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Kuang, Yan. "Modeling and analysis of competing dynamic ecological systems." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/35555.
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Doctor of PhilosophyDepartment of Industrial & Manufacturing Systems Engineering
David H. Ben-Arieh
The dynamic relationship between competing ecological systems has long been and will continue to be one of vital topics in both ecology and mathematical ecology because of its importance and universal existence. Mathematical modeling has become an effective tool to model and simulate the dynamic system, providing decision makers with strategy recommendations. Although a great amount of previous work has attempted to model the biological mechanisms including dispersal, only rarely has there been a systematic investigation on different spatial effects. The author introduces spatial games as a modeling approach with different constructions towards different dynamic systems in order to benefit from the systematic research on spatial dynamics when studying the competing ecological systems. This research developed models of two systems: (1) two-spotted spider mite prey-predator system; (2) tomato spotted wilt virus (TSWV) and west flower thrips (WFT) vector-borne disease system. For two-spotted spider mite system, the author presented four spatial mathematical models as well as a novel spatial game model to describe the spatial movement of two competing species. For the TSWV-WFT system, a spatial game was introduced to describe the spatial dynamics of adult thrips and the novel model was validated with experimental data. The author also gave suggestions for efficiently controlling the vector-borne disease by performing sensitivity analysis towards parameters. The major contribution of this research is to introduce spatial games as a tool to describe the dynamic schemes in ecological systems. Compared to a traditional dynamic model, a spatial game model is more expressive and informative. This approach uses a payoff function and a movement probability function that can be adjusted based on habits, characteristics and mobility schemes of different competing entities, which has enriched its modeling power. The methodology and modeling approach used in this dissertation can be applied to other competing species dynamic systems, and have a broad impact on research areas related to mathematical ecology, biology modeling, epidemiology, pest control, vector-borne disease control, and ecological decision-making processes.
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Khondkaryan, Lusine. "Ecological niche modeling of rodent and flea species /." [Sedeh Boker, Israel] : Ben-Gurion University of the Negev, 2008. http://aranne5.lib.ad.bgu.ac.il/others/KhondkaryanLusine.pdf.
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Lin, Yi. "Bayesian spatial and ecological modeling of suicide rates." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/12568.
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Suicide and suicide attempts constitute major public and mental health problems in many countries. The risk factors of suicide
include not only psychological and other individual features but also the characteristics of the community in which the people live. Therefore, in order to better understand the potential impacts of community characteristics on suicide, the regional level effects of suicide need to be thoroughly examined.
For this thesis, an ecological analysis was incorporated into a Bayesian disease mapping study in order to estimate suicide rates, explore regional risk factors, and discern spatial patterns in suicide risks. Fully Bayesian disease mapping and ecological
regression methods were used to estimate area-specific suicide risks, investigate spatial variations, and explore and quantify the associations between regional characteristics and suicide occurrences. The fact that spatially smoothed estimates of suicide rates highlight the high risk regions can act as stable health outcome indicators at the regional level. Furthermore, regional characteristics explored as potential risk factors of suicide rates can provide a better understanding of regional variations of suicide rates. Both can help in planning future public health prevention programs. In order to avoid multicollinearity among risk factors and reduce the dimensionality of the risk indicators, Principal Component Analysis and Empirical Bayes method (via Penalized Quasi-Likelihood) were applied in variable selection and highlighting risk patterns.
Using 10-year aggregated data for all age groups and both genders, this study conducted a comprehensive analysis of suicide
hospitalization and mortality rates in eighty-four Local Health Areas in British Columbia (Canada). A broad range of regional
characteristics was investigated and different associations with suicide rates were observed in different demographic and gender groups. The major regional risk patterns related to suicide rates across age groups were social and economic characteristics, which include unemployment rates, income, education attainment, marital
status, family structure, and dwellings. Some age groups also showed a relation to aboriginal population, immigrants, and language. The results of this study may inform policy initiatives and programs for
suicide prevention.
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Mak, Sunny Y. "Ecological niche modeling of Cryptococcus gattii in British Columbia." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/31989.
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Cryptococcus gattii unexpectedly emerged on Vancouver Island, British Columbia (BC), Canada in 1999 causing human and animal illness. Prior to its discovery on Vancouver Island, this microscopic fungal organism was limited to tropical and sub-tropical regions of the world with eucalyptus trees as the environmental reservoir. Environmental sampling for C. gattii in southwestern BC has isolated the organism from native vegetation, soil, air and water. Since it is not possible to sample every location for the presence or absence of C. gattii on Vancouver Island or the BC mainland, ecological niche modeling using the Genetic Algorithm for Rule-set Prediction (GARP) was performed to identify the optimal and potential ecological niche areas of C. gattii in BC. Human and animal surveillance and environmental sampling data were used as input data points to build and test the ecological niche models based on 15 predictor environmental data layers (topographic, climatic, biogeoclimatic, and soil). Training and testing accuracy of the C. gattii ecological niche models were 99.4% and 99.2% based on the distribution of human cases, 98.7% and 98.3% based on the distribution of animal cases, and 99.7% and 99.7% based on the distribution of positive environmental sampling locations (p-value <0.0001 for all models). Forecasted optimal C. gattii ecological niche areas in BC include the central and south eastern coast of Vancouver Island, Gulf Islands, Sunshine Coast and Vancouver Lower Mainland. They are characterized by areas of low lying elevations, daily January average temperatures above freezing, and presence within the Coastal Douglas-fir and Coastal Western Hemlock xeric maritime biogeoclimatic zones. The results of these analyses are visualized using Geographic Information Systems, and shared with public health to prioritize future C. gattii environmental sampling in previously unidentified areas and increase public and physician awareness of cryptococcal disease in BC.Arts, Faculty of
Geography, Department of
Graduate
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Lindström, Tom. "Spatial Spread of Organisms : Modeling ecological and epidemiological processes." Doctoral thesis, Linköpings universitet, Teoretisk Biologi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-54839.
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This thesis focuses on the spread of organisms in both ecological and epidemiological contexts. In most of the studies presented, displacement is modeled with a spatial kernel function, which is characterized by scale and shape. These are measured by the net squared displacement (or kernel variance) and kurtosis, respectively. If organisms disperse by the assumptions of a random walk or correlated random walk, a Gaussian shaped kernel is expected. Empirical studies often report deviations from this, and commonly leptokurtic distributions are found, often as a result of heterogeneity in the dispersal process. In the studies presented in two of the included papers, the importance of the kernel shape is tested, by using a family of kernels where the shape and scale can be separated effectively. Both studies utilize spectral density approaches for modeling the spatial environment. It is concluded that the shape is not important when studying the population distribution in a habitat/matrix context. The shape is however important when looking at the invasion of organisms in a patchy environment, when the arrangement of patches deviates from randomly distributed. The introduced method for generating patch distribution is also compared to empirical distributions of patches (farms and old trees). Here it is concluded that the assumptions used for modeling of the spatial environment are consistent with the observed patterns. These assumptions include fractal properties such that the same aggregational patterns are found at different scales. In a series of papers, movements of animals are considered as vectors for between-herd disease spread. The studies are based on data found in databases held by the Swedish Board of Agricultural (SJV), consisting of reported movements, as well as farm location and characteristics. The first study focuses on the distance related probability of contacts between herds. In the following papers, the analysis is expanded to include production type and herd size. Movement data of pigs (and cattle in Paper I) are analyzed with Bayesian models, implemented with Markov Chain Monte Carlo (MCMC). This is a flexible approach that allows for parameter estimations of complex models, and at the same time includes parameter uncertainty. In Paper IV, the effects of the included factors are investigated. It is shown that all three factors (herd size, production type structure and distance related probability of contacts) are expected to influence disease spread dynamics, however the production type structure is found to be the most important factor. This emphasizes the value of keeping such information in central databases. The models presented can be used as support for risk analysis and disease tracing. However, data reliability is always a problem, and implementation may be improved with better quality data. The thesis also shows that utilizing spatial kernels for description of the spatial spread of organisms is an appropriate approach. However, these kernels must be flexible and flawed assumptions about the shape may lead to erroneous conclusions. Hence, the joint distribution of kernel shape and scale should be estimated. The flexibility of Bayesian analysis, implemented with MCMC techniques, is a good approach for this, and further allows for implementation of more complex models where other factors may be included.
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Кубатко, Олександр Васильович, Александр Васильевич Кубатко, and Oleksandr Vasylovych Kubatko. "Modeling the sustainable development with the ecological kuznets curve." Thesis, Видавництво СумДУ, 2009. http://essuir.sumdu.edu.ua/handle/123456789/7908.
