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A Comparative Study Of Biocrusts On Gypsum And Non-Gypsum Soils In The Northern Chihuahuan And Eastern Mojave Deserts, Usa: Biocrust Mosses Respond To Soil, Environmental, And Climatic Conditions, Katelyn Gobbie

Masters Theses

Biological soil crust communities (biocrusts) growing on gypsum soils have been well- documented for their prolific appearance and rich diversity of lichens and bryophytes. However, studies characterizing gypsum biocrusts have primarily occurred outside of the U.S., most of which lack comparisons to other soil types. We conducted intensive field surveys to evaluate the cover and frequency of biocrust functional groups and moss species on gypsum and non-gypsum soils in the U.S. regions with the most extensive gypsum outcrops, the northern Chihuahuan and eastern Mojave Deserts. We employed canonical correspondence analysis (CCA) to relate the observed differences in biocrust abundance and …

Niche Overlap In Sympatric Rocio (Teleostei: Cichlidae) Of Guatemala, Cesar Estuardo Fuentes Montejo

College of Science and Health Theses and Dissertations

Rocio is a small genus of Neotropical freshwater fishes that is distributed in Atlantic drainages of northern Middle America. Two species in the genus exhibit sympatry in the Río Dulce basin (in Izabal, Guatemala), where one species is endemic (R. spinosissima), while the other only includes this area as part of a larger geographic range (R. octofasciata). Unfortunately, the ecology of these species has been poorly studied. This study sought to determine the ecological and morphological differences between these two closely related sympatric freshwater fishes. We hypothesized that R. octofasciata would exhibit greater ecological and morphological …

Black Vulture Conflict And Management In The United States: Damage Trends, Management Overview, And Research Needs, Bryan M. Kluever, Morgan B. Pfeiffer, Scott C. Barras, Brett G. Dunlap, Lee A. Humberg

Human–Wildlife Interactions

Contrary to rapid declines of many vulture (Accipitridae, Cathartidea) species worldwide, black vulture (Coragyps atratus) populations are increasing and expanding their range in North America. Vultures exhibit complex behaviors and can adapt to any human-dominated landscape or land use. These traits, combined with population growth and range expansion, have contributed to increased human–vulture conflicts. Our goal was to summarize the current status and trends in human–black vulture conflicts (hereafter human–vulture conflicts), review available management strategies, identify knowledge gaps, and provide recommendations to enhance management and understanding of this species and the associated conflicts. We found human–vulture conflicts are …

Composition Of Dung Beetle Communities In A Tropical Montane Forest Alters The Rate Of Dung Removal More Than Species Diversity Alone, Elizabeth A. Engle

Browse all Theses and Dissertations

Dung beetles provide key ecological functions by degrading and recycling dung. I used experimentally-assembled communities to examine the role of species richness, community biomass, species diversity, species identity, and community composition in dung removal, using Ateuchus chrysopyge, Copris nubilosis, Onothophagus cyanellus, and Dichotomius satanas. I hypothesized: (1) that as species richness, biomass, and diversity increases within a community, dung removal increases; and (2) species are not functionally equivalent, so community composition should influence dung removal rates. As species richness, biomass, and diversity of experimentally-assembled communities increased, the proportion of dung removed also increased. Also, the four species in this study …

Effects Of Water Table Depth And Edaphic Characteristics On Plant Diversity In A Southern Mississippi Pitcher Plant Bog, Patrick Kirby

Master's Theses

This study examined the effects that water table depth and soil characteristics have on plant species richness and species composition within pitcher plant bogs across seasons. Eight piezometers were installed at random distances to monitor long-term water table depth and pressure fluctuations along a ~710-meter line transect traversing upland and bog habitats. Vegetation sampling quadrats (n=128) were set up near each piezometer. Cover data and water table depths were collected in spring and late summer. Soil samples collected from each treatment group were used to obtain soil texture and nutrient data. The summer collection period yielded a total gdiversity of …

Mammal Species Inventory Using Various Trapping Methods In Zone 4 Of Billy Barquedier National Park, Belize During Rainy Season, Mersady Redding

