Date: January 11, 2017
Source: Senckenberg Research
Institute and Natural History Museum
As a result of the globalization
of trade and transport, in the past decades, tens of thousands of species have
spread into regions where they were not originally at home. Potentially serious
consequences of this include the displacement or extinction of native species
and the spread of health risks. Even though trade flows are known to represent
an important path for the introduction of invasive species, this fact alone is
not enough to explain the observed distribution patterns of species.
Scientists from Germany and
Austria have examined the global spread of 1,380 exotic animal and plant
species under consideration of the trade flows. "A clear pattern is
apparent. A particularly large number of species originates in areas that are
located at a distance of approximately 10,000 kilometers from the place of
introduction. Contrary to this, the majority of the imported goods come from
the immediate neighboring countries," explains Dr. Hanno Seebens of the
Senckenberg Biodiversity and Climate Research Center.
In order to study this apparent
contradiction, the team developed a computer model that combines the
international trade flows with the species' worldwide distribution. The model
shows that short distances of less than 3,000 kilometers primarily serve the
transport of species that already occur in the target country. On the other
hand, non-native species are usually introduced over comparatively much longer
distances.
Here, the global patterns of the
species' spread closely mirror the global trade flows. However, this only holds
true when a species conquers new ground for the first time. Once an exotic
species has gained a foothold outside its region of origin, it can also spread
to new areas over short distances.
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