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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.
51

Breeding season habitat use and response to management activities by greater sage-grouse on Sheldon National Wildlife Refuge, Nevada

Davis, Dawn M. 06 June 2002 (has links)
Greater Sage-Grouse (Centrocercus urophasianus) have experienced declines throughout their range over the last 50 years. Long-term declines in sage-grouse abundance in Nevada and Oregon have been attributed to reduced productivity. From 1995-1997, sage-grouse production on Sheldon National Wildlife Refuge (SNWR), Nevada was greater compared to Hart Mountain National Antelope Refuge (HMNAR), Oregon. Specific causes for the difference were unknown. Thus, the objectives were to: 1) Determine sage-grouse breeding season habitat use (especially with regard to wildfire) on SNWR; 2) Evaluate reproductive parameters to discern differences between SNWR and HMNAR; 3) Compare habitat components which may relate to differences in sage-grouse reproductive success on SNWR and HMNAR; and 4) Establish hematological and serum chemistry reference ranges for sage-grouse hens to assess physiological condition. Cover type was important in selection of nest sites at SNWR; however, nest cover did not affect nesting success and nest-site selection was not related to experience. Vegetative characteristics at successful nest sites were similar to unsuccessful nests but nest sites had greater amounts of tall residual grass (���18 cm) and medium height shrub cover (40-80 cm) than at random sites. Broods used areas with greater forb cover than random sites, indicating use was influenced by availability of forbs. Plant communities in wildfire and associated control sites did not differ appreciably in species composition. Although burning had little stimulatory effect on total forb cover 10-12 years post-burn, alteration of the sagebrush community did not limit sage-grouse use for successful nesting and brood-rearing. Fire did not negatively impact arthropod abundance. Differences in habitat use and sage-grouse productivity between SNWR and HMNAR may be related to differences in forb availability. Forb cover was greater at HMNAR than at SNWR for all cover types. Correspondingly, home range size for sage-grouse broods was greater on SNWR than at HMNAR. Nutrient analysis of forbs indicated higher crude protein, potassium, and magnesium levels at HMNAR than at SNWR; however, these nutrients are not likely to be deficient in most sage-grouse diets. Thus sagebrush-steppe communities supporting these forbs likely meet the dietary nutritional requirements of sage-grouse. Although blood calcium and uric acid levels were greater in sage-grouse hens on HMNAR than at SNWR, differences were attributed to capture date. Furthermore, physiological condition did not affect a hen's ability to nest successfully, nor was condition related to a hen's ability to recruit chicks to 1 August. Causes of sage-grouse decline are varied, but ultimately they are habitat based. Comparisons of reproductive parameters and habitat evaluations, combined with sage-grouse physiology data, may provide insight into habitat differences between study areas not previously recognized. Land management practices (e.g., prescribed fire) which recast the balance of native herbaceous species in degraded big sagebrush communities, may be necessary in the restoration of sagebrush-steppe ecosystems, and ultimately, the recovery of sage-grouse populations. / Graduation date: 2003
52

Les lieux de refuge

Chung, Tevanui 24 January 2011 (has links)
Principe de droit coutumier longtemps honoré, le droit de refuge n’est plus. Les catastrophes de l’« Erika » et du « Prestige », et entre les deux, le périple du « Castor », ont largement mis en lumière cette réalité. À l’origine de ce déclin, les progrès techniques. Certains ayant permis la sauvegarde des marins en perdition sans nécessiter le déroutement du navire vers un abri. D’autres ayant eu pour conséquence de rendre dangereux et polluants la navigation.Le phénomène dit de « lèpre maritime » fut la constante, la pratique adoptée par les États côtiers confrontés à des navires en difficulté susceptibles de porter atteinte à leurs intérêts. Décrit ainsi, le réflexe se perçoit comme légitime. Mais voilà, l’automatisme peut pousser à l’absurde alors que les progrès, encore eux mais a contrario cette fois-ci, permettent de mesurer et tempérer les risques et ainsi revenir vers la voie naturelle du refuge même en présence de navires potentiellement dangereux et/ou polluants / Principle of customary international law which was honored a long time, the right of refuge for ships in distress is in the present day eroded. The disasters of the « Erika » and the « Prestige », and between these two, the event of the « Castor », have largely emphasized this reality.At the origin of this decline, we found technical progresses. Some having permitted rescue of the sailors in distress without requiring the ship to be granted a safe haven. Others having had for consequence to make navigation dangerous and pollutant.The phenomenon known as of « maritime lepers » has been the constant, the practice adopted by the coastal States confronted with ships in distress likely to threaten their interests. Described in this manner, the reflex can be perceived like legitimate. But, the automatism can conduct to the absurdity whereas progresses, but a contrario this time, make possible to measure and moderate the risks and, in consequence, to return towards the natural way of the refuge even in the presence of potentially dangerous and/or polluting ships
53

