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“Thresholding” for Stream Raster

“Thresholding” for Stream Raster


Using ASTER DEM, I have created Flow Accumulation. However, to create stream order, I was asked to input flow accumultation and stream raster. But I cannot find how to get the stream raster. Some forums say that I should threshold flow accumulation. How do I do this? Please guide me in the right direction.

I am using ArcGIS 10.


As you are using ArcGIS 10, search the help for the topic Identifying stream networks. As you'll discover you need to use the CON tool.


The help file entries for Hydrologic Analysis are very good, and lead you step-by-step through the processes needed to create your stream network in ArcGIS.

If you follow these steps in order you should find the answer you're looking for.


How To extract streams and define basins From ASTER.

https://www.youtube.com/watch?v=5T64dpFrZ2Y


Spatial characterization of surface water vulnerability to diffuse pollution related to pesticide contamination: case of the Gimone watershed in France

The preservation of natural resources via the management of diffuse pollution is currently considered to be a significant challenge in France. Pollution reduction policies are notably based on the identification of vulnerable areas. In this context, our work aims to develop a method for characterizing the surface water vulnerability to phytosanitary pollution by implementing an interdisciplinary methodology combining geomatics, environmental science and agronomy. Such work consists in offering local stakeholders a decision support tool towards the participatory management of the diffuse pollution issue. This study is based on the geographic contribution of spatial analysis to the large-scale and high-definition identification of physical elements of the environment. It is also based on the study of agro-environmental indicators for the analysis of phytosanitary pressure on watercourses. The combination of these different data sources will make it possible to assess the vulnerability of diffuse pollution at a territorial level, by taking into account factors of agricultural pressure at plot level (crop types and phytosanitary practices), as well as factors of environmental sensitivity at watershed level (pedology, rainfall, topography, etc.). The results obtained will be mapped at plot level, then at the level of the Gimone watershed located in the southwest of France.

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Descriptions

  • Riegelmann, Edward A.
  • The Cape Verde Islands, off the coast of West Africa, are subject to violent precipitation events that cause extensive soil erosion and degradation of the landscape. A systematic approach to the collection, analysis, and dissemination of hydrophysical and geographic data was needed to effectively analyze the cause and effect variables of landscape erosion at the watershed scale. A methodology incorporating geographic information system (GIS) analysis and modified stream reach inventory and channel stability evaluation techniques was developed for Ribeira da Boca Larga drainage on Santiago Island, Republic of Cape Verde. The stream reach inventory employed is a modified version of Pfankuch's "Stream Reach Inventory and Channel Stability Evaluation" (1975). Modifications were made due to the unique environmental conditions encountered in Cape Verde. The geographic information system runs on an IBM PC-AT compatible micro-computer and consists of three popular vector and raster geographic data storage and analysis software packages linked together by a fourth software bundle developed for custom communication and analysis of geographic data. Data from the stream reach inventory and geographic information system were combined to create uniform channel reach analyses and automated GIS products. These products are designed to assist the watershed manager, land use planner, and agricultural engineer in developing a concerted response to erosional phenomena in the evaluated drainage. The integrated stream reach inventory and geographic information system methodology was developed to serve as a model for watershed analysis throughout the Cape Verde Archipelago.
  • Oregon State University
  • File scanned at 300 ppi (Monochrome) using ScandAll PRO 1.8.1 on a Fi-6770A in PDF format. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR.
  • description.provenance : Approved for entry into archive by Patricia Black([email protected]) on 2012-07-19T20:28:56Z (GMT) No. of bitstreams: 1RiegelmannEdwardA.pdf: 52135806 bytes, checksum: b4a6b13770c6b27ba78a0c955af3269a (MD5)
  • description.provenance : Submitted by Kaylee Patterson ([email protected]) on 2012-07-18T21:33:48ZNo. of bitstreams: 1RiegelmannEdwardA.pdf: 52135806 bytes, checksum: b4a6b13770c6b27ba78a0c955af3269a (MD5)
  • description.provenance : Made available in DSpace on 2012-07-19T20:28:56Z (GMT). No. of bitstreams: 1RiegelmannEdwardA.pdf: 52135806 bytes, checksum: b4a6b13770c6b27ba78a0c955af3269a (MD5) Previous issue date: 1989-02

&ldquoThresholding&rdquo for Stream Raster - Geographic Information Systems

Here we aim to bundle a variety of tools, including those that were used and/or developed in the framework of the BioFresh project . We feature:

The icons for each tool link to the manual, the website, open the tool, show a video tutorial or other relevant information. Just hover your mouse over the icons to learn more.

Freshwater Key Biodiversity Areas

Search for Freshwater Key Biodiversity Areas (KBA) based on parameters such as country, basin type and KBA type.

Freshwater AquaMaps for Europe

Freshwater AquaMaps is an approach to generating model-based, large-scale predictions of freshwater species and is based on a methodology, which was originally developed for marine mammals. Models for the freshwater AquaMaps are constructed from estimates of the environmental tolerance of a given species with respect to elevation, temperature, soil pH, soil moisture, soil carbon, precipitation and the Compound Topographic Index (a wetness index) and occurrence data available through FishBase and GBIF. Maps show the colour-coded relative likelihood of a species to occur in a global grid of half-degree latitude/longitude cell dimensions, which corresponds to about 50 km near the equator.

Predictions are generated by matching habitat usage of species, termed environmental envelopes, against local environmental conditions to determine the relative suitability of specific geographic areas for a given species. Knowledge of species' distributions within FishBase, FAO areas or bounding boxes is also used to exclude potentially suitable habitats in which the species is not known to occur.

Environmental parameter layers and drainage basins based on the Pfaffstetter system have been established for European freshwater fishes, amphibians, and mammals. Parameters were tested by calculating their relative contribution to the predicted distribution patterns for different organisms. Predicted ranges have been tested against IUCN shapefile boundaries based on known distributions. AquaMaps is relatively insensitive to gaps in occurrence data and uses presence only for calculation of ranges.

The European AquaMaps are currently available for a dozen of freshwater species and will be produced for a wider range of species in the near future. These maps can be consulted at European AquaMaps at aquamaps.org

Within the Freshwater Biodiversity Data Portal you can either use the dedicated AquaMaps viewer or visualise the AquaMaps during occurrence searches (if available).

More background information on AquaMaps in general is available at aquamaps.org

Near-global freshwater-specific environmental variables

The dataset consists of near-global, spatially continuous, and freshwater-specific environmental variables in a standardized 1km grid.

The authors delineated the sub-catchment for each grid cell along the HydroSHEDS river network and summarized the upstream environment (climate, topography, land cover, surface geology and soil) to each grid cell using various metrics (average, minimum, maximum, range, sum, inverse distance-weighted average and sum).

