Life Sciences Commons^™

The Contribution Of Environmental Variables On Small Mammal Species Richness And Relative Abundance In Eastern Nevada, Stephanie Harris

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study is to determine how four environmental variables: elevation, latitude, soil type, and vegetation impact the relative abundance of Peromyscus maniculatus and the species richness of small mammal populations in Eastern Nevada. In order to complete this study, a survey of small mammals was completed in the following 8 Eastern Nevada valleys: Delamar, Dry Lake, Dry Lake- Muleshoe,Cave, Lake, Snake, Spring, White River. In each valley, transects of Sherman live traps will be set up for 3 consecutive nights (O'Farrell et al 1977). Data on elevation, latitude, soil type, and vegetation were taken at each trap …

Anaerobic Digester Use In Dairy Farms In The United States, Shaun Elsasser

UNLV Theses, Dissertations, Professional Papers, and Capstones

Anaerobic digestion is a highly efficient process, trapping the methane gas from cow manure and processing it into energy. The steep initial capital costs make anaerobic digesters short-term liabilities, but the long-term benefits far outweigh the long-term costs. An anaerobic digester unit will begin to show a profit after approximately five years of operation. During the lifetime of the unit, estimated at 15 years, the digester will have produced about $ 1,000,000 in profits for the dairy farm, while also providing invaluable benefits to society as a whole.

Population Trends Of Wintering Bald Eagles (Haliaeetus Leucocephalus) At The Lake Mead National Recreation Area, Nevada, Deanna Morrell

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to look at population trends of wintering bald eagles (Haliaeetus leucocephalus) at the Lake Mead National Recreation Area, Nevada from 1991 to 2006. Bald eagles were counted on January 5, 2006 along the entire shoreline of Lake Mead and Lake Mohave. This study focused on two questions: (1) how has the population changed over time? (2) How has the proportion of juvenile eagles to adult eagles changed over time? Question one was supported with the number of bald eagles significantly increasing (r=0.76, p=0.002). Question two was supported as the proportion of juveniles to adults …

Analyzing The Effects Of Various Sign Types Used By The Bureau Of Land Management For Desert Cleanup And Restoration Projects, Christopher Linehan

UNLV Theses, Dissertations, Professional Papers, and Capstones

What is the effectiveness of attempts to curb illegal dumping with prompts on signs posted in the area? Do positive friendly language prompts such as “Restoration in Progress Please Do Not Disturb” generate more positive attitudes and intentions towards illegal dumping problems, than less friendly prompts such as “No Dumping Allowed”?

Results, although inconclusive, did however show a slight trend towards the negative language signs.

Total Suspended Solids In Las Vegas Wash, Mika Koponen

UNLV Theses, Dissertations, Professional Papers, and Capstones

Erosion along the Las Vegas Wash (Wash) has increased steadily along with the rapidly increasing population. The focus of this study is to find out if there is a relationship between lower total suspended solids rate (TSS) and the construction of erosion control structures along the Wash. The study was conducted between 7/15/2003 and 11/29/2004.

The method was water sampling on 7 sites and the samples were analyzed at Southern Nevada Water Systems (SNWS) laboratory at Saddle Island in Boulder City. Additional water quality data was also collected using Quanta, a device measuring different parameters in water. In this study …

A Comparison Of Population Sizes And Number Of Captures For The Desert Woodrat (Neotoma Lepida) In Two Microhabitats In The Las Vegas Wash, Nevada, Jayson Barangan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Planned removal and eradication of saltcedar in the Las Vegas Wash, Nevada could potentially generate adverse impacts on present desert woodrat (Neotoma lepida) populations inhabiting the area. Consequently, research was conducted investigating population sizes of N. lepida in two distinct microhabitat types, saltcedar (Tamarix sp.) and mesquite/quailbush (Prosopis sp./Atriplex lentiformis). The results of this study will aid in gauging the effects of the changes in vegetation once restoration work is completed and assist with logistical scheduling for implementation of control measures. Mark-recapture field techniques were utilized for data collection from July 2002 to June 2003. Population estimates were calculated using …

Observed Omnivory In The Herbivorous Blue Tilapia (Oreochromis Aureus), Stephen M. Oliveira Jr.