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Gilfillan, Dennis, Kimberlee Hall, Timothy Andrew Joyner, and Phillip R. Scheuerman. "Canonical Variable Selection for Ecological Modeling of Fecal Indicators." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/etsu-works/5479.
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More than 270,000 km of rivers and streams are impaired due to fecal pathogens, creating an economic and public health burden. Fecal indicator organisms such as Escherichia coli are used to determine if surface waters are pathogen impaired, but they fail to identify human health risks, provide source information, or have unique fate and transport processes. Statistical and machine learning models can be used to overcome some of these weaknesses, including identifying ecological mechanisms influencing fecal pollution. In this study, canonical correlation analysis (CCorA) was performed to select parameters for the machine learning model, Maxent, to identify how chemical and microbial parameters can predict E. coli impairment and F+-somatic bacteriophage detections. Models were validated using a bootstrapping cross-validation. Three suites of models were developed; initial models using all parameters, models using parameters identified in CCorA, and optimized models after further sensitivity analysis. Canonical correlation analysis reduced the number of parameters needed to achieve the same degree of accuracy in the initial E. coli model (84.7%), and sensitivity analysis improved accuracy to 86.1%. Bacteriophage model accuracies were 79.2, 70.8, and 69.4% for the initial, CCorA, and optimized models, respectively; this suggests complex ecological interactions of bacteriophages are not captured by CCorA. Results indicate distinct ecological drivers of impairment depending on the fecal indicator organism used. Escherichia coli impairment is driven by increased hardness and microbial activity, whereas bacteriophage detection is inhibited by high levels of coliforms in sediment. Both indicators were influenced by organic pollution and phosphorus limitation.
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Gilfillan, Dennis, Kimberlee Hall, Timothy Andrew Joyner, and Phillip Scheuerman. "Canonical Variable Selection for Ecological Modeling of Fecal Indicators." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/etsu-works/5589.
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More than 270,000 km of rivers and streams are impaired due to fecal pathogens, creating an economic and public health burden. Fecal indicator organisms such as Escherichia coli are used to determine if surface waters are pathogen impaired, but they fail to identify human health risks, provide source information, or have unique fate and transport processes. Statistical and machine learning models can be used to overcome some of these weaknesses, including identifying ecological mechanisms influencing fecal pollution. In this study, canonical correlation analysis (CCorA) was performed to select parameters for the machine learning model, Maxent, to identify how chemical and microbial parameters can predict E. coli impairment and F+-somatic bacteriophage detections. Models were validated using a bootstrapping cross-validation. Three suites of models were developed; initial models using all parameters, models using parameters identified in CCorA, and optimized models after further sensitivity analysis. Canonical correlation analysis reduced the number of parameters needed to achieve the same degree of accuracy in the initial E. coli model (84.7%), and sensitivity analysis improved accuracy to 86.1%. Bacteriophage model accuracies were 79.2, 70.8, and 69.4% for the initial, CCorA, and optimized models, respectively; this suggests complex ecological interactions of bacteriophages are not captured by CCorA. Results indicate distinct ecological drivers of impairment depending on the fecal indicator organism used. Escherichia coli impairment is driven by increased hardness and microbial activity, whereas bacteriophage detection is inhibited by high levels of coliforms in sediment. Both indicators were influenced by organic pollution and phosphorus limitation.
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Star, Bastiaan, and n/a. "Space matters : modeling selection in spatially heterogeneous environments." University of Otago. Department of Zoology, 2008. http://adt.otago.ac.nz./public/adt-NZDU20080507.151534.
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Selection in spatially heterogeneous environments is a convenient explanation for the high levels of genetic variation observed in natural populations. Indeed, theoretical studies predict that spatial heterogeneity leads to higher levels of variation in a variety of selection models. These models, however, have assumed quite restrictive parameters (e.g., two alleles, fixed gene flow and specific selection schemes). Therefore, the effect on spatial heterogeneity is still poorly understood for a wider range of parameters (e.g., multiple alleles, different levels of gene flow and more general selection schemes). We have relaxed some of the assumptions that have limited the previous models and studied the effect of spatial heterogeneity using simple single-locus viability selection models.
First, we investigate the rarity of the parts of fitness space maintaining variation for multiple alleles and different levels of gene flow by randomly sampling that space using a "fitness space" approach. The volume of fitness space maintaining variation is always larger in a spatial model compared to a single-population model regardless of gene flow. Moreover, this volume is relatively larger for higher numbers of alleles, indicating that spatial heterogeneity is more efficient maintaining higher levels of variation.
Second, we investigate the ease with which a more natural process of recurrent mutation and selection evolves to the particular area of fitness space maintaining variation using a "construction" approach. Depending on the amount of gene flow, the construction approach leads to both higher and lower levels of variation compared to a single-population model. Thus, spatial heterogeneity can both constrain and promote the ease with which a natural process of mutation and selection evolves to maintain variation. Also, the construction approach results in variation being maintained in a more stable subset of the volume of fitness space than the volume that resulted from the fitness space approach.
Third, we investigate the effect of higher and lower levels of spatial environmental heterogeneity using the construction approach. The different levels of heterogeneity and gene flow interact to influence the amount of variation that is eventually maintained and this interaction effect is especially strong for intermediate levels of gene flow. More heterogeneous environments can maintain higher levels of variation, but selection in these environments also results in a higher level of migration load, lowering the final amount of adaptation that is achieved by the simulated evolutionary process.
Finally, we investigate effect of genetic drift and finite populations using the construction approach. Interestingly, two different effects emerge for smaller and larger populations; in smaller populations genetic drift lowers the amount of variation as expected, whereas, more surprisingly, genetic drift increases the amount of variation in larger populations.
Overall, spatial heterogeneity has profound effects on the outcome of selection, resulting in elevated levels of genetic variation for a wide variety of parameters.
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Zhang, Hongyan. "Ecological modeling of the lower trophic levels of Lake Erie." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1163785412.
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Ward, Gillian. "Statistics in ecological modeling : presence-only data and boosted mars /." May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Ball, George LeRoy. "A spatial dynamic approach to ecological modeling: Simulating fire spread." Diss., The University of Arizona, 1990. http://hdl.handle.net/10150/184986.
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The objective of this dissertation is to develop a new research tool, PROMAP, which will allow the construction of models that satisfy the requirement of spatial distribution and hierarchical interactions within a dynamic framework. An analysis of the form of ecosystems is followed by an examination of current attempts at ecosystem modeling using spatial relationships. An examination of the analytical procedures used in the spatial modeling process, results in a set of criteria that a suitable modeling system should incorporate. These criteria are: the use of real numbers; iterative processing; flexible data retrieval; and neighborhood analytical procedures. The basic configuration of PROMAP is discussed with an emphasis on the mathematical procedures and the capability for designing cellular automata within the system. The representation of biophysical systems into a set of spatial transition functions is described in relation to the development of nested hierarchies called Q-morphisms. Having established the design of PROMAP, a suitable test is devised using the simulation of surface fire spread. A model called FIREMAP is developed and the results are compared to expected fire shapes under Zero State Conditions. These conditions are defined as uniform fuel, zero slope and zero wind with additional factors held constant. Other simulations of fire spread are made by relaxing the conditions to achieve wind driven fires and the response to potential impediments to fire spread. The response of the simulation shows an accurate correspondence between the simulation and the expected fire shape. As a final test of the model, all restrictions are removed and a simulation is made under actual conditions of complex terrain, and non-uniform fuels using data collected on the San Carlos Apache Indian Reservation in southeast Arizona. Deficiencies of PROMAP and FIREMAP are discussed as well as future implications for the FIREMAP model as a management tool.
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Childers, Hope M. "Scale, ecological fallacy, and the river continuum concept." Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1489.
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Thesis (M.A.)--West Virginia University, 2000.Title from document title page. Document formatted into pages; contains vi, 43 p. : ill. (some col.) Vita. Includes abstract. Includes bibliographical references (p. 38-40).
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Schriever, Carola Alexandra. "Modeling ecological risk of runoff for benthic invertebrates in agricultural landscapes /." Leipzig : UFZ, 2007. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=015694027&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
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Sanches, De Oliveira Guilherme. "Scientific Modeling Without Representationalism." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1573571043132428.
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Portela, Rosimeiry G. "Integrated ecological economic modeling of ecosystem services from the Brazilian Amazon rainforest." College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/1958.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2004.Thesis research directed by: Marine-Estuarine-Environmental Sciences. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Willaert, Tom. "Valuation of marine and coastal ecosystems: The role of ecological-economic modeling." Master's thesis, NSBE - UNL, 2014. http://hdl.handle.net/10362/11539.