All variables were subsequently averaged across single lakes and reservoirs of the Global lakes and Wetlands Database that are connected to the river network. Monthly climate variables were summarized into 19 long-term climatic variables following the “bioclim” framework.

To facilitate the generation of freshwater variables for custom study areas and spatial grains, the “r.stream.watersheds” and “r.stream.variables” add-ons for the GRASS GIS software are provided by the authors.

River Network Toolkit (RivTool)

Freshwater ecosystems are one of the most diverse environments of the world and also one of the most endangered. These systems are affected at multiple scales by the surrounding landscape, including all existing human activities in that area. Integrating environmental landscape data and hierarchic river networks with subsequent summarisation and synthesis of information for large and comprehensive areas at different scales (e.g.: basin, sub-basin, upstream drainage area) is a requirement for an effective research, conservation, and management of river basins. By requiring multiple scale analysis combined with the dendritic nature of river networks and the exponential growth of raw layers of digital information for landscape, these analysis lead to demanding hardware requirements and hardly manageable processing times. Common geographic information systems (GIS) are limited to perform summarisations or automatised calculations along the directed, hierarchical pathways of a freshwater network.

The River Network Toolkit (RivTool) is a software that supports combining and analysing areal information from river basins and hierarchical linear data of river networks. It allows the acquisition of (1) information that characterises freshwater networks based on its topographic nature (2) data obtained via mathematical calculations that account for the hierarchical and network nature of these systems and (3) different types of information resulting from up and downstream summarisations. This user-friendly software considers two units of analysis (segment and sub-basin), it uses tabular processes only and is time effective even with large datasets. It contains network, data and label libraries of both ECRINS and CCM2 databases. RivTool facilitates and reduces time required for extracting information for freshwater ecosystems. Thus, it may contribute to increase scientific efficiency, productivity and accurateness when improving or creating novel knowledge on large-scale patterns and processes in river networks.

Maxent software for species habitat modeling. Software based on the maximum-entropy approach for species habitat modeling.

Spatial Analysis in Macroecology (SAM)

SAM (Spatial Analysis in Macroecology) is a Windows program designed as a package of tools for spatial statistical analysis, mainly for applications in Surface Pattern Spatial Analysis.

Geospatial Modelling Environment

GME is an analysis and modeling environment for geospatial analysis that is designed to facilitate rigorous analysis of geospatial data. Windows program requiring the statistical software R and ESRI ArcGIS to drive geospatial analyses.

ModestR: a software tool for managing and analyzing species distribution map databases

Distance sampling

The Distance project provides software for the design and analysis of distance sampling surveys of wildlife populations. This software takes two forms: a Windows-based program and a suite of packages for the statistical programming language R.

WISER methods database

The WISER methods database details national assessment methods used to classify the ecological status of rivers, lakes, coastal and transitional waters from different EU member states.

ASTERICS (version 3.1.1) calculates the ecological status of rivers based on benthic invertebrate taxa lists. The assessment fulfills the demands of the WFD. The German Assessment System PERLODES is part of the software.

An online version is under development and will available end of 2018.

ECOPROF is the Austrian assessment software to calculate the ecological status of rivers and streams based on macro-invertebrates and phytobenthos. The assessment is in accordance with the WFD. ECOPROF also hosts the Austrian macro-invertebrate inventory as well as ecological preferences of species.

EFI+ (Improvement and Spatial extension of the European Fish Index)

The EFI+-tool (Improvement and Spatial extension of the European Fish Index) allows assessing the ecological status of rivers in accordance with the EU Water Framework Directive. The tool is based on the European Fish Index (EFI) developed within the FAME and EFI+ project as a standardized fish-based assessment method applicable across a wide range of European rivers. The EFI employs a number of environmental descriptors (see documentation on the data input matrix) to predict biological reference conditions and quantifies the deviation from reference conditions on a statistical basis.

Taxa Entry Tool

Tool to produce a standardized taxalist for macro-invertebrates macrophytes, fish, phytoplankton or diatoms.

Facilitating the application of Output from REsearch and CAse STudies on Ecological Responses to hydro-morphological degradation and rehabilitation.

More about FORCASTER could be found at the REFORM wiki

STREAMES-EDSS

STream REAch Management: an Expert System. STREAMES-EDSS 1.0 is an Environmental Decision Support System, a computer application that supports the decision-making processes in stream reach management by encompassing heuristic (expert) and empirical information.

Eco Evidence

Eco Evidence is a unique tool for performing systematic literature review. It allows users to document and extract causes and effects and their response direction in a standardized manner. As such, the tool helps users to perform a systematic review of the scientific literature focussing on a specific cause-and-effect hypothesis. Eco Evidence consist of an online database and a desktop application for data analysis.

CADDIS, or the Causal Analysis/Diagnosis Decision Information System, is an online application designed to help users conduct causal assessments, primarily in stream ecosystems. It provides a logical, step-by-step framework for Stressor Identification based on the U.S. EPA’s Stressor Identification Guidance Document, as well as additional information and tools that can be used in these assessments.

R is a powerful, free cross-platform environment for statistical computing and graphics. This software is required to use the packages mentioned below.

Bioclim - Bioclimatic Variables

bioclim recreates the standard 19 bioclimatic variables (BIOCLIM) created using ANUCLIM or used by Worldclim .

Download at cran or install with install.package ("bioclim",repos="http://r-forge.r-project.org")

BIOMOD is R-package for ensemble forecasting of species distributions, enabling the treatment of a range of methodological uncertainties in models and the examination of species-environment relationships.

Download at cran or install with install.packages ("BIOMOD",repos="http://r-forge.r-project.org")

dismo: Species distribution modeling

Functions for species distribution modelling, predicting entire geographic distributions from occurrences at a number of sites.

Download at cran or install with install.packages ("spatstat",repos="http://cran.r-project.org")

gam: Generalized Additive Models

Functions for fitting and working with generalized additive models, as described in chapter 7 of "Statistical Models in S" (Chambers and Hastie (eds), 1991), and "Generalized Additive Models" (Hastie and Tibshirani, 1990).

Download at cran or install with install.packages ("gam",repos="http://cran.r-project.org")

Generalized Boosted Regression Models. gbm package, found in Elith, J, J. R. Leathwick and T. Hastie. 2008. A working guide to boosted regression trees. Journal of Animal Ecology. 77: 802-813.

Download at cran or install with install.packages ("gbm",repos="http://cran.r-project.org")

MASS: Support Functions and Datasets for Venables and Ripley's MASS

Functions and datasets to support Venables and Ripley, 'Modern Applied Statistics with S' (4th edition, 2002).

