Presentation on theme: "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."— Presentation transcript:
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 – 11/17 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. 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? 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 nearly half of all endangered or threatened species Lowers biodiversity
Why does biodiversity matter? Biodiversity = number 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
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.)
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!) Immigration and Emigration 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 The following species are invasive in Washington State (or may be soon) Record brief descriptions of each of the invasive species covered in the next few slides.
Brazilian Elodea Historically sold in pet stores, gets dumped in water bodies (streams, lakes) Grows VERY quickly. 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 (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 (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 Evergreen shrub with thorns and edible fruit Found throughout WA Shades/outcompetes native species Lowers biodiversity
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
Asian Carp Native to Eurasia Outcompete native fish – eat EVERYTHING! Affect fisheries Not here yet…but… http://www.youtube.com/watch?v= qfG4vsJ5_xI http://www.youtube.com/watch?v= qfG4vsJ5_xI
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.