Changes and development are fundamental principles in biocenoses and can affect a multitude of ecological processes. In insect communities phenological and density changes, changes in species richness and community composition, as well as interactions between those changes, are the most important macro processes. However, climate change and other factors like habitat degradation and loss alter these processes leading to shifts and general biodiversity declines. Even though knowledge about insect decline in central Europe increased during the last decades, there are significant knowledge gaps about the development of insect communities in certain habitats and taxa. For example, insect communities in small lentic as well as in forested habitats are under-sampled and reported to be less endangered than communities in other habitats. Furthermore, the changes within habitats and taxa are additionally influenced by certain traits, like host or feeding specialization. To disentangle these influences and to increase the knowledge about the general long-term development of insect communities, comprehensive long-term monitoring studies are needed. In addition, long-term effects of conservation strategies should also be evaluated on large time scales in order to be able to decide on a scientific base which strategies are effective in promoting possibly declining taxa. Hence, this thesis also tackles the effects of an integrative conservation strategy on wood dependent beetle and fungi, beside the development of water beetle and macro moth communities over multiple decades. In Chapter 2 I present a study on the development of water beetle communities (Dytiscidae, Haliplidae, Noteridae) in 33 water bodies in Southern Germany from 1991 to 2018. Time-standardized capture per waterbody was used during three periods: between 1991 and 1995, 2007 and 2008, and 2017 and 2018. Results showed annual declines in both species number (ca. -1%) and abundance (ca. -2%). In addition, community composition shifted over time in part due to changing pH values. Hence, the recorded changes during the 28-year study period partly reflect natural succession processes. However, since also moor-related beetle species decreased significantly, it is likely that water beetles in southern Germany are also threatened by non-successional factors, including desiccation, increased nitrogen input and/or mineralization, as well as the loss of specific habitats. The results suggest, that in small to midsize lentic waterbodies, current development should aim for constant creation of new water bodies and protection of moor waterbodies in order to protect water beetle communities on a landscape scale. In Chapter 3 I present an analysis of the development of nocturnal macro moth species richness, abundance and biomass over four decades in forests of southern Germany. Two local scale data sets featuring a coppiced oak forest as well as an oak high forest were analysed separately from a regional data set representing all forest types in the temperate zone of Central Europe. At the regional scale species richness, abundance and biomass showed annual declines of ca. 1 %, 1.3 % and 1.4 %, respectively. These declines were more pronounced in plant host specialists and in dark coloured species. In contrast, species richness increased by ca. 1.5 % annually in the coppiced forest, while no significant trends were found in the high forest. In contrast to past assumptions, insect decline apparently affects also hyper diverse insect groups in forests. Since host specialists and dark coloured species were affected more heavily by the decline than other groups, habitat loss and climate change seem to be potential drivers of the observed trends. However, the positive development of species richness in the coppiced oak forest indicates that maintaining complex and diverse forest ecosystems through active management might compensate for negative trends in biodiversity. Chapter 4 features a study specifically aiming to investigate the