Download at cran or install with install.packages ("MASS",repos="http://cran.r-project.org")

randomForest: Breiman and Cutler's random forests for classification and regression

Classification and regression based on a forest of trees using random inputs.

Download at cran or install with install.packages ("randomForest",repos="http://cran.r-project.org")

rpart: Recursive Partitioning and Regression Trees

Recursive partitioning for classification, regression and survival trees. An implementation of most of the functionality of the 1984 book by Breiman, Friedman, Olshen and Stone.

Download at cran or install with install.packages ("rpart",repos="http://cran.r-project.org")

Spatial dependence: weighting schemes, statistics and models.

Download or install with install.packages ("spdep",repos="http://cran.r-project.org")

An R library for spatial statistics.

Download at cran or install with install.packages ("spatstat",repos="http://cran.r-project.org")

raster: Geographic data analysis and modeling

Reading, writing, manipulating, analyzing and modeling of gridded spatial data. The package implements basic and high-level functions. Processing of very large files is supported.

Download package at cran or install with install.packages ("raster",repos="http://cran.r-project.org")

Vegan: R functions for vegetation ecologists. Useful tool for vegetation/community analysis. Contains the major ordination methods, dissimilarity indices and tools for biodiversity, species richness and abundance analysis.

Download package at cran or install with install.packages ("vegan")

Or get the development version at R-forge or install with install.packages ("vegan",repos="http://r-forge.r-project.org")

Reol: R interface to the Encyclopedia of Life

An R interface to the Encyclopedia of Life API. Includes functions for downloading and extracting information off the EOL pages.

More info: Barbara L. Banbury & Brian C. O’Meara (2014) Reol: R interface to the Encyclopedia of Life. Ecology and Evolution 4(12):2577–2583. doi:10.1002/ece3.1109

Download package at cran or install with install.packages ("reol",repos="http://cran.r-project.org")

Packages used for statistical testing of model parameters

These packages where for instance used in the parameter selection for AquaMaps.

HH: Statistical Analysis and Data Display: Heiberger and Holland - see details at cran

ROCR: prediction - performance - plot - see details at mpi

Earthpoint Excel to KML

Simple on-line tool to convert coordinates in Excel to a KML-file which can be viewed in Google Earth.

World Coordinate Converter

A tool to convert geodetic coordinates in a wide range of reference systems.

Quantum GIS

User friendly Open Source Geographic Information System (GIS).

Geographic Resources Analysis Support System. Commonly referred to as GRASS, this is free Geographic Information System (GIS) software used for geospatial data management and analysis, image processing, graphics/maps production, spatial modeling, and visualization.


Geography (GEG)

Geographers study places, regions, and human-environment interactions in order to develop a broad, integrated understanding of the earth—the home of humanity. The study of geography helps students understand and appreciate the world’s diverse landscapes, and environments. Geographers bridge the social and natural sciences to examine critical issues such as environmental degradation, economic development, globalization, migration, urbanization, population growth, natural hazards, climate change, and land-use change. Geography is a practical discipline providing a solid foundation for the effective management of earth resources and the creation of sustainable communities.

To help explore and map a changing world, geographers use sophisticated tools such as geographic information systems (GIS ) and remote sensing. Because getting out of the classroom is vital to learning geography, many geography classes offer field trips or experiences with diverse cultures. The Geography Department promotes fieldwork, internships, travel courses, and study abroad. With planning, many courses taken abroad can count toward the Geography major. Geography students also have opportunities to collaborate with faculty on research projects that benefit communities. Geography graduates find vocational opportunities in fields such as GIS , cartography, community development, teaching, location analysis for business, environmental management, and urban and regional planning.

Nine courses distributed as follows:

  1. Three-course Geography core: GEG-101, GEG-102, and GEG-105.*
  2. One regional method course: GEG-232, GEG-233, or GEG-235.
  3. Two courses in geographic research methods: GEG-240 and GEG-342.
  4. Three additional Geography courses, one of which must be at the 300-level (except internships or independent studies).

*GEG-105 may be substituted by taking BIO-101, GEO-111 and GEO-246.

Geography Major with Honors:

The Geography with Honors option is for those students who wish to undertake a significant independent thesis project as a culmination of their study in geography. This opportunity is geared to those students considering entering graduate school. Participation is by application to the department chair during the junior year. To be eligible, students must maintain an overall GPA of at least 3.5. In addition to the course requirements listed above, Honors majors conduct research and write a thesis under the direction of a member of the department and defend their thesis before the department. Honors majors are strongly encouraged to present their thesis at a professional meeting in their senior year. Honors majors enroll in GEG-397 to work on their thesis.

Ten courses distributed as follows:

  1. Three-course Geography core: GEG-101, GEG-102, and GEG-105.*
  2. One regional method course: GEG-232, GEG-233, or GEG-235.
  3. Two courses in geographic research methods: GEG-240 and GEG-342.
  4. Three additional Geography courses, one of which must be at the 300-level (except internships or independent studies).
  5. Honors thesis: GEG-397.

The minor consists of five Geography courses.

  1. One earth system course: GEG-105 or GEG-108.
  2. One human systems course: GEG-101 or GEG-102.
  3. Three Geography electives, no more than one from the 100-level (except Internships and Independent studies).

101 &emsp Introduction to Human Geography &emsp (1 course) &emspLike a work of art, the earth’s surface is a beautiful, intricate, and often bewildering mosaic of places and landscapes. These places and landscapes are arranged and organized according to specific cultural, economic, social, and political processes. Human geography studies those processes in order to understand the resultant patterns they create and ways of life they support. This course is a topical survey of human geography introducing cultural, economic, population, political, and urban geography. SOSCI, Fall and Spring semesters.

102 &emsp World Regional Geography &emsp (1 course) &emspA comparative study of the physical and cultural characteristics of selected world regions including Africa, Latin America, South and East Asia, the Middle East, and Europe. NWEST, Fall and Spring semesters.

105 &emsp Introduction to Physical Geography: Earth System Science &emsp (1 course) &emspThis course focuses on understanding “the way things work” in the biophysical world, and is centered on interactions between the water cycle, atmosphere, biosphere, and the earth’s surface. Students will come to appreciate the complexity and interconnectedness of the earth system as well as the many ways humans interact with it. We investigate earth’s energy budget the cycles of air, carbon, water, and nutrients feedbacks among oceans, atmosphere, ice, and land climate change and the role living creatures play in maintaining planet earth. Students will also learn how physical forces such as wind, glaciers, rivers, and volcanic activity have sculpted the landscapes we inhabit and continue to modify our environment today. NASP, Fall and Spring semesters.

