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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.
21

Vocal communication, nesting, and territoriality in the California scrub jay (Aphelocoma coerulescens)

Dodson, Nancy Donehue 01 January 1977 (has links) (PDF)
This report evaluates vocal communication, nesting, territoriality, and other social behaviors of the California Scrub Jay.
22

Effect of predation risk and food availability on parental care and nest survival in suburban and wildland Florida Scrub-Jays

Niederhauser, Joseph M. 01 January 2012 (has links)
Individual organisms often use cues from their natural environments to determine many behavioral and life-history "decisions." These "decisions" are usually adaptive, i.e. a response to selection, because the environmental cues on which they are based reliably correlate with increased fitness over time. When the selected behavioral response to a natural cue no longer provides a fitness benefit, then selection for a new response may occur but individuals maintaining the previously selected response may suffer reduced survival and reproduction. Especially in human-modified landscapes individuals making a maladaptive behavioral or life-history choice based on those formerly reliable environmental cues may be faced with an "evolutionary trap". In urban, or suburban, environments many factors have been altered in ways that could lead to evolutionary traps. Inappropriate behavioral responses by many individuals could lead to reduced demographic performance of urban populations relative to their wildland counterparts and to the decline of entire urban populations. In birds, maladaptive patterns of nest provisioning or vigilance may occur (a) when human-provided adult foods are easier to feed young because they are more abundant and predictable than foods appropriate for nestlings, or (b) when birds' perception of predation risk, which can be influenced by human disturbance, is greater than the real risk. By provisioning or attending their nests more or less than what is appropriate given the environmental level of resources and risks, the behavior of suburban parents may be contributing to high levels of nest failure during the nesting stage. To determine whether maladaptive parental care influences nest survival during the nestling stage, I conducted an experiment using Florida Scrub-Jays (Aphelocoma coerluscens). Suburban scrub-jays have lower nest survival during the nestling stage but higher survival during the incubation stage relative to wildland jays. Both predators and food abundance vary greatly between suburban and wildland scrub. The suburbs have a greater abundance of predators that may prey on both adult scrub-jays and their nests and more foods appropriate for adults but less nestling-appropriate food. This variation in risks and resources should affect the parental care behavior of suburban scrub-jays, which in turn may affect patterns of nest survival. In pre-treatment observations, I found that suburban females spent more time brooding than wildland birds but suburban males did not provision any more than wildland males. Experimentally increasing the perception of adult predation risk reduced parental care in both suburban and wildland females. Increasing the availability of nestling food reduced parental care in suburban females but had no effect in wildland females. Increasing food availability, but not predation risk, decreased call rates but increased call frequency in nestling scrub-jays from both habitats. However, neither parental care nor food availability had much influence on nest survival during the nestling stage. Instead, side nest concealment and the presence of helpers were the most important variables in nest survival analyses prompting other explanations besides maladaptive parental behavior or lack of nestling food resources for the habitat-specific difference in nest survival during the nestling stage.
23

Using Linear Mixed Models to Analyze Native and Non-Native Species Abundances in Coastal Sage Scrub

anderson, kaylee 01 January 2016 (has links)
Coastal Sage Scrub (CSS) is a low scrubland plant community native to the coasts of California, housing many threatened and endangered species. Due to the invasion of non-native plants, many areas of CSS have type converted to annual grasslands and the fire frequency has accelerated; fire in turn, may facilitate further invasion, leading to a loss of biodiversity. While many studies document post-fire succession in these communities, pre-fire data are rarely available for comparison, especially data on seedling emergence. I analyzed post-fire recovery of a type-converted grassland community, comparing seedling emergence data for the first and third year after fire to the three years preceding the fire. Non-native species abundances declined more after the fire than did native abundances. This pattern was still present in 2015, three years post-fire. Two native species, Amsinckia menziesii var. intermedia (Amsinckia) and Phacelia distans (Phacelia), were subjects of seed addition treatments pre-fire, but I found no evidence that past seeding increased their abundances post-fire. Amsincki did recover to its pre-fire density three years after the fire, while the density of Phacelia declined over 75% in both the year immediately post-fire and three years after the fire. However, a third native species, Lupinus bicolor (Lupinus), was both much more abundant and also more spatially widespread both immediately after the fire and two years later. This supports the hypothesis that Lupinus is stored in the soil seed bank and the fire may have given this species the opportunity to recover by lowering abundances of non-native competitors. This analysis will inform future conservation efforts by improving our understanding of how seed banks impact the post-fire recovery of native species.
24

