The Effect Of Abiotic Heterogeneity And Habitat Size On Wetland Plant Diversity In The Piedmont, Gregory T. Gilmore

All Theses

Ecosystems around the world are seeing an unprecedented decline in biodiversity. However, to better prevent this decline we cannot only understand the drivers of biodiversity loss, but also the factors that support diversity. Traditional ecological hypotheses such as the Habitat Heterogeneity Hypothesis (HHH) and the Theory of Island Biogeography (TIB) have provided frameworks for understanding biodiversity drivers. However, recent research suggests a more nuanced relationship between heterogeneity, habitat size, and diversity than previously thought. This study looks to bridge existing research gaps by examining the ecologically and conservational important habitat of wetlands. Specifically, the study focuses on the plant diversity …


Venom Complexity Within Garter Snakes And The Role Of Diet In Toxin Diversification, Tucker Heptinstall Aug 2024

Venom Complexity Within Garter Snakes And The Role Of Diet In Toxin Diversification, Tucker Heptinstall

All Theses

Complex traits, such as body size and venom, are often under strong selection by

dietary ecology and can increase efficiency of prey capture and processing. To investigate relationships between ecology and trait evolution in Thamnophis, we amassed nearly 10,000 diet records for 32/35 Thamnophis species and classified each species’ dietary repertoire. We categorized 15/32 species as generalist predators and 17/32 species as specialist predators of varying prey groups and investigated the hypothesis that generalist predators have larger body size. However, we found no significant relationship between body size and dietary specialization. Venom has evolved over 100 times across the Tree …


Uvc And Planetary Habitability: Insights From Desert Lichens And Cyanobacteria, Tejinder Singh Aug 2024

Uvc And Planetary Habitability: Insights From Desert Lichens And Cyanobacteria, Tejinder Singh

UNLV Theses, Dissertations, Professional Papers, and Capstones

An important question in astrobiology is whether life can exist under the levels of UVC radiation found on Archean Earth, Mars, and exoplanets. We investigated this question by studying the UVC survival of colonial cyanobacterium and lichens that grow in harsh desert environments and possess natural sunscreens. We irradiated them nonstop in a desiccated state with a UVC flux closely representing the upper limit on those planets: 55-60 W/m². After irradiation, we rehydrated and assessed their survival using chlorophyll fluorometry and by counting the number of viable colonies that formed on agar plates. All three study organisms survived two to …


Effects Of Climate Change On (Semi)-Arid Ecosystems In The Southwestern United States, Charlotte Van Der Nagel Aug 2024

Effects Of Climate Change On (Semi)-Arid Ecosystems In The Southwestern United States, Charlotte Van Der Nagel

UNLV Theses, Dissertations, Professional Papers, and Capstones

Climate change is considered amongst the most severe threats to terrestrial and aquatic ecosystems globally. Ecosystems in the southwestern United States have specifically been impacted by intense drought conditions since 2000. Higher temperatures combined with altered precipitation stresses many ecosystems; however, ecosystem specific responses to such stressors may vary. Here, the effects of climate change on semi-arid ecosystems are analyzed for some of the most vulnerable ecosystems in the southwestern United States: lacustrine, riparian, and dryland ecosystems.

Lakes and reservoirs in arid environments often serve as drinking water sources and recreational areas where high water quality is essential. Climate change …


Phylogenetic And Biogeographic Patterns Of Devonian Proetid Trilobites, Katherine Jane Jordan Aug 2024

Phylogenetic And Biogeographic Patterns Of Devonian Proetid Trilobites, Katherine Jane Jordan

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Ecological disruption events such as mass extinctions can result in the permanent alteration in clades and ecosystems. A pivotal time of change during the history of life on Earth can be seen in the Devonian Period. During this time, major transitions in marine and terrestrial system resulted in a different world at the end of the period in comparison to the beginning. One such group most heavily impacted were trilobites. Trilobites were reduced to one order by the end of the Devonian: Proetida. My dissertation focuses on phylogenetic, biogeographic, and paleocommunity patterns of this group, known as the last of …


Alfred Russel Wallace Notes 31. Wallace’S Personal Copy Of “Life Of Alexander Von Humboldt.”, Charles H. Smith Aug 2024

Alfred Russel Wallace Notes 31. Wallace’S Personal Copy Of “Life Of Alexander Von Humboldt.”, Charles H. Smith

Faculty/Staff Personal Papers

Alfred Russel Wallace owned a personal copy of the two-volume 1873 English edition of the Life of Alexander von Humboldt, now held by the library of the Linnean Society of London. Each volume is highly annotated, and the nature of these notes, and their several-directioned importance, is here discussed.


