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Influences of Mountainside Residential Development to Nutrient Dynamics in a Stream NetworkLin, Laurence Hao-Ran 16 December 2013 (has links)
Forested mountain watersheds provide essential resources and services (e.g., water supply) to downstream ecosystems and human communities. Fast-growing mountainside residential development not only modifies the terrestrial system but also aquatic systems by changing the nutrient input from the terrestrial to aquatic. However, the impacts of mountainside residential development on stream ecosystems are complex because interactions between in- stream process and hillslope soils control in-stream nutrient dynamics, and it is difficult to experimentally study these interactions at broad spatial scales. In my dissertation research, I first developed models for leaf decomposition in a forested headwater stream by synthesizing several important ecological concepts, including ecological stoichiometry, microbial nutrient mining, and microbe-substrate interaction. I then extended the single stream model to a stream network model and further linked the stream network model with a terrestrial model that simulates nutrient processes and hydrology in hillslope soils. With this complete modeling framework, I conducted a global sensitivity analysis to evaluate the importance of terrestrial nutrient input versus in-stream processes in modifying nitrogen export. I also conducted a simulation to investigate the impacts of housing density, buffer zone protection, and stream travel distance from the residential development to the catchment outlet on nitrogen export at the local and regional scale. The model for leaf decomposition performed better for predicting detritus decay and nutrient patterns when microbial groups were divided into immobilizers and miners and when leaf quality was included as a variable. The importance of terrestrial nutrient input versus in-stream nutrient processes greatly depended on the level of terrestrial nutrient input. When terrestrial nitrate input was low, nitrogen export was more sensitive to in-stream net microbial nitrogen flux (mineralization - immobilization) than nitrate input. However, when terrestrial nitrate input was high, nitrate input was more important than in-stream net nitrogen flux. Greater impacts, i.e., higher nitrogen export at the local scale or greater change in nitrogen export at the regional scale, were associated with higher residential density, a lack of buffer zone protection, and shorter stream travel distance from the residential development to the catchment outlet. Although subject to model assumptions and further validation through field experiments, this research provides a general modeling framework for in-stream processes and aquatic-terrestrial linkages and expands an understanding of interactions between terrestrial and in-stream nitrogen dynamics and the impacts of mountainside development on stream ecosystems, identifies directions for further research, and provides insights for land and river management in mountainous areas. / Ph. D.
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Relations between Landscape Structure and a Watershed's Capacity to Regulate River FloodingMogollon Gomez, Beatriz 03 November 2014 (has links)
Climate and human activities impact the timing and quantity of streamflow and floods in different ways, with important implications for people and aquatic environments. Impacts of landscape changes on streamflow and floods are known, but few studies have explored the magnitude, duration and count of floods the landscape can influence. Understanding how floods are influenced by landscape structure provides insight into how, why and where floods have changed over time, and facilitates mapping the capacity of watersheds to regulate floods. In this study, I (1) compared nine flood-return periods of 31 watersheds across North Carolina and Virginia using long-term hydrologic records, (2) examined temporal trends in precipitation, stream flashiness, and the count, magnitude and duration of small and large floods for the same watersheds, and (3) developed a methodology to map the biophysical and technological capacity of eight urban watersheds to regulate floods. I found (1) floods with return periods ≤ 10 years can be managed by manipulating landscape structure, (2) precipitation and floods have decreased in the study watersheds while stream flashiness has increased between 1991 and 2013, (3) mapping both the biophysical and technological features of the landscape improved previous efforts of representing an urban landscape's capacity to regulate floods. My results can inform researchers and managers on the effect of anthropogenic change and management responses on floods, the efficacy of current strategies and policies to manage water resources, and the spatial distribution of a watershed's capacity to regulate flooding at a high spatial resolution. / Master of Science
