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Displaying theses 1-10 of 241 total
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S.B. Mooijman
Master programme: Environmental Management August 28th, 2018
Institute: IBED Research group: Ecosystem & Landscape Dynamics Graduation thesis Supervisor: William Gosling
Between the tropical Andes and the Amazon Characterizing phytolith assemblages over environmental gradients
Phytolith application in paleovegetation reconstructions has increased since the last change of century. Paleovegetation reconstructions provide information about response and resilience of vegetation on environmental changes, including climate change and human impact. Andean-Amazonian environmental gradients provide opportunities to relate phytolith assemblages to plant taxa. In this research, phytoliths from Ecuador’s Andean- Amazonian forests were counted and related to plant taxa. To find controls of forest structure and functioning, taxonomic variance was related to gradients of climate, land use and human disturbance using Canonical Correspondence Analysis and Pearson’s correlations. Stronger human disturbance affected taxonomic composition most, but taxa remained relatively resilient to moderate human disturbance, potentially informing environmental management strategies. Temperature related gradients also strongly affected taxonomic composition. Impact of precipitation related gradients was low, possibly a result of limited reliability of the precipitation data. Palm taxa thrived at warmer low elevations. Grass taxa thrived at cooler higher elevations. No increase of arboreal taxa was found above 1200 meter, although expected as a result of increased moisture availability due to permanent montane cloud formation. Near local roads more agricultural phytoliths were found, reflecting their use by local farmers. Phytolith analysis reflected existing knowledge, emphasizing potential as a paleo proxy.
picture that illustrates the research done
Scientific abstract (pdf 2K)   Data file (pdf 142K)   Full text (pdf 4101K)

H.H.C. Versteegh
Master programme: Environmental Management August 13th, 2018
Institute: IBED Research group: anders Graduation thesis Supervisor: dr. A.C. Seijmonsbergen
Quantification and analyses of global scale terrestrial geodiversity
Geodiversity can be defined as the natural range (diversity) of geological (rocks, minerals, fossils), geomorphological (land form, processes) and soil features. Until now, geodiversity has not been quantified on a global scale. However, a global geodiversity quantification can help to preserve nature and contribute to science. Freely available global datasets of hydrology (shores, lakes, rivers), soils, rock types and slope angles are used to quantify geodiversity within a grid. A global geodiversity index map is created that indicates the geodiversity within the grid cells, using five classes: very low, low, moderate, high and very high. This research indicated that the slope angles have the largest influence on the geodiversity, while the hydrological datasets have the smallest influence. Africa is the continent with the lowest geodiversity and Oceania has the highest geodiversity. Higher geodiversity classes dominate higher elevations. The global geodiversity index shows potential for nature conservation and global-scale monitoring. Therefore the used variables are proposed as global Essential Geodiversity Variables: carefully selected indicators that can be used to observe or monitor geodiversity.
picture that illustrates the research done
Scientific abstract (pdf 1K)     For more info or full text, mail to: A.C.Seijmonsbergen@uva.nl

W.L. Gravemaker
Master programme: Environmental Management August 9th, 2018
Institute: IBED Research group: Ecosystem & Landscape Dynamics Graduation thesis Supervisor: L.H. Cammeraat
photo of the author
Soil inorganic carbon storage and accumulation in southeast Spain under a chronosequence of land abandonment
Soil inorganic carbon (SIC) is of global importance to soil fertility and the long term carbon cycle. Until now, SIC research has focused on Loess soils of China, therefore little is known about soil inorganic carbon on the stony soils of southeast Spain. The current state of knowledge on SIC has been investigated, followed by a field research which tells us how much SIC is stored in the fieldwork area and how SIC storage is influenced by land management, or the absence of land management. This is the first time that the amount of soil inorganic carbon has been estimated in soils with a high rock fraction in this area. Multiple statistical methods were combined to confirm that soils do accumulate a significant amount of inorganic carbon after land abandonment by farmers, and the accumulation rate has been estimated. A model is proposed which addresses the most important factors for SIC accumulation, based on this field research and on theoretical knowledge.
picture that illustrates the research done
Scientific abstract (pdf 4K)     For more info or full text, mail to: l.h.cammeraat@uva.nl

