Transcript Invasive non-native plants

Introduced
Invasive
Plants in
California
Since the arrival of Europeans,
approximately 1,000 plant species
have been introduced in CA
 140 species listed by the CA Exotic
Pest Plant Council as “Plants of
Greatest Ecological Concern”
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How Invasive Plants
Effect Native Biodiversity
Displace native species
 Change the way a normal ecosystem
operates
 Can be hazardous to native fauna
 Reduces biodiversity
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European Beachgrass
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captures sand, decreasing natural sand
movement, and causing the dunes to
increase in height
unsuitable as habitat for nesting snowy
plovers
Displaces three particular species of plants
including beach layia which is federally
listed
Scotch
broom
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Interferes with the establishment of forests
and invades natural areas.
Overruns pastures, utility corridors and
roadsides increasing the maintenance costs
of these operations.
Displaces the native plant species and the
wildlife that depend on them.
Broom infested areas create a fire hazard.
Yellow starthistle
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Native to Eurasia
First found in Alameda county in 1869
Infests 42% of California
Lethal to horse if consumed
Decreases range forage quality
millions of dollars in losses probably occur
from interference with livestock grazing
Depletes soil moisture
Tamarisk
Starting
in the 1850s,
several species of
tamarisk were imported
to the United States as
ornamentals and for use
in erosion control.
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Starting in the 1850s, several species of
tamarisk were imported to the United States as
ornamentals and for use in erosion control
Aggressive invader of desert riparian habitats
Forms impenetrable thickets that suck up water
leaving other plants, birds and fish high and dry
(up to 300 gallons a day!)
Water hyacinth
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Escaped ornamental aquatic plant
Has invaded the Sacramento-San Juaquin Delta
Clogs boating waterways
competitively exclude native submersed and
floating-leaved plants
Low oxygen conditions develop beneath water
hyacinth mats
Arundo
 chokes
riversides and
stream channels
interferes with flood
control
crowds out native plants
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It ignites easily and can create intense fires.
grows vertically without any horizontal
branching and does not provide shading to the
in-stream habitat, which can lead to increased
water temperatures and reduced habitat quality
for fish and other aquatic wildlife