Biological diversity is a hallmark of the Columbia River Gorge, which encompasses two natural transitions in its 80-mile length
The first of these is the east to west transition which begins with near-rain-forest conditions in the western Gorge and changes dramatically within a relatively short distance to arid, near-desert conditions in the eastern Gorge. This transition is driven by the "rain shadow" effect of the Cascades. As rain-laden storms from the Pacific Ocean reach the mountains, the air masses gain elevation and become cooler, less able to hold moisture. In short, it rains a lot in the western Gorge. As the storms pass the crest of the Cascades, they lose altitude and become warmer; warm air holds more moisture, and less of it falls as rain. The eastern slopes of the Cascades are much drier as a result.
The second transition is in altitude. The tallest ridgelines of the central Columbia Gorge exceed 4,000 feet above sea level. Just as spring comes later in the season as we approach the poles, it also comes later as we gain elevation (if you miss the annual bloom of a given wildflower at lower elevations, oftentimes you can climb higher to find it still blooming). All these natural variables - rainfall, temperature, sunlight and shade - create a multitude of what ecologists refer to as "microclimates," relatively small regions of unique conditions that encourage the growth of unique species. In the Columbia Gorge, that's particularly true of wildflowers; there are hundreds of species here, many distributed throughout the Gorge but some isolated to limited regions.
There are over 800 species of flowers in the Gorge; fifteen of these are endemic and are not found anywhere else in the world. You can learn a little about each of these "endemics" below...
The second transition is in altitude. The tallest ridgelines of the central Columbia Gorge exceed 4,000 feet above sea level. Just as spring comes later in the season as we approach the poles, it also comes later as we gain elevation (if you miss the annual bloom of a given wildflower at lower elevations, oftentimes you can climb higher to find it still blooming). All these natural variables - rainfall, temperature, sunlight and shade - create a multitude of what ecologists refer to as "microclimates," relatively small regions of unique conditions that encourage the growth of unique species. In the Columbia Gorge, that's particularly true of wildflowers; there are hundreds of species here, many distributed throughout the Gorge but some isolated to limited regions.
There are over 800 species of flowers in the Gorge; fifteen of these are endemic and are not found anywhere else in the world. You can learn a little about each of these "endemics" below...
Northern Wormwood (Artemisia campestris)
Low-growing (to 30 cm) with leaves and stems covered with fine, silky hairs. Blooms mid-April to mid-June. Most of the suitable habitat was submerged behind Bonneville and The Dalles Dams but the historic range extended along the Columbia River from the mouth of the John Day River to Bingen, Washington |
"You're free to look at them and take pictures - but please don't pick!"