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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and EconomicsThe main objective of this work project is to highlight the progress made in the field of ecological-economic modeling of marine and coastal ecosystems, in particular, by stressing the need to incorporate more realistic biology as well as the spatial dimension in integrated models for sustainable coastal management. The discussion undertaken is based on a recent application of an integrated ecological-economic model that is spatially explicit by Altman et al. (2012), and should provide guidance to the GOI’s research project to the Peniche-Nazaré study site in the Portuguese coast.
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Elsler, Laura G. "Multi-level Interactions between Fisheries and Trade : Modeling intertwined social-ecological systems." Licentiate thesis, Stockholms universitet, Stockholm Resilience Centre, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-159470.
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Sustainable and equitable fisheries are central for addressing the challenges of the UN Sustainable Development Goal 14: Life Below Water. International trade, once presented by Walrasian economists as a panacea for fisheries development, has not markedly decreased poverty and has been related to the overexploitation of marine species. In this light the consequences of a continued expansion of seafood trade are highly uncertain and problematic. Two competing theoretical hypotheses predict either overexploitation or recovery of marine species when connected to international trade, respectively. The empirical literature finds trade relationships and connections of local fisheries to a large-volume market critical factors for social-ecological outcomes. Here, I combine these insights to show that multi-level links, between fishers & different markets (market manuscript) and marine species & trade relationships (squid manuscript), are critical to explain diverging social-ecological outcomes. In the market manuscript we model the transition from local, to multi-level (both local and global), to global markets in a two species fishery. We find this transition is non-linear, leading to fluctuations in species abundance as a result of abrupt switches between target species. Critical fluctuations of species abundance driven by new market connections are a result of large shifts in prices for one species and high asymmetries in expected income between the two species. The squid manuscript provides empirical and modeling evidence that cyclical changes in the ocean can drive social-ecological systems outcomes through changing interactions at multiple levels. The interactions between squid population and fishers and squid distribution and trading structures determines benefit distributions in the fishery. The lack of consideration of multi-level interactions related to trade in models for fisheries management is likely associated with a lack of processes for integrating the empirical and theoretical insights of two disciplines at the core of fisheries science. Social-ecological system scholars study more often empirical and fishery economics the theoretical aspects of interactions between trade and fisheries. One process suggested in this thesis to bridge insights from both disciplines in fishery models is the careful study of the important interactions in the empirical case. Comparison of these interactions with observed empirical interactions in other systems informs the model conceptualization that is then embedded in a theoretical framework. This leads to the development of models of intermediate complexity that integrate insights on regular structures and patterns observed in real social-ecological systems. The squid manuscript exemplifies this integration. We integrate observed multi-level links in a standard fishery model between the squid population fishers and traders, and thus better represent the empirical system. A continuous dialogue between empirics and theorycan help build models of intermediate complexity. To capture the complex elements of these social-ecological systems, in this young field of study, next to a continuous dialogue priority observed empirical dynamics can help question theoretical assumptions. This study seeks to contribute to the development of fisheries management models more suitable to face contemporary challenges of fisheries management by focusing on how multi-level interactions between fisheries and trade shape sustainable and equitable outcomes.
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Bledsoe, April, Danika Mosher, Mitchell Ogden, Monica Ayala, T. Andrew Joyner Joyner, and Ingrid Luffman. "Ecological Niche Modeling and Sustainable Agroforestry: Climate Change Mitigation for Guatemalan Coffee." Digital Commons @ East Tennessee State University, 2019. https://dc.etsu.edu/asrf/2019/schedule/64.
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Coffea arabica is a species with far-reaching impacts on the global economy. Nevertheless, climate-related challenges threaten the coffee industry at its source: its growing regions. The coffee industry is a significant economic driver in Guatemala, but farmers are increasingly reporting losses in crop yield and arable land due to climate-related challenges. Ecological niche modeling (ENM) can be employed to make predictions about the current and future suitability of regions for a species by identifying significant biotic or abiotic indicators. An ENM was used to project suitable land into the future using climate change projection models known as representative concentration pathways (RCPs), for the coffee plant and a number of other species. Due to the potential of shade trees to lessen heat stress on coffee plants, common shade trees for the region were modeled. Additionally, a fungus species responsible for detrimental coffee leaf rust was modeled. Results of these models indicated potential for substantial climate-related habitat losses for the coffee plant in the coming decades. Examination of model predictions allow for greater understanding of the climate-related variables affecting the ecology of the coffee plant, and the potential risks to the industry, in a changing climate. Additionally, ENM models for coffee rust and shade trees can help Guatemalan farmers make informed decisions about farm management.
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Vasconcelos, Maria Jose. "Modeling spatial dynamic ecological processes with DEVS-Scheme and geographic information systems." Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186257.
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The objective of this work is to introduce and illustrate the potential of discrete event, hierarchical modular models for simulating spatial dynamic ecological processes in geographic information systems (GIS). The knowledge based discrete-event simulation environment (DEVS-Scheme) associates stand-alone discrete event models with spatial locations represented in a GIS data base, and couples those models in a coherent manner. The dynamic models can then process spatially distributed information available in a GIS data base, and update it through time. The models also can receive external updated information at any moment, due to the continuous time nature of discrete event specifications. The proposed approach facilitates the representation of reality at several levels of resolution, with model components organized in a hierarchical structure and information flow implemented in the form of message passing. These capabilities are illustrated with two applications. The first is a multi-scale spatial succession model of a wet sclerophyllous forest subject to recurrent fires, and the second is a fire growth model.
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Bledsoe, April, Danika Mosher, Mitchell Ogden, Monica Ayala, Timothy Andrew Joyner, and Ingrid Luffman. "Ecological Niche Modeling and Sustainable Agroforestry: Climate Change Mitigation for Guatemalan Coffee." Digital Commons @ East Tennessee State University, 2019. https://dc.etsu.edu/asrf/2019/schedule/70.
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Coffea arabica is a species with far-reaching impacts on the global economy. Nevertheless, climate-related challenges threaten the coffee industry at its source: its growing regions. The coffee industry is a significant economic driver in Guatemala, but farmers are increasingly reporting losses in crop yield and arable land due to climate-related challenges. Ecological niche modeling (ENM) can be employed to make predictions about the current and future suitability of regions for a species by identifying significant biotic or abiotic indicators. An ENM was used to project suitable land into the future using climate change projection models known as representative concentration pathways (RCPs), for the coffee plant and a number of other species. Due to the potential of shade trees to lessen heat stress on coffee plants, common shade trees for the region were modeled. Additionally, a fungus species responsible for detrimental coffee leaf rust was modeled. Results of these models indicated potential for substantial climate-related habitat losses for the coffee plant in the coming decades. Examination of model predictions allow for greater understanding of the climate-related variables affecting the ecology of the coffee plant, and the potential risks to the industry, in a changing climate. Additionally, ENM models for coffee rust and shade trees can help Guatemalan farmers make informed decisions about farm management.
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Hernandez, Alexander J. "Spatiotemporal Modeling of Threats to Big Sagebrush Ecological Sites in Northern Utah." DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/957.
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This study tested the performance of classification, regression, and ordination techniques to evaluate the spatiotemporal dynamics of threats to big sagebrush ecological sites. The research was focused on invasion by annual exotic grasses and encroachment by woodlands. We sought to identify those areas that have had a persistent coverage of cheatgrass (Bromus tectorum) in big sagebrush ecological sites. We took advantage of the contrast in greenness between multi-temporal (within one year) remotely sensed vegetation indices captured in the spring and summer to find a distinct phenological signature that allowed mapping cheatgrass. We utilized support vector machines (SVM) to classify three temporal scenarios for which field data sets were available. SVM performed very well with accuracies of 70% (producer's) and 95% (user's) for the class of interest (presence of cheatgrass). This was the focus of chapter 2. In chapter 3 we report the development of vegetation continuous fields (VCF) for three years of interest 1996, 2001, and 2007 in order to detect active woodland encroachment. We prepared VCF for shrubs, trees, herbaceous vegetation, and bare ground using a suite of remotely sensed spectral reflectance, vegetation indices, and transformations. We compared the performance of multivariate regression trees (MRT) and random forests (RF) to develop the VCF multi-temporal series. RF outperformed MRT in both accuracy and ability to appropriately map the continuum of percent cover across large landscapes. We estimate that 17,570 hectares of big sagebrush lands showed encroachment by woodlands. Our goal in chapter 4 was to develop a similarity index for large rangeland landscapes. Trend assessments field sites and a long-term annual series (1984 - 2008) of remotely sensed imagery were used in conjunction with multidimensional scaling (MDS) to measure ecological distance to undesired states such as invasion by exotic annuals and encroachment by woodlands. In this chapter our units of analysis were soil-mapping units, which were predominantly composed of one ecological site (>60%). Our MDS results show that different ecological sites can be identified in the reduced MDS statistical space. The observed transitions and trajectories of mountain, Wyoming, and basin big sagebrush sites correlated well with the ecological expectation in semiarid lands. We anticipate that managers can use our protocols to update ecological site descriptions and state and transition models from a remotely sensed perspective.
