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Glossary & Important Terms

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AGTSL3: Percent Agriculture / Grassland on Slopes greater than 3%


E. coli: the bacteria species Escherichia coli

ECOLI_PRED: Escherichia coli Cell Count Predictions (bacterial cells/100 ml)

Ecological Driver: An ecological element that causes a change in an organism, community, ecosystem, or other ecological component of the landscape. An ecological driver may be biotic (e.g., an invasive plant species that causes a decrease in the biological diversity of a forest) or abiotic (e.g., a fire that causes a decrease in the biological diversity of a forest)

Ecological Receptor: An ecological element that is affected (either directly or indirectly) by an ecological driver. For example, the understory plant species that are extirpated as a result of a forest fire are ecological receptors)

Endpoint: Endpoints describe a characteristic of an ecosystem of interest, and should be an ecologically relevant measurement. An endpoint can be any parameter, from a biochemical state to an ecological community's functional condition

EPA: Environmental Protection Agency

Eutrophic: Waters or soils that are rich in nutrients and have high primary productivity

Extirpated: Locally extinct


FGDC: The Federal Geographic Data Committee Exit EPA disclaimer , which coordinates the development of the National Spatial Data Infrastructure


GIS: Geographic Information System(s)


HUC: Hydrologic Unit Code


Karst topography: A type of topography that is formed over limestone, dolomite, or gypsum by dissolution and characterized by sinkholes, caves, and underground drainage


Landsat Exit EPA disclaimer : The satellite based U.S. National Aeronautics and Space Administration project that, in the late 1960s and early 1970s, endeavored to observe land features from space. The program has evolved by the launching of a total of seven satellites to date. Landsat imagery is used for a variety of earth observations

Landscape: A complex concept encompassing several definitions: For the purposes of this report, a landscape is an area containing a mosaic of land-cover "patches", i.e., distinct areas that can be defined or mapped. The traits, patterns, and structure of a specific geographic area including its biological composition, its physical environment, and its anthropogenic or social patterns

Landscape characterization: The process of documenting the traits and patterns of the essential elements of the landscape

Landscape ecology: The study of the distribution patterns of communities and ecosystems, the ecological processes that affect those patterns, and changes in pattern and process over time and space

Landscape indicator: A measurement of the landscape, calculated from mapped or remotely sensed data, used to describe some other spatial or temporal pattern(s) of land-use or land-cover across a geographic area

Landscape metric: A measurement of a component or components (e.g., patches of forest) within the landscape, which is used to characterize composition and spatial configuration of the component within the landscape (e.g., forest size, fragmentation, proximity to other land-cover types). For the purposes of this document, synonymous with a 'Landscape Ecology Metric'

Landscape unit: A reference unit (usually of area) that is being measured, mapped, or described


Natural Breaks: Classes are based on natural groupings of data values. Natural break points are identified by looking for groupings and patterns inherent in the data. The features are divided into classes whose boundaries are set where there are relatively large jumps in the distribution of data values

NED: National Elevation Dataset

NLCD: National Land-Cover Dataset

NWIS: National Water Information System


Oligotrophic: Waters or soils that are poor in nutrients and have low primary productivity

ORD: Office of Research and Development


PAGT: Percent Total Agriculture / Grassland

PAGTC: Land-Cover Percent Agriculture / Grassland Change

Patch: A discrete land-cover unit, for example, a "patch of forest" is a specific 25-acre wooded area in Taney County, Missouri

PBAR: Percent Barren

PCTIARD: Percent Impervious Surfaces

PDF: A document in Adobe Portable Document Format (PDF); the filename extension is .pdf; See EPA's PDF page to learn more.

PERM: Permeability (in / hr)

PFOR: Percent Forest

PFORC: Land-Cover Percent Forest Change

Primary productivity: The rate at which biomass is produced by organisms, which synthesize complex organic substances from simple inorganic substrates, such as in photosynthesis

PRISM: Parameter-elevation Regressions on Independent Slopes Model

PURB: Percent Urban

PURBC: Land-Cover Percent Urban Change


Quantile: Each class contains an approximately equal number (count) of features. A quantile classification is well-suited to linearly distributed data. Because features are grouped by the number within each class, the resulting map can be misleading, in that similar features can be separated into adjacent classes, or features with widely different values can be lumped into the same class. This distortion can be minimized by increasing the number of classes


RAGT120: Percent Total Agriculture / Grassland within 120m of Streams

RDDENS: Road Density (km road/km²)

Reporting Unit: Any defined area (e.g., an 8-digit USGS hydrologic unit code "HUC" or portion, thereof) for which a landscape metric (e.g., percent urban) is calculated

RFOR120: Percent Forest within 120m of Streams

ROUGH: Roughness coefficient (unitless)

RURB120: Percent Urban within 120m of Streams

RUSLE: Revised Universal Soil Loss Equation

RUSLE_A_KHY: Gross Soil Erosion [RUSLE] (kg / ha / yr)

RUSLE_K: Soil surface erodibility [K factor] (unitless)


SEDMOD: Spatially Explicit Sediment Delivery Model

SEDMOD_KHY: Net Sediment Delivery [SEDMOD] (kg / ha / yr)

Standard Deviation: Classes show the amount a feature's attribute value varies from the mean value of the distribution. Class breaks are generated by successively adding or subtracting the standard deviation from the mean. A two-color ramp is best used to emphasize values above or below the mean. It is particularly useful in viewing spatial variability of a parameter

STATSGO: State Soil Geographic (database)

STORET: STOrage and RETrieval system

STRMDENS: Stream Density (km stream/km²)


TAM_PRED: Total Ammonia Concentration Predictions (mg/L)

TP_PRED: Total Phosphorus Concentration Predictions (mg/L)


Water-Quality Pour Point: A field-based water-quality sampling station location, for which an associated subwatershed is determined. Each 'pour point' can be considered the final exit point of surface water, from which precipitation (that falls within the associated subwatershed) exits

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