Transcript Invasive Species - Honors PowerPoint Invasive_species

Invasive species
(Put HW on your desk while you answer this in your notebook)



Why are species like cane
toads a problem? After
all, lots of species have
high population growth
rates and high carrying
capacities.
In other words, what’s
wrong with a species
that grows so quickly?
Discuss, be ready to
share.
Basic terms – “native” and “invasive”





What is a “native species”? Discuss, be ready
to share.
Native Species: Lives in an ecosystem without
having been distributed there by humans.
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.
Note: not all non-native species are invasive
Why should you care?



How do you think invasive species can cause
damage to the economy or the environment?
Discuss.
Economy
 Devastates key industries - seafood,
agriculture, timber, hydro-electricity, and
recreation (boating, fishing…).
 Costs Americans billions of dollars a year
Environment
 Impact/harm nearly half of all endangered or
threatened species
 Lowers biodiversity
Why does biodiversity matter?






What is biodiversity? Discuss.
Biodiversity = #of species in an ecosystem
“Stable” ecosystems have relatively constant
biodiversity over time
How do invasive species affect biodiversity?
Discuss
Invasive species can decrease biodiversity less
stable (big problem)
 Invasives “do better” than native species,
sometimes driving them to extinction
Invasive species can decrease productivity 
fewer resources for human (e.g. food,
pharmaceuticals)
Why do invasive species do so well?


Working with your neighbor, share information on
species you discovered while doing your
homework from last night.
Brainstorm a list of characteristics that invasive
species must generally have in order to “do
better” than native species

You could verbally “invent” an invasive species with these
characteristics if it helps…

Example: All invasive species are well-adapted to
the climate of the ecosystem they “invade”.

Be ready to share.
Factors affecting population growth
(or, why invasive species do so well)





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!)
Abiotic factors
 Well adapted to the climate /conditions of the new
ecosystem (higher birth, lower death rates in the
ecosystem they “invade”)
Immigration and Emigration
 Often continue to arrive in large numbers – because of
humans or their own dispersal (immigration), and tend to
stay put once in the new ecosystem (no emigration)
Examples

The following species are invasive in
Washington State (or may be soon)



Could a few of you share what you
learned (give one example)?
Record brief descriptions of each of the
invasive species covered in the next
few slides or shared by students
Don’t record if you already recorded
information about the species for
homework.
Brazilian Elodea


Historically sold in pet stores, gets
dumped in water bodies (streams,
lakes, etc)
Grows VERY quickly.




Chokes out native plants.
Blocks passage of native salmon
Illegal to buy/sell in WA
(It’s in our jars! I’ll dispose of it
carefully.)
Zebra Mussel
Reproduce VERY quickly
 Filter out nutrients from freshwater
rivers, lakes, harming native
species
 Grow so fast that native species
are crowded out
 Clog water intakes,
hydroelectric dams - $$$
 Not in WA, yet?


Left in zebra mussel-infected waters
for a “few months”…
Atlantic Salmon




Native to eastern US
Escape from “fish farms” (aquaculture)
on west coast
Last sighted in 2000?; still a concern
Why a concern? Bring “sea lice” to wild,
endangered salmon populations

Can kill juvenile salmon…
Nutria
Live in marshy areas,
though not yet well established in WA
 Breed very quickly



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.

Invasive species in the Pacific
Northwest: Tunicates (sea squirts)

Lives in the Puget Sound, displaces
native mussels, clams and oysters




Has abundant food (filter feeds)
No predators
Reproduces quickly
Well adapted
to climate
Himalayan Blackberry

Evergreen shrub with thorns and
edible fruit



Found throughout WA
Shades/outcompetes native species
Lowers biodiversity
English Ivy

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

Common in freshwater ecosystems
throughout North America



Spreads very rapidly
Crowds out native plants
No predators
Purple loosestrife

Common in wetlands throughout
the US




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


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.