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Li, Jiang. "Integration of vegetation indices and thermal measurements for ecosystem modeling." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/185794.
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This study represents a continuation of the historical trend in the analysis of the relationships between climate and vegetation. The focus of the work is on an examination of the association of functioning plants and climatic processes and on the interaction of structured vegetation communities with their environment. Satellite observations and remote sensing technology provide new opportunities for studying the geo-biosphere at high temporal frequencies and for large geographic areas. Integration of spectral vegetation indices and thermal measurements from space is the prime methodology used in this study. The integration of thermal information with vegetation indices has the potential to result in an important contribution to ecological remote sensing. This study has investigated the triangular distribution pattern which has been repetitively observed in spectral domains defined by thermal measurements and vegetation indices. Results show that the triangular shape of an AVHRR data cluster can be consistently observed on different continents and at different times of the year. The triangular data pattern has also been observed using a seasonally averaged data set, representing the mean thermal and biomass conditions of a growing season. The triangular shape of the data spread in feature space clearly suggests an ecosystem triangle model for simulation of the global ecology. A closer analysis of 15 test sites representing the major biomes in the U.S. Southwest study area has shown that each biome has a stable territory in the two dimensional space of temperature and biomass. If the territory of each test site in the triangle can be viewed as a vegetation cell, the ecosystem as a whole may be modeled by using this cell structure. The ecosystem triangle model and the concept of the cell structure have been applied in a vegetation classification exercise. The significant improvement achieved in the vegetation classification supports the conclusion that the ecosystem triangle model is a reflection of surface biomes, and may be used as a tool to study the structure, organization, and function of the biosphere.
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Hopkins, Rob. "Distributional Modeling Of Rare Fishes And Mussels: From Ecological Theory To Biodiversity Conservation." OpenSIUC, 2009. https://opensiuc.lib.siu.edu/dissertations/4.
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Freshwater ecosystems are among the most threatened ecosystems on the planet. In recent years there has been increasing concerns over precipitous declines in population sizes and increasing rates of extinction of native freshwater fauna across North America. Nearly 50% of the mussel species and 25% of the fish species in North America are imperiled. Stream habitat degradation has been cited as the principal cause for declines, with anthropogenic land uses being the leading causes of stream degradation. Species distribution models (SDMs) have become an integral tool in ecological research and conservation planning. SDMs are reliant upon occurrence datasets for the taxa of concern and museum-based information has become a popular source for such data. In the first stage of my research, I developed a centralized database for Kentucky fishes based on museum-based information. Over the course of three years, the SIUC Ichthyology Lab built an occurrence dataset of Kentucky fishes consisting of more than 50,000 records dating back to the 1890s. Each record contains three pieces of information (1) species identification, (2) georeferenced locality, and (3) date of collection. In the second stage of my research, I investigated the use of multiscale landscape data in aquatic species distribution models using a case study of a freshwater mussel. The distribution of Rabbitsfoot (Quadrula cylindrica) in the upper Green River system (Ohio River drainage) was modeled with environmental variables from multiple spatial scales. Four types of landscape environment metrics were used, including: land use/land cover (LULC) pattern, LULC composition, soil composition, and geology composition. The study showed that LULC pattern metrics are very useful in modeling the distribution of Rabbitsfoot. Together with LULC compositional metrics, pattern metrics permitted a more detailed analysis of functional linkages between aquatic species distributions and landscape structure. Moreover, the inclusion of multiple spatial scales was necessary to accurately model the hierarchical processes in stream systems. Geomorphic features played an important role in regulating species distributions at intermediate and large scales while LULC variables appeared more influential at proximal scales. I then further tested the landscape-level approach to aquatic species distribution modeling using a case study of six narrow-range endemic fishes with contrasting biogeographies. Species biogeography did not appear to affect predictive performance and all models performed well statistically. Predictive maps showed accurate estimations of ranges for five of six species based on historical collections. The relative influence of each type of environmental feature and spatial scale varied markedly with between species. A hierarchical effect was detected for narrowly distributed species which were highly influenced by soil composition at larger spatial scales and land use/land cover (LULC) patterns at more proximal scales. Conversely, LULC pattern was the most influential feature for widely distributed at all spatial scales. Lastly, I developed a hierarchical approach to the selection and management of freshwater protected areas in the upper Green River system. By aligning the spatial scales and environmental variables analyzed at each stage in the conservation planning process, from species distribution modeling to reserve selection, I present a more robust methodology to conservation planning compared to traditional approaches. Using models of species richness fitted to landscape attributes, I also provided suggestions for landscape management strategies for each conservation unit. My research comprises the core conservation plan for the focal species in the upper Green River system.
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Swannack, Todd Michael. "Modeling aspects of the ecological and evolutionary dynamics of the endangered Houston toad." Thesis, [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1641.
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Piera, Fernández Jaume. "Signal processing of microstructure profiles: integrating turbulent spatial scales in aquatic ecological modeling." Doctoral thesis, Universitat de Girona, 2002. http://hdl.handle.net/10803/7650.
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The main objective of this thesis was the integration of microstructure information in synoptic descriptors of turbulence, that reflects the mixing processes. Turbulent patches are intermittent in space and time, but they represent the dominant process for mixing. In this work, the properties of turbulent patches were considered the potential input for integrating the physical microscale measurements. The development of a method for integrating the properties of the turbulent patches required solving three main questions: a) how can we detect the turbulent patches from he microstructure measurements?; b) which are the most relevant properties of the turbulent patches?; and ) once an interval of time has been selected, what kind of synoptic parameters could better reflect the occurrence and properties of the turbulent patches?The answers to these questions were the final specific objectives of this thesis.
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Jung, Huicheul. "Modeling the ecological and hydrological responses to climate change in the Korean Peninsula." 京都大学 (Kyoto University), 2009. http://hdl.handle.net/2433/126599.
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Kyoto University (京都大学)0048
新制・課程博士
博士(地球環境学)
甲第14885号
地環博第62号
新制||地環||12(附属図書館)
27307
UT51-2009-K681
京都大学大学院地球環境学舎地球環境学専攻
(主査)教授 松岡 譲, 教授 藤井 滋穂, 准教授 倉田 学児
学位規則第4条第1項該当
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Zhang, Yuying. "Ecological Modeling of American Lobster (Homarus americanus) Population in the Gulf of Maine." Fogler Library, University of Maine, 2005. http://www.library.umaine.edu/theses/pdf/ZhangY2005.pdf.
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Houballah, Mojtaba. "Modeling multi-functional forest management through a social-ecological system framework-based analysis." Thesis, Université Clermont Auvergne (2017-2020), 2019. http://www.theses.fr/2019CLFAC083.