Animal Science Undergraduate Honors Theses

Belize is a small country, but it is extremely ecologically diverse. Based on the few studies conducted in Belize, the abundance of mammals is low but diversity is high. Particular findings note the number and identity of species differed between four sites in the Maya Mountains of Belize, indicating that a data set from a single site is not representative of the Neotropical region. Insufficient data is available to estimate current species richness of many areas in Belize, including Billy Barquedier National Park (BBNP). The objective of this study was to explore trapping and documentation methods of terrestrial mammals in …

A Comparison Of Drone Imagery And Groundbased Methods For Estimating The Extent Of Habitat Destruction By Lesser Snow Geese (Anser Caerulescens Caerulescens) In La Pérouse Bay, Andrew F. Barnas, Brian J. Darby, Gregory S. Vandeberg, Robert F. Rockwell, Susan N. Ellis-Felege

Biology Faculty Publications

Lesser snow goose (Anser caerulescens caerulescens) populations have dramatically altered vegetation communities through increased foraging pressure. In remote regions, regular habitat assessments are logistically challenging and time consuming. Drones are increasingly being used by ecologists to conduct habitat assessments, but reliance on georeferenced data as ground truth may not always be feasible. We estimated goose habitat degradation using photointerpretation of drone imagery and compared estimates to those made with ground-based linear transects. In July 2016, we surveyed five study plots in La Pérouse Bay, Manitoba, to evaluate the effectiveness of a fixed-wing drone with simple Red Green Blue …

Role Of Managed Marine Areas On The Diversity And Individual Responses Of Rocky Intertidal Shore Grazers In Central Chile, Kathy Liu

Scripps Senior Theses

Many different types of marine benthic herbivores or “grazers” inhabit coastal intertidal zones and play a crucial role in inter- and shallow subtidal ecosystems. Chile has one of the most diverse intertidal zones, but many intertidal grazers are exploited for human consumption. Marine protected areas (MPAs) and marine management and exploitation areas (MEAs) are promising tools for Chile to combat over exploitation of these grazer and other marine resources. This study surveyed the impact of sites with contrasting management on the diversity and abundance of all intertidal grazers and their impact on the size frequency and shell length-body weight allometry …

Nutrient Flux From Aquatic To Terrestrial Invertebrate Communities Across A Lakeside Ecotone, Hosanna B. Loreaux

Browse all Theses and Dissertations

In this study, I examined how the spatiotemporal distribution of spider webs and diet changed in a lake riparian zone with increasing distance from an aquatic resource. I surveyed twenty, one-hundred meter transects along the perimeters of Sanford and Escanaba lakes (Wisconsin). Overall, spider web abundance was highest near the lakes and decreased moving into the adjacent forest. Horizontal orb webs, vertical orb webs, and mesh webs showed strong negative relationships with distance from the lakes. Aquatic insects composed an average 36-64% of spider diet for all spider families throughout the riparian zone, suggesting that some spider families are selecting …

Where Birds Chill: An Assessment Of The Habitat Preferences Of Birds Overwintering In Hudson Valley Forests, Elizabeth Claire Axley

Senior Projects Spring 2019

Many avian species overwinter in eastern North America; however, studies on bird populations are rarely undertaken during this critical survival time, and little is known as to their habitat preferences and foraging behavior. In this observational study, we performed a survey of birds overwintering in the Hudson Valley’s temperate, primarily-deciduous forests, assessing avian populations’ habitat preferences through the vegetative structural variables surrounding overwintering birds as they forage. Our results suggest that high canopy cover is critically important to predicting overwintering bird occupancy on a microhabitat scale. Moreover, overwintering birds preferentially occupy forest plots not dominated by sugar maples, in spite …

Population Dynamics Of Off-Host Rhipicephalus (Boophilus) Microplus (Acari: Ixodidae) Larvae In Response To Habitat And Seasonality In South Texas, Brenda Leal, Donald B. Thomas, Robert K. Dearth

Biology Faculty Publications and Presentations

The cattle tick, Rhipicephalus microplus (Canestrini), is an economically destructive arthropod because of its ability to vector bovine babesiosis. It is known that cattle ticks can spend 80–90% of their lifecycle as questing larvae, yet the effect of climatic factors on their off-host behavior and survival is unclear. The goal of this study was to measure the effects of specific ecological factors on off-host questing larvae in nature. The study was conducted in a south Texas pasture over a two-year period, during which time larval populations were surveyed. Simultaneously, weather variables—precipitation, relative humidity, and ambient temperatures—were recorded. Larval survival rates …

