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Articles 31 - 52 of 52

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Effects Of Wave Action On The Structure Of Fish Assemblages Across An Exposure Gradient, Lauren Liddon Aug 2017

Effects Of Wave Action On The Structure Of Fish Assemblages Across An Exposure Gradient, Lauren Liddon

Master's Theses

Disturbance affects the function and diversity of ecosystems. Increased wave exposure to salt marsh can disturb sediments and cause a loss of habitat. The purpose of this study was to explore the effects of increased wave exposure on diversity, abundance, and functional ecology of estuarine fishes. If increased wave exposure is acting as a disturbance to these habitats, ecological theory (Intermediate Disturbance Hypothesis) predicts that diversity will peak at intermediate frequencies and intensities of disturbance. Fish were sampled from 10 sites monthly for 6 years. The sites were assigned to different exposure categories (Open, Intermediate, and Sheltered) using an exposure …

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Interacting Effects Of Land Use And Climate On Rodent-Borne Pathogens In Central Kenya, Hillary S. Young, Douglas J. Mccauley, Rodolfo Dirzo, Charles L. Nunn, Michael G. Campana, Bernard Agwanda, Erik R. Otarola-Castillo, Robert M. Pringle, Kari E. Veblen, Daniel J. Salkeld, Kristin Stewardson, Robert Fleisher, Eric F. Lambin, Todd M. Palmer, Kristofer M. Helgen Apr 2017

Interacting Effects Of Land Use And Climate On Rodent-Borne Pathogens In Central Kenya, Hillary S. Young, Douglas J. Mccauley, Rodolfo Dirzo, Charles L. Nunn, Michael G. Campana, Bernard Agwanda, Erik R. Otarola-Castillo, Robert M. Pringle, Kari E. Veblen, Daniel J. Salkeld, Kristin Stewardson, Robert Fleisher, Eric F. Lambin, Todd M. Palmer, Kristofer M. Helgen

Wildland Resources Faculty Publications

Understanding the effects of anthropogenic disturbance on zoonotic disease risk is both a critical conservation objective and a public health priority. Here, we evaluate the effects of multiple forms of anthropogenic disturbance across a precipitation gradient on the abundance of pathogen-infected small mammal hosts in a multi-host, multi-pathogen system in central Kenya. Our results suggest that conversion to cropland and wildlife loss alone drive systematic increases in rodent-borne pathogen prevalence, but that pastoral conversion has no such systematic effects. The effects are most likely explained both by changes in total small mammal abundance, and by changes in relative abundance of …

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Species Diversity And Community Structure Of Zooplankton In Threedifferent Types Of Water Body Within The Sakarya River Basin, Turkey, Pinar Gürbüzer, Özge Buyurgan, Çağri Tekatli, Ahmet Altindağ Jan 2017

Species Diversity And Community Structure Of Zooplankton In Threedifferent Types Of Water Body Within The Sakarya River Basin, Turkey, Pinar Gürbüzer, Özge Buyurgan, Çağri Tekatli, Ahmet Altindağ

Turkish Journal of Zoology

The aim of this study was to identify differences between different types of water body within the same river basin by comparing the composition of the zooplankton community. The study was conducted in three types of water body in the Sakarya Basin in northwestern Turkey: an alluvial barrier lake (Lake Poyrazlar), a pond (Sorgun Pond), and a reservoir (Çubuk II Reservoir). The spatiotemporal changes of these three types of aquatic habitats were investigated in terms of the zooplankton organisms by examining their diversity, evenness, and differences in the abundance of species. A total of 81 species were identified. Thirty-eight species …

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The Bee Fauna Of The Horse Mountain And Grouse Mountain Region, Humboldt County, California, Carrie Lopez Jan 2017

The Bee Fauna Of The Horse Mountain And Grouse Mountain Region, Humboldt County, California, Carrie Lopez

Cal Poly Humboldt theses and projects

Recent concerns about the ecological well-being of bee communities in California and elsewhere have increased the need for monitoring programs and studies that evaluate the impact of habitat loss and alteration on bee diversity and abundance. Such studies depend critically on the expertise of people trained in taxonomy, but their numbers have declined in recent years. My primary goal was to gain a comprehensive first-hand experience with bee identification by documenting the fauna of a previously unstudied area in the mountains of northwestern California and by writing an identification key, intended for dedicated non-specialists, to the area’s 35 species of …