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L’utilité des forêts s’étend de leur exploitation pour le bois, le tourisme et d’autres fonctions au maintien de la faune, à l’équilibre écologique et à la prévention de l’érosion des sols. Pour atteindre ces objectifs, le facteur essentiel est une bonne gestion des forêts. Cependant, avec l’idée de plus en plus perçue que les forêts sont caractérisées par des interactions complexes liées aux aspects biologiques et sociaux, la gestion des forêts est confrontée à un défi, qui consiste à intégrer les interrelations entre les systèmes écologiques et sociaux. Alors que la gestion durable des forêts est à l’origine considérée comme un rendement constant de l’approvisionnement en bois, les idées modernes de durabilité ont une portée plus large et englobent tous les biens et services de la forêt. De plus en plus, les forêts sont gérées comme des écosystèmes multifonctionnels. Dans cette optique, les forêts sont progressivement considérées comme des systèmes socio-écologiques complexes (SESs), nécessitant une gestion adaptative et multifonctionnelle. Dans cette thèse, nous considérons que la question de l’application de gestion peut être abordée en comprenant comment les infrastructures partagées peuvent faire l’interaction entre l’environnement humain et écologique. En particulier, pour une gestion durable et multifonctionnelle des forêts, la relation entre la capacité de production et l’utilisation fonctionnelle est mise en évidence par le concept des infrastructures partagées de la forêt qui sont principalement composées de routes (services publics d’accessibilité). Cependant, les dilemmes liés à leur fourniture posent certains problèmes lorsqu’ils sont appliqués dans un contexte de fonctions forestières différentes avec des objectifs contradictoires. Par conséquent, pour bien comprendre et intégrer le rôle de l’infrastructure et sa gouvernance dans la science des écosystèmes, nous fondons notre recherche sur trois volets. Nous combinons d’abord l’utilisation du cadre de SES d’Ostrom et du cadre de robustesse d’Anderies et l’appliquons à une étude de cas spécifique (forêt de Quatre-Montagne, Vercors, France) pour mettre en évidence comment les institutions forestières affectent l’écosystème forestier, ses fonctions et ses arrangements sociaux. Ainsi, nous associons le concept de gestion forestière multifonctionnelle à la multifonctionnalité des infrastructures. Nous développons ensuite un modèle mathématique, basé sur la première partie, qui analyse l’évolution du système forestier et ses fonctions lorsqu’il est affecté par des décisions de fourniture d’infrastructures. Nous soulignons le rôle de la gouvernance en attirant l’attention sur son rôle dans la promotion de l’aménagement forestier multifonctionnel. Enfin, nous appliquons des outils mathématiques comme la théorie de la viabilité pour déterminer les techniques et les approches de gestion qui définissent une première étape dans la caractérisation de la gestion adaptative des espaces d’exploitation sécuritaires dans les forêts multifonctionnellesThe usefulness of forests is spread from their exploitation for timber, tourism, and other functions to maintenance of wildlife, ecological balance, and prevention of soil erosion. In achieving these goals, the essential factor is proper forest management. However, with the increasingly perceived idea that forests are characterized by complex interactions related to biological and social aspects, forest management is facing a challenge, which consists in integrating interrelations between ecological and social systems. While sustainable forest management is originally seen as a constant yield of wood supply, modern ideas of sustainability are broader in scope, embracing all goods and services of the forest. Increasingly, forests are being managed as multi-functional ecosystems. In this vein, forests are progressively seen as complex social-ecological systems (SESs), requiring adaptive and multi-functional management. In this Ph.D. thesis, we consider that the question of management application can be tackled by understanding how shared infrastructures mediate the interaction between human and ecological environment. In particular, for sustainable and multi-functional forest management, the relation between the capacity for production as well as multi-functional use is highlighted with the concept of forest’s shared infrastructures that are mainly composed of roads (accessibility utilities). However, dilemmas associated with their provision pose some problems when it is applied in a context of different forest functions with conflicting objectives. Therefore, to fully understand and integrate the role of infrastructure and their governance into ecosystem science, we base our research on three parts. We first combine the use of Ostrom’s SES framework and Anderies’ robustness framework and apply it to a specific case study (Quatre-Montagne forest, Vercors, France) to highlight how forestry institutions affect forest ecosystem, its functions, and its social arrangements. With this, we link the concept of multi-functional forest management to the multi-functionality of infrastructures. We then develop a mathematical model, based on the first partition, which analyzes the evolution of the forest system and its functions when impacted by decisions of infrastructure provision. We highlight the role of governance calling to attention their role in fostering multi-functional forest management. Finally, we apply mathematical tools such as viability theory to identify management techniques and approaches that define a first step in characterizing adaptive managements for safe operating spaces in multi-functional forests
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Hopkins, Robert L. "Distributional modeling of rare fishes and mussels : from ecological theory to biodiversity conservation /." Available to subscribers only, 2009. http://proquest.umi.com/pqdweb?did=1878997421&sid=1&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Thesis (Ph. D.)--Southern Illinois University Carbondale, 2009."Department of Zoology." Keywords: Aquatic species, Biodiversity conservation, Freshwater fish, Mapping. Includes bibliographical references (p. 106-113). Also available online.
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Zavalloni, Matteo <1983>. "Enhancing Resource Management in Socio-Ecological Systems: Modeling Collective Conditionality in Rural Policies." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7440/1/zavalloni_matteo_tesi.pdf.
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The collective approach toward natural resource management in agriculture is increasingly gaining attention, by both the literature and policy makers. In the thesis I analyse the implementation of collective approaches in rural policies aimed at natural resource management. More specifically, I analyse how two design elements of this type of policies, collective conditionality constraints and subsidy levels, affect the 1) emergence of cooperation among farmers and 2) the distribution of the benefits. In the analyses I address the effect of these policies in a range of situations, namely in case the action subsidized by policy is a public good, a club good, or only a private cost (and thus cooperation is purely linked to the implementation of the policy). The distributional effect is addressed only in the club good case.
The results show that indeed the proper use of collective conditionality constraints associated to subsidies can improve the cooperation of farmers and thus leading to more effective agri-environmental policies.
It seems that the collective approach for natural resource management is a strategy that deserves higher attention and policy effort. However, it should not be taken lightly or naively implemented, as the "sophistication" of mechanisms also increases the scope for unexpected policy outcomes. A more aware implementation of such strategy also requires a greater, inter-disciplinary, effort for research, towards a proper understanding of actual effects of real life policy options and coordination mechanisms.
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Zavalloni, Matteo <1983>. "Enhancing Resource Management in Socio-Ecological Systems: Modeling Collective Conditionality in Rural Policies." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7440/.
Full textAbstract:
The collective approach toward natural resource management in agriculture is increasingly gaining attention, by both the literature and policy makers. In the thesis I analyse the implementation of collective approaches in rural policies aimed at natural resource management. More specifically, I analyse how two design elements of this type of policies, collective conditionality constraints and subsidy levels, affect the 1) emergence of cooperation among farmers and 2) the distribution of the benefits. In the analyses I address the effect of these policies in a range of situations, namely in case the action subsidized by policy is a public good, a club good, or only a private cost (and thus cooperation is purely linked to the implementation of the policy). The distributional effect is addressed only in the club good case.
The results show that indeed the proper use of collective conditionality constraints associated to subsidies can improve the cooperation of farmers and thus leading to more effective agri-environmental policies.
It seems that the collective approach for natural resource management is a strategy that deserves higher attention and policy effort. However, it should not be taken lightly or naively implemented, as the "sophistication" of mechanisms also increases the scope for unexpected policy outcomes. A more aware implementation of such strategy also requires a greater, inter-disciplinary, effort for research, towards a proper understanding of actual effects of real life policy options and coordination mechanisms.
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Thomas, Daniel. "Hitchhiking in the Canopy: Ecological Patterns of Forest Mycobiomes." Thesis, University of Oregon, 2018. http://hdl.handle.net/1794/23141.
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The fungal microbiome, or “mycobiome” of plants is diverse and important to
host health, but the fluxes of fungi among plant hosts and with the surrounding
environment are poorly understood. In chapter two, we employed sterile culture
techniques and spatial sampling to examine leaves as possible vectors for transfer of their
endophytic fungi from the canopy to substrate on the forest floor, as predicted by the
Foraging Ascomycete hypothesis. Some foliar endophytic fungal species are also present
as wood-decomposing fungi on the forest floor, that transfer of mycelium across these
two life history stages can occur, that endophytic life history stages are buffered from
environmental conditions in comparison to wood-decomposing fungi, and that spatial
linkages between the two life history stages can be observed. In another study, described
in chapter 3, wood and leaf wood endophytes were sampled across a 25 ha plot, to
explore landscape patterns of mycobiomes, and to explore the concept of a core
microbiome in aerial plant tissues. We found that core microbiomes may be observed in a
real ecological setting, but that the concept of core must be carefully defined and that
some level of buffering from disturbance may be necessary to allow core microbiomes to
assemble. In chapter four, we return to examine some of the assumptions and
implications of the Foraging Ascomycete hypothesis, with an agent-based model. We
model the conditions under which dispersal through falling leaves may represent a
fitness-enhancing dispersal strategy for fungi, and that deforestation as is currently
underway throughout the world may have impacts on fungi that rely upon a canopy-
inhabiting life stage for dispersal. In chapter five, some challenges associated with
environmental sampling of microbes using illumina© MiSeq sequences are critically
examined. We find that biases introduced by random sampling at various stages of
IVenvironmental DNA extraction and illumina© MiSeq sequencing are not well corrected
by currently accepted bioinformatic algorithms. In addition, information loss from
differential extraction, PCR amplification, and sequencing success, requires that users of
MiSeq read libraries to interpret read abundances carefully.
This dissertation includes previously published, co-authored material.
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Edelfeldt, Stina. "Evaluation and Comparison of Ecological Models Simulating Nitrogen Processes in Treatment Wetlands,Implemented in Modelica." Thesis, Linköping University, Department of Science and Technology, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2879.
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Two ecological models of nitrogen processes in treatment wetlands have been evaluated and compared. These models have been implemented, simulated, and visualized in the Modelica language. The differences and similarities between the Modelica modeling environment used in this thesis and other environments or tools for ecological modeling have been evaluated. The modeling tools evaluated are PowerSim, Simile, Stella, the MathModelica Model Editor, and WEST.