Climate-Driven Change In Himalayan Rhododendron Phenology, Robert Evan Hart

Dissertations

Phenology – the seasonal timing of life-history events – is a critical dimension of natural history. It is also one of the earliest and most noticeable traits by which organisms respond to climate change. However, these responses are complex, and only beginning to be understood, especially in the montane and alpine environments that are among the ecosystems most vulnerable to climate change. Drawing from diverse data sets and employing multiple methodologies, I examined how climate affects phenology in Himalayan Rhododendron spp. Comprehensively monitoring flowering phenology over gradients of season and elevation on Mt. Yulong, China – home to a diverse …

Mechanisms Of Diatom Assembly In A Hydrologically-Managed Subtropical Wetland, Sylvia S. Lee

FIU Electronic Theses and Dissertations

Diatoms are useful indicators of ecological conditions but the mechanisms driving assemblage distribution are not clearly defined. Understanding the mechanisms underlying assemblage distribution is necessary to make accurate predictions about the effects of environmental change, such as hydrologic management, restoration, and climate change. The examination of diatom distribution and key drivers across a large wetland over several years can provide a resolved spatio-temporal framework for determining the relative importance of environmental and spatial factors influencing assemblage patterns. I examined a 6-year record of diatom distribution across the Everglades, a large hydrologically-managed subtropical wetland. Successful restoration of this ecosystem depends on …

Mechanics, Diversity, And Ecology Of Gecko Adhesion, Travis Jay Hagey

Biology

The question of why animals are shaped the way they are has intrigued scientists for hundreds of years. Studies of ecological morphology (the relationship between an organism’s form, function, and environment) often bridge multiple disciplines including biomechanics, ecology, phylogenetics, and comparative methods. In this dissertation, I gathered data and tested hypotheses that considered the link between morphology and performance and the relationship between performance and ecology. I focused my research on the adhesive abilities of geckos. Geckos are an understudied, diverse group of lizards, well known for their adhesive toe pads. I propose that geckos are an excellent group to …

Changes In Leaf Morphology, Photosynthesis And Nitrogen Content In Two Coastal Shrubs, Elizabeth Kost

Theses and Dissertations

It is important to understand mechanisms that facilitate expansion of two common shrubs, Morella cerifera and Baccharis halimifolia in coastal environments. The purpose of my study was to investigate the physiological and structural changes that occur as leaves age. Photosynthesis, incident light, chlorophyll, and leaf C:N ratios were quantified for young, intermediate, and old leaves (distal, central and proximal leaves, respectively). Leaf structural differences were also compared. Leaves did not change morphologically with age. Light decreased with leaf age and during winter months. Photosynthesis showed no seasonal or age related patterns. Chlorophyll increased initially and then declined with age due …

Ecology Of The Rock Rattlesnake, Crotalus Lepidus, In The Northern Chihuahuan Desert, Vicente Mata Silva

Open Access Theses & Dissertations

The Rock Rattlesnake, Crotalus lepidus is a small species that is found from southern Arizona, southern New Mexico, and southern Texas, in the U.S., into northern Mexico. To date, little is known about the ecology of this species. Ecological information is becoming desperately needed for supporting the conservation and protection of species living in fragile environments such as the Chihuahuan Desert amid current local and global threats (e.g., habitat destruction and modification, urban development, and climate change). Although rattlesnakes spend a significant amount of time underground while overwintering, little is known about the physiology and behavior of these organisms during …

Population Ecology And Reproductive Biology Of The Diamondback Watersnake, Nerodia Rhombifer (Serpentes: Colubridae), In Southernmost Texas, Ruben D. Zamora