108 &emsp Weather and Climate &emsp (1 course) &emspAn introduction to the science of the atmosphere, exploring the processes that produce weather events and climate patterns. Students begin by studying earth-sun geometry, the earth’s energy balance, and global circulation patterns for wind and water. We then study weather events, such as, precipitation, mid-latitude cyclones, thunderstorms, tornadoes, and hurricanes. Students are introduced to the basic principles of weather forecasting and climate modeling. The course concludes by examining human interactions with the atmosphere, including vulnerability to natural hazards, air pollution, and climate change. NASP, Fall semester.

232 &emsp The American South &emsp (1 course) &emspA study of the past and present physical and cultural landscapes of the South as a distinctive American region. SOSCI, Fall semester.

233 &emsp Central America/Caribbean &emsp (1 course) &emspThis course focuses on the historical and contemporary geographic landscapes of the Central America/Caribbean region. Past and present physical and cultural environments will be examined, including pre-Columbian cultures, the Spanish conquest, colonialism and neo-colonialism, and the impact of commercial farming, logging, and eco-tourism. NWEST, Spring semester, odd years.

234 &emsp Landscapes of the American West &emsp (1 course) &emspAridity may be the fundamental characteristic of most of the West, setting it apart from the rest of the country. The principal task in this course will be to discuss the ways different cultures have shaped this dry country according to their perceptions of both its physical geography and its cultural milieu. We are interested in the process of cultural landscape change and the unfolding of this story, with the help of maps, DVDs, the images of essayists, poets, painters, musicians, photographers, Hollywood “Westerns,” and many virtual field trips via slides. Spring semester, first-half.

235 &emsp Sub-Saharan Africa &emsp (1 course) &emspThis is a regional course providing an introduction to the physical and human geography of the region south of the Sahara. The influence of the African traditional society, the Islamic diffusion, and the European colonial period, commonly called the “triple heritage,” will be examined. NWEST, Fall semester.

236 &emsp Urban Geography &emsp (1 course) &emspThis course explores the setting in which most of the U.S. population and about half of the world’s people live—the urban setting. Throughout history, urban areas have been the centers of economic, political, and cultural life. Further, many of the critical issues in our society—social polarization, economic restructuring, environmental degradation, traffic congestion, and poverty—are concentrated in America’s urban areas. This course examines the forces that give rise to cities, paying particular attention to the geographic location and changing internal spatial arrangement of cities. Prerequisite: GEG-101 recommended. SOSCI, Spring semester.

240 &emsp Geographic Information Systems &emsp (1 course) &emspIn this course we learn how to collect and manipulate geographic data, create maps, and analyze spatial patterns and relationships. Students learn the underlying theories and concepts of geographic Information science. Lectures and labs introduce both vector and raster geographic data models and a variety of tools for spatial analysis and data visualization. Students will incorporate satellite imagery, aerial photography, terrain, land-use, and census data into a geographic information system (GIS) to solve problems encountered in environmental management, city planning, and business. Fall and Spring semesters.

243 &emsp Water Resources Management &emsp (1 course) &emspThis course examines physical as well as cultural elements of water resource management. After an introduction to the principles of surface and groundwater hydrology, the emphasis turns to the socio-economic aspects of water resource development, including the role of federal, state, and local governments, water rights, and water law. Local, national and international water resource problems are examined from ecological, economic, and social perspectives. Prerequisite: GEG-105 or GEO-111 recommended. Spring semester.

244, 344 &emsp Special Topics in Geography &emsp (1 course, 1 course) &emspLecture and discussion on advanced topics in geography, including regional, planning, or environmental themes. The course may involve field work. Prerequisite: permission of instructor.

GEO-246 &emsp Geomorphology &emsp (1 course) &emspThe study of the earth’s surface and the processes that shape it. Processes discussed include those associated with weathering, streams, glaciers, ground ice, ground water, wind, oceans, tectonism, and volcanism. The laboratory is research oriented and consists of learning basic tools (maps and photos) and applying these to several field research problems. Prerequisite: GEG-105 or GEO-111 or permission of instructor. Fall semester.

250 &emsp Nature and Society &emsp (1 course) &emspSociety is constantly interacting with the environment, transforming landscapes, harvesting materials, disposing of wastes, and setting aside areas for preservation. In this course we step back from particular environmental issues to study conceptual approaches that frame questions of society’s relationship with the environment. Why do environmental problems exist? Does climate change, for example, result from misguided ethics, too many people, unquestioned social norms, market failures, unjust development, lack of cooperation or something else? Students investigate diverse theoretical perspectives that attempt to explain our relationship with the natural world, and critically examine underlying assumptions, strengths, and limitations of each perspective. Fall semester.

336 &emsp Urban and Regional Analysis &emsp (1 course) &emspThis course offers an in-depth exploration of the dynamics of urban and regional change through a combination of readings and geographical analysis. The goal is to better understand the forces shaping the growth and change of towns, cities, and regions, so that students become better informed citizens and are prepared for careers or professional training in urban and regional planning or public policy. The course is organized around three key components of healthy communities and regions: economic, social, and ecological sustainability. Prerequisites: GEG-236 and GEG-240, or permission of instructor. Fall semester, odd years.

342 &emsp Research Methods in Geography &emsp (1 course) &emspAn introduction to research techniques employed in geographic investigations. Emphasis is placed on developing and writing an effective research proposal. Students will learn to situate their research within the existing literature, evaluate different research methods and paradigms, collect and analyze data, and consider ethical issues in research. Prerequisite: GEG-240. WRITD , Spring semester.

343 &emsp Geographic Information Systems II &emsp (1 course) &emspThe purpose of this course is the application of GIS to a variety of geographic and environmental topics. More specifically, the goal is to build on the fundamentals introduced in GEG-340, by focusing on GIS problem solving and dealing with such topics as hydrology, demographics, land use, and land cover change. Each student will be required to execute a research project. Prerequisite: GEG-240. Offered occasionally.

345 &emsp Remote Sensing of the Environment &emsp (1 course) &emspThis course is an introduction to how we map, monitor and understand the physical world as observed from afar through remote sensing techniques. Remote sensing has become the leading method for studying land-cover and landuse change, climate and weather, ocean systems and many environmental issues at local scales. In this course, we focus on understanding the fundamentals of acquiring and interpreting data from satellite-based remote sensing systems. We study the interactions of electromagnetic radiation with the atmosphere and Earth’s surface, learn about the various sensors that are currently available, and discover how to extract useful information from remotely sensed imagery to help understand environmental issues. Through readings, discussions and computer lab work, students will gain an understanding of the possibilities-and limitations-of remote sensing for observing earth system phenomena. Prerequisite: GEG-240, Spring semester, even years.

