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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
201

Beech and spruce forest stands conditions in the area of the Moravian-Silesian Beskids and soil zoocenosis

Bayer, Jakub January 2017 (has links)
Soil epigeal fauna of beech and spruce forest stands had been monitored for 8 years (2007-2014) in 37 selected research area in the Moravian-Silesian Beskids. Collection of material carried out twice per year in spring and autumn aspects. Site characteristics of research localities were characterized by high variability while 4 vegetation altitudinal zones, 8 edaphic categories and 12 forest site types had been distinguished. Soil fauna was extracted by Tullgren devices. Within the monitoring, 11 target animal groups were engaged in: mites, springtails, larvae stages of ground beetles, symphylans, diplurans, proturans, centipedes and millipedes, larvae stages of rove beetles, adults of rove beetles, earthworms, larvae stages of click beetles (wireworms). Earthworm´s and wireworm´s cenosis were deterimined into species and genera, respectively. Remaing groups of soil fauna had been studied within larger systematic categories. Subsequently, abundance and dominance of the particular groups of soil epigeal fauna. The outputs had been compared each other and potential relations between particular animal groups to the specific site properties, vegetation altitudinal zones, edaphic categories and forest site types had been assessed thereby. Overall, 274 015 individuals were captured within the monitored soil animal groups. Several groups of soil cenosis were disvored specific relations to the site conditions. Additionally, 12 species of earthwomrs were distinguished while Dendrobaena octaedra seemed to be significantly dominant species representing 68,33 % of total earthworm´s species spectrum. Larvae stages of wireworms were determined into 5 genera. Representatives of Athous genera formed almost 86 % of the population of wireworms.
202

The Abundance, Migration and Management of Mule Deer in Dinosaur National Monument

Franzen, Robert W. 01 May 1968 (has links)
Dinosaur National Monument, in northwestern Colorado and northeastern Utah, is comprised of 206,409 acres and contains several deer winter ranges. A need for deer studies developed because of winter deer mortality and deteriorating range conditions'on some parts of the Monument. Approximately 500 deer winter on the Yampa Bench and approximately 300 deer winter on the Island Park winter range. These are the two main winter ranges within the Monument. Deer on the Yampa Bench migrated an average of 7.3 air miles to the south and summered on the Blue Mountain Plateau during the summer of 1966. This Plateau is owned by the Bureau of Land Management and private individuals. Deer from the Island Park winter range migrated an average of 22.6 air miles to the northwest in 1967, onto the Diamond Mountain Plateau and the Ashley National Forest. Deer tagged on the Split Mountain winter range were found to travel to the south and west. These deer summered mainly upon private lands. Deer remain on Harpers Corner approximately 10 months of the year until deep snows force them to lower elevations on Yampa Bench in early February and from which they return in early April. Vegetation composition and density data gave evidence that the deer and sheep which use the west end of the Yampa Bench are competing for forage. Carrying capacity data suggest that sheep use of this area be reduced. Carrying capacity data for the Split Mountain range suggest that cattle use should be reduced. If grazing use was kept off this area until June, the grasses would have a better opportunity to put on good growth before utilization of them began. Other winter ranges within the Monument are well within their carrying capacity limits. Thus, a safeguard exists on most winter ranges against deer winter mortality. The physical condition of deer on the Monument's winter ranges was very good during the winters of 1966 and 1967. Consequently, deer winter mortality was found to be slight on the Monument's ranges during these two winters. A few does remain on winter range areas within the Monument to summer. They generally 'use the river islands and the relatively inaccessible canyon slopes as fawning grounds. Nearly all of the deer that winter within the Monument migrate to higher elevations off the Monument to summer. This makes them subject to reduction by hunting. Deer hunting pressure on the hunting units adjoining the Monument has in recent years been sufficient to keep deer numbers within their respective winter range carrying capacities.
203

The Influence of Redd Distribution and Microhabitat Availability on the Distribution and Abundance of Young-of-the-year Trout in the Green River, Utah

Buntjer, Michael J. 01 May 1992 (has links)
Redd distribution, redd density, and physical habitat were used to explain the distribution and abundance of young-of-the-year (YOY) brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) in the Green River, Utah. The importance of variables at both a microhabitat and macrohabitat scale were assessed using stepwise regression analysis. Availability of cover (rock and vegetation) and proximity to spawning sites were the most important variables used to explain the distribution and abundance of YOY brown trout and rainbow trout. In addition, YOY brown trout and rainbow trout occupied specific microhabitats and showed patterns of use for particular depths, substrates, and cover. However, the importance of variables differed by year, indicating that variables other than those measured were also influencing their distribution and abundance. The results of my study indicate that variables at both a microhabitat and macrohabitat scale may be important in explaining the distribution and abundance of YOY trout in streams. Therefore, to better understand the habitat requirements of stream fishes and to better explain their distribution and abundance in streams future, studies may need to incorporate both physical habitat variables and variables affecting recruitment.
204

