Life Sciences Commons^™

Ecology, Phylogenetics, And Conservation Of Draba Asterophora Complex: A Rare, Alpine, Endemic From Lake Tahoe, Usa, Emily Ruth Smith Putnam

Theses and Dissertations

Rare, alpine, endemic species are particularly at risk for extinction. Alpine environments are especially vulnerable to climate change and human impacts, such as ski resort development and snowmaking. Draba asterophora Payson is a rare, alpine species that occurs only in three disjunct mountain-top regions surrounding Lake Tahoe. It is currently threatened by human impacts, such as ski resorts, as well as indirect influences of climate change and therefore in need of better understanding for conservation purposes. Draba asterophora may be able to serve as a case study for other similarly vulnerable, rare, alpine, endemic species with conservation needs. We utilized …

Winter Waterbird Ecology On The Great Salt Lake, Utah, And Interactions With Commercial Harvest Of Brine Shrimp Cysts, Anthony J. Roberts

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Interactions among commercial fisheries and birds have been studied in open ocean ecosystems and at aquaculture facilities. On the Great Salt Lake (GSL), Utah, USA, a commercial harvest of brine shrimp (Artemia franciscana) eggs (i.e. cysts) occurs annually during fall and winter. Coinciding with commercial harvest is the use of the GSL by millions of waterbirds which has the potential to result in conflict among industry and birds. The objectives of my research were to examine fall and winter ecology of birds using the GSL and interactions with the brine shrimp cyst harvest. I examined the influence of temperature and …

Distribution And Abundance Of Anopheles Spp. In The Lower Rio Grande Valley, South Texas, Norma Hermelinda Martinez

Theses and Dissertations - UTB/UTPA

This study investigated the relationship between Anopheles abundance, collection sites and environmental variables in the Lower Rio Grande Valley, South Texas. In addition, species composition in the Lower Rio Grande Valley was determined in 2011. A total of 6772 female mosquitoes were identified to six genera and 27 species. The most prevalent genera collected were Culex (53.9%), Ochlerotatus (25.6%) and Aedes (13.6%). Anopheles mosquitoes were collected using resting boxes during summer 2012 at multiple locations along the Lower Rio Grande Valley. ArcGIS was used to identify land cover characteristics and nearest water sources at mosquito collection sites. Estero Llano Grande …

Shovelnose Sturgeon Reproductive Ecology In The Lower Platte River, Nebraska, Mathew L. Rugg

School of Natural Resources: Dissertations, Theses, and Student Research

Biodiversity and abundance of freshwater organisms are experiencing drastic declines. Anthropogenic disturbances have altered the natural flow regimes of large rivers, and have led to declines in species that rely on elements of natural flow. Similarly, shovelnose sturgeon distribution has diminished in the last 100 years due to habitat alteration, overharvest, and water contamination. To fully understand the status and viability of a fish population, basic knowledge of a fish’s reproductive strategy is needed. Aspects of reproduction that should be understood to manage for sustainability include maturation, fecundity, and spawning dynamics. There is currently little published information on age/size of …

The Effects Of Calcium Concentration And Food Levels On Daphnia, Fawn Goodberry

Biology Theses

Many physiological processes of Daphnia are negatively affected at low calcium concentrations. The concentration of calcium within lake water influences how Daphnia populations will survive and reproduce in natural environments. An experiment was designed to test the effects of calcium concentration and food level on the growth and reproduction of a Daphnia hybrid. Daphnia pulex x Daphnia pulicaria were reared in a soft water medium at three calcium concentrations (2.5mg/L, 1.0mg/L, 0.50mg/L) and high and low food levels (5.6 x 10⁵ and 5.6 x 10⁴ cells of the algae Ankistrodesmus sp.) in a 2 x 3 factorial …

Roads And The Reproductive Ecology Of Hesperidanthus Suffrutescens, An Endangered Shrub, Matthew B. Lewis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

We studied the pollination ecology of the endangered Utah desert shrub, shrubby reed-mustard (Hesperidanthus suffrutescens). We also studied the impacts that dust from unpaved roads has on successful reproduction. In addition, we looked at the relationship between the total number of plants, the spacing of plants, and reproduction. We found that shrubby reed-mustard requires pollinators for successful pollination. Pollinators include many small native bees from the genera Andrena, Dialictus, and Halictus. Additionally, we found that reproduction of shrubby reed-mustard is limited, possibly due to scarcity of these bees. We found that dust from the road …

Ecology Of Coyotes On The Valles Caldera National Preserve, New Mexico: Implications For Elk Calf Recruitment, Suzanne J. Gifford

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Valles Caldera National Preserve (VCNP) managers were concerned about low elk recruitment observed at the same time as an apparent increase in sightings of coyotes and observations of coyote predation on elk calves. The goal of this study was to describe coyotes’ ecological interactions with elk, particularly coyote diet and movements on the Valle Grande, a large grassland meadow in the southeastern portion of the VCNP.

