Glacier National Park, in northwestern Montana, is a unique and awe-inspiring national treasure that is often used by the media and public-at-large as a window into the effects of climate change. An updated inventory of glaciers and perennial snowfields (G&PS) in the Park, along with an assessment of their change over time, is essential to understanding the role that glaciers are playing in the environment of this Park. Nine inventories between 1966 and 2015 were compiled to assess area changes of G&PS. Over that 49-year period, total area changed by nearly -34 ± 11% between 1966 and 2015. Volume change, determined from changes in surface topography for nine glaciers, totaling 8.61 km² in area, was +0.142 ± 0.02 km³, a specific volume loss of -16.3 ± 2.5m. Extrapolating to all G&PS in the Park in 1966 yields a park-wide loss of -0.660 ± 0.099 km³. G&PS have been receding in the Park due to warming air temperatures rather than changes in precipitation, which has not changed significantly. Since 1900, air temperatures in Glacier National Park have warmed by +1.3 C°, compared to +0.9 C° globally. Spatially, G&PS at lower elevations and on steeper slopes lost relatively more area than other G&PS.

Eutrophication is one of the primary factors causing harmful cyanobacteria blooms in freshwater lakes; climate change such as warmer temperature can potentially further increase both frequency and intensity of blooms. This study investigated the long-term changes in water quality and summer phytoplankton assemblages in Oswego Lake, OR, in relation to lake management practices (e.g., hypolimnetic aeration and alum treatments), as well as climatic and regional meteorological conditions. Both water quality and phytoplankton assemblages were sampled biweekly during summer seasons between 2001 and 2013. The concentrations of total phosphorus (TP), soluble reactive phosphorus (SRP) and total nitrogen (TN) decreased 66%, 93% and 31%, respectively, in response to the hypolimnetic aeration and alum treatments since 2005. The results of summer phytoplankton assemblages showed a 62% reduction of cyanobacteria biovolume and a switch from cyanobacteria dominance (2001-2005) to diatom and chlorophyte dominance (2006-2013). Cluster analysis identified four statistically different groups of summer phytoplankton assemblages (denoted Groups 1-4). Nonmetric multidimensional scaling analysis indicated that the four groups were associated with different water quality conditions. Group 1 occurred prior to hypolimnetic aeration and was primarily comprised of cyanobacteria, associated with water conditions of high nutrients and high primary production. Group 2, dominated by cyanobacteria and chlorophytes, occurred between hypolimnetic aeration and alum surface application. Group 2 was associated with turbid water conditions. Group 3 was dominated by diatoms, occurring after alum surface application. Group 4 included R-strategist phytoplankton that quickly respond to environmental changes, occurring in the years following alum injection, drawdown and inflow alum treatment. Both Group 3 and 4 were associated with reduced nutrients in the lake. The results demonstrated a strong temporal relationship between the long-term changes in water quality and summer phytoplankton assemblages and the lake management practices. The Pacific Decadal Oscillation (PDO) index, an El-Niño-like pattern of Pacific climate variability, showed a statistically significant correlation with the summer phytoplankton dynamics, while the multivariate ENSO index (MEI) and regional meteorological variables (air temperature, rainfall, wind speed, wind direction and solar radiation) were not significantly related to the changes of phytoplankton communities during the study period. In conclusion, the study results suggest that the lake management practices had strong effects on both production and community compositions of phytoplankton, and suggest the need for a future study on large-scale climate impacts on lake ecosystems and best management practice.

Abstract not available

Abstract not available

Bibliography: leaves 168-187. / viii, a-f, 187, [51] leaves, [12] leaves of plates : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Investigates the environmental control of seasonal reproduction and the role of the pineal in the transmission of multiple environmental signals to the reproductive axis. The principle species studied was the highly seasonal native Australian bush rat, Rattus fuscipes greyi. / Thesis (Ph.D.)--University of Adelaide, Dept. of Obstetrics and Gynaecology, 1994

