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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.
1

Läkemedlet Oxazepam påverkar abborryngel : Exponering under embryonalutvecklingen ger effekter på tillväxt, överlevnad och beteende

Sundelin, Anna January 2012 (has links)
Pharmaceuticals are environmental pollutants that are a major threat to aquatic ecosystems and very little is known about their ecological consequences. In this study growth, survival and behaviour (sociability, activity and boldness) of perch fry (Perca fluviatilis) were examined in order to study the possible effects of exposure to a benzodiazepine anxiolytic drug, Oxazepam, during embryonic development. The study tested following hypotheses: (1) perch growth is affected positively by exposure during embryonic development; (2) early perch survival is affected positively by exposure during embryonic development; and (3) boldness and activity increases while sociability decreases in perch fry exposed during embryonic development. Embryos of naturally spawned perch were exposed to water with two different concentrations of Oxazepam. The embryos were exposed during different parts (24-hour periods) of the embryonic development, because embryos may be more vulnerable at certain times during embryonic development and/or because the exposure at different times can produce different effects. Embryos were also chronically exposed, which is essential for aquatic systems because the influx of pharmaceuticals is more or less continuous. In line with hypothesis 1 treatment with Oxazepam affected growth positively. Similarly, survival increased with Oxazepam exposure as predicted by hypothesis 2. Perch fry exposed to the high concentration and fry exposed late during embryonic development survived better. In addition, as hypothesized in hypothesis 3, perch fry exposed to both concentrations exhibited increased activity and reduced sociability although boldness did not increase. Further studies are required to demonstrate the ecological consequences of Oxazepam in aquatic systems.
2

Is predation performance of Pike (Esox lucius) affected by Oxazepam exposure?

Persson, Josefine January 2015 (has links)
Pharmaceutical contamination is increasing in the environment and the consequences this will bring are of growing concern. The highest contamination of pharmaceuticals can be found in aquatic ecosystems and the organisms of these systems are therefore of utmost importance to research in order to understand the ecological consequences of pharmaceutical contamination. This report will reveal the effect contamination can have on an important apex predator often found in temperate aquatic systems, the Northern pike (Esox lucius) when exposed to the psychiatric pharmaceutical Oxazepam. The predatory performance of pike was studied before and after Oxazepam exposure by monitoring how fast each pike caught three prey of roach (Rutilus rutilus), as well as observing the amount of failed predation attempts when hunting the roach. The exposed pike displayed more failed predation attempts after exposure as opposed to the control group. Furthermore it took the exposed pike longer to catch all three roach after exposure while the mean for the control group decreased. Hence, Oxazepam exposure seem to have an effect on predation performance of pike but no definite conclusion could be drawn about to which extent this affects the foraging success and thereby the survival of the pike considering the complex nature of aquatic systems. More studies are therefore needed in order to determine the full effect pharmaceutical contamination can have on complex aquatic ecosystems and more specifically on an apex predator.
3

Modeling the Ecological Consequences of Visitor Behavior in Off-Trail Areas Dispersed Recreation Use

D'Antonio, Ashley L. 01 August 2015 (has links)
Parks and protected areas are often created to protect important social, ecological, or cultural resources from impairment. In the United States, a large majority of these parks and protected areas are also public land where recreational activities such as hiking or scenic driving are allowed. Managers of many parks and protected areas must therefore try to protect resources while also allowing for recreation use that may put these resources at risk for damage. The field of recreation ecology is interested in understanding how recreation use in parks and protected areas can sometimes cause ecological impacts to vegetation, soil, wildlife, water, air, and soundscapes. This information is then used to help managers prevent undesirable ecological change. When visitors to parks and protected areas leave designated sites such as trails or roads, there is a greater chance that ecological impacts will occur. The studies presented here are designed to help managers better understand how visitor behavior off of designated trails may result in damage to plant communities. These studies examine data on both the social aspects of recreation use (such as visitor behavior and the number of visitors recreating) and the ecological aspects (specifically the plant communities found at popular recreation destinations). By looking at social and ecological data together, these studies can predict locations in parks or protected areas where ecological impact may occur as a result of recreation use. Managers can use these predictions to better allocate resources and time to managing recreation use at locations that are most at risk of impairment.

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