Scrub

Williams, Mark T 13 May 2016 (has links)
No description available.
25

Predator Behavior and Prey Demography in Patchy Habitats

Halstead, Brian J 28 March 2008 (has links)
Habitat loss and fragmentation are among the greatest threats to biodiversity, and these threats can be exacerbated or alleviated by the presence of interacting species. The effect of habitat loss and fragmentation on predator-prey systems has received extensive theoretical attention, but empirical studies of these systems yield few clear patterns. I examined the influence of prey abundance and spatial distribution on the foraging ecology and spatial ecology of Masticophis flagellum (Coachwhip) using capture-mark-recapture and radio telemetry techniques. I also examined the influence of saurophagous snake abundance on the survival rate of Sceloporus woodi (Florida Scrub Lizard) populations. Masticophis flagellum positively selected lizard and mammal prey, but within these categories it consumed prey species in proportion to their availability. Masticophis flagellum was vagile and constrained its movements within large home ranges. At all spatial scales examined, M. flagellum strongly selected Florida scrub habitat and avoided wetland habitats. The negative effect of saurophagous snake abundance best explained differences in S. woodi survival rates among patches of Florida scrub. Further loss and fragmentation of Florida scrub habitat will likely have a strong negative impact upon M. flagellum. Because it is precinctive to Florida scrub, Sceloporus woodi will also be negatively affected by the loss of this unique habitat. The potential positive effects of reduced predation pressure from M. flagellum that may accompany loss and fragmentation of Florida scrub is likely to be offset by increased predation rates by habitat and dietary generalist predators that incidentally prey upon S. woodi. Despite the sensitivity of these species to loss and fragmentation of Florida scrub, the prognosis is good for both M. flagellum and S. woodi on relatively large protected sites containing xeric habitats managed with prescribed fire.
26

Facilitative Interactions Among Native Perennial Shrubs and Native and Exotic Annuals in Recovering Coastal Sage Scrub

Miranda, Courtney Elizabeth 18 May 2013 (has links)
Facilitative interactions can have a powerful influence on the structure of plant communities and must be accounted for in efforts to restore disturbed and invaded habitats, such as the now rare coastal sage scrub (CSS) of California. In this study, I tested for evidence of facilitative effects by the native shrubs Eriogonum fasciculatum var. foliolosum and Artemisia californica on germination and survival of the CSS native annual forb Phacelia distans. P. distans seeds were planted near patches of native shrubs, both under the shrub canopy where any facilitative effects should be strongest, and 0.5 m away in the more exposed grassland. To determine whether the shrub-forb relationship was affected by the presence of invasive annuals, E. fasciculatum sites were assigned either invasive annual removal or non-removal control treatment; no removal treatments were carried out for A. californica. P. distans had significantly higher germination but lower survivorship under the canopy of E. fasciculatum. The results showed no overall effect of invasive removal, but there was a weak interaction effect with location; in shrub-canopy plots, invasive species further lowered survivorship. A. californica showed neither facilitative nor negative effects of this shrub species on either germination or survivorship of P. distans, in contrast with the results for E. fasciculatum. Although E. fasciculatum appears to facilitate the germination of native forbs under its canopy, it also seems to have a negative effect on survival. The weak interaction between location and removal to further decrease survival under the canopy when invasives are present, and the abundance of grasses growing under the canopy, suggest that native shrubs may facilitate the growth of invasive annuals as well as the germination of natives. Consequently, controlling invasive grass abundance may be necessary to capture the benefits of shrub facilitation for the restoration of native CSS herbs.
27

Antiserum titer determination and adherence comparison of three major outer membrane proteins TSA56, TSA47 and TSA22 in Orientia tsutsugamushi