long-term effect of deadwood enrichment as an integrative conservation strategy on saproxylic beetles and fungi in a central European beech forest at a landscape scale. A before–after control–impact design, was used to compare assemblages and gamma diversities of saproxylic organisms (beetles and fungi) in strictly protected old-growth forest areas (reserves) and previously moderately and intensively managed forest areas. Forests were sampled one year before and a decade after starting a landscape-wide strategy of dead-wood enrichment. Ten years after the start of the dead-wood enrichment, neither gamma diversities of saproxylic organisms nor species composition of beetles did reflect the previous management types anymore. However, fungal species composition still mirrored the previous management gradient. The results demonstrated that intentional enrichment of dead wood at the landscape scale can effectively restore communities of saproxylic organisms and may thus be a suitable strategy in addition to permanent strict reserves in order to protect wood dependent organisms in Europe. In this thesis I showed, that in contrast to what was assumed and partly reported so far, also water beetles in lentic water bodies and macro moths in forests decreased in species richness, abundance and biomass during the last three to four decades. In line with earlier studies, especially dark coloured species and specialists decreased more than light-coloured species and generalists. The reasons for these declines could partly be attributed to natural processes and pollution and possibly to climate change. However, further studies, especially experimental ones, will be needed to achieve a better understanding of the reasons for insect decline. Furthermore, analyses of time series data should be interpreted cautiously especially if the number of sampling years is smaller than ten years. In addition, validation techniques such as left- and right- censoring and cross validation should be used in order to proof the robustness of the analyses. However, the lack of knowledge, we are still facing today, should not prevent scientists and practitioners from applying conservation measures. In order to prove the effectiveness of such measures, long-term monitoring is crucial. Such control of success is essential for evidence based and thus adapted conservation strategies of threatened organisms. / Veränderungen und Entwicklung sind grundlegende Prinzipien in Biozönosen und können eine Vielzahl von ökologischen Prozessen beeinflussen. In Insektengemeinschaften stellen Veränderungen in der Phänologie und Dichte, Veränderungen des Artenreichtums und der Artenzusammensetzung sowie die Wechselwirkungen zwischen diesen, die wichtigsten Makroprozesse dar. Klimawandel und andere Faktoren wie der Verlust von Lebensräumen oder deren Qualitätsverschlechterung beeinflussen diese Prozesse jedoch und führen zu Veränderungen und allgemeinen Rückgängen der Biodiversität. Auch wenn die Erkenntnisse zum „Insektensterben“ in Mitteleuropa in den letzten Jahrzehnten zugenommen haben, gibt es erhebliche Wissenslücken über die Entwicklung von Insektengemeinschaften in bestimmten Lebensräumen und Taxa. Beispielsweise ist die Entwicklung von Insektengemeinschaften in kleinen, stehenden Gewässern und in Wäldern wenig erforscht. Darüber hinaus werden die Veränderungen innerhalb von Habitaten und Taxa zusätzlich durch bestimmte Merkmale, wie Wirts- oder Nahrungsspezialisierung, beeinflusst. Um diese verschiedenen Einflüsse auseinanderhalten zu können und das Wissen über die allgemeine Langzeitentwicklung von Insektengemeinschaften zu vergrößern, sind umfassende Langzeitstudien erforderlich. Darüber hinaus sollten auch die langfristigen Auswirkungen von Naturschutzstrategien über lange Zeiträume evaluiert werden, um auf wissenschaftlicher Grundlage entscheiden zu können, welche Strategien zur Förderung bedrohter Taxa wirksam sind. Daher befasst sich diese Arbeit neben der Entwicklung von Wasserkäfer- und Großschmetterlingsgemeinschaften