Rock Climbing or Lichen Climbing? How Rock Climbing Impacts Bryophyte and Lichen Communities Within the Red River Gorge

Reding, Jordan Michael 23 October 2019 (has links)
No description available.
205

The solar abundance of beryllium : constraining the solar problem via non-LTE modelling

Ogneva, Daria January 2023 (has links)
Accurately determining the solar abundance of beryllium is a key to calibrate transport processes at the base of convective zone, which in turn is an improvement upon existing solar models and general understanding of the physical processes within the Sun. To determine an abundance, assumptions about the solar atmosphere must be made. While it is common to assume local thermodynamic equilibrium (LTE) due to the simplicity this brings to the calculations, it is more accurate to assume non-local thermodynamic equilibrium (non-LTE), because it better resembles the physics of the solar atmosphere, where observed spectral lines form. Non-LTE calculations require a model atom that will provide important information about the atom to the radiative transfer code in order to preform necessary calculations. In this project, the solar abundance of beryllium was studied with main purpose of calculating the non-LTE abundance correction to be applied on already known LTE abundances. This was done by creating a comprehensive model atom of beryllium, containing essential information about the atom’s states as well as radiative and collisional transitions coupling those states. Simulations using radiative transfer code were performed and their results analysed to compute non-LTE abundance correction for the solar 3D LTE abundance A(Be) = 1.38. Resulting correction was computed to be equal to +0.03, which, when applied on the LTE abundance,does not affect the abundance significantly, contrary to the -0.060 correction of Korotin &Kučinskas (2021). A possible reason for this result might be that the model atom includes additional collisional transitions (Kaulakys collisions), omitted in Korotin+.
206

Landscape Ecology of Eastern Wild Turkeys in Mississippi

Davis, Annie Moriah 12 August 2016 (has links)
The effects of landscape structure on wildlife populations have drawn more attention from ecologists and wildlife managers as landscapes have rapidly changed worldwide. The objectives of this study were to (1) conduct a statewide habitat suitability assessment for wild turkeys (Meleagris gallopavo) in Mississippi using machine learning methods; (2) determine landscape-abundance relationships of wild turkeys at 2 spatial scales; and (3) measure genetic distinction of wild turkey populations in Mississippi. I found that habitat suitability for wild turkeys was positively related to amount of forest cover. Wild turkey relative abundance peaked at an optimal hardwood forest proportion of 0.29 and increased with enhanced landscape configuration at the annual dispersal scale, supporting the landscape composition hypothesis. Using microsatellite analysis of 224 birds, I found 3 distinct genetic clusters in Mississippi; however, population genetic differentiation neither fit to the isolation by distance or isolation by resistance models but may have behavioral cues.
207

Spillningslevande bladhorningar (Scarabaeoidea) kring Varbergs kustslätt, en återinventering

Malmström, Klara January 2022 (has links)
Dyngbaggar tillhör en av de mest studerade insektsgrupperna inom ekologiska undersökningar på grund av deras förekomst i ett spritt förekommande habitat som spillning. Förekomsten av denna grupp skalbaggar har präglats av det kulturhistoriska brukandet av marker som under en längre tid hävdats genom bete med domesticerade djur på marker av olika karaktär. Idag är dessa habitat sparsamt förekommande i ett landskap präglat av fragmentation och förändrad markanvändning vilket ställer betesberoende populationers överlevnad på prov. För att kartlägga vilken påverkan dessa landskapsförändringar har på insektsfaunan är långsiktig miljöövervakning av stor vikt för att bromsa oåterkalleliga förluster. Syftet med den här studien är att undersöka dyngbaggefaunans artsammansättning och individtäthet under vår-och högsommar på tidigare inventerade lokaler 1997 i utkanten av Varberg i mellersta Hallands län. Sedan 1997 har den totala diversiteten ökat med fem tillkomna arter på de fem undersökta lokalerna där ingen art har försvunnit helt. Det fanns ingen statistisk skillnad mellan art- och individantal men artsammansättningen skilde sig på lokalerna där vissa har ökat i antal, tillkommit eller blivit färre. Detta visar på en potentiellt positiv trend men fortgående övervakning krävs för att detta skall bekräftas. De förändringar som har skett i betesmarkernas lokala klimat avspeglar förändringar i artsammansättningen på grund av att betestrycket blivit lägre, marker har betats över längre tid samt restaureringar som har lett till en positiv utveckling. Lokalerna har blivit mer distinkta och skiljer sig både från varandra och hur de såg ut 1997 vilket skapat en större artrikedom. För en gynnsam bevarandestatus krävs en variation av mikroklimat för att även de habitat-specifika arterna ska ha möjlighet att etablera sig.
208