Characterization of the Shallow Subsurface Geohydrology of the Ni-les'tun Unit on the Bandon Marsh National Wildlife Refuge

Beard, Christopher Madison 24 July 2013 (has links)
The Bandon Marsh is a large marsh restoration project located in southwest Oregon. The land has been previously used for dairy farms and much of the marsh was used for cattle grazing. The goal of the restoration is to recreate a natural habitat for shorebirds and fish. The purpose of this thesis is to gather and analyze data on the geology of the marsh and both ground and surface water quality to evaluate its ability to support biology. The US Fish and Wildlife Service began restoration on the Bandon marsh in 2005. Research on the Ni-les'tun Unit began in that same year with Geoprobe coring, Ground Penetrating Radar (GPR), piezometer well installation, and surface water analysis. Twelve cores were taken with the Geoprobe in 2006 and later analyzed for this thesis. A total of 50 GPR lines were run across the marsh ranging from ~25 m to 1,200 m in length for a total of about 9,700 meters (9.7 km). The ten piezometer wells were sampled to collect groundwater pH, oxidation-reduction potential, salinity, temperature, and well water elevation. Twelve channel sampling sites were chosen to be sampled in three field runs taking place in winter 2011, summer 2011, and winter 2012. The summer 2011 and winter 2012 sampling runs were done after tide gates had been removed from the marsh. The Geoprobe core samples were retrieved for extensive lab analysis. Analyses included; bulk density, porosity, permeability, and grain size studies. Lab results revealed a low permeability fine grained upper sedimentary unit ranging from ~0.5 to ~2.5 meters depth with a coarser grained higher permeability lower unit. GPR lines were analyzed for groundwater surface depths and buried channel cut and fill features (Peterson et. al., 2004). GPR results showed a fairly shallow groundwater surface around 0.5 meters in the north down to 2.0 meters in the south. The piezometer wells showed a seasonal variation in well water elevation with higher elevations in the winter and lower in the summer. Well water chemistry showed both seasonal and spatial variations. Values for pH and dissolved oxygen were lower in the north side of the marsh and higher in the south side, and pH was higher in the summer than in the winter. Wells that were more proximal (within ~400 m) to the Coquille River Estuary showed higher conductivity (salinity) values than those that were more distal (greater than ~400 m). Channel sampling results showed similar trends as the groundwater results. The lower pH values tended to be in the north side of the marsh as well as lower dissolved oxygen values. Again, there was a spatial variability in conductivity with the higher values found closer to the Coquille River. Conductivity in the channel water showed a great seasonal variability with the highest values occurring in the summer time and much lower values in the winter. As expected, channel water increased about 10°C on average from winter to summer. The results of all of these observations and analyses are combined to put together a generalized flow model showing the different water inputs into the channel waters on the Ni-les'tun Unit. Once these inputs were derived, conclusions can be made on the quality of the water and its ability to support small aquatic life.
54

The Biology of Eastern Kingbirds at Malheur National Wildlife Refuge: Survival, Reproduction, and Testosterone Secretion