The evaluation and the analysis have been performed using McCall’s factors for software quality (McCall et al, 1977), a correlation analysis and the Constant Comparative Method (Glaser&Strauss, 1999). The results show that the modeling tools and the models can both be separated into two categories: Simple Components and Complex Components for the modeling tools, and Simple Models and Complex Models for the models. The major difference between the Simple Components and the Complex Components is the higher possibility of the Complex Components to create and reuse separate components and the higher complexity in these components. The similarities between the categories are that they are consistent, easy to overview and use, if no new components are to be created. The major difference between the Simple Models and the Complex models lies in the number of functions and in the possibility of reuse and expansion. The similarities between all the models are that they are all consequent, logical, valid, specialized, and easy to use if the user has programming skill.
To conclude thisthesis, the nitrogen decrease in a constructed treatment wetland can well be simulated using the Nitrification/Denitrification model expressed in Modelica and the MathModelica Model Editor. However, some changes to the Model Editor are recommended to make the creation of the model easier. The most important of these changes are the addition of a tutorial, the ddition of useful error handling and messages, and the removal of unnecessary Visio features.
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DUARTE, Heitor de Oliveira. "A methodology for quantitative ecological risk assessment for industrial accidents." Universidade Federal de Pernambuco, 2011. https://repositorio.ufpe.br/handle/123456789/5960.
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Previous issue date: 2011Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Recentes acidentes industriais, como vazamentos tóxicos, têm causado danos catastróficos ao meio ecológico (i.e. plantas e animais), de modo que um método efetivo para analisar riscos ecológicos tem sido demandado. Em primeiro lugar, este trabalho tem como objetivo propor uma metodologia capaz de quantificar riscos ecológicos inerentes a eventos raros como acidentes industriais. Utiliza-se a modelagem populacional para simular futuras mudanças na abundância populacional de espécies-chave em risco e, assim, estimar a probabilidade de extinção ou declínio, tempo para extinção e outras medidas, para cada cenário acidental. Assim, foi possível desenvolver uma abordagem que combina os danos ecológicos (previstos através da modelagem populacional) com a frequência de ocorrência do cenário acidental (estimada através de dados históricos e análise de confiabilidade). O resultado é uma curva de risco FN (similar ao resultado de uma análise de risco a humanos), onde N é o declínio populacional médio e F a frequência acumulada de acidentes com declínio maior ou igual a N. Em segundo lugar, o trabalho apresenta uma aplicação da metodologia para quantificar os riscos ecológicos provenientes de acidentes associados ao transporte e manuseio de petróleo que abastece uma refinaria no Complexo Industrial Portuário de Suape-PE, no Nordeste do Brasil. Esta instalação está localizada próxima a um rico ecossistema aquático de alta biodiversidade. A população de uma espécie nativa foi estrategicamente escolhida para representar o ecossistema, alguns cenários de derramamento de petróleo foram simulados e suas frequências de ocorrência estimadas. Para cada cenário acidental, a concentração de óleo que atinge a população foi prevista via modelagem de destino e transporte. Os riscos ecológicos foram quantificados e apresentados em uma curva FN. Uma análise de sensibilidade foi feita para explorar como mudanças em parâmetros específicos causam mudanças nas medidas de risco. Além disso, a incerteza foi medida como um intervalo (limite superior e inferior) para as medidas de riscos com base em cenários pessimistas e otimistas. Finalmente, a metodologia mostrou-se viável, eficiente, conveniente e flexível, apesar de que algumas melhorias ainda podem ser feitas e estas foram propostas para trabalhos futuros
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Thomas, Jonathan Armstrong White Joseph Daniel. "Modeling canopy foliar traits and disturbance interactions in central Texas woodlands." Waco, Tex. : Baylor University, 2009. http://hdl.handle.net/2104/5337.
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Brummer, Tyler Jacob. "Non-native species distributions in space and time: integrating ecological theory and predictive modeling." Thesis, Montana State University, 2012. http://etd.lib.montana.edu/etd/2012/brummer/BrummerT0512.pdf.
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Invasive plant species are perceived as a problem globally, but management occurs locally. Theoretical developments concerning the distribution of plant species and invasions have generally focused on coarse scales, with relatively little work performed at finer scales relevant to local landscape management. The majority of such model predictions are static reflections of current conditions. As species invasions are a temporally variable process, the need for tools to predict invasions through both space and time are vital. Thus, this thesis explored distribution models to predict non-native species occurrence, investigated sources of uncertainty in these models, and quantified the key drivers of non-native species metapopulation dynamics. Sampling methodology and sample size requirements to inform logistic regression models used to predict invasive species realized distributions were evaluated with simulation and empirical data from two multi-species surveys. Transect sampling was the most efficient way to generate species occurrence data and consequently landscape scale species distribution models. Empirical and simulation modeling results indicated minimum sample sizes of between 0.06 and 0.23% of the study area to maximize model predictive ability, independent of site characteristics. However, landscape scale species distribution models were more predictive at sites with steeper environmental gradients and for species at their ecophysiological range limits. Detection error in the plant species surveys was also quantified, as well as its effects on predictions and uncertainty of species distributions. Detection error did not practically alter predictions, nor model based uncertainty estimates if the detection rate was greater than 87%. However, at lower detection rates care needs to be taken when interpreting response variables and prediction certainty. Finally, multi-season repeat survey data were used to investigate the key spatial and temporal drivers of non-native species colonization and extinction. The drivers of non-native species colonization and extinction were sometimes simple but other times resulted from complex interactions between dispersal, disturbance, habitat and temporal climatic variation. Overall, these results demonstrate the need for reliable species occurrence records and monitoring data to fully characterize species distributions at present and their dynamics resulting in future distributions. 'Co-authored by Bruce D. Maxwell, Megan D. Higgs, Lisa J. Rew and Subhash R. Lele.'
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D'Antonio, Ashley L. "Modeling the Ecological Consequences of Visitor Behavior in Off-Trail Areas Dispersed Recreation Use." DigitalCommons@USU, 2015. https://digitalcommons.usu.edu/etd/4411.
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Parks and protected areas are often created to protect important social, ecological, or cultural resources from impairment. In the United States, a large majority of these parks and protected areas are also public land where recreational activities such as hiking or scenic driving are allowed. Managers of many parks and protected areas must therefore try to protect resources while also allowing for recreation use that may put these resources at risk for damage. The field of recreation ecology is interested in understanding how recreation use in parks and protected areas can sometimes cause ecological impacts to vegetation, soil, wildlife, water, air, and soundscapes. This information is then used to help managers prevent undesirable ecological change. When visitors to parks and protected areas leave designated sites such as trails or roads, there is a greater chance that ecological impacts will occur.
The studies presented here are designed to help managers better understand how visitor behavior off of designated trails may result in damage to plant communities. These studies examine data on both the social aspects of recreation use (such as visitor behavior and the number of visitors recreating) and the ecological aspects (specifically the plant communities found at popular recreation destinations). By looking at social and ecological data together, these studies can predict locations in parks or protected areas where ecological impact may occur as a result of recreation use. Managers can use these predictions to better allocate resources and time to managing recreation use at locations that are most at risk of impairment.
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Matos, Rafael Pereira de. "Estudos fitogeogrÃficos e modelagem ecolÃgica do gÃnero Dimorphandra Schott (Leguminosae, Caesalpinioideae)." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=15372.
