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Columbia Plateau
(Area - 32,688,600 ha)
Executive Summary |
Description - This is an arid sagebrush steppe and grassland surrounded on
the north, west, and east by moister, predominantly forested, mountainous ecological
regions. It is an oddly shaped physiographic area that covers portions of Washington,
Oregon, Idaho, Nevada, and a small piece of northeast California. It consists of arid
tablelands, intermontane basins, dissected lava plains, and widely scattered low
mountains. There is a more subtle transition to the Basin and Range to the south in which
hotter lowlands are dissected by isolated mountain ranges.
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Conservation recommendations and needs - Issues in this area include conversion of
shrubsteppe and wetlands to agriculture, grazing, and some urban development. Non-native
plant invasions have been particularly damaging here, led by aggressive species such as
cheatgrass and crested wheatgrass. As elsewhere, fire suppression and other practices have
greatly reduced the extent and health of open ponderosa pine habitat. Restoration of a
dry, open, multi-aged ponderosa pine system will require careful silviculture and a
regimen of prescribed fire. Within the shrubsteppe system, it is important to maintain and
restore a dynamic sagebrush ecosystem, including no further net loss of healthy sagebrush,
and restoration of fragmented and degraded areas. Existing wetlands should be protected,
and water regimes restored. The health and complexity of riparian shrub and forest
vegetation has been extensively degraded due in part to livestock grazing and lowering of
water tables. However, restoration activities have been shown to produce relatively good
results. |
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