Recent climate change forecasts have aroused growing interest in the influence of water scarcity and climate on agricultural production and irrigation practice. However, it is common in the economic literature to aggregate disparate crops when modeling irrigation choices. That approach confounds the crop-specific effects of climate and water scarcity that govern such choices. Given the sensitivity of agricultural production to water scarcity and climate, understanding their influence on irrigation choices is a key contribution to policy evaluation. This paper addresses the impact of water scarcity and climate on irrigation choices through estimated models of cropland proportion irrigated (PI), and crop-specific irrigation technology choice (TC) and water application rates (AR). This approach is applied to agricultural production data for major crops (orchard/vineyard, vegetable, wheat, alfalfa, hay, and pasture) on the West Coast (California, Oregon, and Washington). Crop-specific modeling provides information about the distributional impacts of agricultural policy and climate change. This advantage is particularly important for the diverse agricultural landscape of the West Coast, where the distributional impacts of policy can be complex. The most important policy implications that are found involve asset heterogeneity and the distributional impacts of agricultural policy. Several findings provide valuable information about how irrigators would respond and adapt to climate change. The current findings also lead to commonly advocated revisions to federal water subsidy policies. Some key differences between the irrigation choices of higher- and lower-value crops are also identified. Identifying these differences sheds further light on the distributional consequences of agricultural policy. Many findings from this research are crop-specific and will have a high degree of policy relevance to irrigation districts or other agricultural jurisdictions that cultivate some of the West Coast's major crops. Furthermore, the data used in this research has a large degree of variation in water scarcity and climate, making the findings applicable to other Mediterranean climates in the world. It is found that specific crops have a proclivity for certain irrigation technologies that can mitigate particular climatic stressors (i.e., frost damage and heat stress). For example, the results indicate that water pricing policies will tend not to encourage water conservation by technology adoption for many orchards, vineyards, and vegetable farms, thereby imposing pure costs to these producers. In essence, climate heterogeneity limits options available to farmers and reduces the set of production technologies that a farm can use. This finding exemplifies that with climate heterogeneity, the distribution of water policy impacts depends on prior land allocation decisions such as crop choices. Heterogeneity in land quality is also found to have important influences on TC. The effects of temperature on irrigation choices are found to be more profound than the effects of precipitation. Because of the large study region used, the effects of temperature and precipitation on irrigation choices are often found to be quadratic-like. These quadratic-like relationships reveal thresholds where irrigators begin to respond very differently to climate. However, this was not the case for all crops. Thus, it is demonstrated that the effects of climate on irrigation choices are crop-dependent. The results indicate that for several crops, the discontinuance of irrigation water (i.e., water supply or price uncertainty) creates an option value that delays and discourages adoption of water-saving technologies. The discontinuance of irrigation water is also shown to reduce water demand at the farm-level extensive proportion (i.e., PI) and crop-level intensive margin (i.e., AR). Water price is found to impact all three irrigation choices as well. Well depth is found to facilitate adoption of water-saving technologies for several crops. This paper demonstrates that irrigation choices are highly dependent on water scarcity and climate. Institutional arrangements, geographic qualities of the farm, and demographic characteristics of the farmer also exhibit important influences on irrigation choices. By using crop-specific equations, quadratic climate variables, and a study region with large variation in climate conditions, this research resolves many inconsistent findings regarding the determinants of irrigation choices. Furthermore, this study establishes a research agenda for crop-specific analysis of irrigation choices. Some of the estimated results warrant verification with further studies. Future crop-specific irrigation choice studies would benefit from panel micro data with improved land quality variables, and seasonal or monthly climate variables that are better able to identify the effects of climate stress (e.g., heat stress and frost damage) on irrigation choices. / Graduation date: 2013