Sandusky Bay Pre-restoration Fish Community

Wygant, Kelsi 19 December 2022 (has links)
No description available.
209

The response of an avian community to intercropping and forest management practices in a private working pine forest

Bracken, Rebecca Doyne 12 May 2023 (has links) (PDF)
Within managed pine forest systems, a plethora of bird species exist throughout the lifecycle of a stand akin to what may be experienced through post-disturbance regeneration in a natural forest system. I sought to address how breeding avian communities shift across time in response to stand aging and forest management, evaluate species-specific responses to stand conditions, investigate the responses of at-risk avian species to forest management, and determine avian non-breeding, over-wintering presence in a managed loblolly pine (Pinus taeda) forest. I conducted breeding bird point count and vegetation surveys within five stands of privately owned and managed pine forest in Mississippi, each of which was split into quadrants with different management strategies implemented. I designed and executed night surveys for Chuck-will’s-widow (Antrostomus carolinensis). Lastly, I conducted winter bird banding to explore over-wintering diversity, dietary isotope assimilation, and parasite prevalence. I found evidence that the avian community shifted in response to forest stage and structure, with differences created by management practices and forest succession. Switchgrass (Panicum virgatum) intercropping allowed some grassland and early successional species to remain in forest stands with closing canopies longer than in plots with standard management, with few diversity differences between treatments. Abundance of Chuck-will’s-widow was found to relate positively with the percent cover of early successional forest stands, those which were recently harvested and replanted and were in a pine-grassland state. Over-wintering bird species richness remained relatively low, and capture rates were consistently greatest in a young open canopy stand, which contained a higher level of vegetation structure and plant abundance when compared to three older stands. This represents a limited number of studies where investigations into bird community responses to forest management took place in the same forest stands across a long temporal period. Managers in forest systems should consider the implications of management undertaken at different stages in the rotational lifetime of a forest stand. To focus on conservation of priority bird species, managers should increase heterogeneity by maintaining or creating pine-grassland and early successional forest conditions within forest stands while also ensuring stands of various ages exist concurrently within the forest ecosystem.
210

Small Mammals in portions of Great Basin National Park Susceptible to Groundwater Withdrawal: Diversity and Stable Isotope Perspectives

Hamilton, Bryan T. 26 February 2009 (has links) (PDF)
To support population growth in Las Vegas, Nevada, large scale increases in groundwater pumping are planned across the state. This pumping could affect riparian areas in Great Basin National Park by lowering groundwater levels, reducing stream flows, and xerifying riparian vegetation. Great Basin National Park (GBNP) is mandated to manage its resources unimpaired for future generations. Loss of biodiversity is unacceptable under this mandate. If groundwater levels are reduced beyond a threshold, aquatic and riparian diversity would be lost, but the effects on small mammal communities are less clear. To provide baseline information and to consider the effects of groundwater withdrawal a priori, we sampled and compared small mammal communities in two watersheds susceptible to groundwater withdrawal and one non-susceptible watershed. We also used to stable isotopes of nitrogen, carbon, deuterium and oxygen to characterize small mammal communities. Evenness was higher in susceptible watersheds, which were distinct in species composition. Riparian and upland habitats in susceptible watersheds supported complementary small mammal communities, while communities in the non-susceptible watershed were more homogenous. Susceptible watersheds are located at the lowest elevations of GBNP where habitat heterogeneity due to the contrast between mesic riparian and xeric upland habitats is important in maintaining small mammal diversity. Partitioning was primarily seen in nitrogen and carbon isotopes which reflect feeding ecology (trophic level and primary production source), but was also seen in oxygen isotopes. Major differences in nitrogen and carbon isotopes were between taxonomic groups, while similarity was highest within these groups. Shrews and ermine were highest in nitrogen reflecting their high trophic positions. Harvest and piñon mice were intermediate in nitrogen suggesting omnivory, while chipmunks, voles, woodrats and pocket mice were apparently herbivorous. Carbon ratios were consistent with C3 based diets but were relatively enriched in Sigmodontinae species. Small mammal deuterium was similar to stream water suggesting that stream water is an important water source of water to small mammals. Oxygen enrichment relative to stream water and precipitation suggested that small mammals are sensitive to body water evaporation. Contrary to a previous study, oxygen isotopes were inversely related to water use efficiency. Increases in the rate of groundwater pumping adjacent to Great Basin National Park could lower water tables, reduce stream flows, and xerify riparian vegetation. We suggest that groundwater levels, streams flow and riparian vegetation, in addition to small mammal species composition will be important response variables in monitoring the effects of groundwater withdrawal. If predictions of groundwater withdrawal are realized, groundwater levels, stream flows, vegetation, microclimate, and invertebrates riparian dependent as well as small mammals will be negatively affected resulting in a decrease in diversity and loss of riparian species from affected areas.

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