Redmond, Lucas J. 02 December 2015 (has links)
This dissertation presents the results of a study that I undertook to better understand the breeding biology of Eastern Kingbirds (hereafter, kingbirds) at Malheur National Wildlife Refuge in southeastern Oregon from 2003 to 2009. Kingbirds are long-distance migratory songbirds that breed across much of North America. This species is socially monogamous but, via frequent extra-pair copulations, is genetically polygamous. Kingbirds exhibit relatively high breeding site fidelity, often returning to the same tree to nest in subsequent years. Both members of a pair provide parental care, but there are often specific duties performed by both male and female kingbirds. For example, males typically perform much of the vigilant nest defense that this species is well known for and contribute, to an extent, to the feeding of nestlings. Females, on the other hand, are entirely responsible for incubating and brooding. Beginning in 2002, most adults within the population of kingbirds at Malheur had been banded with a unique combination of three colored plastic leg bands and an aluminum USFWS band. Also, as many nests were located in each year as possible, and any young that survived to fledging age were banded with a unique combination of leg bands. Considerable effort was then spent each year to locate as many banded individuals as possible, which allowed me to document adult and juvenile survival. Annual survival rates of adult male and female kingbirds in the population at Malheur did not differ and were relatively high at approximately 0.65. Juvenile survival rate was approximately 0.29, indicating that slightly less than one-third of nestlings survive the interval between fledging and their first potential breeding season. Resighting probability was high for both sexes, although higher for adult males (0.94) than for adult female (0.84). The latter finding is consistent with the higher site fidelity of males than of females. Resighting probabilities for juveniles were much lower at 0.68 and 0.40 for males and females, respectively. Again, this was expected because natal site fidelity is typically much lower than breeding site fidelity. Compared to most other reports, resighting probability and return rates of juvenile kingbirds was high, presumably because the riparian habitats where kingbirds breed at Malheur function as an ecological island surrounded by, for kingbirds, unsuitable high desert habitat. Thus, unless they disperse very long distances, the only option for juvenile kingbirds is to begin nesting on the refuge. The collection of blood samples from birds has become an increasingly common practice in ornithology. The data that can be gained from these samples allow a number of interesting questions to be asked such as understanding the genetic mating system of a species, patterns of hormone secretion, and discerning migratory pathways via stable isotope analysis. The volume of blood collected is usually small and was assumed to cause no long-term negative effects on sampled individuals. However, few studies have rigorously examined the effect of blood sampling on survival. I used a multistate mark-recapture analysis to assess the effect blood sampling on annual survival of kingbirds by combining the annual survival data described above with whether or not individuals were subjected to blood sample collection. The results of this analysis indicated that blood sampling had no effect on annual survival rates of kingbirds. Whether or not this is the case for other species remains to be seen. However, my results support the assumption that when done correctly, blood sampling has little to no long-term negative effects on birds. Comparative analyses of many bird species show that testosterone secretion exhibits fairly predictable patterns among breeding birds of different mating systems. Monogamous species reach a peak during mate attraction and the period of female fertility which is then followed by a sharp decline when young are in the nest. By contrast, males of polygynous species tend to maintain higher levels of testosterone throughout the breeding season to, presumably, maximize opportunities for acquiring additional mates. Kingbirds are socially monogamous but cryptically polygamous. However, because of high rates of extra-pair paternity, variation in reproductive success among males is much higher than what is expected for a monogamous species, and, instead, is similar to what has been reported for polygynous species. Therefore from 2005 to 2009 I measured testosterone concentrations from the blood samples collected from male kingbirds to determine the breeding season profile of testosterone secretion in kingbirds and to understand the factors that influence testosterone variation among individuals. Contrary to expected for a monogamous species, the testosterone profile of kingbirds did not exhibit the brief peak in testosterone followed by a precipitous decline. Testosterone peaked early in the season, but declined very slowly as the nest cycle progressed. I attributed this gradual decline in testosterone to the cryptically polygynous nature of the kingbird extra-pair mating system. I also found substantial variation in testosterone concentration among male kingbirds and was able to identify several factors contributing to this variation. As expected, testosterone declined as the breeding season progressed (independent of stage in nest cycle) and nest density increased, while increases in testosterone were correlated with the number of fertile females within the population. This suggests that male kingbirds were capable of modulating testosterone concentrations to both cope with an increase in conspecific density, but also to ready themselves for times when extra-pair copulations were more likely.
55