Lin, Tung-cheng 07 September 2011 (has links)
Orientia tsutsugamushi, the causative agent of scrub typhus, is an obligate intracellular pathogen. Recent studies show that the complete genome sequence of Orientia tsutsugamushi have been determined. However, the early signaling events involved in the entry of O.tsutsugamushi into mammalian cells remains a challenge. In this study, we demonstrate that adherence ability and comparison of three major outer membrane protein TSA56, TSA47 and TSA22 of O.tsutsugamushi. Through expression and purification of three type-specific antigen 56-kDa (include TSA56-antigen domain I, TSA56-antigen domain III), 47-kDa and 22-kDa of O. tsutsugamushi , antiserum immunoblots from 22 clinical O. tsutsugamushi-infected patients and in vitro adhesion assay of E.coli overexpression outer membrane protein of O. tsutsugamushi , the antiserum titer and adherence ability of bacterial outer membrane proteins are determined. The data show that antiserum titer against three major outer membrane proteins of O. tsutsugamushi was markedly higher in TSA56 compared to TSA47 and TSA22. In adhesion assay, adhesion of host cells by TSA56 was readily than TSA47 and TSA22. Furthermore, adhesion experiment and antiserum titer against antigen-domain I (ADI) region (19-114 aa) in the extracellular domain of TSA56 was also significantly higher than previously reported antigen-domain III(ADIII) region (237-366 aa) which facilitates the invasion of O. tsutsugamushi through interaction with fibronectin .Taken together, these results clearly indicate that O. tsutsugamushi exploits TSA56-mediated bacterial adhesion, abundant antiserum titer and ADI region of TSA56 may draw another adhesion site (except for previously reported ADIII) to invade eukaryotic host cells.
28

Facilitative Interactions Among Native Perennial Shrubs and Native and Exotic Annuals in Recovering Coastal Sage Scrub

Miranda, Courtney Elizabeth 01 January 2013 (has links)
Facilitative interactions can have a powerful influence on the structure of plant communities and must be accounted for in efforts to restore disturbed and invaded habitats, such as the now rare coastal sage scrub (CSS) of California. In this study, I tested for evidence of facilitative effects by the native shrubs Eriogonum fasciculatum var. foliolosum and Artemisia californica on germination and survival of the CSS native annual forb Phacelia distans. P. distans seeds were planted near patches of native shrubs, both under the shrub canopy where any facilitative effects should be strongest, and 0.5 m away in the more exposed grassland. To determine whether the shrub-forb relationship was affected by the presence of invasive annuals, E. fasciculatum sites were assigned either invasive annual removal or non-removal control treatment; no removal treatments were carried out for A. californica. P. distans had significantly higher germination but lower survivorship under the canopy of E. fasciculatum. The results showed no overall effect of invasive removal, but there was a weak interaction effect with location; in shrub-canopy plots, invasive species further lowered survivorship. A. californica showed neither facilitative nor negative effects of this shrub species on either germination or survivorship of P. distans, in contrast with the results for E. fasciculatum. Although E. fasciculatum appears to facilitate the germination of native forbs under its canopy, it also seems to have a negative effect on survival. The weak interaction between location and removal to further decrease survival under the canopy when invasives are present, and the abundance of grasses growing under the canopy, suggest that native shrubs may facilitate the growth of invasive annuals as well as the germination of natives. Consequently, controlling invasive grass abundance may be necessary to capture the benefits of shrub facilitation for the restoration of native CSS herbs.
29

A Study of Post-Fire Recovery in Invaded Coastal Sage Scrub at the Bernard Field Station