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A multiscale analysis and quantification of human impacts on Sumatran tiger (Panthera tigris sumatrae) habitat in Riau, SumatraPoor, Erin Elizabeth 25 September 2018 (has links)
Worldwide, we are losing biodiversity at unprecedented rates, and due to deforestation, degradation and poaching, Southeast Asian wildlife is facing extreme threats. Indonesia recently eclipsed Brazil in having the world's highest deforestation rate, largely due to the rise of the palm oil industry. Indonesia contains multiple biodiversity hotspots and endangered species such as the Sumatran tiger (Panthera tigris sumatrae). While Riau Province, Sumatra, produces approximately 20% of the world's palm oil, tigers still inhabit parts of Riau, though their habitat and prey are understudied. Thus, in this research, I aim to assess and quantify how tiger habitat has changed, how it will continue to change, and provide recommendations on how to improve the landscape for tigers. I create the first accuracy-assessed land cover maps of Riau, and then predict land cover change from 2016 – 2050. Using this newly created land cover map, I assess whether Tesso Nilo National Park, Bukit Tigapuluh National Park, and Rimbang Baling Wildlife Reserve are effective at preventing deforestation. Next, I examine human impacts within Tesso Nilo specifically, due to its suitability for oil palm and its potential as a stepping stone for wildlife movement from the western, mountains to the eastern peatlands of Sumatra. Finally, I examine impacts of human presence within Rimbang Baling on felid-prey relationships. I predict that by 2050, over 60% of natural forest in Riau will be lost, and all protected areas only confer low levels of protection. I determined that Tesso Nilo National Park has nearly 2500 km of roads within it and no areas within the park are untouched by humans. Wildlife detections were low near the boundary of Rimbang Baling and there was evidence of humans negatively impacting mousedeer (Tragulus spp) behavior. I suggest focusing on securing the habitat within Rimbang Baling and Bukit Tigapuluh to ensure habitat for dispersing tigers from the western mountains, in addition to, and perhaps before focusing on restoring Tesso Nilo and creating wildlife corridors. While tiger recovery in Riau will be difficult, with education, dedication, persistence and intelligent planning, tigers may be able to persist in this unique ecosystem in the long-term. / Ph. D. / Worldwide, we are losing plants and animals at unprecedented rates, and due to deforestation, degradation and poaching, Southeast Asian wildlife is facing extreme threats. Indonesia recently passed Brazil in having the world’s highest deforestation rate, largely due to the rise of the palm oil industry. Indonesia has a wide diversity of plants and animals, including endangered species such as the Sumatran tiger. While Riau Province, Sumatra, produces approximately 20% of the world’s palm oil, tigers still inhabit parts of Riau, though their habitat and prey are understudied. Thus, in this research, I aim to assess how tiger habitat has changed, how it will continue to change, and provide recommendations to improve the landscape for tigers. I create the first land cover maps of Riau that have been verified with field data, and then predict land cover change from 2016 – 2050. Using this land cover map, I assess whether Tesso Nilo National Park, Bukit Tigapuluh National Park, and Rimbang Baling Wildlife Reserve are effective at preventing deforestation. Next, I examine human impacts within Tesso Nilo, due to its soil characteristics making it suitable for oil palm and its potential as habitat for wildlife movement from the western, mountains to the eastern swamps of Sumatra. Finally, I examine impacts of humans within Rimbang Baling on wild cat-prey relationships. I predict that by 2050, over 60% of forest in Riau will be lost, and all protected areas only provide slight protection. I determined that Tesso Nilo has nearly 2500 km of roads within it and no areas within the park are untouched by humans. Wildlife sightings were low near the boundary of Rimbang Baling and there was evidence of humans negatively impacting tiger prey behavior. I suggest focusing on securing the forests within Rimbang Baling and Bukit Tigapuluh to ensure forest for tigers that may come from the western mountains, in addition to, and before focusing on restoring Tesso Nilo and creating wildlife movement areas. While tiger recovery in Riau will be difficult, with education, dedication, persistence and intelligent planning, tigers may be able to persist in this unique ecosystem in the long-term.