We examined coyote diet by quantifying undigested remains of food items in coyote scats (feces). The most frequent taxa were rodents (montane voles and pocket gophers), elk (adult and calf), insects (grasshoppers and beetles), …

Integrating, Developing, And Testing Methods To Generate More Cohesive Approaches To Biogeographic Inference, Mallory Elizabeth Eckstut

UNLV Theses, Dissertations, Professional Papers, and Capstones

As a fundamental component of the developing discipline of conservation biogeography, broadscale analyses of biotic assembly and disassembly across multiple temporal and spatial scales provide an enhanced understanding of how geologic transformations and climate oscillations have shaped extant patterns of biodiversity. As with any scientific field, there are limitations in the case of biogeographic historical reconstructions. Historical reconstructions are only as robust as the theoretical underpinnings of the methods of reconstruction (including data collection, quality, analysis, and interpretation). Nevertheless, historical reconstructions of species distributions can help inform our understanding of how species respond to environmental change.

My dissertation takes a …

The Population Dynamics Of Two Rodents In Two Coastal Marshes In Virginia, Robert K. Rose, John A. March

Virginia Journal of Science

The communities of small mammals were evaluated for 13 months with capture-mark-recapture methods in two Spartina-Juncus marshes of the Atlantic coast in Northampton County, Virginia. Small mammals were trapped for three days each month using live traps placed on floats on two study grids. Two rodents were numerically dominant (~90% of small mammals) there: marsh rice rat, Oryzomys palustris, and meadow vole, Microtus pennsylvanicus. Monthly estimates of population density were greater for rice rats (peak: 45/ha) than for those of meadow voles (peak: 30/ha). Survival rates were generally low, especially for rice rats, indicating highly vagile populations. Both …

Ecology Of Glacial Relict Fishes In South Dakota's Sandhills Region, Eli Felts

Electronic Theses and Dissertations

Native stream fish zoogeography has changed substantially across North America during the last century as habitat degradation, stream fragmentation and introductions of nonnative species have led to numerous extinctions, extirpations and altered distributions. Insufficient information regarding imperiled species often results in reactive, rather than proactive, management, and knowledge of species status and ecology is critical in identifying conservation priorities. South Dakota populations of three dace species (northern redbelly dace Chrosomus eos, finescale dace Chrosomus neogaeus, and pearl dace Margariscus margarita) are relict of Pleistocene Glaciation and are isolated from the northern core of their distribution, but little information exists regarding …

First Record Of Pond Sliders (Trachemys Scripta Scripta And T. S. Elegans) At Fredericksburg, Virginia With Observations On Population Size, Age And Growth, Werner Wieland, Yoshinori Takeda

Virginia Journal of Science

We conducted a turtle mark-recapture program within a 160 m stretch of the Fredericksburg Canal with standard, baited hoop nets from May to July 2012 to determine if a population of the introduced Red-eared Slider (Trachemys scripta elegans) and Yellow-bellied Slider (Trachemys s. scripta) are established in this area. We captured and marked nine Red-eared Sliders (1 male, 8 females) and estimated a population size of 23 individuals. Most were reproductively mature. The established population in the canal may be a source of introduction into the Rappahannock River.

Microstonyx (Suidae, Artiodactyla) From The Upper Miocene Of Hayranlı-Haliminhanı, Turkey, Jan Van Der Made, Erksi̇n Güleç, Ahmet Cem Erkman

Turkish Journal of Zoology

The suid remains from localities 58-HAY-2 and 58-HAY-19 in the Late Miocene Derindere Member of the İncesu Formation in the Hayranlı-Haliminhanı area (Sivas, Turkey) are described and referred to as Microstonyx major (Gervais, 1848-1852). Microstonyx shows changes in incisor morphology, which are interpreted as a further adaptation to rooting. This occurred probably in a short period between 8.7 and 8.121 Ma ago and possibly is a reaction to environmental change. The incisor morphology in locality 58-HAY-2 suggests that it is temporally close to this change, which would imply that this locality and the lithostratigraphically lower 58-HAY-19 belong to the lower …

Distribution And Ecology Of Ostracoda (Crustacea) From Troughs In Turkey, Okan Külköylüoğlu, Derya Akdemi̇r, Necmetti̇n Sari, Mehmet Yavuzatmaca, Ceren Oral, Eli̇f Başak

Turkish Journal of Zoology

Troughs are artificially transformed natural springs, underground waters, or related habitats. Some effects of such transformation are mentioned in a few studies, but there has been no extensive study on species composition and diversity in troughs. To contribute to the knowledge on the ostracods in troughs, we examined ostracod composition and diversity in 105 troughs from 6 provinces (Bolu, Erzincan, Gaziantep, Kahramanmaraş, Ordu, Van) in Turkey. The troughs were randomly visited between the years 2006 and 2010. A total of 32 ostracod species and a mean number of 2.16 species per trough were found. The most common 4 species (Heterocypris …

Evaluating The Utility Of Beaver Reintroduction Programs For Enhancing Habitat For Rainbow Trout And Steelhead, Jonathan Rodger Hegna

All Master's Theses

Beaver reintroduction programs are increasingly being viewed as a way to enhance salmonid habitat and production. However, the actual effectiveness of using beavers as a habitat enhancement tool for ESA listed steelhead Oncorhynchus mykiss populations is unknown. We examined the type of habitat, at both the microhabitat and mesohabitat levels, preferred by steelhead in three small streams in the upper Yakima Basin, WA through standard snorkel surveys and habitat measurements. Our results suggest that steelhead in small streams strongly prefer (relative to availability) microhabitats that have deeper water(> 30 cm), slow stream velocities(< 0 .05 mis), and complex cover types. Habitat partitioning among the size-classes (small< 50 mm, medium 50-90 mm, large> 90 mm total length, TL) principally operated …