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Using
Landsat 7 ETM+ Imagery to Map Estuarine Habitats: a Broad Brush
Approach
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Developing
an understanding of the distribution and changes in estuarine and
riparian habitat cover is critical to the management of biological
resources in the lower Columbia River. The Lower
Columbia River Estuary Partnership (Estuary Partnership) completed
a comprehensive ecosystem protection and enhancement plan for the
lower Columbia River and estuary in 1999 (Jerrick, 1999). The plan
identified habitat loss and modification as one of the key threats
to the integrity of the lower Columbia River ecosystem and called
for an inventory of habitat as a key first step in its long-term
restoration effort. In 2000, the Estuary Partnership initiated this
project to produce a spatial data set describing the current location
and distribution of habitat cover types along the lower Columbia
River from the river mouth to the Bonneville Dam (~230 River km).
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Results
from this study will be used by the Estuary Partnership and its cooperators
to: (1) develop indicators of "habitat health" and biological integrity;
(2) develop definitions of "critical salmonid habitat"; (3) identify
and evaluate potential wetland conservation and restoration sites;
(4) track exotic and invasive species; and (5) develop an understanding
of how estuarine and riverine habitats have changed over the past
200 years. This study focused on estuarine and riparian floodplain
habitat cover types, which are important to native species, particularly
juvenile salmonids. Results from this study are meant to provide support
for the multiple efforts currently underway to recover 12 species
of Columbia River salmonids identified as endangered or threatened
under the Endangered Species Act. |
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The
ability to resolve estuarine habitat features depends on the spatial
and spectral resolution of these types imagery. We acquired and are
classifying several types of remotely sensed imagery for this project
including: Landsat 7 ETM+ multispectral and panchromatic imagery,
IRS panchromatic imagery , and CASI hyperspectral
imagery. |
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information will be used in conjunction with several other ongoing
projects: ODFW's
Juvenile salmonid life history reconstruction project, Wetland
Mapping by DSL, Landscape
Scale Habitat Change Analysis, and a Functional Assessment of
Salmonid Habitat. |
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| Results |
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classified estuarine and riparian floodplain habitats along ~230 km
of the lower Columbia River, encompassing an area of 193,000 ha. While
we did classify some of the upland areas in the Chinook watershed,
most of the upland areas along the lower Columbia River were excluded
by a DEM (elevation) mask. As we expected, the largest habitat class
was the deep-water habitat, which covered 30.9% of the classified
area. We found that much of the study area was vegetated: herbaceous
and woody (shrub-scrub and forested) vegetation accounted for 29.9%
and 23.2% of the classified area, respectively. Urban areas accounted
for ~11.0% of the area classified. Vegetated wetland areas (herbaceous,
shrub-scrub and forested) accounted for a relatively small proportion
(8.4%) of the study area and unvegetated areas (mud and sand flats)
subject to tidal inundation accounted for an additional 4.4% of the
study area. Vegetated uplands accounted for 44.7% of the area classified.
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This
study was performed with the help of numerous volunteers and in
cooperation
with
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Reports
and Publications
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Charles
'Si' Simenstad
Wetland
Ecosystem Team
School of Fisheries
University of Washington
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Estuarine
Landcover along the Lower Columbia River Estuary Determined
from Landsat 7 ETM+ Imagery
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| NOTE:
This product is an interim product. Following classification of the
CASI imagery and user input on the current classification, we expect
to revise and re-release the classified Landsat 7 ETM+ classification
at a future date. |
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| Data
Availability All spatial data are available from the Lower Columbia
River Estuary Partnership, 811 SW Naito Pkwy, Suite 120, Portland,
OR 97240 (http://www.lcrep.org/).
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