1. Parasites can be dramatic… Parasitic wasps actually kill their host after a time, but also have a mutualistic relationship with certain plants Image: Encylopedia of Life

2. Parasites can be subtle Eastern Phoebe nest with one Brown-headed Cowbird egg Image: Gala Web Design, Wikipedia Commons

3. Mutualism Both species benefit: provide food or shelter Mycorrhizal Fungi & Plants

4. Commensalism 

5. Gradient of mutualism- commensalism

6. Species Interactions Competition   Predation and herbivory  Parasitism  Mutualism Commensalism 

7. What type of interaction? 1.Orchid and orchid bee 2.Athlete’s foot 3.Wood ducks and Mallards 4.Your tomato plants and weeds 5.Lions and gazelles 6.Wild boar and apple tree 7.Humans and dogs

8. Population ecology Population = how many there are Carrying capacity = theoretical number of how many there could be Population size can change very fast -> especially when there is a big difference between population and carrying capacity (exponential growth/decay) Population size can change slowly -> when fluctuating about carrying capacity in stable ecosystems (logistic growth) Some species are better adapted to feast/famine population cycles

9. Exponential growth

10. Population Time Why is this unrealistic? Limited resources (bottom-up) Predation (top- down)

11. Energy is released to the environment at every step in the food chain Energy vs. nutrient cycle: nutrients constantly cycled on Earth, heat radiated from the Earth, resupplied by sun

12. Logistic growth

13. Reproductive strategies Opportunists –Hydrothermal tube worms –Willow –Salmon –Insects Competitors –Orca whales –Tropical rain forest trees –Humans An female cod produces ~500,000 eggs per kg body weight: 3-year-old female produces ~250,000 eggs 8-yr-old produces ~2.5 million eggs Record 9 million eggs found in a 34-kg female

14. What is today’s carrying capacity?

15. Upwelling? Salmon life cycle: complicated ecosystem(s)!

16. Salmon provide ecosystem services “We have been finding marine carbon and nitrogen in leaf matter of trees growing along river corridors. The only way for it to get there is through salmon swimming up streams, spawning in rivers.” -Jeff Cederholm, WA DNR Image: Ray Troll

17. Salmon nutrient supply is depleted now… Decaying salmon resupply nutrients (particularly N) to forest ecosystem Using historical cannery records (indirect evidence) Cederholm and colleagues estimated that 350-500 million pounds of salmon used to return to WA, OR, ID, CA streams Today estimate 25 - 30 million pounds Barnard, ABC News, “Salmon Bring Nutrients from Ocean to Rivers” 2/7/2011

18. Salmon populations show intense variability over long time scales Records from Kodiak Island show large shifts over the past 2200 years Declines of 100+ years from ~100 BC to 800 AD Indirect method: N isotopes (chemical fingerprint)

20. Lesson: leave room for a margin of error Species lifecycles provide ecosystem services Humans have degraded habitats Climate and uncontrollable changes can strongly impact populations as well Species interactions can be mutualistic: salmon -> trees -> salmon Plan for uncertainty Dead red salmon provide nutrient cycling ecosystem service, image: USFS