über mehrere Jahrzehnte auch mit den Auswirkungen einer integrativen Naturschutzmaßnahme auf xylobionte Käfer und Pilze. In Kapitel 2 stelle ich eine Studie über die Entwicklung von Wasserkäfergemeinschaften (Dytiscidae, Haliplidae, Noteridae) in 33 Gewässern Süddeutschlands von 1991 bis 2018 vor. Die zeitstandardisierte Erfassung pro Wasserkörper erfolgte in drei Zeiträumen: zwischen 1991 und 1995, 2007 und 2008 sowie 2017 und 2018. Die Ergebnisse zeigten einen jährlichen Rückgang sowohl der Artenzahl (ca. -1%) als auch der Abundanz (ca. -2%). Darüber hinaus verschob sich die Artenzusammensetzung im Laufe der Zeit zum Teil aufgrund sich ändernder pH-Werte. Daraus lässt sich schlussfolgern, dass die erfassten Veränderungen während des 28- jährigen Untersuchungszeitraums teilweise natürliche Sukzessionsprozesse widerspiegeln. Da aber auch an moorige Gewässer gebundene Käferarten deutlich abgenommen haben, ist es wahrscheinlich, dass die Wasserkäfer Süddeutschlands auch durch Faktoren wie Austrocknung, erhöhten Stickstoffeintrag und/oder Mineralisierung sowie durch den Verlust spezifischer Lebensräume bedroht sind. Aufgrund dieser Entwicklungen ist es empfehlenswert, auf Landschaftsebene auf die ständige Schaffung neuer Gewässer und den besonderen Schutz von Moorgewässern zu setzen, um Wasserkäfergemeinschaften erfolgreich schützen zu können. In Kapitel 3 präsentiere ich eine Analyse der Diversitäts-, Abundanz- und Biomassenentwicklung von nachtaktiven Großschmetterlingen über vier Jahrzehnte in Wäldern Süddeutschlands. Neben einem bayernweiten Datensatz, der alle typischen Waldtypen der gemäßigten Zone Mitteleuropas beinhaltet, wurden zwei lokale, besonders regelmäßig besammelte Gebiete getrennt analysiert. In diesen Gebieten werden die Eichenwälder als Hoch- bzw. als Mittelwald bewirtschaftet. Bayernweit wiesen Artenreichtum, Abundanz und Biomasse jährliche Rückgänge von ca. 1 %, 1,3 % bzw. 1,4 % auf. Diese Rückgänge waren bei Wirtspflanzenspezialisten und bei dunkel gefärbten Arten besonders stark ausgeprägt. Im Gegensatz dazu nahm der Artenreichtum im Mittelwald jährlich um ca. 1,5 % zu, während im Hochwald keine signifikanten Trends festgestellt werden konnten. Im Gegensatz zu früheren Annahmen betrifft der Insektenrückgang offenbar auch hyperdiverse Insektengruppen im Wald. Da Wirtspflanzenspezialisten und dunkel gefärbte Arten vom Rückgang stärker betroffen waren als andere, scheinen Lebensraumverlust und Klimawandel potentielle Treiber der beobachteten Trends zu sein. Die positive Entwicklung des Artenreichtums im Mittelwald zeigt jedoch, dass der Erhalt komplexer und vielfältiger Waldökosysteme durch aktives Management, negative Biodiversitätstrends zum Teil kompensieren könnte. Kapitel 4 enthält eine Studie, die die Langzeitwirkung von Totholzanreicherung als integrative Naturschutzmaßnahme auf xylobionte Käfer und Pilze in einem mitteleuropäischen Buchenwald auf der Landschaftsebene untersucht. Dabei wurde die Gamma-Diversität und die Artenzusammensetzung dieser beiden Gruppen anhand einer Vorher-Nachher Untersuchung mit Kontrollflächen (Naturwaldreservate) untersucht. Die bewirtschafteten Flächen wurden weiterhin in zuvor mäßig und intensiv bewirtschaftete Flächen eingeteilt. Die Wälder wurden ein Jahr vor und ein Jahrzehnt nach Beginn einer Totholzanreicherungsstrategie auf Landschaftsebene beprobt. Zehn Jahre nach Beginn der Totholzanreicherung spiegelten weder die Gamma-Diversität der xylobionten Organismen noch die Artenzusammensetzung der Käfer die früheren Bewirtschaftungstypen wider, und wiesen keine Unterschiede mehr zu den Naturwaldreservaten auf. Die Pilzartenzusammensetzung spiegelte jedoch noch immer den früheren Bewirtschaftungsgradienten wider. Die Ergebnisse zeigen, dass Totholzanreicherung auf Landschaftsebene positive Effekte auf xylobionte Artengemeinschaften haben kann. Somit stellt Totholzanreicherung eine Naturschutzmaßnahme dar, die zusätzlich zu permanenten Schutzgebieten, eine Grundlage schaffen kann, um holzabhängige Organismen