Global ETD Search

1	Restoration of Burns Bog : cumulative moisture deficit as an indicator of vegetation recovery and peat growth Dilley, Laura 10 June 2014 (has links) Burns Bog covers approximately 3,000 hectares between the Fraser River and Boundary Bay in Delta, BC. An ecologically unique ecosystem, its hydrology and ecology have been widely disturbed. Hydrology strongly shapes the character and distribution of vegetation and Sphagnum growth. This study investigated measures of hydrology, including water table residence times and cumulative moisture deficits, to quantify intuitive relationships between moisture stress and ecological zones. Regression analysis of quantitative field observations reveal statistically significant relationships between cumulative moisture deficits and several key bog plant species and Lodgepole pine (Pinus contorta) diameter at breast height, signifying that these relationships can be used to predict the potential for vegetation recovery. Sphagnum height measurements reveal the unexpected observation that most growth occurs during the cool moist winter and early spring. This study contributes to the hydrological management of Burns Bog and will help to guide the location and mechanisms of restoration efforts. bog Burns Bog moisture deficit peatland restoration vegetation
2	Transport infrastructure slope failures in a changing climate Wilks, Joanna H. January 2015 (has links) Failure of slopes adjacent to the UK transport infrastructure causes delays and these are expensive assets to repair and maintain. Understanding the processes that lead to failure will assist asset managers both now and in the future in the context of a changing climate. The EPSRC-funded multidisciplinary FUTURENET project investigated the effect of climate change on the resilience of the UK transport network and this thesis is a part of that project considering the weather patterns leading to slope failures along transport infrastructure slopes within the UK. To that end a series of slope failure case studies were investigated to understand the processes leading to failure. These were compiled using nationally held datasets as well as news reports. This research used data from the FUTURENET partners that hold national data sets and asset management information. This shows the wide reaching remit of a multidisciplinary collaborative project such as FUTURENET, but also highlights the limitations of datasets collected and used for very specific purposes and not necessarily suited to wider research. From these case studies a suite of slope failure weather thresholds were developed. These thresholds consider the antecedent period, water content within the slope through the soil moisture deficit and triggering rainfall through comparison to the long term average rainfall. Consideration was given to possible future weather using weather event sequences (WESQs), possible weather patterns for 2050 derived from the UKCP09 climate projection data. By considering these possible weather patterns with the slope failure thresholds a picture of a possible future was evaluated. 624.1
3	Drėgmės trūkumo poveikis žirnių morfofiziologiniams rodikliams / The influence of moisture lack on pear morphofizioligical indices Klimas, Tautvydas 16 June 2014 (has links) Magistrantūros studijų baigiamajame darbe pateikiami žirnių fotosintezės pigmentų, prolino, sacharidų bei santykinės drėgmės pokytis lapuose esant drėgmės deficitui. Tyrimų objektas – `Ilgiai` veislės sėjamasis žirnis (Pisum sativum L.). Darbo metodai. Tyrimai atlikti Aleksandro Stulginskio universiteto Agrobiotechnologijos laboratorijoje 2012-2013 metais. Žirniai pasėti į 0,16 m x 0,23 m (aukštis x diametras) vegetacinius indus su substratu (pH − 6,31, P2O5 − 633,94 mg kg-1, K2O – 912 mg kg-1). Eksperimentas vykdytas 6 pakartojimais po 5 augalus inde. Augalai auginti programuojamoje auginimo kameroje esant 20/18 °C (diena/naktis) temperatūrai, 16/8 val. (diena/naktis) fotoperiodui, 50 µmol m-2 s-1 apšviestumui. Augalai auginti programuojamoje auginimo kameroje aukščiau nurodytomis sąlygomis bei esant drėgmės deficitui substrate. Sausros tyrimas pradėtas po sėjos praėjus trims