The study was performed on 24 localities throughout Socotra Island to approach the threatened tree species of Dendrosicyos socotrana (DS, Cucumber tree), its population and regeneration. 14 localities out of these localities contain DS individuals. This survey studied the land-cover classes of High Shrubland with Succulents, Low Croton-Jatropha Shrubland, Sparse Dwarf Shrubland, Wadies, Submontane Grassland, Submontane Shrubland, Frankincense Woodland, Dracaena Woodland, Urban land, Date Palm Plantation, and Frankincense Forest. Studied localities form an area of 96 square kilometres and 204 individuals have been found (excluding seedlings). The basic measurement of specimens had been taken (height, GBH, fertility and coordinates) as well as collected data about biotope site and regeneration. Regeneration occurred approximately on 36 % of all localities. Dendrosicyos socotrana could be fertile on height of 2 m. The estimation of total number of DS population on Socotra Island could be 8 113 individuals. It is conspicuously showing that High Shrubland with Succulents and Wadies are the best habitat for Dendrosicyos socotrana, the reason is that the northern-slopes and wadies protect Dendrosicyos socotrana from the strong monsoon wind in the Island. As for others land-cover, DS species prefers wind-protected locations. In conclusion the DS population are decreasing in whole Island and I am suggesting to seek for a solution for this unique species.

This masters thesis deals with the longterm changes of forest and nonforest woody vegetation in the area of the former Děčín estate. For my analysis I have used the avalaible historical maps and modern ortophotographs, which I have processed using the ArcGIS software. While many places of the Earth are going through deforesation, on the other hand in Europe there is a significant rise in the area covered by woodlands. I have come to the same results in my thesis, in which at the studied site, in which there was an expansion of forest woody vegetation between the years 1953 and 2015. While when comparing the map of The Stabile cadaster and an aerial image from 1953 there was a decrease of forest woody vegetation. These results pary correlate with the demographic development of the Děčín district as well as general political and economic development of the area in the analyzed time period. The results are compared to similar avalaible studies, on the base of which it seems that the resukts of this study are not a unique trend.

This diploma thesis follows up the influence of horizontal and vertical structure of biotopes on biodiversity of bird species of Czech Republic of forest and open sites. Vertical structure model was created from digital model of surface of Czech Republic (1st generation) and digital model of relief of Czech Republic (5th generation). Information about horizontal structure were derived by analyzing aerial imagery. Then single variables were detected from these data. Subsequently, it was analyzed which of these variables and which way influence bird diversity. On both types of sites was found increasing bird diversity with increasing diversity of vertical structure. With increasing horizontal structure, however, bird diversity significantly increased only on open sites. The influence of other characteristics was mostly different on bird diversity of open and forest sites, but, for both types of sites, the positive influence had for example edge density of land cover categories or edge density of height categories. Additional part of this thesis was to explore if vertical characteristics of biotopes could influence prediction of selected bird species. Results was different in forest and open biotopes, nevertheless in both types of sites was found potential use of both horizontal and vertical variables.

The aim of this thesis is to evaluate whether connectivity indices are usable for bird prediction. The study area contains of the whole country but is divided into separate squares with area of 133 km 2 each, where the presence or absence of the bird species is known. The dependence is tested on landscape connectivity indices presented by prof. S. Saura. The land cover contains of Corine land cover 2012 data. The results will be evaluated with logistic regression approach on sample data including 4 different dispersal distances (500 m, 1 000 m, 2 000 m and 3 000 m) and 10 specific bird species typical for given land cover. The corelation between land cover area presence of the bird is also tested.