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Impacts of Land Use and Land Cover Changes, and Climate Variability on Hydrology and Soil Erosion in the Upper Ruvu Watershed, TanzaniaMbungu, Winfred Baptist 10 January 2017 (has links)
Land alterations including deforestation, unsustainable land management practices and an increase in cultivated areas have occurred in the Upper Ruvu watershed in recent decades threatening water and natural resources. This study, which used a combination of remote sensing techniques, field experiments, watershed monitoring, and modeling was designed to investigate impacts of environmental changes on hydrology and soil erosion. The objectives were to: map the extent of land use and land cover change and its influence on soil erosion; correlate the contribution of climate variability and human activities to the changes in hydrology at headwater and watershed scales; estimate surface runoff, sediments and Curve Number at plot scale, and model streamflow responses to changes in land use and land cover using the SWAT watershed model. Results indicate that areas covered by forest decreased from 17% in 1991 to 4% of the total watershed area in 2015. However, areas covered by cropland increased from 14% to 30% of the total watershed area from 1991 to 2015, respectively. Further, results indicate that site characteristics affect runoff and sediment yield as higher soil loss was estimated from cropland with a mean of 28.4 tha-1 in 2015 from 19.8 tha-1 in 1991. Results from monitoring show high sediment loads were from the most disturbed watersheds, compared to Mbezi. Analysis of trends for the long term records at the watershed showed that rainfall had significant decreasing trends. At annual scale, climate variability contributed 46% and human activities contributed 54% of the changes in streamflow. Results from the rainfall simulation experiments show upland rice had higher runoff (48 mmh-1) and soil loss (94 gm-2) compared to grassland and forest. Results from the model outputs showed that average streamflow decreased by 13% between 1991 and 2015. Average peak flows increased by 5% and 12% for 2000 and 2015, respectively compared to the baseline. Land alterations had impacts on surface runoff which increased by 75% and baseflow decreased by 66% in 2015 from the baseline. These results highlight the main areas of changes and provide quantitative information to decision makers for sustainable land and water resources planning and management. / Ph. D.
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Understanding the relationship between land use/land cover and malaria in NepalBhattarai, Shreejana 02 July 2018 (has links)
Malaria is one of the leading causes of mortality and morbidity globally. Land use/land cover (LULC) change have been found to affect the transmission and distribution of malaria in other regions, but no study has attempted to examine such relationships in Nepal. Therefore, this study was conducted in Nepal to assess LULC change between 2000 and 2010, to study the spatial and temporal trend of malaria incidence rate (MIR) between 1999 and 2015, and to understand the relationship between LULC and malaria. The land cover types used for this study are forest, water bodies, agriculture, grassland, shrubland, barren areas, built-up areas and paddy areas. Change detection techniques were used to study LULC change. The temporal trend of MIR in 58 districts, and the relationship between MIR and LULC were evaluated using Poisson and negative binomial regression. Forest, water bodies, snow cover, and built-up area increased in Nepal by 28.5%, 2.96%, 55.12% and 21.19% respectively while the rest of the LULC variables decreased. MIR decreased significantly in 21 districts; however, four districts namely Pyuthan, Kaski, Rupandehi and Siraha had a significantly increasing trend of MIR. During 2001, 2002, and 2003, MIR was positively related to water bodies and paddy areas. Similarly, MIR of 2010 was negatively related to grassland. However, there was no relationship between LULC and MIR in 2000, 2011, 2012 and 2013. It may be because MIR is decreasing significantly in the country and thus the influence of LULC change is also decreasing. / MS
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Spatial Patterns on Virginia's Second Highest Peak: Land Cover Dynamics and Tree Mortality in Two Rare EcosystemsHarris, Ryley Capps 12 June 2020 (has links)
Whitetop Mountain is Virginia's second highest peak and hosts two globally rare, insular ecosystems: a southern Appalachian grass bald and a red spruce-dominated forest. These areas provide important ecosystem services and habitat for rare and endangered species. They are highly prized for their cultural value and recreational areas that support nearby rural economies. This thesis investigated spatial patterns in both ecosystems on Whitetop. We documented a 24.73% decrease of in the extent of the southern Appalachian grass bald across 68 years through analysis of historical aerial photography. In the red spruce-dominated forest, we used a consumer grade unmanned aerial vehicle (UAV) to survey the health of all trees within a 46 ha sample plot. We assessed (dead, dying, healthy) over 9,000 individual trees based on visual patterns in the imagery and produced spatial products that will inform land managers about where resources are most needed. About 7.4% of the red spruce trees in our study area were classified as dead or dying. A model relating spruce mortality to biophysical landscape factors identified no single predictive factor related to mortality. The addition of optical information from the UAV imagery into the model proved utility for remotely-sensed data in identification of dead spruce within the forest canopy at Whitetop and possibly in other similarly structured forests. This research contributed to the limited body of knowledge surrounding the decline of both southern Appalachian grass balds and red spruce forests and provided technical insights for future mortality monitoring. / Master of Science / This thesis investigates land cover changes in two rare ecosystems on Whitetop Mountain, Virginia. The mountain has important biological significance and is a cultural landmark. The high-elevation summit hosts plant and animal species characteristic of northern climates, including a red spruce-dominated forest and a southern Appalachian grass bald. This work documented a 24.73% decrease in the size of the rare southern Appalachian grass bald ecosystem at Whitetop Mountain over 68 years and discussed potential drivers and proposed management for conservation. We also successfully used a camera-equipped unmanned aerial vehicle (drone) to produce high quality imagery for spruce mortality detection within the red spruce forest. Of over 9,000 standing spruce trees, 7.4% were categorized as either dead or dying. We built a predictive model to investigate the relationship between mortality and biophysical environmental factors, but did not identify a single causal factor. A second model that included the color band information from the drone camera revealed that different types of aerial imagery could play a valuable role in detection of tree mortality in forests of similar structure. Overall this research contributes to the body of knowledge surrounding the decline of both southern Appalachian grass bald and red spruce ecosystems and provides insights for management.