This thesis conducts a case study of how MARTA could address climate change adaptation through its transit asset management program. Two climate-modeling approaches are utilized to project potential future climate scenarios within MARTA's service area to identify significant climate stressors. These climate stressors are used to help identify vulnerable assets, operations, and locations in the MARTA system through several interviews conducted with key MARTA staff. The results of this basic climate vulnerability assessment are used to develop a series of short-term and long-term adaptation strategies that address these vulnerabilities. Next, a framework is proposed for addressing climate adaptation through MARTA's existing asset management program. Finally, the thesis proposes a general framework that other transit agencies could utilize to address climate adaptation through their asset management programs. The results of the climate vulnerability assessment indicate that the MARTA service area is likely to experience longer exposure to higher temperatures, flooding, wider variations in temperature, droughts, and more frequent high-wind events. Of these stressors, the MARTA system is most vulnerable to the effects of extreme and prolonged heat as well as flooding caused by intense precipitation events. Adaptation strategies to address these vulnerabilities include more frequent inspection of HVAC systems on buses and rail vehicles, increasing pumping capacity at underground rail stations, and incorporating low-impact developments into surrounded station areas. The limitations of the results of this case study and areas for further research from these limitations are also presented.

Maize production in Africa is constrained by abiotic and biotic stresses. Breeders need to have information on the nature of combining ability of parents, their traits and performance in hybrid combination. This requires careful determination of genetic variability of parents, and studying associations between grain yield and adaptive traits to breed superior cultivars which are better able to withstand such stresses. Therefore, this study was aimed at selecting parental testers with best combining ability in hybrid combination with recombinant inbred lines (RILs); and studying the correlation between grain yield and its components in eastern and western South Africa. It was also aimed at determining genetic variation and associations among adaptive traits in hybrids involving RILs. The final objectives of the study were to determine cultivar superiority of testcrosses involving RILs, and to select the best cultivars within and across four different environments. The 42 RILs were crossed to 9 Zimbabwean tropical testers resulting in 1009 hybrids with sufficient seed for planting in trials. From these a sample of 87 hybrids with adequate seed were selected and planted at four sites for combining ability analysis. The hybrids were evaluated at four sites in two regions; western region (Potchefstroom research station) and eastern region (Cedara, Ukulinga and Dundee research stations), during 2011/12 season. The experiments were laid out as augmented alpha lattice design. Trials were managed in accordance with production culture for each region. All quantitative data was subjected to GenStat and SAS statistical softwares. The results from combining ability study indicated that the line general combining ability (GCA) effects played a non-significant role (p > 0.05) in determining grain yield, grain moisture and anthesis date, while they were significant (p ≤ 0.05) for the other traits such as ear prolificacy. The tester main effects were significant for all the traits except ear prolificacy and plant height. Results also revealed that all the traits were controlled by both additive and non-additive genes, where additive gene action had the most contribution to the traits. The non-additive gene action played a minor role suggesting the total GCA effects attributed to both lines and testers predominantly higher over the specific combining ability (SCA) for all traits. In general the additive effects were preponderant over the non-additive gene effects. One cross (L114 x T12) had a significant and positive SCA effect for grain yield. The correlation between grain yield and secondary traits (number of ears per plant, grain moisture content, ear height, plant height, ear position and anthesis date) suggested that indirect selection can be employed to enhance grain yield by breeding for these particular adaptive traits. Path analysis showed that plant height had the highest direct and indirect effect on grain yield indicating its importance among other secondary traits for grain yield enhancement. Phenotypic coefficient of variation (PCV) was higher than genotypic coefficient of variation (GCV) for all the studied traits across all the four environments. All the traits displayed high heritability at Potchefstroom except anthesis date which was highly heritable at Ukulinga. Cedara was the second best site for heritability of all the traits except for the number of ears per plant. The genetic advance for grain yield was the highest at Cedara followed by Potchefstroom, Dundee and Ukulinga. The hybrids exhibited different patterns of variation and distribution for all the traits. This indicated that selection strategies to exploit GCA should be emphasised. Association studies among grain yield and secondary traits such as ear length, number of ears per plant, plant height, anthesis date, silking date and ear leaf area revealed that there were significant phenotypic correlations between grain yield and secondary traits, and among the secondary traits. Ear length had the highest direct effect on grain yield at Ukulinga; number of ears per plant had the highest direct effect on grain yield at Cedara and Potchefstroom; whereas plant height had the highest direct effect on grain yield at Dundee. Grain yield was least affected by indirect factors at all the sites except Ukulinga, where anthesis date had the highest indirect effect on grain yield through silking date followed by plant height through leaf area. The study reveals that there is significant variation among the hybrids for mean performance, indicating that there is opportunity for selection. Overall the findings suggest that direct selection would be appropriate to enhance grain yield. Path analysis revealed that plant height had the highest direct and indirect effects on grain yield, indicating that plant height can be further exploited as the main trait in future breeding programmes for grain yield increment. Hybrid 10MAK10-1/N3 was the best hybrid at Ukulinga in terms of grain yield, relative yield and economic traits. Whereas hybrid T17/L83 was the best hybrid at Cedara in terms of grain yield and relative yield; however, T11/L102 was selected as the most elite hybrid with respect to grain yield, relative yield and economic traits. Hybrid T3/L48 was identified as thebest hybrid at Dundee with respect to grain yield, relative yield and prolificacy. At Potchefstroom the standard check PAN6611 was identified as the best hybrid in terms of grain yield and relative yield followed by developmental hybrid T1/L28; however, developmental hybrid T1/L28 was the best in terms of earliness, prolificacy and ear aspect. Stability coefficients and cultivar superiority index across the sites revealed that four developmental hybrids were identified as best hybrids and they performed better than the standard check. These hybrids will be recommended for further testing in advanced trials. With respect to cultivar superiority, the desired hybrids are required to combine high grain yield with economic and adaptive traits such as high ear prolificacy, low grain moisture, and low ear aspect score (desired) for them to adapt to production environments in South Africa. There was significant variation among the top 25 yielding hybrids. At least 5 hybrids combined high grain yield with the desired complimentary adaptive traits such as quick moisture dry down, prolificacy and ear aspect. The results showed that there is variation in the performance of high yielding genotypes within all the sites, and that agronomically superior cultivars can be identified. The study shows that there is significant variation among the RILs since they interacted differently with the 9 tropical testers. Even among the top 25 selections of RILs in each environment there was still variation for combinations of the desired traits. Significant associations among grain yield and other economic and adaptive traits were observed with implications for breeding strategy. Above all the significant variation gives large score for future breeding of new unique lines. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.

