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Articles 1 - 15 of 15
Full-Text Articles in Geography
The Predicts Database: A Global Database Of How Local Terrestrial Biodiversity Responds To Human Impacts, Lawrence N. Hudson, Tim Newbold, Sara Contu, Samantha L.L. Hill, Igor Lysenko, Adriana De Palma, Helen R.P. Phillips, Rebecca A. Senior, Dominic J. Bennett, Hollie Booth, Argyrios Choimes, David L.P. Correia, Julie Day, Susy Echeverría-Londoño, Morgan Garon, Michelle L.K. Harrison, Daniel J. Ingram, Martin Jung, Victoria Kemp, Lucinda Kirkpatrick, Callum D. Martin, Yuan Pan, Hannah J. White, Job Aben, Stefan Abrahamczyk, Gilbert B. Adum, Virginia Aguilar-Barquero, Marcelo A. Aizen, Marc Ancrenaz, Enrique Arbeláez-Cortés, Inge Armbrecht, Badrul Azhar, Christopher A. Williams
The Predicts Database: A Global Database Of How Local Terrestrial Biodiversity Responds To Human Impacts, Lawrence N. Hudson, Tim Newbold, Sara Contu, Samantha L.L. Hill, Igor Lysenko, Adriana De Palma, Helen R.P. Phillips, Rebecca A. Senior, Dominic J. Bennett, Hollie Booth, Argyrios Choimes, David L.P. Correia, Julie Day, Susy Echeverría-Londoño, Morgan Garon, Michelle L.K. Harrison, Daniel J. Ingram, Martin Jung, Victoria Kemp, Lucinda Kirkpatrick, Callum D. Martin, Yuan Pan, Hannah J. White, Job Aben, Stefan Abrahamczyk, Gilbert B. Adum, Virginia Aguilar-Barquero, Marcelo A. Aizen, Marc Ancrenaz, Enrique Arbeláez-Cortés, Inge Armbrecht, Badrul Azhar, Christopher A. Williams
Geography
Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species' threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic extents, and that support computation of a range of biodiversity indicators, is necessary to enable better understanding of historical declines and to project - and avert - future declines. We describe and assess a new database of more than 1.6 million samples from 78 countries representing over 28,000 species, collated from existing spatial …
Mapping Licit And Illicit Mining Activity In The Madre De Dios Region Of Peru, Arthur Elmes, Josué Gabriel Yarlequé Ipanaqué, John Rogan, Nicholas Cuba, Anthony J. Bebbington
Mapping Licit And Illicit Mining Activity In The Madre De Dios Region Of Peru, Arthur Elmes, Josué Gabriel Yarlequé Ipanaqué, John Rogan, Nicholas Cuba, Anthony J. Bebbington
Geography
Since the early 2000s, the Madre de Dios Region of southern Peru has experienced rapid expansion of both licit and illicit mining activities, in the form of artisanal and small-scale mining (ASM). ASM typically takes place in remote, inaccessible locations and is therefore difficult to monitor in situ. This paper explores the utility of Landsat-5 imagery via decision tree classification to determine ASM locations in Madre de Dios. Spectral mixture analysis was used to unmix Landsat imagery, using WorldView and QuickBird l imagery to aid spectral endmember selection and validate AMS maps. The ASM maps had an overall area-weighted accuracy …
Land Classification And Change Intensity Analysis In A Coastal Watershed Of Southeast China, Pei Zhou, Jinliang Huang, Robert Gilmore Pontius, Huasheng Hong
Land Classification And Change Intensity Analysis In A Coastal Watershed Of Southeast China, Pei Zhou, Jinliang Huang, Robert Gilmore Pontius, Huasheng Hong
Geography
The aim of this study is to improve the understanding of land changes in the Jiulong River watershed, a coastal watershed of Southeast China. We developed a stratified classification methodology for land mapping, which combines linear stretching, an Iterative Self-Organizing Data Analysis (ISODATA) clustering algorithm, and spatial reclassification. The stratified classification for 2002 generated less overall error than an unstratified classification. The stratified classifications were then used to examine temporal differences at 1986, 1996, 2002, 2007 and 2010. Intensity Analysis was applied to analyze land changes at three levels: time interval, category, and transition. Results showed that land use transformation …
Changing Water Availability During The African Maize-Growing Season, 1979-2010, Lyndon Estes, Nathaniel W. Chaney, Julio Herrera-Estrada, Justin Sheffield, Kelly K. Caylor, Eric F. Wood
Changing Water Availability During The African Maize-Growing Season, 1979-2010, Lyndon Estes, Nathaniel W. Chaney, Julio Herrera-Estrada, Justin Sheffield, Kelly K. Caylor, Eric F. Wood
Geography