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FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgicoEstudar padrÃes de distribuiÃÃo dos organismos à relevante na ecologia, biogeografia e biologia da conservaÃÃo fornecendo subsÃdios para compreender a evoluÃÃo da biodiversidade. Dimorphandra Schott à um gÃnero de distribuiÃÃo neotropical com 25 espÃcies no Brasil, distribuÃdas tanto em formaÃÃes savÃnicas (Cerrado) como ombrÃfilas (Floresta AmazÃnica e AtlÃntica). Este trabalho objetivou entender como està distribuÃda e quais os fatores ambientais estÃo associados à riqueza e a diversidade de Dimorphandra. Foram utilizadas ferramentas de Sistemas de InformaÃÃo GeogrÃfica, modelagem ecolÃgica e dados de ocorrÃncia obtidos da rede SpeciesLink, informaÃÃes bibliogrÃficas e visitas à herbÃrios. Esses dados foram classificados dentro de provÃncias biogeogrÃficas de acordo com um esquema de regionalizaÃÃo biogeogrÃfica e com os grupos gerados por uma anÃlise de agrupamento â UPGMA realizada no programa PC-ORD e uma anÃlise parcimoniosa de endemicidade (PAE) feita por meio do programa PAUP. Paralelamente, modelos ecolÃgicos de distribuiÃÃo baseados em algoritmos (BIOCLIM e CCSM) foram formulados para opassado, presente e futuro em ambiente do MAXENT e DIVA-GIS. Ambos os centros de riqueza e diversidade foram a regiÃo amazÃnica. As espÃcies com mais ampla distribuiÃÃo foram D. mollis Benth. e D. gardneriana Tul., ambas ocorrendo no corredor de formaÃÃes vegetacionais abertas e secas no sentido nordeste-sudeste. TrÃs blocos fitogeogrÃficos foram determinados pela anÃlise de agrupamento: A) AmazÃnia; B) EcÃtono Cerrado/Floresta AtlÃntica; e C) Escudo das Guianas. A anÃlise de PAE evidenciou dois grandes clados com suporte estatÃstico (bootstrap) acima de 80%. Foram estabelecidos os seguintes padrÃes de distribuiÃÃo: 1) Amplo na AmazÃnia, 2) Restrito ao Norte da AmazÃnia (acima do Rio Negro), 3) Escudo das Guianas, 4) EcÃtono Cerrado/Floresta AtlÃntica, e 5) MicroendÃmico aos Cerrados de Minas Gerais. Os resultados da modelagem preditiva demonstraram uma tendÃncia de reduÃÃo da maior parte da Ãrea de ocorrÃncia potencial do gÃnero em um cenÃrio futuro, com exceÃÃo de pequenas regiÃes no Escudo das Guianas, as quais teriam condiÃÃes de expandir a distribuiÃÃo das espÃcies. Como conclusÃes, conheceu-se a distribuiÃÃo do gÃnero pela AmÃrica do Sul, seus centros de riqueza e diversidade, no caso a regiÃo amazÃnica, alÃm de ter sido verificada uma tendÃncia geral na reduÃÃo da Ãrea potencial de ocorrÃncia do gÃnero no futuro e expansÃo em Ãreas de altas altitudes, consideradas refÃgios.
Studying patterns of distribution of organisms is relevant in ecology, biogeography and conservation studies under even to understand the evolution of biodiversity. Dimorphandra Schott. is a widespread neotropical genus with 25 taxa in Brazil, occurring in savanna (Cerrado) and ombrophylous vegetation (Amazonia and Atlantic Rain Forest). This work aims to understand the factor that drives the richness and diversity of Dimorphandra. We used SIG, ecological modeling and databank of SpeciesLink and bibliography. These data were classified within biogeographic provinces according to a biogeographically regionalization scheme and according to groups generated by a cluster analysis in the PC-ORD program and a Parsimony Analysis of Endemicity (PAE) by PAUP program. At the same time, ecological distribution models were formulated to the past, present and future based on algorithms (BIOCLIM and CCSM) using the softwares MAXENT and DIVA-GIS, referring to each group according to the UPGMA results. The richness and diversity centers were in the Amazon region. The species more widespread were D. mollis Benth. and D. gardneriana Tul., occurring in the Seasonal Tropical Dry Forests (STDFs) in the northeast-southeast direction. Three phytogeographic groups were determined by the cluster analysis: A) Amazon and its two subgroups: Broad Amazon and North of Negro River Basin; B) Ecotones Brazilian Savanna/Atlantic Forest; and C) Guyana Highlands. PAE analysis pointed two major clades with good support (>80% bootstrap). Some distribution patterns were determined: 1) Broad Amazon Pattern, 2) Restricted to northern Amazon Pattern, 3) Guyana Shield Pattern, 4) Ecotones Brazilian Savanna/Atlantic Forest Pattern and 5) Micro Endemic Minas Geraisâ Brazilian Savanna Pattern. Predictive modeling results demonstrated a trend on reduction of most potential occurrence areas, except in small regions in Guyana Highlands, which expanded in a future scenario. Finally, we can conclude that distribution of the genus through South America was known as well its richness and diversity centers, besides it has been checked a general trend on reduction of potential occurrence area of this genus in a future scenario except in high areas which are considered refugia.
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Mukhtasor. "Hydrodynamic modeling and ecological risk-based design of produced water discharge from an offshore platform." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ62454.pdf.
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Sorenson, Mary T. "Deterministic vs probabilistic ecological risk assessment modeling at hazardous waste sites : a comparative case study." Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/25303.
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Grinter, Lawton E. "Applications of ecological modeling in managing Central Appalachian upland oak stands for old-growth characteristics." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/35235.
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Old-growth forests provide important habitat for wildlife, support the maintenance of biodiversity and serve as control areas for scientific research. Expanding current old-growth stand area by utilizing neighboring younger, managed stands allows private landowners to meet management needs and enables government agencies and private conservation organizations to meet old-growth forest objectives. Seven old-growth upland oak stands and seven adjacent younger, managed stands of the same site and stand type were measured in the Ridge and Valley, Blue Ridge, and Piedmont provinces of Virginia and Pennsylvania in an effort to characterize species composition, diameter distribution and canopy structure. A computer-based ecosystem/gap model (JABOWA-3) was modified and used to simulate silvicultural manipulations in the younger stands that would reproduce older forest characteristics. Various silvicultural techniques were used to convert the primarily even-aged younger stands into uneven-aged stands and then into old-growth. These manipulations included single-tree selection, herbicide application, culling larger diameter stems and planting seedlings where required. Individual trees within each of the younger, managed stands were removed at various time intervals and these simulated stands were then projected to a point in time in which the stand approximated the diameter distribution and composition of its paired old-growth stand. Several projections were made in each of the younger stands to meet this objective. Once a satisfactory projection was made for conversion of a younger stand to old-growth, a success rate was determined to gauge how close the simulated stand approximated the diameter distribution and composition of its old-growth counterpart. From this information, biologically feasible and environmentally sound management plans were created to carry out the silvicultural manipulations required by the model for each of the sites.Master of Science
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Mattson-Hansen, Kimberly M. "Modeling Ecological Risks at a Landscape Scale: Threat Assessment in the Upper Tennessee River Basin." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/78611.
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There is no single methodology toward freshwater conservation planning, and few analytical tools exist for summarizing ecological risks at a landscape scale. I constructed a relative risk model, the Ecological Risk Index (ERI), to combine the frequency and severity of human-induced stressors with mappable land and water use data to evaluate impacts to five major biotic drivers: energy sources, physical habitat, flow regime, water quality, and biotic interactions. It assigns 3 final risk rankings based on a user-specified spatial grain. In a case study of the 5 major drainages within the upper Tennessee River basin (UTRB), U.S.A, differences in risk patterns among drainages reflected dominant land uses, such as mining and agriculture. A principal components analysis showed that localized, moderately severe threats accounted for most of the threat composition differences among watersheds. Also, the relative importance of threats is sensitive to the spatial grain of the analysis.
An evaluation of the ERI procedures showed that the protocol is sensitive to how extent and severity of risk are defined, and threat frequency-class criteria strongly influenced final risk rankings. Multivariate analysis tested for model robustness and assessed the influence of expert judgment by comparing my original approach to a quantile-based approach. Results suggest that experts were less likely to assign catchments to high-risk categories than was the quantile approach, and that 3 final risk rankings were appropriate.
I evaluated the influence of land use on freshwater ecosystems by studying the relationship between land cover changes and the persistence of freshwater mussels. First, historical species data were collected and the Upper Tennessee River Mussel Database (UTRMD) was constructed. The UTRMD contains >47,400 species records from 1963-2008 distributed across nearly 2,100 sampling sites.
My study suggests that 30 years of land cover change does not explain observed freshwater mussel declines. Quantitative surveys are recommended basin-wide to provide more accurate information about mussel distribution and abundance. Lastly, results suggest that streams with repeated mussel surveys have increasing populations, including active recruitment in several beds. Additional quantitative surveys since 2004 have probably provided more accurate species and population counts, although actual population sizes are still uncertain.Ph. D.
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Bruins, Randall J. F. "Modeling of flooding response and ecological engineering in an agricultural wetland region of central China /." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487947908403558.
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Вороненко, Вячеслав Ігорович, Вячеслав Игоревич Вороненко, and Viacheslav Ihorovych Voronenko. "The study of economic development of countries with the modeling of social, economic and ecological stability." Thesis, Baltija Publishing, 2018. https://essuir.sumdu.edu.ua/handle/123456789/87388.