in Europa zu schützen. In dieser Arbeit habe ich gezeigt, dass im Gegensatz zu dem, was bisher angenommen und zum Teil berichtet wurde, auch Wasserkäfer in stehenden Gewässern und nachtaktive Großschmetterlingen in Wäldern in den letzten drei bis vier Jahrzehnten an Artenreichtum, Abundanz und Biomasse abgenommen haben. In Übereinstimmung mit anderen Studien nahmen vor allem dunkel gefärbte Arten und Spezialisten stärker ab als hell gefärbte Arten und Generalisten. Die Gründe für diese Rückgänge konnten zum Teil auf natürliche Prozesse, Umweltverschmutzung und möglicherweise auf den Klimawandel zurückgeführt werden. Es sind jedoch weitere Studien, insbesondere experimentelle, erforderlich, um die Gründe für das „Insektensterben“ besser zu verstehen. Darüber hinaus sollten Zeitreihendaten mit Vorsicht interpretiert werden, insbesondere wenn die Anzahl der besammelten Jahre kleiner als zehn Jahre ist. Darüber hinaus sollten Validierungstechniken wie Links- und Rechts-Zensierung und Kreuzvalidierung eingesetzt werden, um die Robustheit der Analysen nachzuweisen. Der Mangel an Wissen, mit dem wir heute noch konfrontiert sind, sollte Wissenschaftler und Praktiker jedoch nicht davon abhalten, Naturschutzmaßnahmen anzuwenden. Um die Wirksamkeit solcher Maßnahmen nachzuweisen, ist eine langfristige Überprüfung von entscheidender Bedeutung. Solche Erfolgskontrollen sind für evidenzbasierte und damit angepasste Erhaltungsstrategien bedrohter Organismen unerlässlich.

Indiana University-Purdue University Indianapolis (IUPUI) / Water is fundamental for plant growth, and vegetation response to water availability influences water, carbon, and energy exchanges between land and atmosphere. Vegetation plays the most active role in water and carbon cycle of various ecosystems. Therefore, comprehensive evaluation of drought impact on vegetation productivity will play a critical role for better understanding the global water cycle under future climate conditions. In-situ meteorological measurements and the eddy covariance flux tower network, which provide meteorological data, and estimates of ecosystem productivity and respiration are remarkable tools to assess the impacts of drought on ecosystem carbon and water cycles. In regions with limited in-situ observations, remote sensing can be a very useful tool to monitor ecosystem drought status since it provides continuous observations of relevant variables linked to ecosystem function and the hydrologic cycle. However, the detailed understanding of ecosystem responses to drought is still lacking and it is challenging to quantify the impacts of drought on ecosystem carbon balance and several factors hinder our explicit understanding of the complex drought impacts. This dissertation addressed drought monitoring, ecosystem drought responses, trends of vegetation water constraint based on in-situ metrological observations, flux tower and multi-sensor remote sensing observations. This dissertation first developed a new integrated drought index applicable across diverse climate regions based on in-situ meteorological observations and multi-sensor remote sensing data, and another integrated drought index applicable across diverse climate regions only based on multi-sensor remote sensing data. The dissertation also evaluated the applicability of new satellite dataset (e.g., solar induced fluorescence, SIF) for responding to meteorological drought. Results show that satellite SIF data could have the potential to reflect meteorological drought, but the application should be limited to dry regions. The work in this dissertation also accessed changes in water constraint on global vegetation productivity, and quantified different drought dimensions on ecosystem productivity and respiration. Results indicate that a significant increase in vegetation water constraint over the last 30 years. The results highlighted the need for a more explicit consideration of the influence of water constraints on regional and global vegetation under a warming climate.