Behavioral Observation and Paternal Investment of Eastern Kingbirds at Malheur National Wildlife Refuge

Chutter, Christopher Michael 10 July 2014 (has links)
We have been studying the population of Eastern Kingbirds breeding in riparian habitats in Malheur National Wildlife Refuge (eastern Oregon) since 2002. These efforts have created an ideal research environment wherein most adults in the population have been color banded and DNA sampled and, as part of other research projects, nearly all broods since 2003 have been paternity tested. I decided to use behavioral video recordings of parental nest behavior undertaken between 2003 and 2010 for two unrelated projects. First, I tested the effectiveness of video sampling nesting behavior (see below and chapter 2). Second, I tested whether male kingbirds were able to affect their level of paternal investment in accordance with their level or realized paternity (see below and chapter 3). Chapter 2 was split into three distinct questions: 1) are parental nesting behaviors repeatable, 2) is a one hour sample sufficient to capture variability in these behaviors, and 3) is the first hour of recording sufficient to capture variability in these behaviors. I found overwhelming evidence that the behaviors I measured were repeatable. This is truly important, for if repeatability was disproven, it would call into question the use of sampling throughout the field of animal behavior. I similarly found strong evidence that a one hour sample was sufficient to capture variability in parental behaviors. From this I was able to suggest that further sampling effort would be better spent increasing sample size rather than observation length. Testing whether the first hour of recording was sufficient to capture variability in parental behavior found more muddled results. While there generally was correlation between behavioral values in the first hour and those over a longer observation period, most behaviors were found to have significantly lower values in the first hour. I tested whether this was the result of a lingering observer effect or a natural effect of time of day and concluded that an observer effect was the more likely explanation. In chapter 3, I ran one of the more in depth and complicated tests for a relationship between paternal investment and realized paternity that I was able to find in the literature. I used the standard male feeding rate as a measure of male investment as well as a far more nuanced measure derived from the first Eigenvector of an analysis of six different paternal behaviors. These were both tested using Akaike's Information Criterion against a number of variables likely to affect parental behavior, including realized paternity. Ultimately, I found no evidence that kingbirds were able to affect paternal investment in response to lost paternity, and conclude that they likely had no means to assess realized paternity within the nest of their social mate. However, from the other parameters tested I was able to find that males increased their investment as brood size increased and as the female spent more time attending, but not feeding, the nestlings. Also, male investment decreased as territory density increased and flight feather length increased. Theory surrounding the variability of extrapair paternity in birds can be used to account for these results. In a denser population males are predicted to reduce paternal effort for one of two reasons: increased likelihood of paternity loss in his own nest and an increased investment in pursuing extrapair copulations of his own. Longer flight feathers are a sign of age and quality in kingbirds, so males with this trait are expected to spend more time pursuing extrapair copulations as they are more likely to be successful in this endeavor.
56

Short-term effects of prescribed burning on bird communities in coastal Pine Savanna

Faulkner, Douglas W. January 1996 (has links)
A substantial portion of the remaining coastal pine savanna in the southeastern U.S. is burned periodically to maintain habitat for the endangered Mississippi Sandhill Crane (Grus canadensis pulla). However, the effects of this burning on other species of birds are unknown. Therefore, a one-summer study was conducted to determine the short-term response of non-target bird species to changes in vegetation structure due to winter prescribed burning of coastal pine savanna. Eight 25-ha study plots were censused using the spot-mapping technique from May - July 1995 at the Mississippi Sandhill Crane National Wildlife Refuge. More species were observed on old burn sites (burned 1.5 - 3.5 yr prior to the study) than new burn sites (burned the previous winter). Gross vegetation features did not differ between treatments. A total of 17 breeding species were recorded during the study. Although there were no significant differences within individual species' densities, seven species were observed only on old burn sites. Winter prescribed burning affected the presence of only shrub-characteristic species. / Department of Biology
57

Chypre île refuge, 1192-1473 : migrations et intégration dans le Levant Latin / Cyprus, refuge island, 1192-1473 : migrations and integration in The Latin Levant