UNLV Theses, Dissertations, Professional Papers, and Capstones

Gila seminuda, a native endangered species, and Oreochromis aureus, a nonnative invasive species, share the same habitat in the form of the Reid Gardner Power Plant intake ponds. The purpose of this study is to characterize the feeding habits of Oreochromis aureus within the Reid Gardner Power Plant intake ponds and address the potential predation habits of Oreochromis aureus. Stomach contents of O. aureus were identified and analyzed using chi-square and log-likelihood ratio techniques, with respect to mass, length, girth, gender, or spatial distribution of samples. Results showed omnivorous behavior with a 7.00% predatory/prey relationship, and no difference of feeding …

Vegetation Characteristics Associated With Small Mammal Populations In The Las Vegas Wash, Christine Therese Herndon

UNLV Theses, Dissertations, Professional Papers, and Capstones

Percent litter, average litter depth, percent bare ground, vegetation density, vegetation canopy, and distance to an ecotone boundary were measured and compared to small mammal capture locations in the Las Vegas Wash. Neotoma lepida appear to be greatly dependent upon the foliage litter of T. ramosissima. Alternatively, ecotone boundaries appear to be the most important factor affecting Dipodomys merriami distributions. Peromyscus eremicus distributions may be predicted based on vegetation density and increased canopy during shorter, winter torpor periods. Chaetodipus penicillatus were consistently associated with dense, seed-bearing vegetation, although C. penicillatus is extremely opportunistic and vegetation density should not limit their …

Habitat Preferences Of Four Species Of Lizards Found At The Las Vegas Springs Preserve, Scott Garncarz

UNLV Theses, Dissertations, Professional Papers, and Capstones

Developing an understanding of the habitat usage of reptiles is important when trying to develop a management or restoration plan that is compatible with what is known of the reptile species that are being investigated. There are many lizard species found in the Mojave Desert, but there are only four known to inhabit the Las Vegas Springs Preserve (LVSP) in Las Vegas, Nevada. In the LVSP, sites are going to be restored with native Mojave Desert vegetation. Since there are many habitat types in the Mojave Desert, we must determine which types would be best suited for the four species …

A Study Of Invasive Species Cover Near Roads In A Red Rock Canyon Blackbrush Community, Christopher Keough

UNLV Theses, Dissertations, Professional Papers, and Capstones

The monitoring of Mojave Desert plant communities during and following disturbance is an important process that could provide invaluable information about disturbance/recovery regimes in similar arid environments across the globe. Blackbrush communities are of particular interest because of their low replacement rate, which makes them highly susceptible to disturbance. Roads in the Mojave Desert have been associated with soil compaction resulting in a lack of vegetation as well as an increase in invasive species cover in the immediate proximity. To investigate these statements, eight fifty-foot line transects were established in each of three plot types (perpendicular to dirt roads, perpendicular …

The Effects Of Off-Road Vehicle Use In Desert Tortoise (Gopherus Agassizii) Habitats, Brent D. Clark

UNLV Theses, Dissertations, Professional Papers, and Capstones

The desert tortoise (Gopherus agassizii) populations have been in decline and have been placed on the endangered species list. No single factor is ultimately responsible for the tortoise decline. It is a combination of events that collectively have a negative impact. I chose to focus my study on only one factor, off-road vehicles. By evaluating the damage done to the terrain by off-road vehicles, a better understanding of their impact on the tortoise populations can be assessed and protective measures taken.

The amount of available vegetation does not seem to play a role in their decisions of which plants to …

Defining Soil Type And Habitat Characteristics Of The Arctomecon Californica, Philip S. Childers

UNLV Theses, Dissertations, Professional Papers, and Capstones

A. californica can be considered a rare endemic species, which is believed to be restricted by unique soil relationships. These relationships make the species vulnerable to anthropogenic habitat disturbance. Although A. californica is listed as critically endangered by the state of Nevada, further research is needed before the species can be listed as federally endangered or threatened. This study used primary observational data and secondary GIS compatible data to characterize A. californica habitat. Representative sampling techniques were used to select observations from derived soil types. Although a majority of A. californica populations were found to occur in gypsic soil types, …

The Effects Of Environmentally Relevant Doses Of Perchlorate (Clo4-) On Rana Pipiens Metamorphosis And Development, Andrea N. Golli

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study was to assess the effects of environmentally relevant concentrations of perchlorate on the development and growth of Rana pipiens. Ammonium perchlorate is a rocket fuel oxidizer that is known to interfere with the function of the thyroid gland and some of the highest United States surface water concentration exists in the Las Vegas Wash, NV. Perchlorate not only blocks the body’s ability to incorporate iodine into T3 and T4 hormones through the sodium iodine symporter system, but also depletes the thyroid glands’ internal stores of iodine. Many of the steps that regulate metamorphosis in amphibians …

Travel Time Study At The Wetlands Park National Preserve, Brandon Bair

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis reports on a study of the residence time of water in the Wetlands Park Nature Preserve in Henderson, Nevada. Rhodamine WT was used in order to test for the travel time of the water from the Monson Channel inflow to the Nature Preserve outflow to the Las Vegas Wash. The initial hypothesis was that the water would stay in the system for approximately 8 days. Residence time was tested using an ISCO sampling machine along with a Sequoia-Turner model 450 fluorimeter to test for the fluoresce of the dye in the water. All samples collected were taken immediately …