Influence Of Invasive Species, Drought, And Stream Permanence On Stream Crayfish Species With A Focus On The Imperiled Mammoth Spring Crayfish (Faxonius Marchandi), Leah Marie Bayer Aug 2024

Influence Of Invasive Species, Drought, And Stream Permanence On Stream Crayfish Species With A Focus On The Imperiled Mammoth Spring Crayfish (Faxonius Marchandi), Leah Marie Bayer

Graduate Theses and Dissertations

Freshwater crayfish constitute one of the most-threatened taxonomic groups in North America. Invasion by other crayfish species as well as habitat degradation through alteration of natural flow regime are two of the most prominent threats to crayfish persistence. Additionally, extreme weather events like droughts can amplify threats posed by other stressors on crayfish populations and are expected to increase in frequency, magnitude, and/or duration in the future, which may negatively influence narrow-ranged endemic crayfish populations typical of the Southeast. The Mammoth Spring Crayfish, Faxonius marchandi, is a narrow-ranged endemic that occurs in the Spring River drainage of Arkansas and Missouri …


Spectral Sensitivity Of Circadian Entrainment In Araneoid And Non-Araneoid Spiders, Craig Campbell Aug 2024

Spectral Sensitivity Of Circadian Entrainment In Araneoid And Non-Araneoid Spiders, Craig Campbell

Electronic Theses and Dissertations

Artificial lighting at night is a growing worldwide phenomenon that can negatively impact flora and fauna in the surrounding area. With new technology, there is now opportunity for change: newer LEDs can emit specific wavelengths of light that may be less ecologically damaging. In this study, we aim to describe the circadian spectral sensitivity of two phylogenetically distant urban spider species with similar life histories, the Araneoid Parasteatoda tepidariorum and non-Araneoid Pholcus manueli, to determine differences between them. We exposed these spiders to progressively dimmer levels of white, blue, green, or red light. Despite evidence that spiders lack visual …


Connecting Climate And Geography With Diversification And Conservation Of A Western North American Endemic Mammal, Sorex Monticola, Antonia Androski Jul 2024

Connecting Climate And Geography With Diversification And Conservation Of A Western North American Endemic Mammal, Sorex Monticola, Antonia Androski

Biology ETDs

Repeated glacial cycles of the Pleistocene initiated complex sequences of divergence and secondary contact with gene flow for many North American species. In my first chapter, I expand our understanding of the phylogeography of the montane shrew, Sorex monticola, with range-wide genetic sampling and geospatial analyses to reconstruct the history of clades within this species and test whether evolutionarily divergent clades occupy distinct abiotic niches. In my second chapter, I build upon these hypotheses, providing the first estimates of evolutionary relationships and timing of diversification based on genome-wide markers. In my third chapter, I use a systematic review of the …


Aposematic-Habitat Correlation In Nearctic Species Of Episyron Schiødte (Hymenoptera: Pompilidae: Pompilinae: Pompilini), Frank E. Kurczewski Jul 2024

Aposematic-Habitat Correlation In Nearctic Species Of Episyron Schiødte (Hymenoptera: Pompilidae: Pompilinae: Pompilini), Frank E. Kurczewski

Insecta Mundi

Three Nearctic species of Episyron Schiødte (Hymenoptera: Pompilidae: Pompilinae: Pompilini) were examined morphologically, geographically, and ecologically with intent to infer an aposematic correlation with habitat type, protarsal digging rake morphology, and host spider association. Episyron quinquenotatus quinquenotatus (Say) and E. conterminus cressoni (Dewitz), two subspecies with extensive aposematic markings and more and longer protarsal comb spines, were associated with bare or sparsely vegetated sandy soils near water courses. Episyron biguttatus biguttatus (Fabricius), with few aposematic markings and less and shorter protarsal comb spines, was associated with more densely vegetated terrain and gravelly and loamy soils. Three subspecies of Anoplius …