Ecosystem services are the benefits people obtain from ecosystems. Quantifying these benefits and understanding how they may change under multiple future pressures, such as climate change or land use change, is a highly uncertain exercise. In managing ecosystems to be resilient to future changes, natural resource managers need the most accurate information available, but also need to be informed of when and where they can be confident, or not, in projections of change. In this thesis, I address many of the key aspects of uncertainty in projections of change in ecosystem services, with a particular focus on challenges in West Africa. I show where and for what variables climate models may be reliably used in ecological studies, providing important advice for interpreting the impacts of climate change on biodiversity. Furthermore, I show that uncertainty in climate observations can also have a significant impact on climate change adaptation decisions at both the species level and in terms of protected area management. I also address how vegetation in West Africa may respond to future climate change. I found that even after uncertainties in climate and land use were considered, carbon storage in West African tropical forests was projected to increase where forest degradation remained low or reduced; vegetation productivity was projected to increase in all parts of West Africa, with the exception of locations in the West Sahel where the largest reductions in precipitation were projected; and, importantly for protected areas, ecosystems were projected to shift northwards despite uncertainty in precipitation projections. I also show the sensitivity of 3 major land surface models to uncertainty in vegetation mapping, thereby providing guidance to the remote sensing community on priorities to improve land cover mapping and to the earth system modelling community on bounds of uncertainty in carbon, moisture and energy budgets due to vegetation mapping uncertainties. Lastly, in using the latest land-atmosphere coupled convection-resolving model, I show that it is possible to simulate the observed interaction between landscape heterogeneity and local and regional scale precipitation in West Africa. This provides a timely and relevant tool that will allow scientists and natural resource managers to more accurately assess the impact of changes in land use on the regional climate of West Africa.

Made available in DSpace on 2014-06-11T19:22:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-16Bitstream added on 2014-06-13T18:49:03Z : No. of bitstreams: 1 prado_fa_me_prud.pdf: 2522184 bytes, checksum: a4acb46054fde8c9233bacf1d5c21128 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Os mapeamentos da cobertura da terra apresentam o relevante papel de permitir avaliar as alterações na paisagem provocadas pela ação antrópica e fornecer importantes informações para o manejo eficiente dos recursos naturais constituindo-se, assim, em ferramentas essenciais para o planejamento regional e urbano. Entretanto, os atuais mapeamentos atendem a propósitos muito específicos e, conseqüentemente, são limitados na sua capacidade de definir a ampla variedade de tipos existentes de cobertura da terra. Nesse contexto, a proposta central desta pesquisa é desenvolver um sistema hierárquico de classificação, amplo e abrangente, partindo de um nível generalizado de definição de classes de cobertura da terra, para mapeamentos em escala regional, e especializando essas classes para ambientes urbanos. Para cada escala de mapeamento é proposta a nomenclatura das classes e os critérios usados para defini-las. Um estudo de caso é desenvolvido para testar o sistema hierárquico em dois níveis de detalhamento distintos, nas escalas regional e urbana, e são utilizadas diferentes abordagens de classificação multiespectral para extrair as informações temáticas de interesse a cada nível de aplicação... / Land cover mappings present the relevant role of allowing to evaluate the changes in the landscape caused by the man's action and to supply important information for the efficient handling of the natural resources. Thus, those are essential tools for the regional and urban planning. However, current mappings are related to very specific purposes and, consequently, they are limited in their capacity to define the wide variety of existent types of land cover. In that context, the main proposal of this research is to develop a wide and including hierarchical classification system, starting from a generalized level of definition of land cover classes for mappings in regional scale and specializing those classes for urban environment. It is proposed the nomenclature of the classes and the criteria used to define them for each scale of mapping. A study case is developed to test the hierarchical system in two detailing levels, in the regional and urban scales, and different approaches of multispectral classification are used to extract the thematic information of interest to each application level... (Complete abstract click electronic access below)

abstract: The partitioning of available solar energy into different fluxes at the Earth's surface is important in determining different physical processes, such as turbulent transport, subsurface hydrology, land-atmospheric interactions, etc. Direct measurements of these turbulent fluxes were carried out using eddy-covariance (EC) towers. However, the distribution of EC towers is sparse due to relatively high cost and practical difficulties in logistics and deployment. As a result, data is temporally and spatially limited and is inadequate to be used for researches at large scales, such as regional and global climate modeling. Besides field measurements, an alternative way is to estimate turbulent fluxes based on the intrinsic relations between surface energy budget components, largely through thermodynamic equilibrium. These relations, referred as relative efficiency, have been included in several models to estimate the magnitude of turbulent fluxes in surface energy budgets such as latent heat and sensible heat. In this study, three theoretical models based on the lumped heat transfer model, the linear stability analysis and the maximum entropy principle respectively, were investigated. Model predictions of relative efficiencies were compared with turbulent flux data over different land covers, viz. lake, grassland and suburban surfaces. Similar results were observed over lake and suburban surface but significant deviation is found over vegetation surface. The relative efficiency of outgoing longwave radiation is found to be orders of magnitude deviated from theoretic predictions. Meanwhile, results show that energy partitioning process is influenced by the surface water availability to a great extent. The study provides insight into what property is determining energy partitioning process over different land covers and gives suggestion for future models. / Dissertation/Thesis / M.S. Civil and Environmental Engineering 2012