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A Global Edna Comparison Of Freshwater Bacterioplankton Assemblages Focusing On Large-River Floodplain Lakes Of Brazil, Michael Tessler, Mercer R. Brugler, Rob Desalle, Rebecca Hersch, Luiz Felipe M. Velho, Bianca T. Segovia, Fabio A. Lansac-Toha, Michael J. Lemke Sep 2016

A Global Edna Comparison Of Freshwater Bacterioplankton Assemblages Focusing On Large-River Floodplain Lakes Of Brazil, Michael Tessler, Mercer R. Brugler, Rob Desalle, Rebecca Hersch, Luiz Felipe M. Velho, Bianca T. Segovia, Fabio A. Lansac-Toha, Michael J. Lemke

Publications and Research

With its network of lotic and lentic habitats that shift during changes in seasonal connection, the tropical and subtropical large-river systems represent possibly the most dynamic of all aquatic environments. Pelagic water samples were collected from Brazilian floodplain lakes (total n = 58) in four floodpulsed systems (Amazon [n = 21], Araguaia [n = 14], Paraná [n = 15], and Pantanal [n = 8]) in 2011–2012 and sequenced via 454 for bacterial environmental DNA using 16S amplicons; additional abiotic field and laboratory measurements were collected for the assayed lakes.We report here a global comparison of the bacterioplankton makeup of freshwater …

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Discovery And Delimitation: Criconematid Nematodes Of North American Grasslands, Magdalena Jean Olson Jul 2015

Discovery And Delimitation: Criconematid Nematodes Of North American Grasslands, Magdalena Jean Olson

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

Approximately 200 years ago, North American landscapes were dominated by vast expanses of grassland. The Great Plains, an ecologically complex and diverse ecoregion, extended from Canada to the Gulf of Mexico, and from the Rocky Mountains to the border of the eastern hardwood forest in Indiana. Now the original tallgrass prairie exists in small widely dispersed remnant patches surrounded by agroecosystems. This study is an effort to characterize soil nematode diversity and population structure within those remnant patches. The plant parasitic nematode family Criconematidae serves as our indicator for nematode diversity, due to its global distribution, high abundance in natural …

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Documenting Annual Differences In Vegetation Cover, Height And Diversity Near Barrow, Alaska, Timothy Frederick Botting Apr 2015

Documenting Annual Differences In Vegetation Cover, Height And Diversity Near Barrow, Alaska, Timothy Frederick Botting

Masters Theses

Vegetation in the Arctic has been shown to respond to climate change. Documented changes have the potential to result in numerous ecosystem consequences. Therefore, understanding vegetation change is of great importance. This study documents changes in tundra vegetation with a focus on understanding the influence of annual differences in weather. Vegetation was sampled using a point frame method on 98 1-m2 plots in 2010 and 2013 near Barrow, Alaska. A subset of 30 of these plots was also sampled in 2012 and 2014. Plant encounters were identified to species and grouped into one of the following functional groups: bryophytes, …

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Factors Influencing The Distribution And Structure Of Tropical Vascular Epiphyte Communities At Multiple Scales, Carrie Woods Aug 2013

Factors Influencing The Distribution And Structure Of Tropical Vascular Epiphyte Communities At Multiple Scales, Carrie Woods

All Dissertations

Understanding the factors that determine species distributions is a central question in ecology. Niche-based theories stress the importance of environmental heterogeneity in influencing species distributions while neutral-based theories emphasize the effects of dispersal limitation. The relative importance of these factors in influencing species distributions may depend on spatial scale - deterministic factors may be more important at small spatial scales where fine-scale habitat factors become more relevant and stochastic factors may be more important at larger spatial scales where dispersal limitation becomes more relevant. I examined the influence of deterministic and stochastic factors on the distribution and structure of vascular …

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International Polar Year (Ipy) Back To The Future (Btf): Changes In Arctic Ecosystem Structure Over Decadal Times Scales, Sandra Villarreal Jan 2013

International Polar Year (Ipy) Back To The Future (Btf): Changes In Arctic Ecosystem Structure Over Decadal Times Scales, Sandra Villarreal

Open Access Theses & Dissertations

Arctic vegetation communities are responding to climate warming through shifts in species composition and diversity but most observations have been made over relatively short time frames, and/or in association with experimental manipulations. Because vegetation plays a key role in regulating ecosystem productivity, nutrient cycling, surface energy budgets, and trophic interactions in the Arctic, there is a need to better understand shifts in tundra vegetation communities over decadal time scales. Understanding these shifts and their impact on ecosystem structure and function in the Arctic has important implications for predicting the future state of both the Arctic and the Earth System. Long …