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Terrestrial ecosystem impacts on air qualityWong, Yik Hong 16 July 2024 (has links)
The terrestrial ecosystem is an integral component of the Earth System. Constant atmosphere-biosphere exchanges of energy and material affect both the physics and chemistry of the atmosphere. While the general roles of terrestrial ecosystems in regulating ozone and particulate matter air pollution have long been acknowledged, our understanding at both individual process and system level are far from perfect. Also, new process-level discoveries about terrestrial atmosphere-biosphere exchanges are not timely incorporated in numerical models routinely used to study and forecast air quality. These hinder our ability to understand how air quality respond to environmental changes and variabilities. Chapter 1 of this dissertation provides a brief overview on these topics.
In Chapter 2 of this dissertation (Wong et al., 2019), we conduct global long-term simulations of ozone dry deposition velocity with four different types of dry deposition parameterizations. We find that none of the tested parameterizations universally stands out in terms of matching observed ozone deposition velocity over different land cover types. Combining this with sensitivity simulations from a global 3-D atmospheric chemistry model (GEOS-Chem), we find that the choice of dry deposition parameterizations can affect the mean, trend and variability of simulated surface O3 level.
In Chapter 3 of this dissertation (Wong et al., 2022), we analyze long-term ozone flux observation from three field sites to examine the effects of extreme heat and dryness on ozone deposition. We find that non-stomatal ozone uptake tends to increase during hot days, which either partially offsets or dominates over the reduction in stomatal ozone uptake anticipated by ecophysiological theory. While the response of ozone deposition to dryness is more varied, changes in non-stomatal deposition are usually important. Current dry deposition parameterizations often fail to capture such changes in non-stomatal ozone uptake, resulting in considerable potential error in simulated surface ozone level during hot and dry days.
In Chapter 4 of this dissertation (Wong and Geddes, 2021), we conduct global GEOS-Chem numerical experiments with anthropogenic emission inventories and land surface remote sensing products to compare the effects land cover versus land management changes on O3 and fine particulate matter air quality over 1992 – 2014. We find that land cover has stronger effects on O3, while land management has stronger effects on fine particulate matter pollution. We also find that land management has significantly altered regional and global nitrogen deposition, and therefore the risk of critical load exceedance.
Chapter 5 of this dissertation includes the concluding remarks and suggestions for future work. In addition, I outline and present the preliminary result from a project examining the future of soil reactive nitrogen emissions and their impacts on air quality.
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Typologie změn krajinného pokryvu a jeho struktury v postkomunistických státech Střední Evropy / Typology of land cover changes and landscape structure in the post-communist countries of the Central EuropeKuna, Petr January 2013 (has links)
Study of landscape change is a subject of interest for a wide range of professional work both in the Czech republic and abroad. This thesis therefore does not give a simple description of the changes in the landscape, but rather focuses on the further synthesis of these findings and the subsequent creation of a typology of land cover changes and their impacts on landscape structure in the region of interest, including also its heterogeneity. It is therefore a process of allocated areas that formed and still form the same processes that lead to homogenization of the landscape, as opposed to its fragmentation. Area of interest is so-called Visegrad Group of countries (Czech Republic, Slovakia, Hungary and Poland). There are four countries of the former Eastern bloc in Central Europe, which shared some relatively similar initial conditions for the further development of the landscape after the "release" of the regime change in 1989. The landscape began to develop in different way. Each country began a different way to approach a completely different landscape interfering in its development. Review starts with describing landscape development in the period up to 1989, when it was not too taken of the ecological functions and the importance of the landscape. This period was characterized by the...