The world is dominated by cold environments that include the poles, the deep ocean, and alpine regions. Polar algae support the aquatic food chain and are increasingly threatened by climate change. With a changing climate, ice cover is decreasing with increased temperatures, leading to changes in light availability and salinity. Using two closely related but geographically distant algal species, Chlamydomonas priscuii and Chlamydomonas malina, we examined how the heat stress responses changed depending on their culturing conditions. C. malina was isolated from the Beauford Sea in the Canadian Arctic and C. priscuii is from the permanently ice-covered Lake Bonney, Antarctica. This work looks at two questions; (1) how cold adapted algae responds to changing conditions and subsequent heat stress, and (2) what contributes to stress resistance? We found that algae show robust growth across a wide spectrum of light and salinity but have the fastest growth rates at low salinity and high light intensities. These fast-growing algae are the most susceptible to heat stress indicating liability during climate change. High salinity grown algae were more resilient when challenged by heat stress in the terms of maintaining photosynthetic efficiency, attenuated ROS production, and delayed cell death. At high salinity C. priscuii produces high levels of glycerol which for the first time in green algae has been shown to contribute to thermotolerance. Overall, this work provides insight into the stress resilience of psychrophiles, something that is especially pertinent in our age of rapid climate change.

Forests provide important ecosystem services and play a dominant role in the global carbon and hydrologic cycles. These ecosystems are becoming more vulnerable to climate change-related threats such as extreme temperature and precipitation events, drought and wildfires. In addition, forest ecosystems have also undergone land use changes and a significant reduction in cover area, specifically in North America. There has been renewed realization to restore and rehabilitate forest ecosystems because they are a major carbon sink and play a key role in sequestering atmospheric carbon dioxide. In response, plantation forests are being widely established to sequester carbon, increase biodiversity, secure water resources and generate economic revenue when harvested. Forest managers employ different management practices such as thinning or retention harvesting to enhance growth, plant structural and species diversity within forest plantations, with the ultimate goal of emulating the characteristics and benefits of natural forests. However, the influence of these forest management practices on the growth, productivity and specifically water cycling in plantation forests is not well studied and reported in the literature. This experimental study investigated the effect of four different variable retention harvesting (VRH) treatments on evapotranspiration and water balance in an 83-year-old red pine (Pinus resinosa) plantation forest in the Great Lakes region in Canada. These VRH treatments included 55% aggregated crown retention (55A), 55% dispersed crown retention (55D), 33% aggregated crown retention (33A), 33% dispersed crown retention (33D) and unharvested control (CN) plot. Tree-level experimental work was conducted in the control plot and showed that most of the water transport (65%) occurred in the outermost sapwood, while only 26% and 9% of water was transported in the middle and innermost depths of sapwood, respectively. These results help to avoid overestimation of transpiration, which may cause large uncertainties in water budgets in pine forests. Study results further showed that the 55D treatment had the highest tree-level transpiration followed by 33D, 55A, 33A and CN plots. During periods of low precipitation, vapor pressure deficit (VPD) was the main driver or control on transpiration in VRH treatments. However, transpiration was more closely coupled with photosynthetically active radiation (PAR) in the control plot. Moreover, the 55D treatment resulted in on average 58% of total water loss from canopy as transpiration and 42% from the understory and ground surface as evapotranspiration. These findings suggest that dispersed or distributed retention of 55% basal area (55D) provides the optimal environmental conditions for forest growth with reduced competition of trees for water as shown by enhanced transpiration. This study will help researchers, forest managers and decision-makers to improve their understanding of thinning impacts on water and carbon exchanges in forest ecosystems and select and adopt viable forest management practices to enhance their carbon sequestration capabilities, water use efficiency and resilience to climate change. / Thesis / Doctor of Philosophy (PhD)

No description available.

