Ecosystem functions
Energy circuits, food chains, diversity patterns in time and space,
nutrient cycles, development and evolution, and control within an
ecosystem.
Ecotone
A habitat created by the juxtaposition of distinctly different habitats;
an edge habitat; an ecological zone or boundary where two or more
ecosystems meet.
Environmental Monitoring and Assessment Program (EMAP)
It was a research program run by USEPA’s Office of Research and
Development to develop the tools necessary to monitor and assess
the status and trends of national ecological resources. EMAP developed indicators to monitor the condition of ecological resources.
Entire
Being whole, not convoluted or divided into distinct spatial parts. In
EMAP, this property affects the precision of certain sample
statistics.
Environment
“The sum of all external conditions affecting the life, development,
and survival of an organism.”
Environmental
assessment
An environmental analysis prepared pursuant to the National Environmental Policy Act to determine whether a federal action should
significantly affect the environment and thus require a more detailed
environmental impact statement.
EPA Spatial Data Library
System (ESDLS)
It is utilizing coordinates from the geospatial structures.
Epidemiologic ecology
The study of the effects of human, physical, biological, and chemical stressors on conditions of ecosystems, broadly conceived. This
area of ecology uses epidemiological concepts and methods to
associate ecological effects or responses with stressors through
assessments, long-term monitoring data, and results of research.
Equal-area (equivalent)
projection
One of a class of map projections that preserves area relationships
between the map and the surface of the earth. On an equal-area
projection, two areas that are equal on the surface of the earth will
also be equal on the map. A projection cannot be both conformal
and equal area.
Estuary
“Regions of interaction between rivers and nearshore ocean waters,
where tidal action and river flow mix fresh and salt water. Such
areas include bays, mouths of rivers, salt marshes, and lagoons.
These brackish water ecosystems shelter and feed marine life, birds,
and wildlife.” In EMAP, large estuaries are defined as those estuaries greater than 260 km2 in surface area and with aspect ratios
(i.e., length/average width) of less than 20. Large tidal rivers are
defined as that portion of the river that is tidally influenced (i.e,
detectable tide >2.5 cm), greater than 260 km
2
, and with an aspect
ratio of greater than 20. Small estuaries and small tidal rivers are
those systems whose surface areas fell between 2.6 km
2 and
260 km
2
.
Extensive resource
A resource covering a large area that is not ecologically integrated
and is not a collection of natural units, for example, large marshes or
rangelands. Characterization of an extensive resource is scaledependent.
40-hex
The landscape description hexagon that is established on each of the
grid points in the EMAP grid. Actual size of these hexagons is
634.5/16 ¼ 39.7 km2.
Forest
Land with at least 10% of its surface area stocked by trees of any
size or formerly having had such trees as cover and not currently
built up or developed for agricultural use.
5 Geographic Information Systems and Remote Sensing Applications in Environmental. . . 223
Energy circuits, food chains, diversity patterns in time and space,
nutrient cycles, development and evolution, and control within an
ecosystem.
Ecotone
A habitat created by the juxtaposition of distinctly different habitats;
an edge habitat; an ecological zone or boundary where two or more
ecosystems meet.
Environmental Monitoring and Assessment Program (EMAP)
It was a research program run by USEPA’s Office of Research and
Development to develop the tools necessary to monitor and assess
the status and trends of national ecological resources. EMAP developed indicators to monitor the condition of ecological resources.
Entire
Being whole, not convoluted or divided into distinct spatial parts. In
EMAP, this property affects the precision of certain sample
statistics.
Environment
“The sum of all external conditions affecting the life, development,
and survival of an organism.”
Environmental
assessment
An environmental analysis prepared pursuant to the National Environmental Policy Act to determine whether a federal action should
significantly affect the environment and thus require a more detailed
environmental impact statement.
EPA Spatial Data Library
System (ESDLS)
It is utilizing coordinates from the geospatial structures.
Epidemiologic ecology
The study of the effects of human, physical, biological, and chemical stressors on conditions of ecosystems, broadly conceived. This
area of ecology uses epidemiological concepts and methods to
associate ecological effects or responses with stressors through
assessments, long-term monitoring data, and results of research.
Equal-area (equivalent)
projection
One of a class of map projections that preserves area relationships
between the map and the surface of the earth. On an equal-area
projection, two areas that are equal on the surface of the earth will
also be equal on the map. A projection cannot be both conformal
and equal area.
Estuary
“Regions of interaction between rivers and nearshore ocean waters,
where tidal action and river flow mix fresh and salt water. Such
areas include bays, mouths of rivers, salt marshes, and lagoons.
These brackish water ecosystems shelter and feed marine life, birds,
and wildlife.” In EMAP, large estuaries are defined as those estuaries greater than 260 km2 in surface area and with aspect ratios
(i.e., length/average width) of less than 20. Large tidal rivers are
defined as that portion of the river that is tidally influenced (i.e,
detectable tide >2.5 cm), greater than 260 km
2
, and with an aspect
ratio of greater than 20. Small estuaries and small tidal rivers are
those systems whose surface areas fell between 2.6 km
2 and
260 km
2
.
Extensive resource
A resource covering a large area that is not ecologically integrated
and is not a collection of natural units, for example, large marshes or
rangelands. Characterization of an extensive resource is scaledependent.
40-hex
The landscape description hexagon that is established on each of the
grid points in the EMAP grid. Actual size of these hexagons is
634.5/16 ¼ 39.7 km2.
Forest
Land with at least 10% of its surface area stocked by trees of any
size or formerly having had such trees as cover and not currently
built up or developed for agricultural use.
5 Geographic Information Systems and Remote Sensing Applications in Environmental. . . 223