Fenoy, Laurent 19 November 2011 (has links)
Bien des sources chrétiennes relayées par des études des XIX et XXe siècles considèrent la domination des Lusignan en Chypre comme la manifestation d’un double affrontement interconfessionnel. Les rois latins auraient fait de l’île un refuge face à l’expansion de l’Islam avant d’avilir les autochtones Grecs en s’appuyant sur des « réfugiés conquérants », à savoir les Francs et leurs alliés chrétiens orientaux chassés du Proche-Orient. Mais à l’aune de l’écheveau migratoire de la Méditerranée orientale, sauf à exagérer l’impact de l’affrontement entre croisade et jihad, l’ampleur et la nature des migrations affectant Chypre entre 1192 et 1473 ne permettent pas de caractériser l’île par la notion de refuge chrétien: dans la continuité de migrations pluriséculaires Chypre demeure une terre d’accueil façonnée par des dynamiques réticulaires souvent étrangères aux logiques de confrontations interconfessionnelles. Le rôle de Chypre comme île refuge se lit mieux dans sa dimension de conservatoire des nations, lequel s’affirme au même rythme que s’érige une identité chypriote. La reconnaissance officielle de la singularité de chaque communauté peut parfois hiérarchiser la société au profit des seulsLatins : elle n’en fonde pas moins une organisation insulaire consensuelle, car en revêtant un tour intercommunautaire le débat social et identitaire prémunit des dynamiques assimilatrices et favorise l’intégration progressive de tous les Chypriotes aux affaires du royaume. L’île s’impose alors comme un refuge des cultures où une hyper-identité chypriote coiffe autant d’hypo-identités que Chypre compte de nations, permettant à tous les Kypriotes de vivre ensemble sans se confondre. / Many christian sources relieved by studies of the XIX and XXth centuries consider the Lusignan rule over Cyprus as the expression of a double interconfessional confrontation. Latin kings would have turned the island into a refuge in front of the expansion of the Islam before degrading the Greek natives by leaning on “conquering refugees”, namely Franks and theireastern christian allies, forced to flee the Middle East. But compared with the migratory hank of the oriental Mediterranean Sea, unless overstating the impact of the confrontation between crusade and jihad, the scale and the nature of the migrations regarding Cyprus between 1192 and 1473 do not allow to characterize the island by the notion of christian refuge: in the continuity of plurisecular migrations Cyprus remains a land of welcome shaped by reticular dynamics often extraneous to interconfessional confrontations. The role of Cyprus as refuge island is clearer in its dimension of nations conservatory, which asserts itself with the same rhythm as sets up itself a Cypriot identity. The official recognition of the singularity of every community can sometimes organize into a hierarchy the society for the benefit of the Latins only ones: but it founds a consensual island organization, because by taking on an intercommunity turn, the social and identity debate protects against assimilatrices dynamics and favours the progressive integration of all the Cypriots into the kingdom’s affairs. The island then stands out as a refuge of the cultures where a chypriote hyper-identity heads up so manyhypo-identities as Cyprus boasts nations, allowing all Kypriotes to live together without becoming confused.
58

LäsRefuger : En målbild för att skapa harmoniska läsmiljöer på bibliotek / Reading-Refuge : Harmonious indoor environments for reading in libraries

Karlsson, Tove January 2021 (has links)
The aim is to develop guidance for indoor design that inspire a desire to read. The background is that there is dissatisfaction with the work environments in open offices. The starting point for the thesis is that "Prospect-Refuge" theory is atttracting interest among architects working with outdoor environments. The theory's basis is that the natural selection has resulted in a preference for places where one can "see wihout being seen". The case study builds on 77 questionnaire answers and 14 interviews. The contacts have included dialogue about lighting design and reading dogs. The librarians would like their libraries to invest in reading recesses, but they also worry about risks with not visible areas. There is interest in stimulating, intelligible library layouts with cosy seating's where the readers feel safe to have their "back free", i.e. that nobody will approach (from behind) without being detected. However, almost all library investments in indoor environments are restricted to faults and risks, usually related to physical accessibility. None of the interviewees' are aware of any policy document that promote library investments in comfortable circumstances for reading. The library persons view is that the Reading-Refuge concept has the potential to be useful as a guide for development of settings for reading. The concluding part make use of theories about restorative recovery. There is a need for reading environments that match people's inherited and acquired abilities to build and manage mental energy. The thesis concludes with tangible recommendations for design of reading-promoting library layout, reading refuges and lighting design. This is a two years master's thesis in Library and information science.
59