Climate change has sparked growing interest in the relationship between food security and our climate systems. Crop productivity is tightly correlated with fluctuating temperatures, carbon dioxide (CO2), and rainfall. The purpose of this research is to examine the quantitative relationship between these factors to better understand the magnitude of global systematic risk. Econometric models are constructed for three different contexts: a global analysis of country-level crop yields is explored using a fixed-effects panel regression model; a meta-analysis of farm-level experiments exposed to varying levels of CO2 and temperatures; and a regional analysis of Saskatchewan rural municipalities using a spatial dataset of historical weather data. In summary, reduced yields occur beyond peak thresholds of temperature and rising CO2 will lead to substantial increases in yield potential and reduced water use. These relationships vary in magnitude across crop species, but the underlying direction of the relationships are the same. This research improves upon previous methods in the literature, explores novel datasets, and contributes to the estimation of climate impacts in agriculture. / Graduate

Climate change as a global phenomenon threatens human rights and causes social injustices. This thesis examines the genealogies of climate justice discourse and climate change denial discourse in the context of international climate change politics. The aim is to understand the construction of and the correlation between the discourses and how the discourses relate to human rights. The thesis employs discourse analysis with a conception of climate justice and a neoclassical realist theory applied to climate change politics. Climate justice discourse is found to interact with chiefly moral and political terms, whereas the denial discourse interacts mainly with economic and scientific terms. Consequently, there is a lack of interaction between the discourses as they operate in different levels of communication and it has, to some extent, caused stalemate in climate change politics. Additionally, while climate justice discourse makes use of the human rights framework, the denial discourse undermines it.

Climate change could aggravate periodic and chronic shortfalls of water, particularly in arid and semi-arid areas of the world (IPCC, 2001). Climate change is likely to accelerate the global hydrological cycle, with increase in temperature, changes in precipitation patterns, and evapotranspiration affecting the water quantity and quality, water availability and demands. The various components of a surface water resources system affected by climate change may include the water availability, irrigation demands, water quality, hydropower generation, ground water recharge, soil moisture etc. It is prudent to examine the anticipated impacts of climate change on these different components individually or combinedly with a view to developing responses to minimize the climate change induced risk in water resources systems. Assessment of climate change impacts on water resources essentially involves downscaling the projections of climatic variables (e.g., temperature, humidity, mean sea level pressure etc.) to hydrologic variables (e.g., precipitation and streamflow), at regional scale. Statistical downscaling methods are generally used in the hydrological impact assessment studies for downscaling climate projections provided by the General Circulation Models (GCMs). GCMs are climate models designed to simulate time series of climate variables globally, accounting for the greenhouse gases in the atmosphere. The statistical techniques used to bridge the spatial and temporal resolution gaps between what GCMs are currently able to provide and what impact assessment studies require are called as statistical downscaling methods. Generally, these methods involve deriving empirical relationships that transform large-scale simulations of climate variables (referred as the predictors) provided by a GCM to regional scale hydrologic variables (referred as the predictands). This general methodology is characterized by various uncertainties such as GCM and scenario uncertainty, uncertainty due to initial conditions of the GCMs, uncertainty due to downscaling methods, uncertainty due to hydrological model used for impact assessment and uncertainty resulting from multiple stake holders in a water resources system. The research reported in this thesis contributes towards (i) development of methodologies for climate change impact assessment of various components of a water resources system, such as water quality, water availability, irrigation and reservoir operation, and (ii) quantification of GCM and scenario uncertainties in hydrologic impacts of climate change. Further, an integrated reservoir operation model is developed to derive optimal operating policies under the projected scenarios of water availability, irrigation water demands, and water quality due to climate change accounting for various sources of uncertainties. Hydropower generation is also one of the objectives in the reservoir operation. The possible climate change impact on river water quality is initially analyzed with respect to hypothetical scenarios of temperature and streamflow, which