Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 108 for “"Aridity"”.
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Adaptation to aridity in lizards of the Egernia Whitei species-group
122 leaves : ill.
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Paleo-aridity records investigated through drip water chemistry in Lehman Caves, Nevada
… This will improve our understanding of the paleo-aridity of the Great Basin region, as well as provide useful context for the changing precipitation patterns expected with modern climate change.
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Sociality in the common mole-rat, Cryptomys hottentotus hottentotus : the effects of aridity
… mole-rat was used as a model to assess the Aridity Food-Distribution Hypothesis (AFDH), as an explanation for the evolution of bathyergid sociality. The AFDH correlates mole-rat sociality with habitat aridity and the pattern of food distribution. Aspects relating to ecological constraints, …
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Influence of Aridity and Fire on Holocene Vegetational Patterns in the Tallgrass Prairie Peninsula
Because of limitations inherent in delta13C analysis of substrates such as charcoal, new techniques are needed to understand C 3 and C4 grass fluctuations. A method of isolating fossil grass pollen for delta13C analysis was developed, and the delta 13C composition of modern and fossil grass pollen …
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Aridification of the Indian subcontinent during the Holocene : implications for landscape evolution, sedimentation, carbon cycle, and human civilizations
… the δ13Cwax record shows a gradual increase in aridity-adapted vegetation from ~4,000 until 1,700 years ago followed by the persistence of aridity-adapted plants to the present. The oxygen isotopic composition of planktonic foraminifera from this site indicates drought-prone conditions began as …
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Aridification of the Indian subcontinent during the Holocene : implications for landscape evolution, sedimentation, carbon cycle, and human civilizations
… record shows a gradual increase in aridity-adapted vegetation from ~4,000 until 1,700 years ago followed by the persistence of aridity-adapted plants to the present. The oxygen isotopic composition of planktonic foraminifera from this site indicates drought-prone conditions began as …
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Climatic influences on hillslope soil transport efficiency
… climate proxies (mean annual precipitation, aridity index, and mean annual temperature) with the goal of characterizing climatic influences on soil transport efficiency. The new measurements were performed at sites that extend the range into both drier and wetter climates than those …
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Quantifying uncertainties and trends in the climate change trajectory
… chapter, the drivers, timing, and impacts of aridity change over the 21st century are assessed using an ensemble of general circulation models (GCMs) together with population statistics. Results indicate that drier regions are projected to dry earlier, more severely and to a greater extent …
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Determinants of the structural niches of columnar cacti in the Southwest
… do exist, they are correlated with variation in aridity. Carnegiea and Pachycereus in less xeric environments have more branches, greater total branch length, and earlier initiation of branching than those of equal height in more xeric environments. I found no evidence of evolutionary divergence …
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The nitrogen cycle and ecohydrology of seasonally dry grasslands
… rooting depths decrease with increasing aridity, while in humid climates, rooting depths increase with aridity. In all climates, rooting depths increase with increased nitrogen supply. Further, relative root-carbon allocation always increases with aridity and decreases with nitrogen …
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Assessing changes in pollen assemblage and charcoal accumulation during known changes in climate from c. 5,400 to 3,300 Years Before Present at the forest-prairie ecotone in Alberta, Canada
… that has been subject to periods of enhanced aridity occurring at multi-decadal to centennial-scale cycles throughout much of the last 6000 years. To assess the ecotonal response to changes in effective moisture, as inferred by diatom-inferred salinity, temporal variations in pollen and …
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The spatial and temporal dynamics of diversification in Tylecodon, Cotyledon and Adromischus (Crassulaceae) in southern Africa
… and consequences of adaptations to extreme aridity and summer drought in members of the group.
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Unraveling an uncertain future for the Great Basin: how climate, grass invasion, and wildfire interact to drive ecosystem function
… and laboratory experiment to identify how soil aridity influences root exudation by cheatgrass (Bromus tectorum), an invasive annual grass, alters the cycling of carbon (C) and nitrogen (N) in the soil. We observed that cheatgrass was able to uniquely access N in dry soils, and that changes in …
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Climate, Ecology, and Human Evolution during the Plio-Pleistocene
… on climate and human evolution. The notion that aridity and seasonality have increased over the Pliocene and Pleistocene has remained central to models of environmental change (i.e. C<sub>4</sub> grass expansion) and human evolution; however, few empirical records of terrestrial climate are …
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Hydrology and Hydrogeochemistry of the South Fork, Wright Valley, Southern Victoria Land, Antarctica
… and particularly of the extreme cold and aridity.
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Assessing the Robustness of Deep Learning Streamflow Models Under Climate Change
… data from hydrological years of high (low) aridity and testing on data from hydrological years of low (high) aridity, we can begin to quantify the performance and relative robustness of that performance under climate nonstationarity. We benchmark against a calibrated conceptual model (the …
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Inter-seasonal and intra-seasonal rainfall variability in the North West Province South Africa
… of the clusters show that C1 is increasing in aridity while in C2 the rainfall is showing an increase pattern. Mann Kendal trend test and Sens' slope estimator were used to study variability and trends in NWP rainfall. Trend analysis results of North West Province 1984-2015 seasonal rainfall …
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The evolution of annuality in association with a shift to more arid environments in the daisy genera Ifloga and Tricogyne
… study I evaluated the idea that increases in aridity should be associated with the evolution of an annual life history. I also investigated the correlated evolution of annuality and growth form. Ancestral character states for life history characters and climate variables were mapped onto a …
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Evaluating the ecosystem services and disservices provided by Mediterranean woodlands
… years, suggesting that forests are adapting to aridity by reducing evapotranspiration rates. Evidence of river flow recovery towards control conditions, with continued forest aging, was found in nine studies. However, significant recovery was associated with a long-term trend of increasing …
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Permaculture as an alternative to present commercial resettlement farming practices in Namibia
… eventually texture destruction. Furthermore, the aridity of Namibia makes crop and livestock farming difficult. Permanent agriculture (permaculture) is a way of living sustainably in the environment and it is proposed as an alternative farming method for the mostly poor and illiterate settlers on …
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