268, 368 &emsp Career Exploration, Internship &emsp (Course value to be determined) &emspOff-campus employment experience in geography position related to the student’s interest. Prerequisite: one other geography course. Fall, Spring semesters and January Interim.

291, 391 &emsp Independent Study &emsp (.5 to 1 course) &emspIntensive study in any of several topical or regional areas selected by the student after consultation with the advisor. May involve field study away from the campus. Prerequisites: Two other geography courses and submission of study proposal to advisor. Fall and Spring semesters and January Interim.

397 &emsp Geography Honors Thesis &emsp (1 course) &emspStudents perform original research and write a scholarly thesis paper or conduct an advanced mapping/spatial analysis project. Senior geography honors majors are eligible to enroll in this course.


Geography (GEG)

Geography is the study of the relationship between humans and their environments. Geographers study the diversity of the world’s people and places and the processes--both natural and cultural--that build and shape landscapes. Geography draws on the natural and social sciences as both of these ways of producing knowledge are important to understanding the interrelationship of humans and the world around them. Geographers are interested in space and scale and how local processes influence regional and global processes, and vice versa. Because of the attention paid to scale and the uneven distribution of the Earth’s resources, many geographers share a concern for social justice, environmental justice, sustainability, and global equity. Many geographers want not just to study the world, but to change it for the better. Geography is a “muddy boots” discipline: while geographers use books, libraries, classrooms, computers, and labs, a lot of our learning occurs “in the field.” Whether the field is a prairie, farm, forest, desert, suburb, or city, geographers like to study the real world in real time.

The Geography Department cultivates a holistic understanding of human-environment relationships a critical awareness of environmental and global change and knowledge of the world’s diverse regions. We seek to play a major role in the College’s mission of providing an education that “is both interdisciplinary and international in perspective” while simultaneously modeling effective, just engagement with local communities. Geography courses are intellectually stimulating: students are challenged to new understandings of the world around them while developing deeper values of community, service, and justice. We encourage curiosity, problemsolving, collaboration, reflection, and strong oral and written communication. We promote fieldwork, community service, and internships. Study away semesters, cross-cultural learning experiences, and travel courses are strongly encouraged.

Geography graduates continue to careers in natural resource conservation, geospatial analysis, international and community development, urban planning, environmental law and policy, and teaching and research.

Geography Major: Ten courses distributed as follows:

  1. Three-course Geography core: GEG-101, GEG-102, and GEG-105.
  2. Two courses in geographic research methods: GEG-240 and GEG-242.
  3. Five additional Geography courses, one of which must be at the 300-level (except internships or independent studies).

Geography Major with GIS Concentration: Eleven courses distributed as follows:

  1. Three-course Geography core: GEG-101, GEG-102, and GEG-105.
  2. Four courses in geographic research methods: GEG-240, GEG-242, GEG-343, and GEG-345.
  3. One statistics or computer programming course: MCS-140, MCS-142, MCS-177, or E/M-125.
  4. Three additional Geography courses.

Geography Major with Honors: The Geography with Honors option is for those students who wish to undertake a significant independent thesis project as a culmination of their study in geography. This opportunity is geared to those students considering entering graduate school. Participation is by application to the department chair during the junior year. To be eligible, students must maintain an overall GPA of at least 3.5. In addition to the course requirements listed above, Honors majors conduct research and write a thesis under the direction of a member of the department and defend their thesis before the department. Honors majors are strongly encouraged to present their thesis at a professional meeting in their senior year. Honors majors enroll in GEG-242 no later than their junior year to develop a thesis research proposal. During the senior year, Honors majors enroll in GEG-397 to work on their thesis.

Ten courses distributed as follows:

  1. Three-course Geography core: GEG-101, GEG-102, and GEG-105.
  2. Two courses in geographic research methods: GEG-240 and GEG-242.
  3. Four additional Geography courses, one of which must be at the Level III (except internships or independent studies).
  4. Honors thesis: GEG-397.

Geography Minor: The minor consists of five Geography courses.

  1. One earth systems course: GEG-105 or GEG-108.
  2. One human systems course: GEG-101 or GEG-102.
  3. Three Geography electives, no more than one from the Level I (except Internships and Independent studies).

Geographic Information Systems Minor: The minor in Geographic Information Systems (GIS) is limited to students who are not majoring in Geography. The minor consists of five courses selected in consultation with a departmental advisor.

  1. One course in geographic concepts: GEG-101 or GEG-105.
  2. Two GIS courses: GEG-240 and GEG-343.
  3. One statistics or computer programming course: MCS-140, MCS-142, MCS-177, E/M-125, or PSY-224.
  4. One course from: GEG-345, GEG-368 (GIS related), or GEG-391 (GIS related).

Geography Courses

101 Introduction to Human Geography (1 course) Geography is the study of the earth, the home of humanity. This course introduces key geographic theories, models, and concepts in order to explain spatial patterns of human activities, to understand the processes that make and remake places, and to interpret and appreciate the earth’s diverse cultural landscapes. Major topics include the growth and migration of the human population geographic patterns of language, religion, and ethnicity agriculture, resources, and rural land uses the changing geography of the world economy urban diversity and urban land uses and the political organization of territory. SOSCI, Fall and Spring semesters.

102 World Regional Geography (1 course) This course helps students make sense of the world and its diversity of peoples, environments, places, and regions. Central to the course is the exploration of the relationships between global processes and local outcomes In select regions including Africa, Latin America, South and East Asia, the Middle east, and Europe. This course counts toward the African Studies and the Peace Studies minors. GLOBL, Fall and Spring semesters.

105 Introduction to Physical Geography: Earth System Science (1 course) This course focuses on understanding “the way things work” in the biophysical world, and is centered on interactions between the water cycle, atmosphere, biosphere, and the earth’s surface. Students will come to appreciate the complexity and interconnectedness of the earth system as well as the many ways humans interact with it. We investigate earth’s energy budget the cycles of air, carbon, water, and nutrients feedbacks among oceans, atmosphere, ice, and land climate change and the role living creatures play in maintaining planet Earth. Students will also learn how physical forces such as wind, glaciers, rivers, and volcanic activity have sculpted the landscapes we inhabit and continue to modify our environment today. NASP, Fall semester, odd years, and Spring semesters.

108 Weather, Climate, and Society (1 course) An introduction to the science of the atmosphere, exploring the processes that produce weather events and climate patterns. Students begin by studying earth-sun geometry, the earth’s energy balance, and global circulation patterns for wind and water. We then study weather events, such as, precipitation, mid-latitude cyclones, thunderstorms, tornadoes, and hurricanes. Students are introduced to the basic principles of weather forecasting and climate modeling. The course concludes by examining human interactions with the atmosphere, including vulnerability to natural hazards, air pollution, and climate change. NASP, Fall semester.