are affected by changes in precipitation and air temperature respectively. These possible hypothetical scenarios are constructed for the streamflow and river water temperature based on recent changes in the observed data. The water quality response is simulated, both for the present conditions and for conditions resulting from the hypothetical scenarios, using the water quality simulation model, QUAL2K. A Fuzzy Waste Load Allocation Model (FWLAM) is used as a river water quality management model to derive optimal treatment levels for the dischargers in response to the hypothetical scenarios of streamflow and water temperature. The scenarios considered for possible changes in air temperature (+1 oC and +2 oC) and streamflow (-0%, -10%, -20%) resulted in a substantial decrease in the Dissolved Oxygen (DO) levels, increase in Biochemical Oxygen Demand (BOD) and river water temperature for the case study of the Tunga-Bhadra River, India. The river water quality indicators are analyzed for the hypothetical scenarios when the BOD of the effluent discharges is at safe permissible level set by Pollution Control Boards (PCBs). A significant impairment in the water quality is observed for the case study, under the hypothetical scenarios considered. A multi-variable statistical downscaling model based on Canonical Correlation Analysis (CCA) is then developed to downscale future projections of hydro¬meteorological variables to be used in the impact assessment study of river water quality. The CCA downscaling model is used to relate the surface-based observations and atmospheric variables to obtain the simultaneous projection of hydrometeorological variables. Statistical relationships in terms of canonical regression equations are obtained for each of the hydro-meteorological predictands using the reanalysis data and surface observations. The reanalysis data provided by National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) are used for the purpose. The regression equations are applied to the simulated GCM output to model future projections of hydro-meteorological predictands. An advantage of the CCA methodology in the context of downscaling is that the relationships between climate variables and the surface hydrologic variables are simultaneously expressed, by retaining the explained variance between the two sets. The CCA method is used to model the monthly hydro-meteorological variables in the Tunga-Bhadra river basin for water quality impact assessment study. A modeling framework of risk assessment is developed to integrate the hydro¬meteorological projections downscaled from CCA model with a river water quality management model to quantify the future expected risk of low water quality under climate change. A Multiple Logistic Regression (MLR) is used to quantify the risk of Low Water Quality (LWQ) corresponding to a threshold DO level, by considering the streamflow and water temperature as explanatory variables. An Imprecise Fuzzy Waste Load Allocation Model (IFWLAM) is adopted to evaluate the future fractional removal policies for each of the dischargers by including the predicted future risk levels. The hydro-meteorological projections of streamflow, air temperature, relative humidity and wind speed are modeled using MIROC 3.2 GCM simulations with A1B scenario. The river water temperature is modeled by using an analytical temperature model that includes the downscaled hydro-meteorological variables. The river water temperature is projected to increase under climate change, for the scenario considered. The IFWLAM uses the downscaled projections of streamflow, simulated river water temperature and the predicted lower and upper future risk levels to determine the fraction removal policies for each of the dischargers. The results indicate that the optimal fractional removal levels required for the future scenarios will be higher compared to the present levels, even if the effluent loadings remain unchanged. Climate change is likely to impact the agricultural sector directly with changes in rainfall and evapotranspiration. The regional climate change impacts on irrigation water demands are studied by quantifying the crop water demands for the possible changes of rainfall and evapotranspiration. The future projections of various meteorological variables affecting the irrigation demand are downscaled using CCA downscaling model with MIROC 3.2 GCM output for the A1B scenario. The future evapotranspiration is obtained using the Penman-Monteith evapotranspiration model accounting for the projected changes in temperature, relative humidity, solar radiation and wind speed. The monthly irrigation water demands of paddy, sugarcane, permanent garden and semidry crops quantified at nine downscaling locations covering the entire command area of the Bhadra river basin, used as a case study, are projected to increase for the future scenarios of 2020-2044, 2045-2069 and 2070-2095 under the climate change scenario considered. The GCM and scenario uncertainty is modeled combinedly by deriving a multimodel weighted mean by assigning weights to each GCM and scenario. An entropy objective weighting scheme is proposed which exploits the information contained in various GCMs and scenarios in simulating the current and future climatology. Three