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Seasonal Composition And Population Density Of Zooplankton In Lake Karaboğaz From The Kızılırmak Delta (Samsun, Turkey), Ertunç Gündüz, Yasemi̇n Saygi, Fatma Yildiz Demi̇rkalp, Seli̇m Süalp Çağlar, Si̇bel Atasağun, Sabri̇ Kilinç Jan 2013

Seasonal Composition And Population Density Of Zooplankton In Lake Karaboğaz From The Kızılırmak Delta (Samsun, Turkey), Ertunç Gündüz, Yasemi̇n Saygi, Fatma Yildiz Demi̇rkalp, Seli̇m Süalp Çağlar, Si̇bel Atasağun, Sabri̇ Kilinç

Turkish Journal of Zoology

Zooplankton composition and abundance were investigated seasonally at 6 sites in Lake Karaboğaz in relation to some physicochemical conditions. A total of 63 taxa were identified, among them 51 species of rotifers, 8 cladocerans, and 4 copepods. Rotifera represented the predominant component (79% of the total community), followed by nauplii, cladocerans, and copepods (15%, 5%, and 1%, respectively). The average total zooplankton abundance ranged from 9603 to 22,968 ind/m^3. The maximum and the minimum densities were measured in June and August of 2009, respectively. Of the identified zooplankton, 39 taxa were species with a low frequency in the lake. Among …

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Ecology Of The Late Neogene Extinctions: Perspectives From The Plio-Pleistocene Of Florida, Shubhabrata Paul Jan 2013

Ecology Of The Late Neogene Extinctions: Perspectives From The Plio-Pleistocene Of Florida, Shubhabrata Paul

USF Tampa Graduate Theses and Dissertations

The ecological impact of past extinction events is one of the central issues in paleobiology. In face of present environmental changes, a better understanding of past extinctions will enable us to identify the magnitude of biodiversity crises and their underlying processes. The Late Neogene was a time of extraordinary climatic reorganization, including Northern Hemisphere glaciation, the rise of the Central American Isthmus, and associated changes in environmental conditions. Therefore, the Late Neogene extinctions of marine molluscs of South Florida present an ideal platform to examine the interaction between environmental changes and biotic response. In the present study, three different aspects …

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Phylogenetic Community Structure Of Aquatic Beetle Assemblages In A Multi-Wetland Experiment, Sandor Lawrence Kelly Jan 2012

Phylogenetic Community Structure Of Aquatic Beetle Assemblages In A Multi-Wetland Experiment, Sandor Lawrence Kelly

Electronic Theses and Dissertations

Phylogenetic Community Structure (PCS) metrics are becoming more common in community ecology. PCS metrics estimate the phylogenetic relatedness among members of an ecological community or assemblage. If ecological traits are conserved, then phylogenetic clustering (i.e., taxa are more closely related than expected by chance) indicates habitat filtering as the key process in community assembly. On the other hand, a pattern of phylogenetic overdispersion (i.e., taxa are more distantly related than expected by chance) suggests competition is dominant. Most studies to date have used PCS of unmanipulated ecosystems, but the value of PCS metrics will be best revealed in experiments. This …

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Multi-Scale Patch Dynamics Of Coral Communities: A Cross-Caribbean Investigation Using A Landscape Ecology Approach, Brittany Huntington Oct 2011

Multi-Scale Patch Dynamics Of Coral Communities: A Cross-Caribbean Investigation Using A Landscape Ecology Approach, Brittany Huntington

Open Access Dissertations

The overarching objective of this dissertation was to improve our knowledge of the relationship between seascape heterogeneity and diversity of stony coral assemblages across spatial scales. Coral communities on patch reefs in three regions of the Caribbean were used as a model system to investigating this relationship because patch reef heterogeneity could be readily quantified within the seascape using remote sensing and image analysis techniques. I began with a theoretical approach, exploring the origins of observed species diversity among coral communities at increasing spatial scales. Hierarchical sampling and null models revealed that coral diversity was governed by non-random processes at …

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Community And Functional Ecology Of Lianas In The Yasuní Forest Dynamics Plot, Amazonian Ecuador, Hugo Geovanny Romero-Saltos May 2011

