Thesis (Ph. D.)--University of Wyoming, 2006. / Title from PDF title page (viewed on Dec. 17, 2007). Includes bibliographical references (p. 187-197).

<p>Generellt går det att hantera klimatförändringar på två sätt. Dels genom att minska utsläppen av växthusgaser och dels genom att anpassa sig till de klimatförändringar som kommer. I denna uppsats kommer jag att fokusera på klimatanpassning. Ett av de områdena i Sverige som beräknas drabbas värst är runt Vänern, framförallt då sannolikheten för översvämningar väntas öka på grund av klimatförändringarna. Syftet är att ta reda på vilka problem det finns med att genom klimatanpassning minska risken vid översvämningar kring Vänern, samt undersöka vem som har ansvaret att lösa dessa problem. Metoden är en kvalitativ fallstudie med semi-strukturerade intervjuer som analyserats enligt ”grounded theory”. Även en mindre litteratundersökning har genomförts. Slutsatsen är att de övergripande problemen är att det finns en osäkerhet angående förutsättningen för klimatanpassning, att klimatanpassning är ett så nytt begrepp att det inte riktigt är implementerat i den politiska strukturen än, att det finns bristande medel för genomförandet samt att det finns en brist på samordning. Det övergripande ansvaret att minska sannolikheten för översvämningar ligger på staten. Det övergripande ansvaret att minska sårbarheten ligger till viss del på kommunerna, men är till stor del oklart. Något som skulle vara intressant att studera vidare är kopplingen i praktiken mellan klimatanpassning och hållbar utveckling.</p> / <p>In general there are two ways of coping with climate change. One way is through mitigation and the other is through climate adaptation. This essay will focus on climate adaptation. One of the areas in Sweden which is expected to be the most afflicted is around the lake Vänern, mainly because of the flooding risk which is expected to rise because of climate change. The purpose of this study is to find out what kind of problems there are with climate adaptation as a way of reducing flooding risk around the lake Vänern, and to find out who is responsible to solve these problems. The method used is a qualitative case study with semi-structured interviews. A miner literature study has also been made. The conclusion is that the general problems are insecurity about the background of climate adaptation, climate adaptation is a new concept which has not been implemented in the political structure yet, there is shortage of means for the implementation and there is a lack of coordination. The main responsibility of decreasing the probability of flooding is on the state. The main responsibility to reduce the vulnerability is partly on the county but for some part unclear. Something interesting to study further is the connection between climate adaptation and sustainable development.</p>

Le milieu souterrain est une étape importante dans l'histoire évolutive des arthropodes. Selon l'hypothèse de Ghilarov, les sols, de par leur nature poreuse, ont permis le passage du milieu aquatique au milieu aérien. Les cavernes auraient été colonisées plus tard, par des espèces provenant de la surface. Sol profond, ou milieu endogé, et cavernes partagent nombre de caractéristiques: obscurité, atmosphère généralement saturée en eau, amplitude thermique réduite. Elles diffèrent cependant par l'espace disponible pour se mouvoir et par la présence dans certaines cavernes d'inondations pendant l'hiver. Au vu de ces caractéristiques abiotiques, l'objectif de ce travail a été l'identification d'analogies et de différences morphologiques, physiologiques, écologiques et trophiques entre les acariens vivant dans le sol profond et ceux vivant dans les cavernes, et la mise en relation de ces caractéristiques avec les facteurs du milieu. Une étude extensive des acariens de 25 grottes wallonnes a permis de conclure que leur abondance était fortement diminuée dans les sites inondables. Au moins six nouvelles espèces ont été découvertes. Il existe peu de similarité des peuplements entre cavernes géographiquement proches, ce qui est expliqué par la structure fragmentée de celles-ci. Une étude plus intensive de deux cavernes, des deux sols forestiers situés au-dessus de celles-ci et d'un troisième site endogé sur schiste a été réalisée. La répartition spatiale du carbone ne diffère pas systématiquement entre les deux habitats considérés. La matière organique semble être le principal facteur limitant et structurant pour les populations d'acariens dans le milieu endogé. Dans les cavernes, la plus grande mobilité des acariens liée à l'espace disponible semble partiellement masquer les structures spatiales. L'abondance des microarthropodes est fortement influencée par les inondations dans les grottes. Elles tuent une partie des individus présents, en emportent d'autres et importent des espèces accidentelles, qui sont destinées à mourir, éventuellement dévorées par des prédateurs. Les communautés des deux habitats sont bien distinctes, et les peuplements cavernicoles sont plus variables que les endogés. Un certain nombre d'espèces strictement troglobies ou endogées ont été récoltées, ce qui pourrait être expliqué par une compétition interspécifique faible. Les prédateurs et phorétiques sont plus nombreux dans les cavernes que dans les sols. Du fait de l'espace disponible, les acariens cavernicoles peuvent être de plus grande taille que les endogés. La proportion d'Oribates "supérieurs" (Brachypilina) augmente suivant l'humidité de microhabitats, des cavernes jusqu'aux écorces. Cela est interprété comme une séquence évolutive d'habitats, les adaptations à la sécheresse étant considérées comme responsables de l'importante radiation observée chez les Brachypilina. De ce fait, une hypothèse nouvelle de colonisation des cavernes est proposée, sans passage par les milieux de surface. D'autres adaptations sont relevées au niveau spécifique, grâce à la comparaison de deux espèces d'Oppiidae: Medioppia obsoleta, espèce endogée, et Hypogeoppia n.sp., espèce troglobie. L'espèce cavernicole a de plus longs ongles pour se déplacer plus facilement sur des substrats gorgés d'eau, et des taenidies pour résister aux immersions dans l'eau. Cette étude démontre que les acariens des milieux souterrains peuvent être valablement étudiés dans une optique adaptative et évolutive.

