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Manager's Tool Kit
Vectors and Pathways

Discusses the movement of invasive species, including both natural and man-made pathways. See our Pathways and Risk Assessment sections for more information and resources.

Flushing Nemo: Home Aquarium Species a Potential Threat to California Waters (Jan 9, 2013)
University of California - Davis.
Well-intentioned children and aquarium hobbyists seeking to "free" their pet fish down a toilet bowl or into a local waterway may inadvertently be contributing to the threat of invasive species downstream, according to a new report from the University of California, Davis.
See Aquatic Invasive Species Vector Risk Assessment Project (PDF | 449 KB) for background information about the project and the Final Report - Aquatic Invasive Species Vector Risks Assessments: A Vector Analysis of the Aquarium and Aquascape ('Ornamental Species') Trades in California (Jul 2012; PDF | 4 MB).

UCSB Study Shows Forest Insects and Diseases Arrive in U.S. Via Imported Plants (Apr 9, 2012)
University of California, Santa Barbara.
The trade in live plants from around the world has become a major industry in the U.S., with new imports now valued at more than $500 billion annually. According to a study conducted by researchers at UC Santa Barbara's National Center for Ecological Analysis and Synthesis, however, what has proved to be a boon for the economy has also been shown to have devastating effects on the environment. The multidisciplinary working group found that almost 70 percent of the most damaging non-native forest insects and diseases currently afflicting U.S. forests arrived via imported live plants.

UF-led Study: Invasive Amphibians, Reptiles in Florida Outnumber World (Sep 15, 2011)
University of Florida News.
Florida has the world's worst invasive amphibian and reptile problem, and a new 20-year study led by a University of Florida researcher verifies the pet trade as the No. 1 cause of the species' introductions. From 1863 through 2010, 137 non-native amphibian and reptile species were introduced to Florida, with about 25 percent of those traced to one animal importer.

Pathways are the means by which species are transported from one location to another. Natural pathways include wind, currents, and other forms of dispersal in which a specific species has developed morphological and behavioral characteristics to employ.

Man-made pathways are those pathways which are enhanced or created by human activity. These are characteristically of two types.

The first type is intentional, which is the result of a deliberate action to translocate an organism. Examples of intentional introductions include the intended movement of living seeds, whole plants, or pets. Intentional introductions as a whole should not be labeled as either good or bad. A specific intentional pathway can only be judged by the positive or negative impact of the specific organisms that are moving along that means.

The second type of man-made pathways are those pathways which unintentionally move organisms. Examples of unintentional pathways are ballast water discharge (e.g. red-tide organisms), soil associated with the trade of nursery stock (e.g. fire ants), importation of fruits and vegetables (e.g. plant pests), and the international movement of people (e.g. pathogens). In these and countless other unintentional pathways the movement of species is an indirect byproduct of our activities.

For the purposes of the National Invasive Species Council, the term "vector" is viewed as a biological pathway for a disease or parasite (i.e. an organism that transmits pathogens to various hosts) and is not completely synonymous with the much broader definition of a pathway.

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Last Modified: Jun 22, 2017
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