Next time you’re cruising the open highway or
ambling along a backwoods two-track, be wary of hitchhikers with
barbed seedlings and spiky thistles. New studies from the
University of California, Davis show that roads significantly
promote the spread of invasive weeds.
Noxious weeds such
as cheatgrass, leafy spurge and knapweed already occupy over 133
million acres nationwide. Weeds displace native plant species,
increase fire risk and destroy wildlife habitat and rangeland
forage — and they’re continuing their invasion at a
rate of 1.7 million acres a year.
The UC Davis studies,
authored by doctoral student Jonathan Gelbard, environmental
science professor Susan Harrison and U.S. Geological Survey
ecologist Jayne Belnap, say the invasion is accelerating. Roads are
a major reason: They create avenues where weeds, hitching rides off
radiator grilles and gusts from passing vehicles, can penetrate and
alter ecosystems. The new studies provide fodder for advocates of
planned rural development, and offer yet another reason for the
protection of public roadless lands.
For a copy of the
report, contact Jayne Belnap at 435-719-2333 or
jayne_belnap@usgs.gov.
This article appeared in the print edition of the magazine with the headline Another roadside detraction.
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