No description available.

Peatlands are peat forming ecosystems in which not fully decomposed plant material builds up the soil. The sequestration of carbon into peat is mainly associated with the bryophyte genus Sphagnum (peat mosses), which dominate and literally form most peatlands. The responses of Sphagnum to environmental change help us to understand peatland development and function and to predict future changes in a rapidly changing world. In this thesis, the overarching aim was to use ecophysiological traits to investigate mechanisms behind the response of Sphagnum to elevated N deposition, and, processes connected to ecosystem shift and ecosystem function of peatlands. Regarding elevated N deposition, three experiments were performed at different scales (country-wide to greenhouse). Independent of scale and species, apical tissue N concentration increased with increasing N input until N saturation was reached. Maximum photosynthetic rate, a trait evaluating photosynthetic capacity, increased with N input and could be well predicted by tissue N concentration. Thus, the physiological responses of Sphagnum to N deposition are often positive and I found no evidence of toxic effects. Production did, however, not increase with N input, and results of the N:P ratio suggested that P limitation, and possibly other elements, might hamper growth under high N input. The effect of P limitation was, in contrast to current view, most pronounced in fast growing species indicating species specific responses to nutrient imbalance. I explored the puzzling, but historically frequently occurring, rich fen to bog ecosystem shift; a shift from a species-rich ecosystem dominated by brown mosses, to a species-poor one with greater carbon storage that is Sphagnum-dominated. The bog-dwelling species of Sphagnum grew well, to our surprise, when in contact with rich fen water but was not a strong competitor compared to rich fen Sphagnum species. If submerged under rich fen water (high pH), the bog Sphagnum species died while rich fen species of Sphagnum were unaffected. These results show that differences in two physiological traits (growth rate and tolerance to flooding) among species, can explain when a peatland ecosystem shift might occur. In the last study, the function of peatlands was related to trade-offs between traits and allometric scaling in Sphagnum. Results suggested that growth strategies are determined by the distribution of Sphagnum relative to the water table in order to minimize periods with suboptimal hydration. Allometric analyses stressed the importance of resource allocation among and within shoots (apical part vs. stem), although the allocation patterns in Sphagnum were not always consistent with those of vascular plants. Interestingly, data indicated a trade-off between photosynthetic rate and decomposition rate among Sphagnum species.

The main objective of this study is to understand and asses flood risk perception among people living in Msimbazi Valley in Das es Salaam, Tanzania. Many of the people I have interviewed are experiencing flooding every year but it is rarely considered disastrous. Looked at individually they may not be disasters but cumulatively they may be. The rapid urbanisation, in this part of the world, forces people to live on hazardous but central land because of the livelihood opportunities available there. The government and the local communities are well aware of the risk of floods in the area and are considered as a serious threat to the families. People are still living in these areas because they find the benefits big enough to make up the risks.