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На сьогодні у розвитку національних економік найважливішим є забезпечення сталого розвитку та досягнення стабільності функціонування соціально-екологічної та економічної систем. Відповідно до цієї потреби необхідно не тільки розробити ефективну систему управління стабільністю економіки країни, а й формалізувати систему моделей розвитку, які забезпечуватимуть ефективність управлінських рішень. У цьому випадку необхідно виконати порівняння результатів моделювання елементів системи управління розвитком.На сегодняшний день в развитии национальных экономик наиболее важным является обеспечение устойчивого развития и достижение устойчивости функционирования социально-экологических и экономических систем. В соответствии с этой потребностью необходимо не только разработать эффективную систему управления устойчивостью экономики страны, но и формализовать систему моделей развития, обеспечивающих эффективность управленческих решений. В этом случае необходимо выполнить сравнение результатов моделирования элементов системы управления разработкой.
For today in the development of national economies the most important is ensuring sustainable development and achieving the stability of the functioning of socio-ecological and economic systems. According to this need it is necessary not only to design effective system for managing the stability of the country’s economy, but also to formalize a system of development models that will ensure the effectiveness of management decisions. In this case, it is necessary to perform a comparison of the results of simulation of elements of the control system of development.
This research was funded by the grants from the Ministry of Education and Science of Ukraine (№ g/r 0117U003932)
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Negreiros, Gustavo Hees de. "Understanding and modeling ecological processes controlling flammability in seasonally dry evergreen forests of the Brazillian Amazon /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/5528.
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Brandt, Marilyn Elizabeth. "Coral Disease Epizootiology in the Florida Keys (U.S.A.) and Cayman Islands (British West Indies), and the Development of the Simulation of Infected Corals Model." Scholarly Repository, 2007. http://scholarlyrepository.miami.edu/oa_dissertations/57.
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Understanding coral disease dynamics within the heterogeneous populations in which they act is critical for predicting how the structure of reefs may change as a result of enzootic or epizootic levels of these important sources of mortality. This work focused on combining field studies and the development and testing of a spatially-explicit, individual-based epizootiological computer model with the aim of gaining a greater understanding of the dynamics and impact of white plague, a significant source of mortality on reef-building corals in the Caribbean region. Field studies focused on the incidence and distribution of all sources of coral mortality, including suspect white plague in situ, at two locations; the Florida Keys (United States of America) and Little Cayman Island (Cayman Islands, British West Indies). Results indicated that in both regions disease was the most significant source of mortality during the monitoring time periods, and that suspect white plague type II in Cayman is likely contributing to major structural changes. In Florida, observations made during a mass bleaching event indicated that a significant relationship exists between bleaching severity and disease incidence, and that mortality during the event was largely the result of disease and not bleaching. The simulation model was developed using a long-term data set from Little Cayman, and results of calibration indicated that suspect white plague type II on these reefs is transmissible between colonies within a limited field and require a yearly input from an outside source, and that host susceptibility to infection is low and likely not variable among species. Parameters describing the distribution and composition of the coral population were varied, and results indicated a significant effect of colony density, aggregation, and mean size on the impact of disease. Scenario testing of various disease management strategies indicated that should local prevention measures be developed in the future, it is they, and not treatment, that will likely be the most effective in limiting the impact of disease.
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Ryu, Hyung Cheal. "Modeling the per capita ecological footprint for Dallas County, Texas: Examining demographic, environmental value, land-use, and spatial influences." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2404.
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This study addresses factors driving the variation in the per capita Ecological
Footprint (EF) in Dallas County, Texas. A main hypothesis was that scientifically
estimated demography, environmental values, spatial attributes, and land-use patterns
surrounding an individual are significant factors in the size of per capita EF. This study
was based on the survey method and GIS routines. Additionally, a multiple regression
method was employed to address the study question. The survey measured respondents??
EF using an ??Ecological Footprint Quiz?? consisting of sixteen questions regarding
individual food, mobility, housing, and goods/services consumption. GIS technologies
were used to objectively measure spatial attributes. The environmental values were
measured by selected questions regarding ecological crises.
This study found from the descriptive analysis that Dallas County??s average
personal EF was 26.4 acres: food (5.1), mobility (3.3), shelter (8.3), and goods and services (9.8). The study indicates that the residents need ecologically productive land
more than 105 times the area of the county.
Based on the explanatory analysis, the following summary points can be made
about the factors driving of the variance, not only in the per capita composite footprint
but also in each of the personal footprint components:
First, a highly educated, non-married, older male living in a high income
household located in a low population density area is more likely to have a larger
personal composite footprint. Second, a person with a weak environmental awareness
living where the ratio of employment opportunities (places to work) is worse, and living
far from freeways and major lakes but close to major malls, is more likely to have a
larger personal food footprint. Third, a younger person living in a high income
household located close to major malls but far from Dallas/Fort Worth Airport is more
likely to have a larger mobility footprint. Fourth, a highly educated non-married older
male living in a highly developed area is more likely to have a larger shelter footprint.
Fifth, a highly educated non-married older male living in a high income household
located in a low population density area is more likely to have a larger goods and
services footprint.
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Bornancin, Elaine Cristina. "Acharadria crocea (Cnidaria: Hydrozoa): estudo integrado da ecofisiologia do assentamento larval e modelagem de nicho ecológico." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/41/41133/tde-14122011-080739/.
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Acharadria crocea é um hidrozoário comum do Atlântico Sul-Ocidental. Na costa brasileira, a espécie possui um padrão de sazonalidade bem definido, sendo abundante nos meses frios do ano e ausente ou rara no verão e outono. Durante o inverno, a espécie apresenta intenso crescimento assexuado por brotamento, permitindo o rápido desenvolvimento da colônia. Esta se torna fértil em um curto espaço de tempo e produz uma grande quantidade de larvas, o que favorece o estabelecimento de novas colônias. Além destas características, a espécie já foi associada com transporte antrópico, por meio de incrustação em cascos de navios, o que a torna uma espécie potencialmente invasora. Este trabalho avaliou experimentalmente a tolerância ecofisiológica das larvas de A. crocea a temperatura e salinidade da água, bem como sua capacidade de colonização de diferentes substratos, tanto naturais (carapaças de cracas e mexilhões) como artificiais (fragmentos de PET e alumínio). A influência de um biofilme multiespecífico de bactérias no assentamento da espécie também foi analisada. Com base nos dados de tolerância ecofisiológica das larvas, foi realizada e modelagem de nicho da espécie utilizando GLM (Modelos Lineares Generalizados), que gerou mapas de sua distribuição potencial. Utilizando dados de ocorrência geográfica disponíveis na literatura, foram gerados também mapas de distribuição potencial das colônias adultas utilizando o algoritmo MAXENT. Para integrar as informações das fases bentônica e planctônica de A. crocea, foi realizada subsequentemente a intersecção dos mapas gerados por ambas as metodologias, gerando assim uma predição unificada de sua ocorrência.Acharadria crocea is a common South-occidental Atlantic hydrozoan. On the Brazilian coast it presents a well defined seasonality pattern, being abundant on the cool months of the year and absent or rare on summer and autumn. During winter, the specie increases its numbers by asexual stolonal growth, as well as the colony size. The colony becomes fertile and produces a great amount of larvae, allowing the establishment of new colonies. Besides these characteristics, A. crocea was already found colonizing ship hulls, being considered a highly invasive species. This report experimentally evaluated the ecophysiological tolerance of A. crocea larvae to water temperature and salinity, as well as its ability to colonize different substrates, both natural (mussel and barnacle shells) and artificial (plastic bottles and aluminum). The influence of a bacterial film on its adaptation was also analyzed. Based on the ecophysiology of the larvae, an ecological niche modeling was built using GLM (generalized linear models) to create maps of the distribution of the larvae. Using literature based graphic occurrence data and the MAXENT algorithm, maps of the adult colonies potential distribution were also created. To relate information of benthonic and planctonic phases of A. crocea, an intersection of the maps was built from both methods.
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Fisher, David. "Postglacial Transient Dynamics of Olympic Peninsula Forests: Comparing Predictions and Observations." Thesis, University of Oregon, 2013. http://hdl.handle.net/1794/13328.
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Interpreting particular climatic drivers of local and regional vegetation change from paleoecological records is complex. I explicitly simulated vegetation change from the late-Glacial period to the present on the Olympic Peninsula, WA and made formal comparisons to pollen records. A temporally continuous paleoclimate scenario drove the process-based vegetation model, LPJ-GUESS. Nine tree species and a grass type were parameterized, with special attention to species requirements for establishment as limited by snowpack. Simulations produced realistic present-day species composition in five forest zones and captured late-Glacial to late Holocene transitions in forest communities. Early Holocene fire-adapted communities were not simulated well by LPJ-GUESS. Scenarios with varying amounts of snow relative to rain showed the influence of snowpack on key bioclimatic variables and on species composition at a subalpine location. This study affirms the importance of exploring climate change with methods that consider species interactions, transient dynamics, and functional components of the climate.