Revision Of Trachyderines Related To Sphaenothecus From North America With Description Of Three New Genera, And New Species Of Lophalia Casey, 1912, Mannophorus Leconte, 1854, And Ischnocnemis Thomson, 1864 (Coleoptera: Cerambycidae: Cerambycinae: Trachyderini), Bryan K. Eya Jul 2024

Revision Of Trachyderines Related To Sphaenothecus From North America With Description Of Three New Genera, And New Species Of Lophalia Casey, 1912, Mannophorus Leconte, 1854, And Ischnocnemis Thomson, 1864 (Coleoptera: Cerambycidae: Cerambycinae: Trachyderini), Bryan K. Eya

Insecta Mundi

The genera Lophalia Casey, 1912, Mannophorus LeConte, 1854 and Ischnocnemis Thomas, 1864 (Coleoptera: Cerambycidae: Cerambycinae: Trachyderini) are recharacterized by providing additional morphological features to enhance the delineation of these genera. Two species, Lophalia cribricollis Bates, 1892 and Ischnocnemis luteicollis (Bates, 1885), are transferred to a new genus Lophaliamorpha Eya with Lophaliamorpha luteicollis (Bates) new combination as the type species. Ischnocnemis skillmani Chemsak and Hovore, 2010 is transferred to a new genus Paramannophorus Eya with Paramannophorus skillmani (Chemsak and Hovore) new combination as the type species. A new genus Microteroschema is created to accommodate two additional species from Mexico: Microteroschema parvum …


Antimicrobials Produced By Ants: Chemical Properties And Microbe Specificity, Katy Chon Jul 2024

Antimicrobials Produced By Ants: Chemical Properties And Microbe Specificity, Katy Chon

Master's Theses

Antibiotic resistance is a growing public health concern worldwide, and for over a decade, we have been witnessing the growth of difficult to treat infectious diseases caused by bacteria that are becoming resistant to antibiotics. This resistance can be mostly related to the misusing and improper use of antibiotics in both humans and animals. To restore this problem, humans have turned to new sources for the production of antibiotics. In this study, we focused on using ants. Social insects, including ants and bees, have faced strong disease pressures during their evolution and have developed a range of methods to fight …


An Analysis Of The Genus Aleyrodes Latreille (Hemiptera: Sternorrhyncha: Aleyrodidae) In California, With Three Synonymies, Natalia Von Ellenrieder, Raymond J. Gill Jul 2024

An Analysis Of The Genus Aleyrodes Latreille (Hemiptera: Sternorrhyncha: Aleyrodidae) In California, With Three Synonymies, Natalia Von Ellenrieder, Raymond J. Gill

Insecta Mundi

Abstract

Based on the examination of an extensive series of specimens and available type material, three out of the six species of Aleyrodes Latreille (Hemiptera: Sternorrhyncha: Aleyrodidae) described from California, A. diasemus Bemis, 1904, A. essigi Penny, 1922, and A. osmaroniae Sampson, 1945, are newly synonymized under A. spiraeoides Quaintance, 1900. The species of Aleyrodes reported from California are keyed and diagnosed based on characters from puparia and male genitalia, and character variability is documented and illustrated.

Resumen

Basado en el examen de una extensa serie de especímenes y material tipo disponible, tres de las seis …


A New Species Of Gaindaphodius Král And Mencl From Nepal (Coleoptera: Scarabaeidae: Aphodiinae), Stefano Ziani Jul 2024

A New Species Of Gaindaphodius Král And Mencl From Nepal (Coleoptera: Scarabaeidae: Aphodiinae), Stefano Ziani

Insecta Mundi

A new species from Nepal, Gaindaphodius marigold (Coleoptera: Scarabaeidae: Aphodiinae), is described, illustrated and compared with G. gainda Král and Mencl, 2024, the only other species in the genus Gaindaphodius Král and Mencl, 2024.


