may be used to mean variety at the genetic, species
or ecosystem level.
living a particular area, including their genetic variants
and the unique ecosystems or plant communities that
develop, are of inherent value. These assemblages of
species represent the products of millions of years
of adaptation and evolution within a dynamic landscape.
They are quite literally irreplaceable. Each locally
adapted species represents a unique genetic variant,
that if lost, will not be seen again.
are significant for the richness of their flora, and
in our area include high elevation grasslands (balds)
and the Columbia River corridor. The Columbia Coast
does not live in isolation. Other areas of high diversity
within 100 miles of the coast are the Olympic Mountains
and Columbia Gorge.
for Introduced Species
Humans, with an amazing capacity to tot
other species from place to place, have done much to
reduce biodiversity and homogenize ecosystems around
the Columbia River acts as a corridor to promote diversity
in the regional flora, it also acts as a vector, bringing
new species to the region through modern shipping. Plant
hunting along freshwater tideflats can be particularly
rewarding, for new species that are sighted, and frustrating,
trying to figure out where in the world they have come
from and correctly identify them.
carries more than fish, barges and ships. It
carries seeds downstream from urban and agricultural
areas upriver, including common reed, reed canary grass,
purple nutsedge, purple loosestrife. Ballast water may
also carry foreign animals such as zebra mussel, European
green crab, Chinese mitten crab, to name a few potentially
devastating species now in or approaching our area that
have been carried around the world in water ballast.
particularly of ruminants, brings dozens of new forage
species into natural landscapes. Forage seed mixes often
contain "weedy" species that were as undesirable
in their old habitats as they are in the new. Seeds
also accompany hay, cereal feeds and animals as they
are transported from one area to another.
as it is generally practiced, virtually eliminates native
vegetation and replaces it with a palette of species
from around the world. These include a collection of
species used to grow lawns, vegetables, and a wide variety
of ornamentals, all with their attendant weeds. Alterations
to soil hydrology, fertility, aeration, and the use
of impervious surfaces collectively result in the permanent
loss of all but the toughest natives.
Hydrological changes are intended to dry
out landscapes, lowering water tables, reducing water
storage capacity and creating upland-like conditions
for farming, grazing and urban development. Collectively
these changes result in long term loss of wetland habitat
and capacity, which often goes unnoticed until floods,
wetter winters and resulting displacement of humans
or property damage comes to community notice. Practices
include ditching, diking, filling, groundwater pumping,
and alternatively, the creation of lakes by impounding
water behind dams.
building is the single most destructive step
taken in otherwise pristine habitats. Roads may alter
hydrology by damming off small streams, replacing open
streambeds with culverts, or running along flood plains,
act as a permanent source of new sediments during winter
rain events. By opening the soil, bringing in rock and
gravel from other sites, and allowing regular vehicular
traffic, roads allow the transport of seeds and vegetative
progules from other areas. The result is that a group
of common, mostly European species of grasses and herbs
can now be found on most roadsides throughout the region.
Sadly, they often spread into nearby forests, meadows,
marshes and riparian areas.
foresty magnifies road disturbance and the possibility
of weed seed transmission by regularly clearing off
the land, opening up soils, disturbing duff layers,
burning, and replanting.
in disturbance regimes include fire and
These habitats are common throughout the region. Road
building, industrial timberland management, agriculture,
shipping, and urbanization bring a familiar collection
of predominately European species. Upland species include
dandelion, hairy cats'ear, velvetgrass, orchard-grass,
Queen Anne's lace, tansy ragwort, English plantain,
ribwort, quack-grass, and many others. Wetland species
include purple loosestrife, canary reedgrass, creeping
buttercup, smooth cordgrass, giant knotweed, and common
reed. Woody species include Scots broom, several blackberries,
gorse, ivy and holly.