J. Yang
Master programme: Environmental Management July 30th, 2018
Institute: IBED Research group: Computational Geo-Ecology Graduation thesis Supervisor: Emiel van Loon
Trap efficiency in muskrat control, based on field data from Flevoland, the Netherlands
Muskrat is considered an invasive species in the Netherlands. A year-round control program has been carried out for years. Yet the efficiency of traps has not been investigated sufficiently in detail. The study aims to compare the working efficiency between different trap types currently used in Flevoland, Netherlands. Three criteria are used namely catch efficiency, cost efficiency and target specificity. The comparison was done by analyzing field data, sending out questionnaire to professional trappers and a small scale field experiment.
picture that illustrates the research done
Scientific abstract (pdf 5K)   Data file (zip 7751K)   Full text (pdf 2887K)

B.R.N. Sweerts
Master programme: Geo-ecological Dynamics July 3rd, 2018
Institute: Other Research group: Institute for Atmospheric and Climate Science, ETH Graduation thesis Supervisor: Bob van der Zwaan
photo of the author
The long-term impact of aerosol emissions on photovoltaic power generation in China
China is the largest manufacturer and consumer of solar photovoltaic energy in the world. The amount of electricity generation with PV panels depends directly on the ultimate source of energy of our planet: the sun. Before sunlight reaches the surface and hits the PV panels, it must travel through the atmosphere. Here, clouds as well as aerosols absorb and scatter incoming radiation. Increases in anthropogenic aerosol emissions in China have substantially reduced the amount of sunlight that reaches the surface. We use measured sunlight data to show that this has resulted in an estimated 11-13% reduction in photovoltaic energy generation across China. However, stringent and successful air pollution control measures may reverse this trend - with with tens of terra-watt hours of electricity and billions of dollars of economic benefit as the result.
picture that illustrates the research done
Scientific abstract (pdf 1K)     For more info or full text, mail to: bob.vanderzwaan@tno.nl

C.C.M. Vredevoort
Master programme: Environmental Management June 23rd, 2018
Institute: IBED Research group: Paleo-ecology and Landscape Ecology Graduation thesis Supervisor: John van Boxel
Precipitation patterns under climate change: Constructing statistical precipitation models using historical European persistence trends.
During this research historical precipitation patterns in Europe were analyzed by looking at annual trends in consecutive days of rainfall and dryness. Linear trends in persistence were derived from precipitation datasets provided by the European Climate Assessment & Database project. Furthermore, trends in occurrence of intense rainfall periods and prolonged dry and wet spells were calculated to identify precipitation extremes. Transition probabilities between dry, light, medium and heavy rainfall days were assessed for calibrating Markov transition matrices. The first order Markov models generally generated realistic precipitation statistics but failed to simulate long dry and wet spells. The model output displayed high agreement with historical observations and was subsequently extrapolated to project future precipitation statistics. Some historical datasets lacked reliable precipitation measurements, resulting in unrealistic future precipitation projections. Model improvements are required to simulate precipitation more accurately. Markov models can eventually be used as a relatively simple tool to generate fairly accurate precipitation statistics based on meteorological persistence. These statistics can be used for impact assessments under climate change.
picture that illustrates the research done
Scientific abstract (pdf 2K)   Data file (docx 213K)   Full text (docx 10092K)