Fluctuations In Chinook Salmon (Oncorhynchus Tshawytscha) Counts At Three Lower Columbia River Spawning Sites, Eric Michael Loomis

UNLV Theses, Dissertations, Professional Papers, and Capstones

Several hypotheses were developed to explore the pronounced increase in Chinook salmon (Oncorhynchus tshawytscha) returning to spawning grounds at the Cowlitz, Kalama, and Lewis Rivers, three tributaries of the lower Columbia River. The study was conducted using data compiled over a ten-year span from 1991-2001. Preliminary indications are that trends in climate are linked to these increases, with the absence of El Niño events and fluctuations in winter precipitation as likely explanations of these phenomena. The unique nature of Chinook life cycles causes them to utilize a variety of habitats that require ideal conditions for maximum survival rates. Correlations between …

The 100th Meridian Initiative In Nevada: Assessing The Westward Movement Of The Zebra Mussel To The Lake Mead National Recreation Area, Megan Mccoy

UNLV Theses, Dissertations, Professional Papers, and Capstones

Zebra mussels, Dreissena polymorpha, are a concern for all bodies of water in North America. East of the 100th Meridian, zebra mussels have infested the waters and dramatically changed the natural ecosystems. The US Fish and Wildlife Services set up the 100th Meridian Initiative project to monitor the boat traffic to and from infested and non-infested waters of the United States and Canada. Surveys were conducted from October 19, 2002 through March 31, 2003, focusing specifically on the Lake Mead National Recreation Area (LMNRA) for the scope of this thesis. This study addresses the movement of trailers, boats, and other …

An Analysis Of Materials Suitable For Use As A Pitfall Trap In A Desert Environment, R. Renee Brown

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this study is to identify a type of pitfall trap container that can withstand the temperature extremes of the Mojave Desert in which the terrestrial, or above ground, drift fence with pitfall traps will be utilized for trapping reptiles. A pitfall trap is a container, such as a plastic bucket with a plastic lid, that is buried in the ground up to the lip of the bucket and used to catch small ground dwelling fauna that fall into the trap. Many different pitfall trap materials have been utilized in the trapping of small ground-dwelling fauna. Plastic has …

Assessment Of Potential Environmental Impacts Of Nature-Based Tours Originating Within Clark County, Nevada, Beth Domowicz

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this thesis was to assess the potential magnitude of negative environmental damage of nature-based tours originating in Clark County, Nevada. An ordinal ranking system was used for assessment of five variables. These variables were resource use, noise pollution, soil degradation, vegetation degradation, and wildlife disturbance. There were two proposed answers. The first was that as distance increased, negative tour impact would increase. This was not supported, since tours had high impacts for destinations that were close by and far away. The second was that most tours were not causing high damage to the environment. This hypothesis was …

Genesis And Morphology Of Soil Pendants In Quaternary Landforms Of Pahranagat Valley, Nevada, Amy Lynn Brock

UNLV Theses, Dissertations, Professional Papers, and Capstones

Five geomorphic surfaces present in the northern Pahranagat Valley, Lincoln County, Nevada range in age from Early Pleistocene to Recent (Q1-Q5) and vary in clast lithology from dolomite to volcanic tephras. Two chronosequences and 5 lithosequences were compared to evaluate micro and macromorphic characteristics and development of soil pendants. This study presents a new interpretation for soil pendant development. Key features observed in the Pahranagat Valley pendants provide evidence for precipitation at the clast-pendant contact suggesting that newer deposits are not always found at the pendant terminus as other studies have assumed. These features include a void at the clast-pendant …

Mosquito Population Dynamics During The Establishment Phase Of A Constructed Desert Wetland, April Newman

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Nature Preserve at the Clark County Wetlands Park is a constructed wetland that has the potential to produce new mosquito habitat. This thesis evaluates the potential for the development of a mosquito problem at the newly constructed wetland system by assessing the population dynamics of mosquitoes within the Nature Preserve. Based on data collected from May 2001 through January 2002, I describe fluctuations in mosquito genus and relative abundance during the first summer through winter period of wetland development.