Repeat photography, the process of retaking an existing photograph from the same vantage point, can give insight into long-term land cover dynamics. I advance the use of repeat photography to quantify landscape change in two ways: first, I demonstrate that rigorous field and post-processing methods can lead to highly accurate co-registration of images; second, I show that oblique photographs can provide land cover composition information similar to conventional satellite (Landsat) imagery for dominant land cover types, and that oblique photographs are better at resolving narrow or steep landscape features. I then present a novel approach to evaluate long-term biodiversity change using repeat photography: I measure land cover composition in 46 historical and modern photograph pairs in the Willmore Wilderness Park, Alberta, Canada, and use that land cover information as input into species-habitat models to predict the probability of occurrence of 15 songbird species. I show that coniferous forest cover increased over the past century, leading to a homogenization of the landscape which increased the probability of occurrence of forest-adapted species but negatively impacted non-forest-adapted species. / Graduate / 2019-04-18

Validation of global forest change detection databases Abstract The main aim of the thesis is to validate selected databases of changes in forest areas based on the analysis of satellite imagery time series in the Czech Republic. For this purpose we are using databases of M. C. Hansen and P. V. Potapov which are mapping the evolution of forest areas internationally. For the purposes of validation, we have proposed a methodology primarily based on historical ortophotographs from 2000-2012, the same time period which is documented in the validated databases. The results obtained were statistically processed, allowing to assess the accuracy of validated databases. At the end of the thesis, we are discussing the causes of identified inaccuracies and presented with recommendations for future improvements of detection of changes in forest areas. Keywords: validation, forest, land cover, change detection, Hansen, Potapov

Urban areas are responsible for the majority of global anthropogenic CO2 emissions. Urbanization has altered the structure and function of terrestrial ecosystems and is increasing rapidly, further modifying global carbon cycling. The three research papers in this dissertation explore the role of urban vegetation in the carbon cycle using a combination of atmospheric observation, field measurements, remote sensing, and modeling. First, I characterized the spatiotemporal patterns of observed atmospheric CO2 mixing ratios and compared these data to estimated CO2 fluxes at three sites across Boston's urban-to-rural gradient. Total fossil fuel emissions estimates ranged from 1.5 to 37.3 Mg C ha-1 yr-1 between rural Harvard Forest and urban Boston. Despite large differences in emissions, atmospheric CO2 concentrations only differed by approximately 5%. The growing season length in Boston was approximately 31 days longer than in Harvard Forest, enhancing the period for biological carbon uptake. In Boston, gross primary production was 3.8 Mg C ha-1 yr-1, which was ~75% lower than gross primary production at Harvard Forest and ~10% of total anthropogenic carbon fluxes in Boston. Second, I assessed how forest-to-urban land cover change affected both aboveground biomass and productivity across eastern Massachusetts. I found that urban land covers contained less than half the biomass of adjacent forests, but the mean basal area increment of existing trees nearly doubled with development over time from 17.1 ± 3.0 to 35.8 ± 4.7 cm2 yr-1. Scaling this increase in growth suggests an aboveground biomass growth rate of 1.8 ± 0.4 Mg C ha-1 yr-1, a rate similar to that found in Harvard Forest, despite having only ~1/3 the standing aboveground biomass. Last, I assessed how above- and belowground ecosystem characteristics changed as a function of time since development and development intensity. I found that soil C and aboveground biomass showed significant differences with time since development. My data suggests that soil C, N, and bulk density are dependent on land use history, with previously agricultural sites consistently showing higher rates of soil N and C accumulation than previously forested and grassland sites. Taken as a whole, this dissertation highlights the potential consequences of altered ecological and environmental conditions on tree growth, the legacy effects of land use history, climate, and land management practices on below ground soil C and N, and the importance of vegetation in the C cycle in urban areas.