Norms And Variance Fail To Predict Butterfly Effects On Social Dynamics By Idiosyncratic Individuals, Stephen F. Stringham, Lynn Rogers, Ann Bryant Jul 2024

Norms And Variance Fail To Predict Butterfly Effects On Social Dynamics By Idiosyncratic Individuals, Stephen F. Stringham, Lynn Rogers, Ann Bryant

Animal Sentience

Adaptations and adjustments to current environmental conditions are manifest in behavioral norms. Knowing norms facilitates population-level prediction, but doesn’t predict individual behavior where idiosyncrasies might trigger “butterfly effects." Knowledge of individual quirks is particularly important for risk assessment and management during close encounters between humans and potentially lethal wildlife, including bears (Ursus spp.). Innovative foraging techniques can alter population vigor and viability. Traits at the tails of a bell curve might hold the greatest potential for adapting to environmental change.


The Effect Of Moon Phase On Predator And Prey Activity Levels On Turnbull National Wildlife Refuge, Jeff Schell, Charlotte Milling Jul 2024

The Effect Of Moon Phase On Predator And Prey Activity Levels On Turnbull National Wildlife Refuge, Jeff Schell, Charlotte Milling

2024 Symposium

Variation in nighttime illumination linked to moon phase has been demonstrated to affect the activity patterns of both prey and predator species. However, evidence of lunarphobia in ungulates is mixed. Turnbull National Wildlife Refuge (TNWR) in Spokane County spans 23,000 acres; features a diverse landscape of channeled scablands, wetlands, and Ponderosa pine (Pinus ponderosa); and is situated within 20 km of the second largest city in Washington. Our objective was to assess the influence of nighttime illumination on activity levels of common mammals on TNWR by quantifying the relationship between moon phase and visitation rate at trail cameras …


Evaluating Mountain Lion Diet Before And After A Removal Of Feral Horses In A Semiarid Environment, Peter C. Iacono, Kathryn A. Schoenecker, Kezia R. Manlove, Pat J. Jackson, David C. Stoner Jul 2024

Evaluating Mountain Lion Diet Before And After A Removal Of Feral Horses In A Semiarid Environment, Peter C. Iacono, Kathryn A. Schoenecker, Kezia R. Manlove, Pat J. Jackson, David C. Stoner

Wildland Resources Faculty Publications

Non-native species can affect ecosystems by influencing native predator-prey dynamics. Therefore, management interventions designed to remove non-natives may inadvertently lead to increased predation on native species. Feral horses are widely distributed throughout the arid parts of western North America. A growing body of research indicates that horses can be an important prey species to mountain lions in ecosystems where they overlap. In December 2020, the Bureau of Land Management removed 455 horses from the Delamar Mountains, Nevada, USA. We leveraged this management intervention to implement a before–after–control–impact study to test hypotheses about predation on horses and native ungulates. We predicted …


Populations Of The Stygobiotic Amphipod Palearcticarellus Pusillus (Martynov, 1930) Maintain Genetic Connectivity Between The Mountain Springs And The Deep Bottom Habitats Of Lake Teletskoye (Altai Mountains, Russia), Ivan Marin, Liubov Yanygina, Svetlana Ostroukhova, Dmitry Palatov Jul 2024

Populations Of The Stygobiotic Amphipod Palearcticarellus Pusillus (Martynov, 1930) Maintain Genetic Connectivity Between The Mountain Springs And The Deep Bottom Habitats Of Lake Teletskoye (Altai Mountains, Russia), Ivan Marin, Liubov Yanygina, Svetlana Ostroukhova, Dmitry Palatov

International Journal of Speleology

The diversity of underground fauna is often associated with the presence of karst areas, which have extensive underground cavities and connecting channels. Non-karst areas, however, make up a larger portion of the planet’ surface, and our understanding of the distribution and dispersal abilities of underground fauna in these areas currently remains limited. During a recent study of the diversity of stygobiotic crustaceans in the mountain streams of the Kurai Mountain Range (Altai, Russia), a small-sized species of crangonyctid amphipod, Palearcticarellus pusillus (Crustacea, Amphipoda, Crangonyctidae) was found in high-altitude springs. This species has been previously known only from deep-water habitats in …