Community And Functional Ecology Of Lianas In The Yasuní Forest Dynamics Plot, Amazonian Ecuador, Hugo Geovanny Romero-Saltos

Open Access Dissertations

I studied the community of lianas in the Yasuní Forest Dynamics Plot (YFDP), in Amazonian Ecuador. I found that species diversity of lianas in valley habitat was higher than in ridge habitat, but liana abundance was similar. I also found that community structure (species composition and their abundances) of lianas in ridge was distinct from that in valley because of the differential distribution and abundance of certain species along the topographic gradient. In an attempt to explain this phenomenon deterministically, I took two approaches: (1) to explore if trait expression of leaf-based traits, wood specific gravity and stem growth rate …

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Liana Communities In Three Tropical Forest Types In Xishuangbanna, South-West China, Zhi-Quan Cai, Stefan A. Schnitzer, Yu-Long Zheng, Frans Bongers Jul 2009

Liana Communities In Three Tropical Forest Types In Xishuangbanna, South-West China, Zhi-Quan Cai, Stefan A. Schnitzer, Yu-Long Zheng, Frans Bongers

Biological Sciences Faculty Research and Publications

Lianas are an important growth form in tropical forests around the world. However, they are relatively unknown in south-east Asia. We identified, measured and determined the climbing and dispersal modes for lianas in five 0.1-ha plots in three common forest types at the tropical-temperate transitional zone in Xishuangbanna, SW China, namely, montane forest, evergreen broad-leaved forest and seasonally wet forest. Liana diversity in the three forests combined was high; we found a total of 147 liana species, representing 48 families and 75 genera. The mean density of lianas was 3407 ha-1 and varied significantly between the three forests, with 445, …

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The Relationship Of Herpetofaunal Community Composition To An Elephant (Loxodonta Africana) Modified Savanna Woodland Of Northern Tanzania, And Bioassays With African Elephants, Nabil A. Nasseri Jan 2009

The Relationship Of Herpetofaunal Community Composition To An Elephant (Loxodonta Africana) Modified Savanna Woodland Of Northern Tanzania, And Bioassays With African Elephants, Nabil A. Nasseri

College of Graduate Studies: Theses & Dissertations

Herpetofauna diversity and richness were compared in areas that varied in the degree of elephant impact on the woody vegetation (Acacia spp.). The study was conducted at Ndarakwai Ranch in northeastern Tanzania. Elephants moving between three National Parks in Kenya and Tanzania visit this property. From August 2007 to March 2008, we erected drift fences and pitfall traps to sample herpetofaunal community and examined species richness and diversity within the damaged areas and in an exclusion plot. I captured 143 individuals comprising 13 species of reptiles in the order Sauria and nine species of anurans. Areas of heavy damage yielded …

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Comparative Bacterial Diversity In Recent Hawaiian Volcanic Deposits Of Different Ages, Vicente Gomez-Alvarez, Gary M. King, Klaus Nüsslein Apr 2007

Comparative Bacterial Diversity In Recent Hawaiian Volcanic Deposits Of Different Ages, Vicente Gomez-Alvarez, Gary M. King, Klaus Nüsslein

Faculty Publications

Volcanic activity creates new landforms that can change dramatically over time as a consequence of biotic succession. Nonetheless, volcanic deposits present severe constraints for microbial colonization and activity. We have characterized bacterial diversity on four recent deposits at Kilauea volcano, Hawaii (KVD). Much of the diversity was either closely related to uncultured organisms or distinct from any reported 16S rRNA gene sequences. Diversity indices suggested that diversity was highest in a moderately vegetated 210-year-old ash deposit (1790-KVD), and lowest for a 79-year-old lava flow (1921-KVD). Diversity for a 41-year-old tephra deposit (1959-KVD) and a 300-year-old rainforest (1700-KVD) reached intermediate values. …

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Liana Habitat Associations And Community Structure In A Bornean Lowland Tropical Forest, Saara J. Dewalt, Kalan Ickes, Reuben Nilus, Kyle E. Harms, David F.R.P. Burslem Oct 2006

Liana Habitat Associations And Community Structure In A Bornean Lowland Tropical Forest, Saara J. Dewalt, Kalan Ickes, Reuben Nilus, Kyle E. Harms, David F.R.P. Burslem

