Posts Tagged ‘invasive species


Double Barreled Tree Danger

photography-beaver-ivy-damage-nature-tree-swittersbThe Beaver & English Ivy

The Portland Metro area has pods of English Ivy, a very invasive vine that eventually smothers the host tree. Many volunteers attack the vine in the forests such as in the above image. This habitat area is managed by volunteers, who come in to remove the vine. Unfortunately for this young, Alder tree the Beaver has other ideas for its future.

“Like other exotic species, Ivy has predominantly been spread to areas by human action. H. helix is labeled as an invasive species in many parts of the United States, and its sale or import is banned in the state of Oregon.” (more)


National Invasive Species Week (Think Before You Buy, Plant or Dump)

Well, the Nat’l Invasive Species Week (March 3-8) is a good time to stress the economic impact of invasive species. Here is an Oregon run down of plant species that cause problems.


Madeline Von Foerster’s painting “Invasive Species II”

 “Invasive weeds and pests are more than a gardener’s dilemma. These species are not native to our area and pose a threat to natural areas, human health, and our local economy.

The estimated economic impact of invasive species totals 143 billion dollars per year within the United States. Within the state of Oregon, the impact associated with just twenty-one invasive weed species costs Oregonians $125 million dollars per year in lost agricultural production, fire damage, and control expenses. We all pay the bill through increased food costs, higher taxes, and decreased property values. These impacts clearly show the economic benefits associated with controlling invasive weeds.”

Factor in exotic animals, water borne invasions with the plant and the non-native tweaking of the habitat does have consequences for us all.



Science Teachers Release Non-Natives Into Waterways

Interesting findings by Oregon State University Prof. Sam Chan. When her queried some 2,000 teachers that had run science projects that required the release of the studied critters after the completion of the project…many released them into their immediate environment. Problem is they maybe should not be in that environment.

Apparently, wildlife officials had been baffled by Lousiana crayfish being found in N.E. Oregon waters. Crayfish, gold fish, assorted other non-native-invasive species have been released in that feel good moment by the students and teachers. Now, vendors of critters to science project teachers are releasing instructions to ‘clueless’ teachers on how to dispose of the critters. (Oregonian article by Ian Campbell)

Well, at least our Invasive Gold Fish populations are thriving.


NW Salmon (The Good Intentions of Hatchery Fish)

Salmon Running the Gauntlet (PBS @ Fly Fisherman Anonymous)

This is a pretty informative piece by PBS re the history of NW Salmon and the origins of the hatchery concept. The piece is a portion of a longer show, which you can access via the above link. There are additional spin off pieces about the Columbia River dams.

“Most discussions about the causes of declining salmon runs focus on the four H’s: habitat, hatcheries, harvest and hydropower. But the most important factor may be an ‘I’, as in invasive species.”     (Report here)


Northern Snakeheads (U.S. Distribution Map Updated)

U.S. Geological Survey: Invasive Species Map

Northern Snakehead (Channa argus) Susan Trammel Artist

Snakehead Stuff

Arkansas Snakehead Cleanup Efforts Explains the Problem


Lion Fish Invasive…Kill All of Them…Careful Poisonous



New Zealand Mud Snail (Potamopyrgus antipodarum)

Evolution, adaptation, migration, speciation, invasion, successful reproduction, adaptive radiation. How do you stop this natural process?

“Enter Potamopyrgus antipodarum, the New Zealand Mud Snail. These tiny, aquatic, freshwater mollusks are migrating out of New Zealand, not into it, but their impact on an ecosystem they had no previous place in could have similar repercussions for native species.

Carried by world-trotting humans, these critters made their North American debut in the 1980’s in the Snake River, and have been drifting west ever since. They are now present in Yellowstone National Park.

How do these diminutive invaders hop from river to river, lake to lake, establishing an almost unshakeable presence as they go? Humans again, I’m afraid. The New Zealand Mud Snail is prone to hitchhiking on boats and fishing gear. So a careless or messy angler on an extended fishing trip can spread the little devils far and wide. Mud Snails are quite hardy enough to make the trip as well. They’re so small ( 6mm long, maximum, and sometimes as small as a grain of rice), and they so much resemble tiny flecks of mud, that they often go undetected. They can survive out of water for several days, and can live in many kinds of freshwater environments. They’re even resilient enough to handle low temperatures (anything above freezing) and can pass unharmed through the digestive tract of most fish. Moreover, they reproduce asexually, and are “livebreeders“, meaning they produce a number of perfectly formed little clones, so even one can spawn a colony. New Zealand Mud Snail densities of more than 2 million snails per square yard have been found in Yellowstone Park.

With no natural predators to keep it in check there’s every possibility native snail species will be out-competed into extinction and native plant species overwhelmed. Such an unbalancing presence can decimate other species, such as trout, something that gives dedicated Wyoming, Montana, & Idaho fishing enthusiasts reason for pause.

Efforts are being made to curb the New Zealand Mud Snail invasion.”


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