An Ethical Framework For Interpreting The United States Endangered Species Act, Cathryn M. Elgin

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this study I argue that a holistic approach is better than an individualistic approach for interpreting the United States Endangered Species Act (ESA). I propose that the use of a holistic ethical framework, based on fundamental environmental philosophy, is better in that it more effectively fulfills the ESA's goals of species and ecosystem conservation. Holistic ethics is based on concern for a community as a whole, while individualistic ethics is based on concern for the individual. A holistic approach, I argue, is more beneficial to nature than is an individualistic approach or other non-holistic approaches. I set up basic …

Green Sea Turtle (Chelonia Mydas) Hatchlings Success: The Effects Of Artificial Lights And Other Human Impacts, Hui-Yu Tracy Liang

UNLV Theses, Dissertations, Professional Papers, and Capstones

Sea turtles appeared more than 200 million years ago in the late Triassic period. They grow very slowly, taking an average of 25 years to reach sexual maturity, with a life span averaging 40-50 years. From May to October green sea turtles (Chelonia mydas) emerge during the night and follow light cues toward the sea. Recently, beachfront development has increased hatchling mortality rate. When hatchlings emerge from nest, high densities of artificial lights lead them toward the land where they either desiccate and die, or are preyed upon. Short-wavelength high intensity light and the distance of artificial light are the …

Mapping The Boulder City Wetlands Using A Global Positioning System (Gps) And A Geographic Information System (Gis), Jennifer Lea Bishop

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Boulder City Wetlands is a constructed wetlands park located in Boulder City, Nevada, approximately 23 miles southeast of Las Vegas, Nevada. Currently, a baseline study of water quality is being conducted in the Boulder City Wetlands. This baseline study of the wetlands is an important step in understanding the development of the Boulder City Wetlands over time. As wastewater is eventually introduced into the existing community tap water running through the wetlands, it is expected that the nitrogen within the water will enhance the growth of vegetation in the surrounding area. Comparing the vegetation growth over time is only …

Reciprocal Transplantation Of The Desert Soil Crust: Can It Be Done?, Christina D. Cole

UNLV Theses, Dissertations, Professional Papers, and Capstones

A 100 meter X 100 meter study site was chosen at White Rock Springs in Red Rock Canyon National Conservation Area, Nevada. To examine Syntrichia caninervis, a desert crustal moss, reciprocal transplantations (20 mm and 40 mm diameter cores) were performed between shaded to shaded, exposed to exposed, and shaded to exposed microsites to determine if it was possible to transplant the study organism with reasonable survivorship. Transplants were inspected following rain events for percent hydration, number of dead stems, and change in percent cover. Data indicated that there was a low mortality rate of S. caninervis stems, and few …

Vegetation Analysis: A Graphical Analysis Of Plant Succession In Desert Communities Affected By Fire, Jeff Lantow

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Mojave Desert is affected by fire every year. With each fire comes the removal of old growth and, in its place, new growth – consisting primarily of those species which thrive in disturbed areas. The focus of my research is to look at plant communities that have been disturbed by fire, and examine the successional pathway of these disturbed environments. The seven environments I analyzed were burned within the last twenty years and are found in the Coleogyne ramosissima ecotone throughout the Spring Mountain range near Las Vegas, Nevada. The data was collected with randomly chosen circle plots in …

Water Conservation In The Las Vegas Valley, Judith M. Keir

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis deals primarily with residential use of water in the Las Vegas Valley, an arid climate located in the Mojave Desert, and whether the education of people living here has any bearing on whether or not they conserve water. Many of the residents of the Las Vegas Valley have moved from other areas of the country, and perhaps are not aware of the fact that there is a limited supply of water available to the Valley. I believe that people are not necessarily wasteful, and that they would want to conserve water, if they were aware that conservation and …

Effects Of Oxygen Variation On The Ecology Of Devil's Hole, Death Valley National Park, Norma J. Azad

UNLV Theses, Dissertations, Professional Papers, and Capstones

The inability to rear Devil's Hole pupfish, Cyprinodon diabolis Wales, in captivity, when captive propagation has been successful with other species of pupfish, led to the examination of environmental factors which are unique to Devil's Hole. It has been suggested that C. diabolis regularly experience developmental arrest due to hypoxic conditions. This arrest may be reversible in areas of the shallow shelf during periods of photosynthetic activity. Oxygen measurements over the shallow shelf reveal a gradient of oxygen variation with the greatest diel variability over the inner portion of the shelf diminishing to nearly imperceptible diel variation toward the outer …

The Real Cost Of Beef: A Monetary Assessment Of The Environmental Degradation Caused By Beef Production, Carolyn Babcock

UNLV Theses, Dissertations, Professional Papers, and Capstones

The environmental degradation caused by beef production is severe. The current literature assesses the ecological damage, but falls short of assigning a per pound dollar amount to reflect the real cost of beef. In the United States, most of the environmental focus has been centered around the use of public lands for grazing and the grazing fee the government considers appropriate. The fee covers the maintenance of the grazing program, which includes maintenance of the actual land. This paper will concentrate on beef-related environmental degradation and select specific damage for monetary valuation.