20.3 Delineation of the Assessment Area and Land Units
20.3 Delineation of the
Assessment Area
and Land Units
20.3.1 Delineation of the
Assessment Area
The assessment area is the region in which data are
gathered and analyzed to characterize biodiversity
(see Chapters 1 and 7) and to recommend ecologically sensible conservation actions that meet the
conservation objectives. This requires a first approximation of broad-scale correlations among regional driving variables (e.g., climate, landforms
such as mountain ranges), broad biotic patterns
(e.g., biomes), and planning units. A number of
ecoregional frameworks (e.g., see Chapters 22 and
23; also Grossman et aI., 1999) can be used as is
or easily modified. Alternatively, de novo frameworks can be created for specific objectives. A can.+.
o 50
200
400 km
295
didate system should be evaluated for its usefulness for a given conservation objective before its
implementation (see Chapter 22), because ecoregions have been reported as both appropriate (Host
et aI., 1996; Bourgeron et aI., 1999a) and not appropriate (Wright et aI., 1998) as a level of analysis for ecological patterns.
A second level, the analysis area, may also need
to be delineated. The analysis area is the geographic
area in which conservation and management actions directly influence patterns in the area's component land units. Often, the assessment area is several times larger than the analysis area and may
need to be subdivided. In this case, RA is conducted
within each analysis area. Such a subdivision of the
assessment area was performed during the Sierra
Nevada Ecosystem Project (SNEP, 1996) for the
selection of biodiversity management areas (Davis
et aI., 1996) and during the Interior Columbia
Basin Ecosystem Management Project (ICBEMP)
(Quigley and Arbelbide, 1997) for conducting land/
/
/
/
/
/
/
/
/
- - Assessment area
CJ Provinces
CJ Analysis area
(Middle Rocky Mounta in Province)
Land unit (Biophysical polygon)
FiGURE 20.1. Map of interior Columbia River basin showing relationships among assessment area, analysis area
(province), and land unit (basic unit of selection for conservation areas).
20.3 Delineation of the
Assessment Area
and Land Units
20.3.1 Delineation of the
Assessment Area
The assessment area is the region in which data are
gathered and analyzed to characterize biodiversity
(see Chapters 1 and 7) and to recommend ecologically sensible conservation actions that meet the
conservation objectives. This requires a first approximation of broad-scale correlations among regional driving variables (e.g., climate, landforms
such as mountain ranges), broad biotic patterns
(e.g., biomes), and planning units. A number of
ecoregional frameworks (e.g., see Chapters 22 and
23; also Grossman et aI., 1999) can be used as is
or easily modified. Alternatively, de novo frameworks can be created for specific objectives. A can.+.
o 50
200
400 km
295
didate system should be evaluated for its usefulness for a given conservation objective before its
implementation (see Chapter 22), because ecoregions have been reported as both appropriate (Host
et aI., 1996; Bourgeron et aI., 1999a) and not appropriate (Wright et aI., 1998) as a level of analysis for ecological patterns.
A second level, the analysis area, may also need
to be delineated. The analysis area is the geographic
area in which conservation and management actions directly influence patterns in the area's component land units. Often, the assessment area is several times larger than the analysis area and may
need to be subdivided. In this case, RA is conducted
within each analysis area. Such a subdivision of the
assessment area was performed during the Sierra
Nevada Ecosystem Project (SNEP, 1996) for the
selection of biodiversity management areas (Davis
et aI., 1996) and during the Interior Columbia
Basin Ecosystem Management Project (ICBEMP)
(Quigley and Arbelbide, 1997) for conducting land/
/
/
/
/
/
/
/
/
- - Assessment area
CJ Provinces
CJ Analysis area
(Middle Rocky Mounta in Province)
Land unit (Biophysical polygon)
FiGURE 20.1. Map of interior Columbia River basin showing relationships among assessment area, analysis area
(province), and land unit (basic unit of selection for conservation areas).