215 Political Geography: Power, Territories, and States (1 course) This course considers the uneven distribution of political power in the world. It analyses the development of the modern state system, the political boundaries that divide and organize the world, and the rise of nationalism and ethnic conflicts. We pay particular attention to the political organization of space through the study of: states and their territories, geopolitics, and power struggles between and among state, sub-state, and supra-state actors. At the end of the course students will be able to identify, understand, and critically analyze the spaces and places where political power operates both at home and abroad. Pre-requisites: GEG-101 or GEG-102 recommended. SOSCI, Spring semester.

230 The Anthropocene: How Humans are Transforming the Earth (1 course) Some scientists argue that we are entering a new geological epoch, one where the activities of humans are so pronounced that a permanent impact is being left upon the landscape. This epoch is known as the Anthropocene, the age of humans. In this course, we will survey some of these significant bio-geophysical transformations, including discussions of why these transformations are taking place, and what they mean for both natural and human systems now and in the future. Topics will include the geomorphic and hydrologic impact of watershed management the ecological impact of land cover change, wildfire management, and human-introduced invasive species and the geochemical implications of air pollution and widespread fertilization. Pre-requisites: GEG105, GEO-111 or GEO-120 recommended. Spring semester, odd years.

234 Landscapes of the American West (.5 course) Aridity may be the fundamental characteristic of most of the West, setting it apart from the rest of the country. The principal task in this course will be to discuss the ways different cultures have shaped this dry country according to their perceptions of both its physical geography and its cultural milieu. We are interested in the process of cultural landscape change and the unfolding of this story, with the help of maps, DVDs, the images of essayists, poets, painters, musicians, photographers, Hollywood “Westerns,” and many virtual field trips via slides. Spring semester, first-half.

235 Sub-Saharan Africa (1 course) This is a regional course providing an introduction to the physical and human geography of the region south of the Sahara. The influence of the African traditional society, the Islamic diffusion, and the European colonial period, commonly called the “triple heritage,” will be examined. This course counts toward the African Studies and the Peace Studies minors. GLOBL, Spring semester.

236 Urban Geography (1 course) This course explores the setting in which more than half of the world’s people live—the city. Throughout history, urban areas have been the centers of economic, political, and cultural life. Further, many of the world’s critical issues—social polarization, economic restructuring, environmental degradation, traffic congestion, and poverty—are concentrated in urban areas. In short, cities are complex and vibrant phenomena shaped by conflicting economic and cultural processes. This course examines the forces that give rise to cities, and shape their internal spatial patterns. Prerequisite: GEG-101 recommended. SOSCI, Fall semester.

238 Migration and Globalization (1 course) The course explores geographical issues related to migration and globalization. The course is based on recent theoretical contributions within the subfield of the geography of migration. Globalization processes and changes in national states have significance for migrants in our time. The course discusses issues related to multiculturalism, transnationalism, religion, neoliberal political trends, and populism. The course also covers various aspects of international migration like migration flows (including labor migration), irregularity, citizenship, and ethnic identity. Prerequisite: GEG-101 or GEG-102 recommended. GLOBL, Fall semester.

240 Fundamentals of Geographic Information Systems (1 course) In this course we learn how to collect and manipulate geographic data, create maps, and analyze spatial patterns and relationships. Students learn the underlying theories and concepts of geographic informa- tion science. Lectures and labs introduce both vector and raster geographic data models and a variety of tools for spatial analysis and data visualization. Students will incorporate satellite imagery, aerial photography, terrain, land-use, and census data into a geographic information system (GIS) to solve problems encountered in environmental management, city planning, and business. Fall and Spring semesters.

242 Research Methods in Geography (1 course) An introduction to research techniques employed in geographic investigations. Emphasis is placed on developing and writing an effective research proposal. Students will learn to situate their research within the existing literature, evaluate different research methods and paradigms, collect and analyze data, and consider ethical issues in research. Prerequisite: GEG-101 or 102. WRITD, Fall semester, offered Spring 2016.

243 Hydrology and Water Resources (1 course) This course examines physical as well as cultural elements of water resource management. After an introduction to the principles of surface and groundwater hydrology, the emphasis turns to the socio-economic aspects of water resource development, including the role of federal, state, and local governments, water rights, and water law. Local, national and international water resource problems are examined from ecological, economic, and social perspectives. Prerequisite: GEG-105 or GEO-111 recommended. Fall semester, odd years.

244, 344 Special Topics in Geography (1 course, 1 course) Lecture and discussion on advanced topics in geography, including regional, planning, or environmental themes. The course may involve field work. Prerequisite: permission of instructor.

GEO-246 Surface Processes (1 course) The study of the earth’s surface and the processes that shape it. Processes discussed include those associated with weathering, streams, glaciers, ground ice, ground water, wind, oceans, tectonism, and volcanism. The laboratory is research oriented and consists of learning basic tools (maps and photos) and applying these to several field research problems. Prerequisite: GEG-105 or GEO-111 or permission of instructor. Fall semester.

250 Nature and Society (1 course) Society is constantly interacting with the environment, transforming landscapes, harvesting materials, disposing of wastes, and setting aside areas for preservation. In this course we step back from particular environmental issues to study conceptual approaches that frame questions of society’s relationship with the environment. Why do environmental problems exist? Does climate change, for example, result from misguided ethics, too many people, unquestioned social norms, market failures, unjust development, lack of cooperation or something else? Students investigate diverse theoretical perspectives that attempt to explain our relationship with the natural world, and critically examine underlying assumptions, strengths, and limitations of each perspective. Spring semester, also offered Fall semester, 2015.

336 Urban and Regional Analysis (1 course) This course offers an in-depth exploration of the dynamics of urban and regional change through a combination of readings and geographical analysis. The goal is to better understand the forces shaping the growth and change of towns, cities, and regions, so that students become better informed citizens and are prepared for careers or professional training in urban and regional planning or public policy. The course is organized around three key components of healthy communities and regions: economic, social, and ecological sustainability. Prerequisites: GEG-236 or permission of instructor. Spring semester, even years.

343 Problem-Solving Using Geographic Information Systems (1 course) This course introduces students to advanced GIS concepts and the application of GIS theories to a variety of geographic and environmental topics and case studies. The course builds upon GIS fundamentals introduced in GEG-240 by focusing on problem-solving in topical areas such as hydrology, demographics, land use, and land cover change. Cutting-edge GIS concepts will be explored through laboratory exercises, while a semester project allows students to apply GIS concepts to a discipline or area of interest of their choosing. Pre-requisite: GEG-240, Spring semester, even years.