Trees are considered one of the most sensitive indicators of the environmental condition from all life forms. They are most suitable for the evaluation of the environmental changes. Due to the structure of crown trees have better contact with the atmosphere, so they filter the flowing air mass better than other vegetation forms, determine the processes in the ecosphere and react sensitively to the anthropogenic factors and consequently indicate the condition of the forest ecosystems by anatomical and morphological symptoms. Tree rings, their width and structure integrally reflect the complex impact of environmental factors. Therefore the role of tree rings, as the indicator of environmental conditions, is important for the evaluation of environmental changes. Forest ecosystems growing close to the pollution sources suffer the greatest impact because the concentration of harmful materials in the local pollution zone often exceeds permissible amounts. The objective of the research was to analyse the changes of annual radial increment of pine stands (Pinus sylvestris L.) in the zones of local alkalizing, acidifying and eutrophying pollution and to determine the regularities of radial increment recovery after the decrease of pollution. First time in Lithuania a comprehensive dendrochronological research on the impact of climatic factors and industrial pollution on the radial increment of Scots pine (Pinus sylvestris L.) has been carried out in the surroundings of “Akmenės... [to full text] / Medžiai yra vieni jautriausių aplinkos būklės indikatorių, iš visų gyvybės formų labiausiai tinkamų aplinkos pokyčiams vertinti. Dėl lajų struktūros ypatumų jie glaudžiau kontaktuoja su atmosfera ir daugiau negu kitos augalijos formos filtruoja pernešamo oro masę, lemia ekosferoje vykstančius procesus bei jautriai reaguoja į antropogeninius veiksnius, anatominiais ir morfologiniais požymiais indikuoja miško ekosistemų būklę. Medžių metinių rievių dinamika suteikia informaciją apie ekologines bei klimatines vietovės sąlygas, aplinkoje vykstančius reiškinius, o jų plotis ir struktūra integraliai atspindi kompleksinį aplinkos veiksnių poveikį. Labiausiai nukenčia arti taršos šaltinių augančios miško ekosistemos, kadangi vietinės taršos zonoje kenksmingų medžiagų koncentracija dažnai viršija ribines leistinas normas. Darbo tikslas – ištirti paprastosios pušies (Pinus sylvestris L.) medynų metinio radialiojo prieaugio pokyčius vietinės šarminančios, rūgštinančios ir eutrofizuojančios taršos poveikio zonose bei radialiojo prieaugio atsikūrimo dėsningumus sumažėjus taršos poveikiui. Pirmą kartą Lietuvoje atlikti išsamūs dendrochronologiniai klimato veiksnių ir pramonės taršos poveikio paprastosios pušies (Pinus sylvestris L.) metiniam radialiajam prieaugiui tyrimai „Akmenės cemento“ poveikio zonoje. Darbe taip pat analizuotas cemento dulkių poveikis paprastosios pušies metiniam radialiajam prieaugiui; įvertinti antropogeniniai radialiojo prieaugio pokyčiai „Akmenės cemento“ ir... [toliau žr. visą tekstą]