Collaborative Knowledge Braiding For Restoration: Assessing Climate Change Risks And Adaptation Options At Wuda Ogwa In Southeastern Idaho, United States, Sofia Koutzoukis, Will Munger, Lindsay Capito, Darren Parry, Brad Parry, Sarah C. Klain, Mark W. Brunson, Nancy Huntly, Travis Taylor Jul 2024

Collaborative Knowledge Braiding For Restoration: Assessing Climate Change Risks And Adaptation Options At Wuda Ogwa In Southeastern Idaho, United States, Sofia Koutzoukis, Will Munger, Lindsay Capito, Darren Parry, Brad Parry, Sarah C. Klain, Mark W. Brunson, Nancy Huntly, Travis Taylor

Wildland Resources Faculty Publications

The restoration of culturally significant landscapes poses formidable challenges given more than 160 years of settler-colonial land use change and a rapidly changing climate. A novel approach to these challenges braids Indigenous and western scientific knowledge. This case study braids Indigenous plant knowledge, species distribution models (SDMs), and climate models to inform restoration of the Bear River Massacre site in Idaho, now stewarded by the Northwestern Band of the Shoshone Nation. MaxEnt SDMs were used to project the future spatial distribution of culturally significant plant species under medium (SSP2-4.5) and high (SSP5-8.5) emissions scenarios. These results support Tribal revegetation priorities …


The Behavioral Specialization Of African Ant-Following Birds On Dorylus Driver Ants, Patricia F. Rodrigues Jul 2024

The Behavioral Specialization Of African Ant-Following Birds On Dorylus Driver Ants, Patricia F. Rodrigues

LSU Doctoral Dissertations

Ant-following birds, that forage on arthropods flushed by swarm raiding army ants, are an iconic phenomenon in tropical forests around the globe. Despite capturing the attention of naturalists for over a century, research on ant-following birds has largely focused on Neotropical species. Decades of research on Neotropical ant-following birds has revealed fascinating aspects of their specialization, including complex cognitive and behavioral adaptations that allow birds to locate and track nomadic army ants. Despite this breadth of research on Neotropical species, virtually nothing is known of the behavioral ecology of African ant-following birds, and it remains unknown whether they exhibit adaptations …


An Exploration Of The Drivers Of Intraspecific Variation In Arthropod Phenotypes, Jamie Phelps Jul 2024

An Exploration Of The Drivers Of Intraspecific Variation In Arthropod Phenotypes, Jamie Phelps

LSU Doctoral Dissertations

Herein we explore the various forces that drive phenotypic variation in arthropods focusing on spatial and temporal differences as well as sexual dimorphism. We use both marine, Tigriopus californicus, and terrestrial, Melitaeini, organisms to investigate these forces.

Tigriopus californicus and Heat Hardening: The study explores how Tigriopus californicus, a copepod, adapts to thermal variation along the North American Pacific Coast. Researchers investigated intraspecific variation in heat hardening, measuring differences in upper lethal limits (ULLs) and potential fecundity costs across five populations. We found a cost of heat hardening: the size of the first brood produced after heat shock …


Seed Dispersal By Martu Peoples Promotes The Distribution Of Native Plants In Arid Australia, Rebecca Bliege Bird, Douglas Bird, Christopher T. Martine, Chloe Mcguire, Leanne Greenwood, Desmond Taylor, Tanisha M. Williams, Peter M. Veth Jul 2024

Seed Dispersal By Martu Peoples Promotes The Distribution Of Native Plants In Arid Australia, Rebecca Bliege Bird, Douglas Bird, Christopher T. Martine, Chloe Mcguire, Leanne Greenwood, Desmond Taylor, Tanisha M. Williams, Peter M. Veth

Faculty Journal Articles

Commensal relationships between wild plants and their dispersers play a key ecological and evolutionary role in community structure and function. While non-human dispersers are often considered critical to plant recruitment, human dispersers have received much less attention, especially when it comes to non-domesticated plants. Australia, as a continent historically characterized by economies reliant on non-domesticated plants, is thus a key system for exploring the ecological role of people as seed dispersers in the absence of agriculture. Here, we utilize a controlled observation research design, employing ecological surveys and ethnographic observations to examine how seed dispersal and landscape burning by Martu …


