No description available.

In the dawning of what may become Earth’s 6th mass extinction the topic of this thesis, understanding extinction processes and what determines the magnitude of species loss, has become only too relevant. The number of known extinctions (~850) during the last centuries translates to extinction rates elevated above the background rate, matching those of previous mass extinction events. The main drivers of these extinctions have been human land use, introduction of exotic species and overexploitation. Under continued anthropogenic pressure and climate change, the current extinction rates are predicted to increase tenfold. Large perturbations, such as the extinction drivers mentioned above, affects species directly, causing a change in their abundance. As species are not isolated, but connected to each other through a multitude of interactions, the change in abundance of one species can in turn affect others. Thus, in addition to the direct effect, a perturbation can affect a species indirectly through the ecological network in which the species is embedded. With this thesis, I wish to contribute to our basic understanding of these indirect effects and the role they play in determining the magnitude of species loss. All the studies included here are so called in silico experiments, using mathematical models to describe ecological communities and computer simulations to observe the response of these communities to perturbation. When a perturbation is severe enough, a species will be driven to extinction. The loss of a species from a system is in itself a large perturbation, and may result in further extinctions, so called secondary extinctions. The traits of the species initially lost, can be a potential predictor of the magnitude of secondary species loss. In Paper I of this thesis, I show that when making such predictions, it is important to incorporate temporally dynamic species interactions and abundances, in order not to underestimate the importance of certain species, such as top predators. I further show that species traits alone are not particularly good predictors of secondary extinction risk (Paper I), but that in combination with community level properties they are (Paper II). Indeed, there seems to be an interaction such that the specific property making a community prone to secondary species loss, depends on what kind of species was lost in the primary extinction. As different types of perturbation put different types of species at risk of (primary) extinction, this means that the specific property making a community prone to secondary species loss, will depend on the type of perturbation the community is subjected to. One of the predicted main drivers of future species extinction is climate change. If the local climate becomes adverse, a species can either migrate to new and better areas or stay and evolve. Both these processes will be important in determining the magnitude of species loss under climate change. However, migration and evolution do not occur in vacuum – the biotic community in which these processes play out may modulate their effect on biodiversity. In paper III, I show that the strength of competition between species modulates the effect of both dispersal and evolution on the magnitude of species loss under climate change. The three-way interaction between interspecific competition, evolution and dispersal, creates a complex pattern of biodiversity responses, in which both evolution and dispersal can either increase or decrease the magnitude of species loss. Thus, when species interactions are incorporated, it is clear that even though migration and evolution may alleviate the impact of climate change for some species, they may indirectly aggravate the situation for others. In Paper III, the aspect of climate change incorporated in the model is an increase in mean annual temperature. But climate change is also predicted to increase environmental variability. Paper IV shows that species-rich communities are more sensitive to high environmental variability than species-poor ones. The smaller population sizes in the species-rich communities increased the extinction risk connected to population fluctuations driven by the variable environment. Hence, systems such as tropical forests and coral reefs are predicted to be particularly sensitive to the increased variability that may follow with climate change. In Paper IV, primary extinctions of primary producers result in extinction cascades of consumer species, when they lose their prey. However, in reality a consumer species might be able to switch to another prey, and such flexibility has both been observed and suggested as a potential rescue mechanism. But what is beneficial for an individual predator in the short-term can become detrimental to the ecological community in the long-term. Paper V shows that consumer flexibility often led to consumers continuously overexploiting their new prey, in the worst case to the point of system collapse. Thus, the suggested rescue mechanism aggravated the effect of initial species loss, rather than ameliorating it. Overall, the research presented here, underscores the importance of including population dynamics and biotic interactions when studying the effects of perturbation on biodiversity. Many of the results are complex, hard to foresee or even counter-intuitive, arising from the indirect effects of the perturbation being translated through the living web of species interactions.

No description available.

The possibility for plants to utilize phosphorus in soil is a prerequisite for conducting agricultural production, both small scale and professional. Spreading of phosphorus fertilizers and manure is therefore seen as a necessity in today's agriculture in order to achieve high yield. Manure management, livestock farming and manure storage could contribute to the eutrophication of lakes and rivers. For instance, when the ground becomes saturated, phosphorus leakage could be seen in surface runoff or in point sources resulting from inadequate manure storage management. In the municipality of Växjö there is still many bodies of water that do not reach the Swedish environmental water quality standard of "good ecological status". This thesis has therefore analyzed the manure management and storage on agricultural farms which may have contributed to eutrophication in the municipality. The method for this thesis was a literature study, a questionnaire survey with 820 receivers and a summary of issued inspection reports from 2013. The results highlight the ways in which agriculture may have contributed to the eutrophication of lakes and streams in the municipality of Växjö. The survey showed that there is a large number of farmers that are unknown to the inspectors in the municipality and the inspection reports reveal many shortcomings in terms of manure management. The results also indicates that there is an overall lack of knowledge among farmers about why it is important to have a safe manure management as well as storing the manure safely. More information needs to reach the operators, higher standards and more regulatory controls are needed to reduce farms contribution to eutrophication and for Sweden to reach environmental targets and environmental quality standards for water.