Medžiai yra vieni jautriausių aplinkos būklės indikatorių, iš visų gyvybės formų labiausiai tinkamų aplinkos pokyčiams vertinti. Dėl lajų struktūros ypatumų jie glaudžiau kontaktuoja su atmosfera ir daugiau negu kitos augalijos formos filtruoja pernešamo oro masę, lemia ekosferoje vykstančius procesus bei jautriai reaguoja į antropogeninius veiksnius, anatominiais ir morfologiniais požymiais indikuoja miško ekosistemų būklę. Medžių metinių rievių, kaip aplinkos būklės indikatoriaus, vaidmuo vertinant aplinkos pokyčius yra svarbus. Metinių rievių dinamika suteikia informaciją apie ekologines bei klimatines vietovės sąlygas, aplinkoje vykstančius reiškinius, o jų plotis ir struktūra integraliai atspindi kompleksinį aplinkos veiksnių poveikį. Lietuvoje didžiausią naigiamą įtaką miško ekosistemoms turi vietiniai taršos šaltiniai. Jų aplinkoje augančios miško ekosistemos nukenčia labiausiai, kadangi vietinės taršos zonoje kenksmingų medžiagų koncentracija dažnai viršija ribines leistinas normas. Darbo tikslas – ištirti paprastosios pušies (Pinus sylvestris L.) medynų metinio radialiojo prieaugio pokyčius vietinės šarminančios, rūgštinančios ir eutrofizuojančios taršos poveikio zonose bei radialiojo prieaugio atsikūrimo dėsningumus sumažėjus taršos poveikiui. Pirmą kartą Lietuvoje atlikti išsamūs dendrochronologiniai klimato veiksnių ir pramonės taršos poveikio paprastosios pušies (Pinus sylvestris L.) metiniam radialiajam prieaugiui tyrimai „Akmenės cemento“ poveikio zonoje... [toliau žr. visą tekstą] / Trees are considered one of the most sensitive indicators of the environmental condition from all life forms. They are most suitable for the evaluation of the environmental changes. Due to the structure of crown trees have better contact with the atmosphere, so they filter the flowing air mass better than other vegetation forms, determine the processes in the ecosphere and react sensitively to the anthropogenic factors and consequently indicate the condition of the forest ecosystems by anatomical and morphological symptoms. Tree rings, their width and structure integrally reflect the complex impact of environmental factors. Therefore the role of tree rings, as the indicator of environmental conditions, is important for the evaluation of environmental changes. Forest ecosystems growing close to the pollution sources suffer the greatest impact because the concentration of harmful materials in the local pollution zone often exceeds permissible amounts. The objective of the research was to analyse the changes of annual radial increment of pine stands (Pinus sylvestris L.) in the zones of local alkalizing, acidifying and eutrophying pollution and to determine the regularities of radial increment recovery after the decrease of pollution. First time in Lithuania a comprehensive dendrochronological research on the impact of climatic factors and industrial pollution on the radial increment of Scots pine (Pinus sylvestris L.) has been carried out in the surroundings of “Akmenės... [to full text]