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Land cover, land use and habitat change in Volyn, Ukraine : 1986-2011Anibas, Kyle Lawrence January 1900 (has links)
Master of Science / Department of Geography / Douglas G. Goodin / Volyn Oblast in Western Ukraine has experienced substantial land use/land cover change over the last 25 years as a result of a change in political systems. Remote sensing provides a framework to quantify this change without extensive field work or historical land cover records. In this study, land change is quantified utilizing a post-classification change detection technique comparing Landsat imagery from 1986-2011(Post-Soviet era began 1991). A variety of remote sensing classification methods are explored to take advantage of spectral and spatial variation within this complex study area, and a hybrid scheme is ultimately utilized. Land cover from the CORINE classification scheme is then converted to the EUNIS habitat classification scheme to analyze how land cover change has affected habitat fragmentation. I found large scale agricultural abandonment, increases in forested areas, shifts towards smaller scale farming practices, shifts towards mixed forest structures, and increases in fragmentation of both forest and agricultural habitat types. These changes could have several positive and negative on biodiversity, ecosystems, and human well-being.
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Analyse de la détérioration de la forêt de la Cordillère de la Costa dans le sud chilien : géomatique et modélisation prospective appliquée sur une forêt patrimoniale de la province d'Osorno (41º 15’ - 41º 00’ latitude Sud) / Analysis of the deterioration of forest in the Cordillera de la Costa in southern Chile : geomatics and prospective modeling applied to a national forest in the province of Osorno (41°15' - 41°00' south latitude)Toro Balbontin, Darío 08 September 2014 (has links)
On étudie une zone de la Cordillère de la Costa au sud du Chili (41°15'S-41°00'S), habitée par l'ethnie Mapuche. Là, il y a encore des précieuses forêts tempérées, qui ont une haute priorité de conservation au plan mondial. Mais, il est constaté, un processus continu de transformation lié à l'extraction de bois de chauffe, l'élevage extensif, la perturbation de l'habitat du conifère Fitzroya cupressoides, et le déploiement des plantations forestières. Sur la base d'une classification multi-temporelle d'images satellite, une modélisation spatio-temporelle a été mise en œuvre pour comprendre et anticiper la dynamique de la détérioration de la forêt. L'analyse rétrospective révèle qu'entre 1976 et 2008, la forêt a été réduite 12400 ha, soit un taux de déforestation 0,25% par an. 20 modèles de déforestation sont calibrés, 4 d'entre eux sont sélectionnés pour construire des scénarios prospectifs. La simulation prévoit que la diminution de forêt entre 2008 et 2040 pourrait atteindre 13000 ha. Deux autres modèles mis en œuvre simulent l'évolution de la qualité de l'habitat de F. cupressoides. Les scénarios prévoient une augmentation de la surface détériorée ; l’extrapolation à partir de la période d’apprentissage 2001-2008 pendant laquelle la plus grande part de terres indigènes a été légalisée, par rapport à la période précédente à 2001, prédit une augmentation plus significative de la surface détériorée. On fournit un outil pour amplifier la gestion territoriale des systèmes environnementaux toujours non incorporée dans la planification chilienne. Enfin, la thèse met également d'intéressantes comparaisons entre modèles qui diffèrent par rapport aux paramètres de calibration. / SAn area of the Cordillera de la Costa is studied in southern Chile (41°15'S - 41°00'S), inhabited by ethnic Mapuche. There are still valuable temperate forests that have high conservation priority worldwide. But it is found, a continuous process of transformation related to the extraction of firewood, ranching, disruption of habitat conifer Fitzroya cupressoides, and deployment of forest plantations. Based on a multi-temporal satellite images classification, a spatial-temporal modeling was implemented to understand and predict the dynamics of the deterioration of the forest. Retrospective analysis revealed that between 1976 and 2008, the forest has been reduced 12,400 ha, a deforestation rate of 0.25% per annum. 20 models of deforestation are calibrated, 4 of them are selected to construct scenarios. The simulation predicted that reductions of forest between 2008 and 2040 could reach 13,000 ha. Two other models implemented simulate changes in habitat quality F. cupressoides. Scenarios predict an increase in the damaged surface; extrapolating from the learning period 2001-2008 during which the largest share of indigenous lands was legalized, compared with the previous period to 2001, predicts a significant increase in the damaged surface. In this way, it provides a tool to enhance the local management of environmental systems still not incorporated into the Chilean planning. Finally, the thesis also makes interesting comparisons between models that differ with respect to the calibration parameters.
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