Von Schaumburg, Dana Marie 01 January 2014 (has links)
Coastal sage scrub (CSS), a lowland plant community native to California, is home to many rare, threatened, or endangered plants and animals. Fire, a natural feature of CSS, is essential for maintaining species diversity. However, the invasion of non-native grasses has altered the fire regime in CSS, increasing fire frequency and fire season length and decreasing fire intensity. Changes in the historical fire regime may in turn cause feedbacks that favor non-native species, resulting in the loss of biodiversity in invaded CSS sites. Numerous studies have examined patterns of post-fire succession in CSS; however, the role that the pre-fire seed bank and the relative abundance of natives to non-natives play in vegetation regrowth and community recovery is unclear. A lack of adequate pre-fire data on community composition makes testing hypotheses about the role of seed banks in post-fire recovery challenging. I propose to study recovery of the plant community in two differentially invaded CSS sites (East and West field) following a fire at the Bernard Field Station in September 2013. Data collected at the two sites from 2009-2013 reveal that non-native grass cover was significantly higher than native cover at both sites, though the West field had slightly higher native forb cover. Furthermore, the invasive grass Bromus diandrus almost entirely dominated the East field. Vegetation cover in the West field was more diverse with the abundance of other non-natives (Bromus hordeaceus, Bromus madritensis, Vulpia myuros) and natives (Amsinckia menziesii, Lupinus spp.) significantly higher than in the East field. To determine the effects of these pre-fire differences on recovery processes, I will carry out a randomized block experiment with four treatments (control, native seed addition, non-native grass removal, and both native seed addition and removal of non-native grasses). Twelve blocks will be evenly divided between the East and West fields. I propose to measure relative seedling abundance for both native and non-native species after each significant rainstorm over a three-year study period. I hypothesize that the composition of seed banks pre-fire will predict vegetation regrowth post-fire. Specifically, I predict that, under control conditions, B. diandrus will dominate the East field post-fire given its high abundance pre-fire. Further, I predict that regrowth in controls plots in the West field will be more variable given its more diverse seed bank pre-fire. Lastly, I predict that native forbs will exhibit the greatest degree of recovery in plots where active restoration methods (seeding and non-native grass removal) are employed; the effects of these restoration methods should be strongest in the East field because the pre-fire vegetation community was more heavily weighed towards non-native species. This study will add crucial knowledge to our understanding of how the pre-fire seed bank in CSS affects its recovery post-fire, which may inform future conservation efforts to ensure the continued health and protection of CSS sites around California.
30

Vad innebär patientcentrerad vård för operationssjuksköterskan? : En kvalitativ intervjustudie / What is Patient Centered Care to the Scrub Nurse? : A qualitative interview study

Nero, Emma, Carlsén, Sara January 2014 (has links)
Introduktion: I litteraturen finns få studier som beskriver patientcentrerad vård i perioperativ vårdmiljö. Den patientcentrerade vården (PCV) syftar till att tillvarata patientens perspektiv för att kunna anpassa vården. Begreppet beskrivs som vård anpassad utifrån patientens behov och värderingar. Behoven identifieras, förutses, samordnas och integreras i vården. PCV kännetecknas av respekt och värdighet för patienten som ges valmöjlighet i alla situationer. Syfte: Studiens syfte var att undersöka operationssjuksköterskans uppfattning om patientcentrerad vård och hur det tar sig uttryck i den perioperativa vårdmiljön Metod: Studien bygger på semistrukturerade intervjuer som analyserats med kvalitativ innehållsanalys. Urvalet bestod av 10 kvinnor med åldersspannet 29-59 år med arbetslivserfarenhet som operationssjuksköterska mellan 2-28 år. Resultat: Operationssjuksköterskorna beskrev PCV som att ha patienten i fokus vilket leder till patientcentrerade vårdhandlingar. Dessa vårdhandlingar innefattar att anpassa sig och omvårdnaden utifrån de behov som identifierats hos patienten. Möjligheterna att utöva patientcentrerad vård påverkas av olika yttre och inre faktorer som arbetsmiljön, stress och framför allt operationssjuksköterskans personliga uppfattning. Konklusion: För operationssjuksköterskorna i studien innebär PCV att ha fokus på patienten och att möjliggöra patientens delaktighet i sin vård. Detta kan göras genom olika omvårdnadshandlingar där värderingar och uppfattningar kring patientcentrerad vård speglas. Både yttre och inre faktorer påverkar vilken patientcentrerad omvårdnad operationssjuksköterskan ger patienten.

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