Understanding how global change is impacting African agriculture requires a full physical accounting of water supply and demand, but accurate, gridded data on key drivers (e.g., humidity) are generally unavailable. We used a new bias-corrected meteorological dataset to analyze changes in precipitation (supply), potential evapotranspiration (Ep, demand), and water availability (expressed as the ratio P/Ep) in 20 countries (focusing on their maize-growing regions and seasons), between 1979 and 2010, and the factors driving changes in Ep. Maizegrowing areas in Southern Africa, particularly South Africa, benefitted from increased water availability due in large part to demand declines driven primarily by declining …
Spatially-Explicit Simulation Of Urban Growth Through Self-Adaptive Genetic Algorithm And Cellular Automata Modelling, Yan Liu, Yongjiu Feng, Robert Gilmore Pontius
Spatially-Explicit Simulation Of Urban Growth Through Self-Adaptive Genetic Algorithm And Cellular Automata Modelling, Yan Liu, Yongjiu Feng, Robert Gilmore Pontius
Geography
This paper presents a method to optimise the calibration of parameters and land use transition rules of a cellular automata (CA) urban growth model using a self-adaptive genetic algorithm (SAGA). Optimal calibration is achieved through an algorithm that minimises the difference between the simulated and observed urban growth. The model was applied to simulate land use change from non-urban to urban in South East Queensland's Logan City, Australia, from 1991 to 2001. The performance of the calibrated model was evaluated by comparing the empirical land use change maps from the Landsat imagery to the simulated land use change produced by …
Validation Of Satellite Rainfall Products For Western Uganda., Jeremy E. Diem, Joel N. Hartter, Sadie J. Ryan, Michael W. Palace
Validation Of Satellite Rainfall Products For Western Uganda., Jeremy E. Diem, Joel N. Hartter, Sadie J. Ryan, Michael W. Palace
Geography
Central equatorial Africa is deficient in long-term, ground-based measurements of rainfall; therefore, the aim of this study is to assess the accuracy of three high-resolution, satellite-based rainfall products in western Uganda for the 2001–10 period. The three products are African Rainfall Climatology, version 2 (ARC2); African Rainfall Estimation Algorithm, version 2 (RFE2); and 3B42 from the Tropical Rainfall Measuring Mission, version 7 (i.e., 3B42v7). Daily rainfall totals from six gauges were used to assess the accuracy of satellite-based rainfall estimates of rainfall days, daily rainfall totals, 10-day rainfall totals, monthly rainfall totals, and seasonal rainfall totals. The northern stations had …
Hog Daddy And The Walls Of Steel: Catch Shares And Ecosystem Change In The New England Groundfishery, Jennifer F. Brewer
Hog Daddy And The Walls Of Steel: Catch Shares And Ecosystem Change In The New England Groundfishery, Jennifer F. Brewer
Geography
The U.S. National Oceanic and Atmospheric Administration implemented marketbased fishery management in the New England groundfishery as catch shares, controlling aggregate harvests through tradable annual catch quotas allocated to fishing groups called sectors. Policy supporters assert that resulting markets raise conservation incentives. In compliance with the Magnuson–Stevens Fishery Conservation and Management Act, species assessments permit catch shares to replace more spatially and temporally specific constraints on fishing gear, time, areas, and daily harvest limits. Qualitative evidence from field interviews and participant observation questions the efficacy of catch shares. Fishing industry members observe that increased presence of large trawl vessels in …
Harvesting A Knowledge Commons: Collective Action, Transparency, And Innovation At The Portland Fish Exchange, Jennifer F. Brewer
Harvesting A Knowledge Commons: Collective Action, Transparency, And Innovation At The Portland Fish Exchange, Jennifer F. Brewer
Geography
While localist visions of alternative food systems advocate for the expansion of local ecological knowledge through more proximate producerconsumer relationships, globalized seafood supply-demand chains persist. Moving beyond this dichotomy, commons scholars recognize that collective action among resource users at the local level can shape cross-scalar producer relations with government and more capitalized firms operating in regional and global markets. In the case of the New England groundfishery, a quasi-public fish auction not only transformed the scalar, logistical, and financial parameters of harvester-buyer relationships, it altered the production and use of local knowledge among some harvesters, and their technological choices. Resulting …