savaitėms. Darbo rezultatai. Esant drėgmės deficitui, patikimai didžiausi chlorofilo a ir b bei karotenoidų kiekiai žirniuose (atitinkamai 2,501 ir 0,821, bei 1,059 mg l-1) nustatyti praėjus 8 dienoms po laistymo. Esmingai didžiausi prolino ir sacharidų kiekiai (atitinkamai 46,543 μM g-1 ir 0,155 g kg-1) žirniuose, esant drėgmės deficitui, nustatytas praėjus 12-ai dienų. Dirvožemio drėgnis (SWC) esmingai kito visą tyrimų laikotarpį. Mažiausias dirvožemio drėgnis (15,12 proc.) nustatytas paskutinę tyrimų dieną, praėjus 16-ai dienų po paskutinio laistymo. Santykinis vandens kiekis lapuose (RWC) esmingai... [toliau žr. visą tekstą] / Master’s thesis submitted to pea’s photosynthesis pigments, proline, saccharins and relative humidity change in leaves and the influence of humidity. The object of researches – ‘Ilgiai’ variety of sowing peas (Pisum sativum L.) Methods. Research carried out at Aleksandras Stulginskis University in Laboratory of Agrobiotechnology 2012–2013. Peas were sown in 0.16 m x 0.23 m (height x diameter) vegetative vessels with the substratum (pH – 6.31, P2O5 – 633.94 mg kg-1, K2O – 912 mg kg-1). The experiment was carried out in 6 replicates of 5 plants in container. Plants were cultivated at programmable climatic chamber at 20/18 °C (day/night) temperature, 16/8 hours (day/night) photoperiod, 50 µmol m-2 s-1 illumination. Plants were grown at programmable climatic chamber by conditions which are set out above and with deficit of moisture in substrate. The investigation of drought launched after three weeks of sowing. Results. In the moisture deficit, reliably the largest chlorophyll a and b and carotenoids amount in peas (respectively 2.501 and 0.821, and 1.059 mg l-1) were determined after 8 days after watering. Essentially the maximum proline and saccharins contents (by 46.543 μM g-1 and 0.155 g kg1) in peas at the moisture deficit were set after 12 days. Soil water content (SWC) was essentially varying through all period of researches. Minimum soil humidity (15.12 percent) was established at the last day of researches, passing 16 days after last watering. Relative water content in... [to full text] Agronomy Žirniai Drėgmės deficitas Fotosintezės pigmentai Prolinas Sacharidai Peas The moisture deficit Pigments of photosynthesis Proline Saccharin
4	Drėgmės trūkumo poveikis žaliosios šerytės morfofiziologiniams parametrams / Effect of moisture deficit on morphophysiological parameters of green millet Kopūstas, Aurentas 21 June 2013 (has links) Magistrantūros studijų pateikiami drėgmės deficito poveikio žaliosios šerytės morfofiziologiniams parametrams tyrimų rezultatai. Darbo objektas – žalioji šerytė (Setaria viridis (L.) P. Beauv.). Darbo metodai: žaliosios šerytės augalai auginti programuojamoje auginimo kameroje esant 20/18 °C (diena/naktis) temperatūrai, 16/8 val. (diena/naktis) fotoperiodui, 50 µmol m-2 s-1 apšviestumui. IV organogenezės tarpsnyje augalai auginti esant drėgmės deficitui substrate. Vertintas fotosintetinių pigmentų kiekiai, augalo žalia masė, sausos medžiagos kiekis bei santykinis vandens kiekis lapuose. Darbo rezultatai. Esant nedideliam drėgmės trūkumui substrate, chlorofilo a sintezė žaliosios šerytės augaluose vyko intensyviau, lyginant su kontrole, tuo tarpu pirmą drėgmės deficito savaitę neturėjo esminės įtakos chlorofilo b ir karotenoidų kiekiams. Modeliuojant drėgmės deficitą substrate ilgiau nei savaitę chlorofilų a ir b bei karotenoidų kiekiai statistiškai patikimai mažėjo. Chlorofilų a ir b santykis statistiškai patikimai padidėjo jau po trijų drėgmės deficito dienų. Chlorofilų ir karotenoidų santykis žaliosios šerytės augaluose pradėjo mažėti po 5 sausros dienų. Ilginant sausros trukmę, santykinis vandens kiekis žaliosios šerytės augaluose, augintuose drėgmės deficito sąlygomis, nuosekliai mažėjo ir buvo esmingai mažesnis, lyginant su kontroliniais augalais. Drėgmės deficitas substrate esmingai mažino žaliosios masės kaupimąsi žaliosios šerytės augaluose. Pirmą sausros savaitę... [toliau žr. visą tekstą] / The objective of this study was to investigate the effect of moisture deficit on morphophysiological parameters of green millet plants. Object of the work – green millet (Setaria viridis (L.) P. Beauv.). Methods of the work: green millet plants were growing in growth chamber under 20/18 °C (day/night) temperature, 16/8 h (day/night) photoperiod, 50 µmol m-2 s-1 light intensity. Moisture deficit treatment was applied when plants were in organogenesis stage four. Amount of photosynthetic pigments, fresh mass of plants, dry weight and relative water content in plant leaves were investigated. The results of work. Relatively slight moisture deficit resulted in more intensive chlorophyll a synthesis in green millet plant in comparison with control, while first week of moisture deficit didn’t have any effect on chlorophyll b and carotenoids contents. For more than a week-long drought significantly inhibited the chlorophyll a and b contents as well as carotenoids content in green millet plants. The ratio of chlorophyll a and b significantly increased after three days of moisture deficit. The ratio of chlorophylls and carotenoids decreased after five drought days. Elongation of drought stress resulted in decreasing of relative water content in plant leaves. The fresh mass of plants significantly decreased under moisture deficit treatment. First week of drought stress resulted in increasing of dry weight, while under treatment of 9-18 days of drought treated plants accumulate... [to full text] Agronomy Raktažodžiai: drėgmės deficitas Morfofiziologiniai parametrai Žalioji šerytė Key words: moisture deficit Morphophysiological parameters Green millet
5	Diurnal Trends in Water Status, Transpiration, and Photosynthesis of Saltcedar Williams, Mary Ellen, Anderson, Jay E. 16 April 1977 (has links) From the Proceedings of the 1977 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 15-16, 1977, Las Vegas, Nevada / Relative water content (RWC), water potential (P), and gas exchange were measured on saltcedar at the Bernardo, New Mexico, lysimeter site. RWC and s were closely correlated; but, water potential measurements, taken with a pressure bomb, were more convenient and reliable. RWC and r decreased sharply from sunup until about 0900, when minimum values of about -26 bars T or 80% RWC were reached. Water status then remained constant or improved slightly through late afternoon. Transpiration rates typically remained high until about noon and then began a steady, gradual decrease that continued throughout the afternoon. The data suggest that water stress may be a factor in initiating stomatal closure; however, transpiration continued to decline despite a constant or improved leaf water status. Maximum net photosynthetic rates occurred by 0900, and depressions throughout the remainder of the day were largely accounted for by increased leaf temperatures. Afternoon depressions in transpiration and photosynthesis occurred in twigs held at constant temperature and relative humidity, suggesting that a diurnal rhythm may be involved in control of gas exchange. Water status of plants growing on the lysimeters was comparable to that of plants in adjacent natural stands; gas exchange rates were slightly higher for the lysimeter-grown plants. Hydrology -- Arizona. Water resources development -- Arizona. Hydrology -- Southwestern states. Tamarisk Diurnal Consumptive use Water utilization Transpiration control Photosynthesis Moisture uptake Moisture deficit Pores Respiration Water loss Stomata Lysimeters Plant physiology
6	Multispectral imaging of Sphagnum canopies: measuring the spectral response of three indicator species to a fluctuating water table at Burns Bog Elves, Andrew 02 May 2022 (has links) Northern Canadian peatlands contain vast deposits of carbon. It is with growing urgency that we seek a better understanding of their assimilative capacity. Assimilative capacity and peat accumulation in raised bogs are linked to primary productivity of resident Sphagnum species. Understanding moisture-mediated photosynthesis of Sphagnum spp. is central to understanding peat production rates. The relationship between depth to water table fluctuation and spectral reflectance of Sphagnum moss was investigated using multispectral imaging at a recovering raised bog on the southwest coast of British Columbia, Canada. Burns