Abstract [sv] I det tidigare hamn- och industriområdet Alderholmen i Gävle planeras byggnation av 600 nya lägenheter med start år 2020. Vid provtagningar påträffades höga kon-centrationer av polyaromatiska kolväten (PAH) i marken på Gävle Strand där Etapp 3 ska byggas. Bland dessa PAH-er påträffades kreosot, som innehåller en blandning av många olika fenoliska beståndsdelar som guaiacol och meta-kresol (m-kresol). I dagsläget finns det inte många studier som behandlar jästsvampars nedbrytning av guaiacol och m-kresol utan litteraturen tenderar att undersöka bakteriell nedbryt-ning. I den här studien undersöktes om fem jästisolat tillhörande Ascomycota och Ba-sidiomycota kunde växa i närvaro guaiacol och m-kresol, och bryta ned dem. De jäst-isolat som studerades var Candida argentea FGAA004, Rhodotorula araucariae FMYH002b, Goffeauzyma gastrica FMYH004, Debaryomyces sp. FLYA002 och en oi-dentifierad jästsvamp, SGY001. Ur de experimentella testerna som genomfördes framgick att samtliga jästisolat klarade av att växa i närvaro av guaiacol och m-kresol. Det framkom också att m-kresol var mer toxiskt än guaiacol för samtliga jästisolat, vilket bekräftade tidigare utförda studier om jästsvampars relativa känslighet mot guaiacol och m-kresol. Det var det oidentifierade jästisolatet SGY001 som klarade av att växa i de högsta guaiacol- och m-kresolkoncentrationerna. Därför beslutades att endast undersöka om SGY001 kunde bryta ned guaiacol och m-kresol. Vid biodegra-deringsförsöken som följde kunde ingen nedbrytning detekteras av vare sig guaiacol eller m-kresol, och det skulle ha kunnat bero på att för låga koncentrationer hade valts. Jästcellerna (SGY001) hade antingen utvecklat resistens på grund av de låga koncentrationerna, eller nedärvd resistens mot de båda föroreningarna. Jästcellerna i denna studie tålde en högre koncentration av guaiacol och m-kresol än jästisolat i andra studier, vilket syntes på IC50-värdena. Det kan ha berott på närvaron av glukos i odlingsmediet som användes i den här studien. Jästcellerna kan eventuellt ha und-vikit att använda guaiacol eller m-kresol som kolkälla och istället valt att använda glukos. Med tanke på att SGY001 inte kunde biodegradera vare sig guaiacol eller m-kresol skulle inte jästisolatet kunna användas som in situ-metod på Gävle Strand vid Etapp 3 i dagsläget. I ett större perspektiv finns däremot förhoppningen att den här studien kan bidra med nya infallsvinklar i jästsvampars potential för nedbrytning av föroreningar på Gävle Strand vid Etapp 3, samt i andra stadsmiljöer. Abstract [en] 600 new apartments are planned to be built in the former harbor- and industry area Alderholmen, Gävle, starting in 2020. Soil samples have shown high concentrations of polyaromatic hydrocarbons (PAH) in the ground where Etapp 3 is to be built at Gävle Strand. Creosote was present among these PAHs, and it consists of a mixture of many different phenolic compounds, such as guaiacol and meta-cresol (m-cresol). At present, there are few studies on the biodegradation of guaiacol and m-cresol by yeasts, since the literature tends to examine bacterial degradation. The present study investigates if five yeast isolates, belonging to Ascomycota and Basidiomycota could grow in the presence of guaiacol and m-cresol, and biodegrade them. The iso-lates studied were, Candida argentea FGAA004, Rhodotorula araucariae FMYH002b, Goffeauzyma gastrica FMYH004, Debaryomyces sp. FLYA002 and an unidentified yeast, SGY001. Based on the results of the experimental tests for tolerance level off each isolate, it was concluded that all yeast isolates were able to grow in the presence of guaiacol and m-cresol. Another finding was that m-cresol was more toxic to all the isolates as compared to guaiacol, which confirmed prior studies regarding the rela-tive sensitivity of the yeasts to guaiacol and m-cresol. It was the unidentified yeast isolate SGY001, which manage to grow at the highest guaiacol- and m-cresol con-centrations. Thus, it was decided to only investigate whether SGY001was able to biodegrade guaiacol and m-cresol. During the biodegradation tests that followed, no degradation of guaiacol and m-cresol could be detected, and this could have been due to the selection of too low concentrations. The yeast cells (SGY001) had either developed resistance because of the low concentrations used, or they had inherent resistance to the two contaminants. The yeasts of this study withstood a higher con-centration of guaiacol and m-cresol than yeast isolates in other studies, which was evidenced by the IC50 values. It could have been due to the presence of glucose in the growth medium. The yeast cells could have avoided the utilization of guaiacol or m-cresol as carbon source, and instead chosen to use glucose. Considering that SGY001 was not able to biodegrade guaiacol nor m-cresol, this isolate would not be possible to apply in an in situ method at Gävle Strand by Etapp 3 at present. In a larger perspective, there is a hope that the present study could contribute new ap-proaches as to the potential of yeasts as biodegrading agents of contaminants at Gäv-le Strand by Etapp 3, and in other urban environments.

<p>Betyg 180601.</p>

<p>Betyg 180601.</p>

No description available.

Abstract The purpose of this study was to highlight the problem of low groundwater levels and water shortage by analyzing how Sweden's management and adaptability capabilities work in comparison with risk management strategies. The collected result was analyzed against the so-called 4-E Strategies (Enforcement, Engineering, Education, and Economic) as the main framework. In addition, the study aimed at investigating how the ability can be created through these strategies and which of these the municipalities consider to be most effective. The data collection took place through individual semi-structured interviews with representatives from 5 municipalities. The answers from the interviews were then analyzed with qualitative content analysis, where responses generated from the qualitative content analysis were set against the 4-E strategies. The result shows that the interviewees believe that all prevention strategies may be useful depending on the context and when it is used. In addition, they must also be adapted to the local conditions in the current geographic area. The result also shows that all 4-E strategies are needed to create efficient handling and adaptability for drinking water management. The study's results show that the Swedish municipalities' management and adaptability to these strategies is satisfactory. Keywords Risk management, 4-E strategies, 3-E strategies, Drinking water management, Sweden

No description available.