Records Of The Red-Bellied Snake (Storeria Occipitomaculata) In Central And Northeastern Nebraska, Taylor Lowe, Sarah M. Bailey, Dan D. Fogell, Keith Geluso Jul 2024

Records Of The Red-Bellied Snake (Storeria Occipitomaculata) In Central And Northeastern Nebraska, Taylor Lowe, Sarah M. Bailey, Dan D. Fogell, Keith Geluso

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Red-bellied Snakes (Storeria occipitomaculata) are a distinctive, small species that live in moist woodlands throughout much of eastern North America. In the Great Plains, isolated populations exist in South Dakota, Wyoming, and Nebraska. In Nebraska, the only known extant population occurs in wooded riparian habitats along the Big Bend Reach of the Platte River in southcentral parts of the state. Herein, we report on new county records of Red-bellied Snakes in Nebraska, with two observations from Merrick County along the Platte River adjacent to known populations and two observations of a new population in the extreme northeastern part …


The Role Of Sexual Network Core Groups In Disease Epidemics, Jason Janeaux Jul 2024

The Role Of Sexual Network Core Groups In Disease Epidemics, Jason Janeaux

LSU Doctoral Dissertations

Sexually transmitted infections (STIs) remain an economic and social burden, non-discriminately affecting sexually active individuals worldwide. The unique transmission of STIs is dependent upon host and pathogen life histories, as well as the underlying network structure of the host population. Within a population there is a group of individuals, the core group, that maintains STI presence and helps sustain ongoing transmission both within the core group and in the surrounding population. While the presence of these core groups is well documented, the criteria for inclusion into a sexual core group is not. In this dissertation, I explore common factors that …


Elevational Gradients Shape Bee Network Structure And Community Composition Across Tropical Lowland To Montane Forests In Costa Rica, Jenny Hsu Jul 2024

Elevational Gradients Shape Bee Network Structure And Community Composition Across Tropical Lowland To Montane Forests In Costa Rica, Jenny Hsu

Online Theses and Dissertations

Mutualistic networks, such as those between plants and pollinators, play a crucial role in ecosystem stability and resilience. Previous theoretical work has posited that mutualistic networks with higher diversity, connectance, nestedness, interaction diversity and more generalist species are more resilient and stable. However, in some ecosystems, specialized interactions and specialists may promote network stability. Drivers of network properties in the neotropics, especially low and mid-elevations, remain relatively unknown, and thus this area should receive special attention. Replicated empirical networks comparing properties along environmental gradients in these regions can help contribute to resolving this debate. A total of 28 networks, replicated …


Patterns Of Stand Structure And Species Composition Through Time And Space In A Piñon- Juniper Woodland In The Southwestern Us, Kyle H. Gonterman Jul 2024

Patterns Of Stand Structure And Species Composition Through Time And Space In A Piñon- Juniper Woodland In The Southwestern Us, Kyle H. Gonterman

Biology ETDs

Piñon- juniper (PJ) woodlands in the Southwest United States are expected to see mortality and structural change in response to climate change. The extent to which this habitat structures itself as well as its response to these changes over time are not well known yet and have not been examined to this extent for the location of this study within the Sevilleta National Wildlife Refuge. Within a small range, we discovered these woodlands consist of persistent woodland, shrubby woodland, and juniper savanna in which structural, spatial, and regeneration patterns differ. In this study, we discovered the specific differences between these …


Impact Of Containment And Elevation On Created Marsh Plant Community And Ecosystem Dynamics, Kevin R. Stoner Jul 2024

Impact Of Containment And Elevation On Created Marsh Plant Community And Ecosystem Dynamics, Kevin R. Stoner

LSU Master's Theses

Coastal marsh restoration is increasing globally, as marshes are impacted by anthropogenic impacts. Billions of dollars are allocated to marsh restoration in the Mississippi River delta where wetland loss rates are extremely high. The recovery of structural and functional attributes of created marshes varies by attribute measured and project. Here, two marshes created in 2018 and one natural marsh were used to examine how variations in hydrologic connectivity and marsh elevation influence subsurface hydrology and salinity, vegetation community structure, soil properties, accretion, and denitrification. I established a comparative field study in a created marsh contained within a higher elevation containment …