Bog is a temperate oceanic ombrotrophic bog. Three ecohydrological indicator species of moss were chosen for monitoring: S. capillifolium, S. papillosum, and S. cuspidatum. Three spectral vegetation indices (SVIs) were used to characterize Sphagnum productivity: the normalized difference vegetation index 660, the chlorophyll index, and the photochemical reflectance index. In terms of spectral sensitivity and the appropriateness of SVIs to species and field setting, we found better performance for the normalized difference vegetation index 660 in the discrimination of moisture mediated species-specific reflectance signals. The role that spatiotemporal scale and spectral mixing can have on reflectance signal fidelity was tested. We were specifically interested in the relationship between changes in the local water table and Sphagnum reflectance response, and whether shifting between close spatial scales can affect the statistical strength of this relationship. We found a loss of statistical significance when shifting from the species-specific cm2 scale to the spectrally mixed dm2 scale. This spatiospectral uncoupling of the moisture mediated reflectance signal has implications for the accuracy and reliability of upscaling from plot based measurements. In terms of species-specific moisture mediated reflectance signals, we were able to effectively discriminate between the three indicator species of Sphagnum along the hummock-to-hollow gradient. We were also able to confirm Sphagnum productivity and growth outside of the vascular growing season, establishing clear patterns of reflectance correlated with changes in the local moisture regime. The strongest relationships for moisture mediated Sphagnum productivity were found in the hummock forming species S. capillifolium. Each indicator Sphagnum spp. of peat has distinct functional traits adapted to its preferred position along the ecohydrological gradient. We also discovered moisture mediated and species-specific reflectance phenologies. These phenospectral characteristics of Sphagnum can inform future monitoring work, including the creation of a regionally specific phenospectral library. It’s recommended that further close scale multispectral monitoring be carried out incorporating more species of moss, as well as invasive and upland species of concern. Pervasive vascular reflectance bias in remote sensing products has implications for the reliability of peatland modelling. Avoiding vascular bias, targeted spectral monitoring of Sphagnum indicator species provides a more reliable measure for the modelling of peatland productivity and carbon assimilation estimates. / Graduate peatland peatland restoration peatland monitoring peatland modelling peat peat moss multispectral multispectral imaging multicamera array multitemporal multiple linear regression linear mixed effects Sphagnum sphagna Sphagnum capillifolium Sphagnum papillosum Sphagnum cuspidatum spatiospectral uncoupling near-sensing remote sensing phenospectral phenology phenologies phenospectral bias phenospectral libraries carbon assimilation carbon dioxide carbon dynamics carbon emissions carbon geographies carbon mineralization carbon sequestration carbon source carbon sink carbon storage irrecoverable carbon climate forcing methane Ecological Restoration restoration ecology ecohydrology ecohydrological restoration hydrology ecohydrological gradients ecological integrity reflectance nature based solutions ombrotrophic moss raised peatland mires mires photochemical reflectance index normalized difference vegetation index chlorophyll index climate change climate forcing climate envelope climatope nonvascular vascular bias plant functional type plant functional types structure equation models spectral vegetation indices hummock hollow acrotelm catotelm diplotelmic biocrusts organic soil periodicity moisture deficit senescence rejuvenescence productivity photosynthesis light use efficiency photosynthetic function photosynthetically active radiation water table hydrology rewetting depth to water table landscape change landscape degradation peat subsidence Burns Bog

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