Système dynamique stochastique de certains modèles proies-prédateurs et applications. / Stochastic dynamics of some predator-prey systems and applications

Slimani, Safia 10 December 2018 (has links)
Ce travail est consacré à l’étude de la dynamique d’un système proie-prédateur de type Leslie-Gower défini par un système d’équations différentielles ordinaires (EDO) ou d’équations différentielles stochastiques (EDS), ou par des systèmes couplés d’EDO ou d’EDS. L’objectif principal est de faire l’analyse mathématique et la simulation numérique des modèles construits. Cette thèse est divisée en deux parties : La première partie est consacrée à un système proie-prédateur où les proies utilisent un refuge, le modèle est donné par un système d’équations différentielles ordinaires ou d’équations différentielles stochastiques. Le but de cette partie est d’étudier l’impact du refuge ainsi que la perturbation stochastique sur le comportement des solutions du système. Dans la deuxième partie, nous considérons un système proie-prédateur couplé en réseau. Il s’agit d’étudier comment des couplages plus ou moins forts entre plusieurs systèmes affectent l’existence et la position des points d’équilibre, et la stabilité de ces systèmes. / This work is devoted to the study of the dynamics of a predator-prey system of Leslie-Gower type defined by a system of ordinary differential equations (EDO) or stochastic differential equations (EDS), or by coupled systems of EDO or EDS. The main objective is to do mathematical analysis and numerical simulation of the models built. This thesis is divided into two parts : The first part is dedicated to a predator-prey system where the prey uses a refuge, the model is given by a system of ordinary differential equations or stochastic differential equations. The purpose of this part is to study the impact of the refuge as well as the stochastic perturbation on the behavior of the solutions of the system. In the second part, we consider a networked predator-prey system. We show that symmetric couplings speed up the convergence to a stationary distribution.
60

Selenium in aquatic habitats at Cibola National Wildlife Refuge.

Welsh, Daniel. January 1992 (has links)
I studied selenium contamination at Cibola National Wildlife Refuge (Cibola NWR) in the lower Colorado River Valley, California and Arizona. My objectives were to: (1) determine whether local irrigation practices resulted in exposure of fish to toxic levels of selenium; (2) assess the risks to humans of consuming fish from Cibola NWR; (3) assess whether diversity and abundance of fish were related to selenium concentrations or other water quality variables. Water, sediment, fish, crayfish, and aquatic plants were collected from sites which received irrigation return flows and sites which did not. Selenium was below toxic levels at sites receiving irrigation return flows. Selenium was at the toxicity threshhold for fish at two sites receiving water directly from the Colorado River. Concentrations of selenium in fillets of largemouth bass (Micropterus salmoides) from one lake exceeded levels that elicit consumption advisories in California. Most people would be unlikely to consume toxic amounts of fish, but an advisory should be posted to inform people about potential risks. Gill nets were used to determine species diversity and abundance. There were no strong correlations between selenium levels and indices of species richness and equitability. There was a consistent inverse relationship between selenium levels and catch-per-unit-effort for all species combined. This inverse relationship suggested that selenium may be one of a suite of factors limiting abundance of fish. Correlations between indices of species diversity and abundance and values of water quality variables generally were not significant. Temperature and salinity may have limited abundance of some species seasonally. Increases in selenium levels at sites that are already at the toxicity threshhold could impair reproduction of sensitive species. Population declines and concern about edibility of fish could impair the recreational fishery. Therefore, site-specific ways to reduce selenium accumulation should be studied and implemented. Site-specific limnological conditions may play a role in accumulation of selenium to toxic levels, but major sources of selenium appear to be upstream in the Colorado River basin rather than local agricultural practices. Therefore, selenium input to the Colorado River from sources throughout the basin should be monitored and reduced where possible.

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