Transcript Invasive Species - General Bio Invasive_species_3

Warmup – verbal
Why are Australian
cane toads a problem?
After all, lots of species
have high population
growth rates and high
carrying capacities.
What’s wrong with
a species that grows
so quickly?
Discuss, be ready
to share.
Invasive species – 11/23
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What is an “invasive species”? Discuss.
Invasive Species: NOT native to an
ecosystem
 Introduced to the ecosystem by humans
 Causes harm to the ecosystem, human
health, or our economy.
What is a “native species”? Discuss.
Native Species: Lives in an ecosystem
without having been distributed there by
humans.
Note: not all non-native species are invasive
Why should you care?
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How do you think invasive species cause damage
to the economy or the environment? Discuss.
Economy
 Devastates key industries - seafood,
agriculture, timber, hydro-electricity, and
recreation (boating, fishing…).
 Costs Americans > 130 $billion/year (WA
Invasive Species Council)
Environment
 Impact/harm nearly half of all endangered or
threatened species
 Lowers biodiversity
Why does biodiversity matter?
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What is biodiversity? Discuss.
Biodiversity = #of species in an ecosystem
“Stable” ecosystems have relatively constant
biodiversity over time
How do invasive species affect biodiversity?
Invasive species can decrease biodiversity less
stable (big problem)
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Disrupt established food webs;
Alter physical environment
Allow for rapid changes to which native species can’t adapt
Less stable systems are less able to respond to changes
Invasive species can decrease productivity  fewer
resources for humans (e.g. food, pharmaceuticals)
Why do invasive species do so well?
Working with your neighbor, design a species (plant,
animal, fungi, or bacteria/virus) that could become an
invasive species in Mountlake Terrace.
In your own notebook:
 Name and describe the species
 it’s ok to be a little creative, but keep it reasonable…
 Describe its birth and death rates
 Include what it would need to do in order to have
these birth and death rates
 Use the words limiting factors, predation, competition,
disease, birth rate, death rate, immigration, and
emigration in your explanation
 Please complete this by the time on the board.
 Be ready to share.
 (Notes: your video notes on the Cane Toad, an
invasive species in Australia, might help.)
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Factors affecting population growth
(or, why invasive species do so well)
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Competition
 Better able to compete for resources like food, shelter,
space (higher birth, lower death rates)
Predation
 Have no/few predators (incl. parasites/diseases) or can
easily avoid them (lower death rate)
Reproduction
 Are able to quickly produce high numbers of successful
offspring (high birth rate!)
Immigration and Emigration
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Often continue to arrive in large numbers (immigration), and tend to
stay put once in the new ecosystem (no emigration)
Abiotic factors
 Well adapted to the climate /conditions of the new
ecosystem (higher birth, lower death rates in the
ecosystem they “invade”)
Examples
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The following species are invasive in
Washington State (or may be soon)
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Record brief descriptions of each of the
invasive species covered in the next
few slides.
Brazilian Elodea
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Historically sold in pet stores, gets
dumped in water bodies (streams, lakes)
Grows VERY quickly.
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Chokes out native plants.
Blocks passage of native salmon
Not much eats it very quickly
Well adapted to Pacific NW
Illegal to buy/sell in WA
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(It’s in our jars! I’ll dispose of it carefully.)
Zebra Mussel
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Reproduce VERY quickly
Filter out nutrients from freshwater
rivers, lakes, harming native species
(better competitors for food)
Grow so fast that native species are
crowded out (comp for space)
No real predators
Clog water intakes, hydroelectric dams
Not in WA, yet?
Himalayan Blackberry
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Evergreen shrub with thorns and
edible fruit
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Found throughout WA
Shades/outcompetes native species
Lowers biodiversity
Nutria
Live in marshy areas,
though not yet well established in WA
 Breed very quickly
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in Louisiana population went from 20 to 20
million in two decades!
Eat tremendous amounts of food –
degrading wetlands and removing food for
native species
Can cause destroy dikes,
dams, cause flooding.
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Invasive species in the Pacific
Northwest: Tunicates (sea squirts)
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Lives in the Puget Sound, displaces
native mussels, clams and oysters
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Has abundant food (filter feeds)
No predators
Reproduces quickly
Well adapted
to climate
Asian Carp
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Native to Eurasia
Outcompete native fish – eat
EVERYTHING!
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Affect fisheries
Not here yet…but…
http://www.youtube.com/watch?v=
qfG4vsJ5_xI
English Ivy
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A woody evergreen vine or shrub, English Ivy is
found throughout Washington state
 Grows and spreads very, very quickly
 Can crowd native plants
 Reduces animal foraging
 Very hard to remove from an ecosystem
Eurasian Milfoil
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Common in freshwater ecosystems
throughout North America
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Spreads very rapidly
Crowds out native plants
No predators
Purple loosestrife
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Common in wetlands throughout
the US
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Crowds out native species, eliminating
food sources for many aquatic (often
endangered or threatened) birds
Destroys wetland habitat
Cannot be killed by an pesticides, no
known predators
State law requires landowners to
control it!
Cane Toads – a Review
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Think back to the Cane Toad video.
Take out your notes if you need a
refresher.
Working alone, list reasons
explaining why Cane Toads are such
a successful invasive species in
Australia. Specifically refer to what
we just discussed in class.