Extractive Industries, Livelihoods And Natural Resource Competition: Mapping Overlapping Claims In Peru And Ghana, Nicholas Cuba, Anthony J. Bebbington, John Rogan, Marco Millones
Extractive Industries, Livelihoods And Natural Resource Competition: Mapping Overlapping Claims In Peru And Ghana, Nicholas Cuba, Anthony J. Bebbington, John Rogan, Marco Millones
Geography
Taking the cases of Perú and Ghana, this paper examines overlaps between the extraction of minerals, oil and gas on the one hand, and river basins, agricultural land use, and protected areas on the other hand. In particular the paper considers how far such overlaps can be revealed and analyzed on the basis of (relatively) accessible and affordable data, without having to use more expensive data generated by remote sensing or fieldwork. We use concessions as our indicator of the presence of extractive industry activity, focusing on both mineral and hydrocarbon concessions, and areas of exploration and of active resource …
The Research Journey: Travels Across The Idiomatic And Axiomatic Toward A Better Understanding Of Complexity, Katharine A. Mcgowan, Frances Westley, Evan D.G. Fraser, Philip A. Loring, Kathleen C. Weathers, Flor Avelino, Jan Sendzimir, Rinku Roy Chowdhury, Michele Lee Moore
The Research Journey: Travels Across The Idiomatic And Axiomatic Toward A Better Understanding Of Complexity, Katharine A. Mcgowan, Frances Westley, Evan D.G. Fraser, Philip A. Loring, Kathleen C. Weathers, Flor Avelino, Jan Sendzimir, Rinku Roy Chowdhury, Michele Lee Moore
Geography
In this paper, seven researchers reflect on the journeys their research projects have taken when they engage with and synthesize complex problems. These journeys embody an adaptive approach to tackling problems characterized by their interconnectedness and emergence, and that transcend traditional units of analysis such as ecosystems. In this paper we argue that making such a process deliberate and explicit will help researchers better combine different research paradigms such as expert-driven and participant-directed work, thus resulting in both broad explanations and specific phenomenon; research tensions traditionally defined as oppositional must be approached as complimentary. This paper includes researchers’ personal journeys …
Convergent Surface Water Distributions In U.S. Cities, M. K. Steele, J. B. Heffernan, N. Bettez, J. Cavender-Bares, P. M. Groffman, J. M. Grove, S. Hall, S. E. Hobbie, K. Larson, J. L. Morse, C. Neill, K. C. Nelson, J. O'Neil-Dunne, L. Ogden, D. E. Pataki, C. Polsky, Rinku Roy Chowdhury
Convergent Surface Water Distributions In U.S. Cities, M. K. Steele, J. B. Heffernan, N. Bettez, J. Cavender-Bares, P. M. Groffman, J. M. Grove, S. Hall, S. E. Hobbie, K. Larson, J. L. Morse, C. Neill, K. C. Nelson, J. O'Neil-Dunne, L. Ogden, D. E. Pataki, C. Polsky, Rinku Roy Chowdhury
Geography
Earth's surface is rapidly urbanizing, resulting in dramatic changes in the abundance, distribution and character of surface water features in urban landscapes. However, the scope and consequences of surface water redistribution at broad spatial scales are not well understood. We hypothesized that urbanization would lead to convergent surface water abundance and distribution: in other words, cities will gain or lose water such that they become more similar to each other than are their surrounding natural landscapes. Using a database of more than 1 million water bodies and 1 million km of streams, we compared the surface water of 100 US …
Decolonizing Cascadia?, Wes Attewell, Dan Cohen, Juliane Collard, Rosemary Collard, Lisa Dumoulin, May Farrales, Alan Grove, Jessica Hallenbeck, Sarah Hunt, Samuel Johns, Kyle Loewen, Jonathan Luedee, Alan Mcconchie, Paige Patchin, Sage Ponder, Sarah Mathisen Przedpelska, Carolyn Prouse, Duncan Ranslem, Max Ritts, Emily Rosenman, Sam Walker, Sophie Webber
Decolonizing Cascadia?, Wes Attewell, Dan Cohen, Juliane Collard, Rosemary Collard, Lisa Dumoulin, May Farrales, Alan Grove, Jessica Hallenbeck, Sarah Hunt, Samuel Johns, Kyle Loewen, Jonathan Luedee, Alan Mcconchie, Paige Patchin, Sage Ponder, Sarah Mathisen Przedpelska, Carolyn Prouse, Duncan Ranslem, Max Ritts, Emily Rosenman, Sam Walker, Sophie Webber
Geography
This essay reflects on attempts to organize a conference that sought to trouble the colonial nature of conference structures, academic knowledges and hierarchies, and the ‘Cascadia’ bioregion of Northwestern North America.