Faculty Publications

Lianas (woody vines) contribute substantially to the diversity and structure of most tropical forests, yet little is known about the importance of habitat specialization in maintaining tropical liana diversity and the causes of variation among forests in liana abundance and species composition. We examined habitat associations, species diversity, species composition, and community structure of lianas at Sepilok Forest Reserve, Sabah, Malaysia in northeastern Borneo among three soil types that give rise to three distinct forest types of lowland tropical rain forest: alluvial, sandstone hill, and kerangas (heath) forest. Alluvial soils are more nutrient rich and have higher soil moisture than …

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Uncovering Bacterial Diversity On And Below The Surface Of A Hyper-Arid Environment, The Atacama Desert, Chile, Danielle Rene Bagaley Jan 2006

Uncovering Bacterial Diversity On And Below The Surface Of A Hyper-Arid Environment, The Atacama Desert, Chile, Danielle Rene Bagaley

LSU Master's Theses

The Atacama Desert in Chile extends from latitudes 17º S to 28º S between longitudes 69º W and 71º W. It has been reported that surface soils in the hyper-arid region contain low numbers of culturable heterotrophic bacteria. These soils are considered Mars-like and offer an ideal setting to investigate the application of life detection systems. Thirty-three surface sites were sampled to examine further the extent of the hyper-arid region. We also excavated four soil pits, 40 cm to 90 cm in depth, to explore subsurface microbial communities. One pit was dug in a southern region of the desert compared …

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Phytoplankton Biomass And Species Composition Of Lake Gölbaşı (Hatay-Turkey), Mehmet Naz, Mustafa Türkmen Jan 2005

Phytoplankton Biomass And Species Composition Of Lake Gölbaşı (Hatay-Turkey), Mehmet Naz, Mustafa Türkmen

Turkish Journal of Biology

Seasonal distributions of phytoplanktonic organisms in Lake Gölbaşı were investigated in samples collected from 2 stations between May, 2001, and April, 2002. At each station, monthly sampling was performed from the surface water. The flora consisted of 41 taxa belonging to Bacillariophyta (24), Chlorophyta (12), Pyrrophyta (2), Cyanophyta (2) and Chrysophyta (1). During the 1-year study period, the most dominant group was Chrysophyta followed by Bacillariophyta, Chlorophyta, Cyanophyta and Pyrrophyta. The highest numbers of Chrysophyta were observed in both stations in May, 2001, January, 2002 and April, 2002. Bacillariophyta had the highest biomass in both stations, followed by Chrysophyta, Pyrrophyta, …

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The Role Of Colonization In Establishing Patterns Of Community Composition And Diversity In Shallow-Water Sedimentary Communities, Paul V. R. Snelgrove, J. Frederick Grassle, Judith P. Grassle, Rosemarie F. Petrecca, Karen I. Stocks Jan 2001

The Role Of Colonization In Establishing Patterns Of Community Composition And Diversity In Shallow-Water Sedimentary Communities, Paul V. R. Snelgrove, J. Frederick Grassle, Judith P. Grassle, Rosemarie F. Petrecca, Karen I. Stocks

Journal of Marine Research

To determine whether pattern and diversity in benthic sedimentary communities are set primarily at colonization or by post-settlement biological interactions, we collected faunal cores and conducted reciprocal sediment transplant experiments at a sandy and a muddy site at 12 m depth, ~3 km apart off New Jersey. Multivariate analyses of cores collected at these sites in September 1994 indicated differences in the taxa determining local pattern, with the bivalve Spisula solidissima and the polychaete Polygordius sp. being dominant at the sandy site, and oligochaetes, several polychaete species and the bivalve Nucula annulata dominant at the muddy site. Individual cores from …

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Avian Habitat Use In Southern Nevada Riparian Areas With Varying Amounts Of Tamarix Ramosissima, Sandra Lou Haigh Jan 1996

Avian Habitat Use In Southern Nevada Riparian Areas With Varying Amounts Of Tamarix Ramosissima, Sandra Lou Haigh

UNLV Retrospective Theses & Dissertations

Avian species richness, species diversity, and density were measured and compared over a 21 month period on six riparian sites in Lake Mead National Recreation Area (LMNRA), southern Nevada. Sites consisted of two lake shore areas with almost pure stands of Tamarix ramosissima and four stream side areas, two with mixed Tamarix and native vegetation and two with only native vegetation. Overall mean avian species richness, diversity, and density were lowest on lake shore sites, intermediate on mixed stream sites and highest on stream sites with native vegetation. Differences in these values were significant between lake shore and stream sites …

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