C.L. Thomas
Master programme: Geo-ecological Dynamics June 20th, 2018
Institute: IBED Research group: Ecosystem & Landscape Dynamics Graduation thesis Supervisor: Boris Jansen
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Soil Legacies: Using lipid biomarkers to verify illicit whisky distilling sites on the isle of Arran, Scotland
For this thesis, soil samples were taken from two areas on the isle of Arran in Scotland that were identified as potential illicit distillation sites. Additionally, samples from the various steps of the whisky distillation process were obtained from the Isle of Arran distillery. Lipids extracted from the soil samples were compared to lipids found in the whisky samples. The goal of the research was to determine whether this method could be used to provide evidence of past illicit distillation at the sampled sites. It was determined that straight-chain lipids were present in the whisky samples and were well-preserved in the soil. In addition, based on the analysis, at least one of the sites was likely used for illicit distillation.
picture that illustrates the research done
Scientific abstract (pdf 3K)     For more info or full text, mail to: B.Jansen@uva.nl

J. Groot
Master programme: Geo-ecological Dynamics June 15th, 2018
Institute: IBED Research group: Computational Geo-Ecology Graduation thesis Supervisor: A.C. Seijmonsbergen
photo of the author
Reedbed Identification and Temporal Signature Analysis Using Sentinel-1 Time Series in the Google Earth Engine
Since 1900 more than 50 percent of global wetlands has disappeared due to anthropogenic causes. To assess the current status and extent of wetlands a scalable method based on radar satellite data was developed. This method used existing annotation data to train a random forest classifier to identify reedbed vegetation. The method was tested on lake Balaton in Hungary and applied to several areas within Europe with very promising results.
picture that illustrates the research done
Scientific abstract (pdf 1K)     For more info or full text, mail to: a.c.seijmonsbergen@uva.nl

F.J.W. Vlaar
Master programme: Geo-ecological Dynamics May 21st, 2018
Institute: IBED Research group: Ecosystem & Landscape Dynamics Graduation thesis Supervisor: Dr. L.H. Cammeraat
Soil water repellency along a lime poor and lime rich chronosequence in the Luchterduinen, the Netherlands
Soil water repellency (SWR) and how it is influenced by vegetation succession and lime content is studied in the Luchterduinen. This area contains a lime rich and lime poor soil-vegetation chronosequence as a result of dune blowouts that have been stabilized randomly over the past 100 years. Soil samples were taken at 0-5 and 5-15 cm depth and SWR was measured using the water drop penetration time (WDPT) test, sessile drop (SD) test and molarity of an ethanol droplet (MED) test. The main conclusion of this study is that SWR increases with vegetation succession but it does not significantly differ between the lime poor and lime rich chronosequence. The WDPT and MED method also indicate a decrease in SWR over depth. Another finding is that the results of the three SWR methods are comparable. Furthermore, pH, soil organic matter, lime content and plant species and cover were included to have a more detailed understanding of SWR development. All soil properties correlate significantly (weak to very strong) to the three SWR methods and soils underneath Dicranum scoparium, mosses, lichen, grasses, herbs and plants with a symbiotic relationship with Vesicular Arbuscular Mycorrhizal (VAM) fungi correlate significantly with SWR.
picture that illustrates the research done
Scientific abstract (pdf 2K)     For more info or full text, mail to: l.h.cammeraat@uva.nl

J. Steenvoorden
Master programme: Geo-ecological Dynamics April 9th, 2018
Institute: IBED Research group: Computational Geo-Ecology Graduation thesis Supervisor: Daniel Kissling
photo of the author
Assessing the Ecological Importance of Unburned Islands in the Conservation and Management of Wildlife Species: a Case Study on Greater Sage-Grouse Populations in the Sagebrush Ecosystems of South-Eastern Oregon
In this thesis, I assessed the effect of unburned islands (wildfire refugia) on the population dynamics of the greater sage-grouse, a bird of conservation concern in the Great Basin of North America. First, I assessed the effect of unburned islands on sage-grouse population dynamics after fire in comparison to burned areas using yearly male counts on mating locations (leks). Second, I evaluated the effect of post-fire habitat composition on the population recovery and persistence of these populations, to find out if certain habitat characteristics could explain patterns in population dynamics after fire.
picture that illustrates the research done
Scientific abstract (pdf 5K)     For more info or full text, mail to: W.D.Kissling@uva.nl

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