Who Wants to Beat An Invasive Species Nipping Invasive Species in the Bud

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Who Wants to Beat An Invasive Species?Nipping
Invasive Species in the Bud

• With your Host Donald Povatah
• Judges Carolyn Hull Sieg
• Pete Z. Fule

Created by Guy McPherson, Carolyn Hull Sieg,
Lori Hidinger Modified by Donald Povatah
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• How many hectares in North America are currently
  infested with exotic flora?

40 million hectares of land are currently
infested in North America alone, including over 7
million ha of public lands in the western United
States. (Crawford et al., 2001, citing report by
Fed. Interagency Committee for Management of
Noxious and Exotic Weeds)
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• In his article, Kaye et al. states fire
  suppression is a principal threat to what percent
  of endangered flora in the U.S.?
• .41 percent
• 4.1 percent
• 41 percent
• none of the above

4.1 percent of the endangered flora in the United
States (Schemske et at 1994)
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• Species vigorous, persistent, prolific, and
  widespread enough to cause serious economic and
  environmental impacts are considered
• Exotic
• Noxious
• Non-native
• Invasive

d. Invasive
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Why not just focus on controlling designated
noxious species?
The definition of noxious, as well as what
species qualify, varies from state to state.
Case in point cheatgrass (Bromus tectorum)
the terror of the Intermountain West is
designated as noxious in only one state.
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What is the one state where cheatgrass is
designated as noxious?
Hint This state has 54, 14,000 ft. peaks
Answer Colorado
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• Approximately how many nonnative species have
  invaded the United States as a result of human
  activities?
• 50 c. 5000
• 500 d. 50,000

d. 50,000 According to Pimentel et al. (2000,
Environmental and economic costs of nonindigenous
species in the United States, BioScience 5053-65)
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Your neighbor has planted some pretty yellow
flowers in her yard (Dalmatian toadflax), and
when you mentioned to her that they might be
invasive, she says that they haven't expanded
since last year (well, OK, maybe there are a
couple of new plants...).
Do you a) pull out the plants some night, b)
spray them with an herbicide as you walk the
dogs, c) call the County, or d) mind your own
business.
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It depends, does the neighbor have a gun? A big,
mean dog (or husband)?
Toadflax sprouts, so pulling will probably
increase stem densities. Toadflax has a waxy
coat, so herbicides probably won't work (but
maybe you could get the dogs to pee on them --
that seems to kill most plants). The county
probably won't care. But, populations of many
invasive species stay at small levels and then
suddenly expand explosively. So, next year you
can tell her that you were right.
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• Approximately how many species in the United
  States are threatened with extinction because of
  invasions by nonnative species?
• 1 c. 90
• 9 d. gt900

d. gt900 Competition with or predation by exotic
species threaten 49 of imperiled or listed
species. Exotic species affect 57 of imperiled
plants, or about 600 species. Stein et al. 2000.
Precious Heritage the status of biodiversity in
the United States. Oxford University Press.
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You have 25 ha of Canada thistle that has been
around for 50 years, and 1 ha of yellow star
thistle, new to the area. Funding allows for the
control of 1 of the 2 species -- which do you
choose and why?
The yellow star thistle The Canada thistle rarely
displaces native plant species at landscape
scales, but the star thistle does, and control
efforts are far more expensive once a species
gets gt1ha cover -- I would target the new star
thistle on my land (and my neighbors) to prevent
rapid reinvasion, and I would look for strong
native competitors for site restoration. Go
after the Canada thistle if more funds become
available.
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Which of the following attributes makes a species
invasive? a. rapid growth rate b. high
proportion of reproduction to
growth c. rapid dispersal of young
individuals d. spines
None (or all) of the above. All species are
potential invaders to novel sites. Biological
invasions are all about the match between species
attributes and the environment.
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Your biological control agent for Canada thistle
just started munching on native thistles when the
invasives were reduced to small populations.
What do you do?
Yikes -- this actually happened in Rocky Mountain
National Park, and the non-native thistles were
hammered far more than the native thistles, so
set up a monitoring program, set acceptable
levels of change, and be prepared to control the
control agent if necessary.
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• Which of the following attributes makes a
  community susceptible to invasion?
• high species diversity
• low species diversity
• high productivity
• low productivity

None (or all) of the above. All communities are
susceptible to biological invasions, depending on
the match between the nonnative species and the
environment.
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• How do you decide what exotic plants are
  priorities for control? Should you focus on
• species known to be invasive in similar
  ecosystems?
• species that produce seeds that tend to stay
  viable in seedbanks?
• perennials?
• designated noxious species?

All (or none) of the above. There are examples
of species that fit one or more of these
categories that are not a problem.
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Why do exotics and invasives increase in areas
that have experienced fire?
Severe disturbances that open forest canopies
and expose mineral soil provide habitat for
exotics and invasivesthese conditions are
associated with severe wildfire. (Sieg et al.,
in Friederici, 2003)
Photo www.fs.fed.us/r3/coconino/fire_pumpkin.sht
ml
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How can restoration treatments be modified to
decrease the probability of exotic plant
invasion?
By limiting the amount and intensity of soil
disturbances and by using local soil and seed
amendments. (Korb. 2001. PhD. Dissertation, NAU).