Sunday, January 04, 2009

Invasive Species, all/some Roads lead to Washington

By definition, invasive species move because of human activity. These movements are grouped by kind in pathways. Pathways include industry as in cargo and trade, tourism as in hiking and boating, gardening, as in new plant introductions and sales, and ground transportation such as roads. The chart is from a report, Standardising and Structuring Pathways and Impacts of Invasive Species, Prepared for the Invasive Species Specialist Group (ISSG), October 2003, by James Russell

Invasion pathways to new locations
Local dispersal methods
Acclimatisation Societies
Acclimatisation Societies (local)
Agriculture (local)
Aquaculture (local)
Aquarium trade
Biological control
Escape from confinement
Floating vegetation/debris
For ornamental purposes (local)
For ornamental purposes
Forestry (local)
Garden escape/garden waste
Ignorant possession
Hikers' clothes/boots
Internet sales/postal services
Mud on birds (local)
Landscape/fauna "improvement"
Off-road vehicles
Live food trade
On animals
Other (local)
Mud on birds
People foraging
Nursery trade

People sharing resources (local)
Road vehicles
People sharing resources
Self-propelled (local)
Road vehicles (long distance)
Translocation of machinery (local)
Seafreight (container/bulk)
Transportation of habitat material (local)
Water currents
Ship ballast water
Ship/boat hull fouling
Taken to botanical garden/zoo
Translocation of machinery
Transportation of domesticated animals
Transportation of habitat material

There are three major phases of species invasion: introduction, colonization and naturalization. Given the current federal definition, an ecosystem which is disturbed by anthropogenic factors, an invasion opportunity is provided to an alien propagule. Gradually, it may overcomes the eco–system’s environmental balance and begin to negatively impact the eco-system. Roads are a significant means by which natural eco-systems come under invasive species pressure.
This brings us to the news of the day from Washington which “… would allow Plum Creek Timber to pave roads passing through Forest Service land.” One step forward, 900 miles of roads backwards.

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