GCMs, viz., CGCM2 (Meteorological Research Institute, Japan), MIROC3.2 medium resolution (Center for Climate System Research, Japan), and GISS model E20/Russell (NASA Goddard Institute for Space Studies, USA) with three scenarios A1B, A2 and B1 are used for obtaining the hydro-meteorological projections for the Bhadra river basin. Entropy weights are assigned to each GCM and scenario based on the performance of the GCM and scenario in reproducing the present climatology and deviation of each from the projected ensemble average. The proposed entropy weighting method is applied to projections of the hydro-meteorological variables obtained based on CCA downscaling method from outputs of the three GCMs and the three scenarios. The multimodel weighted mean projections are obtained for the future time slice of 2020-2060. Such weighted mean hydro-meteorological projections may be further used into the impact assessment model to address the climate model uncertainty in the water resources systems. An integrated reservoir operation model is developed considering the objectives of irrigation, hydropower and downstream water quality under uncertainty due to climate change, uncertainty introduced by fuzziness in the goals of stakeholders and uncertainty due to the random nature of streamflow. The climate model uncertainty originating from the mismatch between projections from various GCMs under different scenarios is considered as first level of uncertainty, which is modeled by using the weighted mean hydro-meteorological projections. The second level of uncertainty considered is due to the imprecision and conflicting goals of the reservoir users, which is modeled by using fuzzy set theory. A Water Quantity Control Model (WQCM) is developed with fuzzy goals of the reservoir users to obtain water allocations among the different users of the reservoir corresponding to the projected demands. The water allocation model is updated to account for the projected demands in terms of revised fuzzy membership functions under climate change to develop optimal policies of the reservoir for future scenarios. The third level of uncertainty arises from the inherent variability of the reservoir inflow leading to uncertainty due to randomness, which is modeled by considering the reservoir inflow as a stochastic variable. The optimal monthly operating polices are derived using Stochastic Dynamic Programming (SDP), separately for the current and for the future periods of 2020-2040 and 2040-2060 The performance measures for Bhadra reservoir in terms of reliability and deficit ratios for each reservoir user (irrigation, hydropower and downstream water quality) are estimated with optimal SDP policy derived for current and future periods. The reliability with respect to irrigation, downstream water quality and hydropower show a decrease for 2020-2040 and 2040-2060, while deficit ratio increases for these periods. The results reveal that climate change is likely to affect the reservoir performance significantly and changes in the reservoir operation for the future scenarios is unable to restore the past performance levels. Hence, development of adaptive responses to mitigate the effects of climate change is vital to improve the overall reservoir performance.

No description available.

abstract: The implications of a changing climate have a profound impact on human life, society, and policy making. The need for accurate climate prediction becomes increasingly important as we better understand these implications. Currently, the most widely used climate prediction relies on the synthesis of climate model simulations organized by the Coupled Model Intercomparison Project (CMIP); these simulations are ensemble-averaged to construct projections for the 21st century climate. However, a significant degree of bias and variability in the model simulations for the 20th century climate is well-known at both global and regional scales. Based on that insight, this study provides an alternative approach for constructing climate projections that incorporates knowledge of model bias. This approach is demonstrated to be a viable alternative which can be easily implemented by water resource managers for potentially more accurate projections. Tests of the new approach are provided on a global scale with an emphasis on semiarid regional studies for their particular vulnerability to water resource changes, using both the former CMIP Phase 3 (CMIP3) and current Phase 5 (CMIP5) model archives. This investigation is accompanied by a detailed analysis of the dynamical processes and water budget to understand the behaviors and sources of model biases. Sensitivity studies of selected CMIP5 models are also performed with an atmospheric component model by testing the relationship between climate change forcings and model simulated response. The information derived from each study is used to determine the progressive quality of coupled climate models in simulating the global water cycle by rigorously investigating sources of model bias related to the moisture budget. As such, the conclusions of this project are highly relevant to model development and potentially may be used to further improve climate projections. / Dissertation/Thesis / Ph.D. Mechanical Engineering 2013