Heat And Drought Extremes Likely To Stress Ecosystem Productivity Equally Or More In A Warmer, Co2rich Future, Christopher A. Williams
Heat And Drought Extremes Likely To Stress Ecosystem Productivity Equally Or More In A Warmer, Co2rich Future, Christopher A. Williams
Geography
Reduced carbon uptake caused by recent heat and drought extremes raises concerns about biospheric feedbacks that amplify global warming. However, elevated carbon dioxide is expected to boost terrestrial ecosystem productivity over the 21st century, potentially alleviating some of the adverse carbon impacts of climate extremes. Using CMIP5 earth system model (ESM) results, Ian Williams and colleagues (2014 Environ. Res. Lett. 9 094011) find that the carbon impacts of heat and drought extremes in the future are likely to be similar to those seen in today's climate only shifted toward fluctuations around a higher average temperature. However, they also find that …
Impacts Of Disturbance History On Forest Carbon Stocks And Fluxes: Merging Satellite Disturbance Mapping With Forest Inventory Data In A Carbon Cycle Model Framework, Christopher A. Williams, G. James Collatz, Jeffrey Masek, Chengquan Huang, Samuel N. Goward
Impacts Of Disturbance History On Forest Carbon Stocks And Fluxes: Merging Satellite Disturbance Mapping With Forest Inventory Data In A Carbon Cycle Model Framework, Christopher A. Williams, G. James Collatz, Jeffrey Masek, Chengquan Huang, Samuel N. Goward
Geography
Forest carbon stocks and fluxes are highly dynamic following stand-clearing disturbances from severe fire and harvest and this presents a significant challenge for continental carbon budget assessments. In this work we use forest inventory data to parameterize a carbon cycle model to represent post-disturbance carbon trajectories of carbon pools and fluxes for specific forest types growing in high and low site productivity class settings. We then apply these trajectories to landscapes and regions based on forest age distributions derived from either the FIA data or from Landsat time series stacks (1985-2006) for 54 representative scenes throughout most of the conterminous …
A Full Greenhouse Gases Budget Of Africa: Synthesis, Uncertainties, And Vulnerabilities, R. Valentini, A. Arneth, A. Bombelli, S. Castaldi, R. Cazzolla Gatti, F. Chevallier, P. Ciais, E. Grieco, J. Hartmann, M. Henry, R. A. Houghton, M. Jung, W. L. Kutsch, Y. Malhi, E. Mayorga, L. Merbold, G. Murray-Tortarolo, D. Papale, P. Peylin, B. Poulter, P. A. Raymond, M. Santini, S. Sitch, G. Vaglio Laurin, G. R. Van Der Werf, Christopher A. Williams, R. J. Scholes
A Full Greenhouse Gases Budget Of Africa: Synthesis, Uncertainties, And Vulnerabilities, R. Valentini, A. Arneth, A. Bombelli, S. Castaldi, R. Cazzolla Gatti, F. Chevallier, P. Ciais, E. Grieco, J. Hartmann, M. Henry, R. A. Houghton, M. Jung, W. L. Kutsch, Y. Malhi, E. Mayorga, L. Merbold, G. Murray-Tortarolo, D. Papale, P. Peylin, B. Poulter, P. A. Raymond, M. Santini, S. Sitch, G. Vaglio Laurin, G. R. Van Der Werf, Christopher A. Williams, R. J. Scholes
Geography
This paper, developed under the framework of the RECCAP initiative, aims at providing improved estimates of the carbon and GHG (CO2, CH4 and N2O) balance of continental Africa. The various components and processes of the African carbon and GHG budget are considered, existing data reviewed, and new data from different methodologies (inventories, ecosystem flux measurements, models, and atmospheric inversions) presented. Uncertainties are quantified and current gaps and weaknesses in knowledge and monitoring systems described in order to guide future requirements. The majority of results agree that Africa is a small sink of carbon on an annual scale, with an average …