345 Remote Sensing of the Environment (1 course) An introduction to how we map, monitor and understand the bio-physical world as observed from afar through remote sensing techniques. Remote sensing is a leading method for studying land-cover and land-use change, climate and weather, ocean systems and many environmental issues at local scales. In this course, we focus on the fundamentals of acquiring, analyzing and interpreting data from satellite-based remote sensing systems. Through readings, discussions and computer lab work, students will gain an understanding of the possibilities—and limitations—of remote sensing for observing earth. Prerequisite: GEG-240, Fall semester, even years.

268, 368 Career Exploration, Internship (Course value to be determined) Off-campus employment experience in geography position related to the student’s interest. Prerequisite: one other geography course. Fall, Spring semesters and January Interim.

291, 391 Independent Study (.5 to 1 course) Intensive study in any of several topical or regional areas selected by the student after consultation with the advisor. May involve field study away from the campus. Prerequisites: Two other geography courses and submission of study proposal to advisor. Fall and Spring semesters and January Interim.

397 Geography Honors Thesis (1 course) Students perform original research and write a scholarly thesis paper or conduct an advanced mapping/spatial analysis project. Senior geography honors majors are eligible to enroll in this course. Fall and Spring semesters.


Abstract

Core Ideas

  • Clay content, soil organic matter, slope, NDVI, and topographic wetness index delineate management zones.
  • Hard and fuzzy clustering analysis resulted in divisions of two and three areas.
  • Wavelet analysis revealed variability in temporal soil water dynamics between zones.

Due to spatial variability of soil genesis, topography, and resulting soil properties in farmers' fields, soil and crop processes vary in space and time. Therefore, optimum rates and timing of resource applications, such as nutrients and irrigation water, may vary as well. It remains a challenge to quantify the spatial variability of a field and to identify effective ways to manage fields in a site-specific manner. The objective of this study was to delineate management zones within a farmer's field based on relatively easily obtainable information that is statistically integrated. Moreover, soil water temporal dynamics should be evaluated regarding their spatial differences in different zones. The set of direct and indirect observations included clay and silt content, apparent electrical conductivity, soil chemical properties (pH organic matter and total N, P, K, Ca, Mg, and Zn), satellite-based normalized difference vegetation index (NDVI), and lidar-based topographic variables in a western Kentucky field. Several key variables and their capability to describe spatial crop yield variability were identified by using principal component analysis: soil clay content, slope, soil organic matter content, topographic wetness index, and NDVI. Two types of cluster analysis were applied to delineate management zones. The cluster analyses revealed that two to three zones was the optimal number of classes based on different criteria. Delineated zones were evaluated and revealed significant differences in corn (Zea mays L.) yield and temporally different soil moisture dynamics. The results demonstrate the ability of the proposed procedure to delineate a farmer's field into zones based on spatially varying soil and crop properties that should be considered for irrigation management.

Abbreviations

Understanding and managing soil and crop yield variability remains a long-standing challenge. In agroecosystems and natural systems, soil properties such as clay content, pH, soil organic matter (SOM) content, nutrient levels, and profile depth can vary drastically even within the same field ( Beckett and Webster, 1971 Downes and Beckwith, 1951 Koestel et al., 2013 ). Precision agriculture is an approach in agroecosystem management to distribute resources site-specifically according to this variability and the associated varying input demands. The foundation of this concept is the spatial and temporal characterization of soil and crop processes through field measurements taken directly or remotely for maximizing local yield while minimizing environmental risk. Most of the research on management zone delineation has been focused on fertilization, particularly on nitrogen (N) application ( Kitchen et al., 2003 Peralta et al., 2015 Ruffo et al., 2006 ). In other studies, weeds ( Peña et al., 2013 ) and irrigation ( Haghverdi et al., 2016 Landrum et al., 2014 Yari et al., 2017 ) were managed in a site-specific manner.

The application of precision agriculture has increased with advances in remote (largely distanced from the object by using platforms such as towers, vehicles, aircrafts, or satellites) and proximal (in direct contact with the object or close to it) sensing tools ( Vereecken et al., 2016 ). Georeferenced data describing spatial and temporal variability of soil and crop state variables and related processes can be obtained for farmers' fields at high resolution. Yield maps, digital elevation models (DEMs), maps of normalized difference vegetation index (NDVI), or other canopy reflectance indices and apparent electrical conductivity (ECa) are among the most frequently used sources for site-specific management decisions. Yield maps are obtained from yield-monitoring systems installed on combines ( Schepers et al., 2004 ). Digital elevation models can be derived from different sources, including existing soil maps, and at a finer resolution using lidar ( James et al., 2007 ). Many examples exist for using ECa or electrical resistivity to define management zones based on their relationship with other important state variables, such as soil clay content ( Corwin and Lesch, 2003 Moral et al., 2010 Schepers et al., 2004 Sudduth et al., 2003 ). The NDVI can be obtained from different sources, such as proximal sensing (e.g., Greenseeker [ Walsh et al., 2012 ]) or remote sensing (e.g., LANDSAT, MODIS [ Brown et al., 2006 ]). The NDVI is a canopy reflectance index that is strongly related to crop status and fitness. Because it reflects N demand over substantial parts of the growing period of many agricultural crops, NDVI has been frequently studied as a tool in site-specific N application decisions ( Raun et al., 2002 ). Another example of remotely sensed information is the use of cosmic ray neutron probes to characterize soil moisture that has increased in recent years. Cosmic ray neutron probes measure fast neutron intensity, which strongly depends on hydrogen. This intensity can be associated with soil moisture, although it should be calibrated considering that sources of hydrogen besides soil water exist in the field ( Desilets et al., 2010 Ochsner et al., 2013 ). Stationary probes integrate soil moisture over an area that is 100 m in diameter, getting continuous readings of temporal variation. The more recent mobile devices (cosmic ray neutron probe rovers) can cover larger areas ( Finkenbiner et al., 2018 Franz et al., 2015 ) and can be combined with other methods, such as ECa ( Gibson and Franz, 2018 ), although they require surveys to be performed at different times to characterize the temporal variability. Informative data can be obtained through remote and proximal sensing approaches in a much cheaper way and with higher spatial (and in some cases temporal) resolution than with collecting soil and plant samples in cumbersome field campaigns at several times during the growing season. It remains unclear, however, what soil and crop information obtained through remote or proximal sensing, including the previous years' yield maps, is helpful to understand present-year spatial variability of soil and crop stand and to manage the field site-specifically in accordance with previous year information layers.