Theses and Dissertations - UTB/UTPA

Nerodia rhombifer is a polytypic, semi-aquatic snake with a broad geographical distribution ranging from the American Midwest southward to Chiapas, Mexico. Although relatively abundant throughout much of its range, few ecological studies of the species have been conducted. This study provides basic population ecology information in a subtropical habitat. Population data were obtained in a mark-recapture study at Santa Ana National Wildlife Refuge, Hidalgo County, Texas, from August 1995 to December 1998. Specimens taken elsewhere in Hidalgo County provided information on the reproductive biology. This study provides the first absolute density estimates from anywhere within the species’ range. Quantitative information …

Differential Response Of Amp Activated Protein Kinase (Ampk) And Hsp70 To Temperature Stress In The Gastropod, Nucella Lapillus, Emily Zimmermann

All Theses And Dissertations

Populations of the gastropod Nucella lapillus are polymorphic for shell color, with light-colored shells predominating on warmer, wave-protected shores and dark-colored shells limited primarily to cooler, wave-exposed shores. During thermal stress, darker shells attain higher body temperatures than lighter shells. These results suggest that heat stress may determine field distribution patterns. However, there is currently little evidence of physiological consequences of thermal stress in these organisms. Following the guiding hypothesis that heat stress leads to cellular energy depletion, we explored whether the central energy regulator AMP-activated Protein Kinase (AMPK) is activated by heat stress. We compared this response in both …

Ecological Genomics: Understanding Gene And Genome Function In The Natural Environment, M. C. Ungerer, L. C. Johnson, M. A. Herman

School of Biological Sciences: Faculty Publications

The field of ecological genomics seeks to understand the genetic mechanisms underlying responses of organisms to their natural environments. This is being achieved through the application of functional genomic approaches to identify and characterize genes with ecological and evolutionary relevance. By its very nature, ecological genomics is an interdisciplinary field. In this review, we consider the significance of this new area of study from both an ecological and genomic perspective using examples from the recent literature. We submit that by considering more fully an ecological context, researchers may gain additional insights into the underlying genetic basis of ecologically relevant phenotypic …

On Estimating The Exponent Of Power-Law Frequency Distributions, Ethan P. White, B. J. Enquist, J. L. Green

Biology Faculty Publications

Power-law frequency distributions characterize a wide array of natural phenomena. In ecology, biology, and many physical and social sciences, the exponents of these power-laws are estimated to draw inference about the processes underlying the phenomenon, to test theoretical models, and to scale up from local observations to global patterns. Therefore, it is essential that these exponents be estimated accurately. Unfortunately, the binning-based methods traditionally utilized in ecology and other disciplines perform quite poorly. Here we discuss more sophisticated methods for fitting these exponents based on cumulative distribution functions and maximum likelihood estimation. We illustrate their superior performance at estimating known …

Statmod: A Tool For Interfacing Arcview® Gis With Statistical Software To Facilitate Predictive Ecological Modeling, Christine M. Garrard

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As geographical information systems and spatial data become more accessible, predictive spatial modeling in ecology is becoming more common. Unfortunately, not all ecologists possess the necessary skills to successfully combine statistical models and geographical information systems. In response to this problem, I wrote an extension for ArcView^® GIS called StatMod. This extension interfaces ArcView GIS with SAS^® and S-PLUS^® statistical software and walks the user through creating and mapping logistic regression and classification and regression tree models.

StatMod was then used to run a series of analyses that would have been difficult without such a tool. A …

The Ecology Of Lianas And Their Role In Forests, Stefan A. Schnitzer, Frans Bongers

Biological Sciences Faculty Research and Publications

Recent studies have demonstrated the increasingly important role of lianas (woody vines) in forest regeneration, species diversity and ecosystem-level processes, particularly in the tropics. Mechanisms responsible for the maintenance of liana species diversity could yield new insights into the maintenance of overall species diversity. Lianas contribute to forest regeneration and competition, not only by competing directly with trees, but also by differentially affecting tree species and thus changing how trees compete among themselves. In addition, they contribute considerably to ecosystem-level processes, such as whole-forest transpiration and carbon sequestration. As the rate of tropical forest disturbance increases, they are likely to …

A Critical Evaluation Of Research Techniques In Animal Ecology, Michelle A. Baker

Biology Faculty Publications

No abstract provided.

Ecology Readings From The University Of Wisconsin, Michelle A. Baker

Michelle A. Baker

No abstract provided.