Generellt går det att hantera klimatförändringar på två sätt. Dels genom att minska utsläppen av växthusgaser och dels genom att anpassa sig till de klimatförändringar som kommer. I denna uppsats kommer jag att fokusera på klimatanpassning. Ett av de områdena i Sverige som beräknas drabbas värst är runt Vänern, framförallt då sannolikheten för översvämningar väntas öka på grund av klimatförändringarna. Syftet är att ta reda på vilka problem det finns med att genom klimatanpassning minska risken vid översvämningar kring Vänern, samt undersöka vem som har ansvaret att lösa dessa problem. Metoden är en kvalitativ fallstudie med semi-strukturerade intervjuer som analyserats enligt ”grounded theory”. Även en mindre litteratundersökning har genomförts. Slutsatsen är att de övergripande problemen är att det finns en osäkerhet angående förutsättningen för klimatanpassning, att klimatanpassning är ett så nytt begrepp att det inte riktigt är implementerat i den politiska strukturen än, att det finns bristande medel för genomförandet samt att det finns en brist på samordning. Det övergripande ansvaret att minska sannolikheten för översvämningar ligger på staten. Det övergripande ansvaret att minska sårbarheten ligger till viss del på kommunerna, men är till stor del oklart. Något som skulle vara intressant att studera vidare är kopplingen i praktiken mellan klimatanpassning och hållbar utveckling. / In general there are two ways of coping with climate change. One way is through mitigation and the other is through climate adaptation. This essay will focus on climate adaptation. One of the areas in Sweden which is expected to be the most afflicted is around the lake Vänern, mainly because of the flooding risk which is expected to rise because of climate change. The purpose of this study is to find out what kind of problems there are with climate adaptation as a way of reducing flooding risk around the lake Vänern, and to find out who is responsible to solve these problems. The method used is a qualitative case study with semi-structured interviews. A miner literature study has also been made. The conclusion is that the general problems are insecurity about the background of climate adaptation, climate adaptation is a new concept which has not been implemented in the political structure yet, there is shortage of means for the implementation and there is a lack of coordination. The main responsibility of decreasing the probability of flooding is on the state. The main responsibility to reduce the vulnerability is partly on the county but for some part unclear. Something interesting to study further is the connection between climate adaptation and sustainable development.

One of the world’s largest freshwater deltas (~4000 km2), the Peace-Athabasca Delta (PAD), is located at the convergence of the Peace and Athabasca rivers and Lake Athabasca in northern Alberta, Canada. Since the early 1970s, there has been increasing concern regarding the ecological impacts on the PAD after flow regulation of the Peace River began in 1968, decreased discharge in the Peace and Athabasca rivers as a result of hydroclimatic changes in Western Canada, and increased Athabasca River water usage by oil sands development to the south. This thesis is part of an ongoing, multi-disciplinary project assessing current and past hydrological and ecological conditions in the PAD. Research conducted in this thesis aims to better understand the processes controlling water balance of lakes in the PAD using mainly stable water isotope data collected from lakes and their input sources. Isotope data are used to describe and quantify hydrological processes for individual lakes (seasonal and annual) and across the delta and are supported by other chemical and hydrometric data. An isotopic framework in d18O-d2H-space is developed for the PAD using evaporation-flux-weighted local climate data, and isotopic data collected from a reference basin, lakes throughout the PAD, and lake input sources (i.e., snowmelt, rainfall, and river water). The framework is comprised of two reference lines, the Local Meteoric Water Line, which is based on measured isotopic composition of precipitation, and the Local Evaporation Line, which is based on modelled isotopic composition of reference points. Evaporation pan data is used to assess short-term variations in key isotopic reference values, which are important for addressing short-term changes in the isotopic signature of shallow basins. This framework is used in subsequent chapters including assessment of seasonal and annual water balance of two hydrologically-contrasting shallow lakes, and to quantify the impacts of flood water and snowmelt on a set of 45 lakes in spring 2003. Five years of isotope data using time-series analysis and the isotopic framework suggested that a perched (isolated) lake and its catchment (forest and bedrock) in the northern, relict Peace sector captured sufficient rain, snow, and runoff to maintain a relatively stable water balance, and also that a low-lying lake in the southern, active Athabasca sector was regularly replenished with river water in both spring and summer. Snowmelt and rainfall were found to have diluted the perched basin by an average of 16% and 28 % respectively, while spring and summer floods were found to almost completely flush the low-lying lake. Using the spring 2003 regional dataset, flooded lakes were separated from snowmelt-dominated lakes through use of suspended sediment concentrations, isotope data, and field observations. Application of an isotope mixing model translated d18O values into a range of replenishment amount by either river water or snowmelt, which compared well with hydrological conditions at the time of sampling and previously classified drainage types of the lakes. Spatial mapping of replenishment amounts illustrated flooding of much of the Athabasca sector due to ice-jams, except for two sub-regions isolated from flooding by artificial and natural northern diversion of flow from the Athabasca River. It is also shown that most of the relict landscape of the Peace sector was replenished by snowmelt except for a few low-lying lakes close to the Peace River and its tributaries. Overall, improved understanding of lake and regional hydrology in the PAD, especially the ability to quantify the affects of various lake inputs, will improve the ability to develop effective guidelines and management practices in the PAD as lakes respond to future changes in climate and river discharge.