The challenge persists to manage field soils site-specifically to maximize biomass production efficiency and environmental benefits. Dividing a field into management zones is a promising strategy to overcome this challenge. Management zones are delineated by separating the field into different areas. Some of the areas have different response behaviors, while others may show the same behaviors ( Kitchen et al., 2005 ). Whether areas can be considered to have homogeneous characteristics depends on the situation and is not well known. Whether or not an area is considered homogeneous depends on the variable selected. For example, the delineation of management zones can be based on crop yield maps. The spatial variability of crop yield has been reported to be related to variables such as SOM content ( Mann et al., 2002 ), clay content ( Tremblay et al., 2012 ), and NDVI ( Teal et al., 2006 ). However, spatial yield patterns vary among different years because different processes during the growing season influence them ( Schepers et al., 2004 ). Especially different weather conditions in different years can cause different spatial yield variability patterns even for the same crop species growing in the same field. The key processes and their spatial effect may vary by season, making the spatial biomass production and yield difficult to predict between different seasons. Electrical conductivity (EC) also varies in space and time, being strongly affected by soil moisture and by the salinity of sodic soils, although EC can be used to predict other variables when a strong relationship exists ( Corwin and Scudiero, 2016 ). Moreover, EC data are spatially structured and can be combined in co-regionalization with other variables that remain stable in time, such as topography, soil depth, and clay content.

The delineation of management zones for precision agriculture based on cluster analysis has been proven to be effective to combine the impacts of different variables on the outcome ( Cohen et al., 2013 Johnson et al., 2003 Li et al., 2007 Peralta et al., 2013 Vitharana et al., 2008 Yari et al., 2017 ). The analysis is centered on finding dissimilarities between observations by using a clustering algorithm through partitioning or hierarchical methods ( Kaufman and Rousseeuw, 1990 ). These dissimilarities can be caused by different response behaviors between a target variable and various underlying processes. In a partitioning method, k clusters (data organized in groups) are constructed, and data are classified into k groups. Based on a selected index, the optimal number of clusters within a particular domain can be identified. For example, to work on site-specific irrigation management (e.g., Sadler et al., 2005 ), the right amount of water should be applied at the right time, but locations and their specific behavior in the field should also be considered. Spatial differences in topography and soil physical and chemical properties can be found within the same field. Thus, water infiltration and soil water movement also vary spatially when irrigation is applied. Examples found in the literature ( Nielsen et al., 1973 Wendroth et al., 1999 ) illustrate the spatial and temporal variability of soil water at the field scale. Considering the spatial and temporal variability of soil water at field scale, it may be environmentally and agronomically advantageous to supply irrigation water at variable rates according to field soil water characteristics and the resulting temporal soil water dynamics. Therefore, variables that influence or correlate with soil hydraulic properties and soil water status and dynamics have to be considered in the delineation of areas. Dissimilar soil water temporal variation scales can be expected for different soil properties in different areas of the field. To analyze time-variable behavior at different zones, a wavelet analysis ( Grinsted et al., 2004 ) is an effective strategy because it decomposes time series data in frequency and time, simultaneously allowing to observe periodic variations at different scales and times. In addition, wavelet coherence analyzes and identifies the correlation of pairs of time series data at different time scales. Studies of spatial and temporal changes in soil water using a wavelet analysis are presented by Biswas (2014) , Biswas and Si (2011) , and Yang et al. (2016) .

The challenge of using numerical solutions to delineate management zones is to provide results that are appropriate to be used under farm conditions. Regarding the variable selection, it is essential to consider whether a specific variable represents the field variation of essential processes that underlies site-specific management or what other indirect variable could provide similar information for site-specific management, while its collection is more affordable than another more directly related variable that may be cumbersome to measure. The objective of this study was to apply easily obtainable data using proximal and remote sensing tools to define management zones in a farmer's field located in western Kentucky, which is a typical crop production region in the southeastern United States. Variables should be identified based on different approaches, and zones should be delineated by using fuzzy and hard clustering algorithms. Different approaches should be examined to evaluate if they would result in different delineations. A second objective was to evaluate differences or similarities in process behavior among delineated management zones by comparing spatial differences in corn yield and in temporal dynamics of soil moisture.


Recovery of submersed vegetation in a high mountain oligotrophic soft-water lake over two decades after impoundment

Recovery of the submersed vegetation is a target for the management of soft-water shallow lakes if they are to meet water quality and biodiversity standards. Knowledge of patterns of macrophyte space occupation and time to recovery is poor and mostly restricted to free floating species or riparian vegetation. Here we use pre- and post-impact monitoring data over 20 years showing the evolution of submersed aquatic vegetation of lake Baciver (Pyrenees), and develop models to infer space occupation and time to recovery. We use pre-impact macrophyte distribution in relation to bathymetry-derived data to fit logistic models to further simulate lake equilibrium scenarios. Depth and slope were found to be the best predictors, and models suggested that an assemblage dominated by Sparganium angustifolium was, at time of this study, over 95% of its potential distribution area. A dense, newly grown monospecific Isoetes lacustris population occupied <10% of its potential area and model projections suggest that it will take decades to recover. An I. lacustris residual population remains below the estimated depth threshold for survival and is bound to disappear. The lake appears to evolve towards a new steady-state where the current lake hypsography promotes the expansion of algae (Nitella sp.) over angiosperms.

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Comparative assessment of soil erosion modelling approaches in a Himalayan watershed

The quantitative estimate of soil erosion, in space and time, is valuable information to initiate land degradation measures at a watershed level. In this study, two models, Morgan Morgan Finney (MMF) and universal soil loss equation (USLE), were used in GIS environment to assess the soil erosion, as a function of land use/land cover, soil and topography in a mountainous watershed in the Kashmir Himalayan region, India. The two modelled soil erosion estimates were validated using the available land degradation maps of the area in order to determine their efficacy for soil erosion modelling. The results from the two models showed some similarity between the two soil erosion estimates. However, keeping in view the soil deposition being taken into consideration by MMF (47.33% of watershed area), the disagreement with the USLE soil estimates is understandable. USLE estimated 72.52% of watershed area under 0–1 kg m −2 year −1 while as the MMF model estimated only 41.27% of the watershed area in this category. In both the model results, almost equal area of the watershed has been classified with erosion > 10 kg m −2 year −1 category. Based on the model validation with the available land degradation data, the USLE estimates of soil erosion were found more reliable because of the good correlation with the land degradation maps. The erosion estimates worked out in this study, particularly the categories under very high, high, severe and very severe eroded areas, shall go a long way in framing up the strategies for mitigation and control of soil erosion in the mountainous Himalayan watershed.

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