An ad hoc network is a collection of mobile wireless devices that cooperate with each other to route packets amongst themselves. The main difficulty in designing routing algorithms for such a network is the large number of topology changes that the network undergoes due to device movement. Selective flooding is a routing technique that is more resilient to topology changes than traditional algorithms but is more bandwidth efficient than pure flooding. An on-demand selective flooding algorithm has been designed and tested on the ns-2 simulator. In scenarios involving a large number of topology changes, selective flooding outperforms other ad hoc network routing techniques. Unfortunately, selective flooding is much more bandwidth hungry and is unable to scale to handle reasonable traffic loads. Interestingly, the analysis of selective flooding reveals major problems with traditional ad hoc networking techniques. Many current algorithms demonstrate shortcomings when dealing with bursty traffic, and current wireless hardware cannot handle ad hoc networking traffic in an efficient manner. These issues need to be addressed before ad hoc networking technology can become feasible for widespread use.

One of the world’s largest freshwater deltas (~4000 km2), the Peace-Athabasca Delta (PAD), is located at the convergence of the Peace and Athabasca rivers and Lake Athabasca in northern Alberta, Canada. Since the early 1970s, there has been increasing concern regarding the ecological impacts on the PAD after flow regulation of the Peace River began in 1968, decreased discharge in the Peace and Athabasca rivers as a result of hydroclimatic changes in Western Canada, and increased Athabasca River water usage by oil sands development to the south. This thesis is part of an ongoing, multi-disciplinary project assessing current and past hydrological and ecological conditions in the PAD. Research conducted in this thesis aims to better understand the processes controlling water balance of lakes in the PAD using mainly stable water isotope data collected from lakes and their input sources. Isotope data are used to describe and quantify hydrological processes for individual lakes (seasonal and annual) and across the delta and are supported by other chemical and hydrometric data. An isotopic framework in d18O-d2H-space is developed for the PAD using evaporation-flux-weighted local climate data, and isotopic data collected from a reference basin, lakes throughout the PAD, and lake input sources (i.e., snowmelt, rainfall, and river water). The framework is comprised of two reference lines, the Local Meteoric Water Line, which is based on measured isotopic composition of precipitation, and the Local Evaporation Line, which is based on modelled isotopic composition of reference points. Evaporation pan data is used to assess short-term variations in key isotopic reference values, which are important for addressing short-term changes in the isotopic signature of shallow basins. This framework is used in subsequent chapters including assessment of seasonal and annual water balance of two hydrologically-contrasting shallow lakes, and to quantify the impacts of flood water and snowmelt on a set of 45 lakes in spring 2003. Five years of isotope data using time-series analysis and the isotopic framework suggested that a perched (isolated) lake and its catchment (forest and bedrock) in the northern, relict Peace sector captured sufficient rain, snow, and runoff to maintain a relatively stable water balance, and also that a low-lying lake in the southern, active Athabasca sector was regularly replenished with river water in both spring and summer. Snowmelt and rainfall were found to have diluted the perched basin by an average of 16% and 28 % respectively, while spring and summer floods were found to almost completely flush the low-lying lake. Using the spring 2003 regional dataset, flooded lakes were separated from snowmelt-dominated lakes through use of suspended sediment concentrations, isotope data, and field observations. Application of an isotope mixing model translated d18O values into a range of replenishment amount by either river water or snowmelt, which compared well with hydrological conditions at the time of sampling and previously classified drainage types of the lakes. Spatial mapping of replenishment amounts illustrated flooding of much of the Athabasca sector due to ice-jams, except for two sub-regions isolated from flooding by artificial and natural northern diversion of flow from the Athabasca River. It is also shown that most of the relict landscape of the Peace sector was replenished by snowmelt except for a few low-lying lakes close to the Peace River and its tributaries. Overall, improved understanding of lake and regional hydrology in the PAD, especially the ability to quantify the affects of various lake inputs, will improve the ability to develop effective guidelines and management practices in the PAD as lakes respond to future changes in climate and river discharge.