Case Study: Cascading food-web Effects of invasive species

Objectives You should be able to… Identify and describe ecosystem services Create a model of a food-web that includes the biotic interactions Predict outcomes of disturbances related to management decisions Explain the possible consequences of invasive species

What is an ecosystem service? Benefits people obtain from ecosystems Rainforest So lets define an ecosystem service. Ecosystem services are a result of complex ecosystem interactions. Many of the services we have discussed are very valuable to us. These services are valuable but free! Now, using our rainforest ecosystem, can I hear a few of your ideas about what ecosystem services we obtain from rainforests. In fact, the tropical rainforests are the single greatest terrestrial source of air that we breathe. "37% of all medicines prescribed in the US have active ingredients derived from rainforest plants." "70% of the plant species identified by the US National Cancer Institute as holding anti-cancer properties come from rainforests.“ "90% of the rainforest plants used by Amazonian Indians as medicines have not been examined by modern science." . . . "of the few rainforest plant species that have been studied by modern medicine, treatments have been found for childhood leukemia, breast cancer, high blood pressure, asthma, and scores of other illnesses." The tropical rainforests are being destroyed at an alarming rate. "If present rates of destruction continue, half our remaining rainforests will be gone by the year 2025, and by 2060 there will be no rainforests remaining." Every second . . we lose an area the size of two football fields!

Great Lakes Coastal Wetlands What about Great Lakes Coastal Wetlands…is this a place that you would like to hang out for fun and sun? Probably not, but they provide important ecosystem services such as water treatment. MAKE A QUICK POINT ABOUT THE COMPLEX INTERACTIONS THAT MAKE UP THE ECOSYSTEM SERVICE.

Coastal waste water treatment facility Think of waste treatment facilities and how much it would cost to build, run and maintain. The East Lansing waste treatment facilities, can handle 18.75 Million Gallons per Day capacity (presently treating 12.6 millions gallons per day) and is staffed 24 hours per day, 7 days per week. An approximate cost to treat waste water is $729 per million gallons treated. That means that it costs $9,185 per day just to treat the water which is $3,352,671 per year. This does not include building costs, or the cost of employing staff 24 hrs a day 7 days a week. A comparable natural waste facility is a wetland or waste treatment pond, which provides the same function for free. Today we want to tie together these complex ecological interactions and how they work together to provide services.

Wetland management for waste water treatment (hybrids) Now, we are making “hybrids”, we are managing wetlands for water treatment.

Boreal forest ecosystem Ok, now what about this ecosystem (boreal forest)? What services do you think we obtain from the boreal forest? Is the boreal forest a source or a sink for carbon? Why do you think it is a sink? Look at where boreal forests are on the map…what is the weather like there? MAKE A QUICK POINT ABOUT THE COMPLEX INTERACTIONS THAT MAKE UP THE ECOSYSTEM SERVICE. If the carbon reservoir in peatlands were to decompose and all was emitted to the atmosphere, there would be a doubling of atmospheric CO2 concentrations

The balance of nature is very delicate and easy to upset strongly agree Agree Neutral Disagree strongly disagree

Humans have the right to modify the natural environment to suit their needs strongly agree Agree Neutral Disagree strongly disagree

The amount of grass will increase. The amount of grass will stay the A national park is home to large populations of mountain lions, deer, rabbits, and grass. Recently, park rangers decided to introduce wolves to the park. If the number of deer and rabbits eaten by the mountain lions stays the same, what will happen to the grass after wolves are introduced? Use only the relationships between the plants and animals described above. The amount of grass will increase. The amount of grass will stay the same. C. The amount of grass will decrease.  

Flathead Lake Ecosystem Orient on map. For homework, you build a model of the natural Flathead Lake ecosystem. Now, take out your models. Let’s take a few minutes for you to compare your model with your neighbors model.

Phytoplankton Cladocerans Copepods Kokanee Salmon Lake Trout Bald Eagles Grizzlies

What species was introduced in the 1970s? More bald eagles Oppossum shrimps Lake trout Coho salmon

Why were the shrimps introduced? To increase the number of lake trout To increase the number of tourists coming for wildlife viewing or fishing To increase the number of kokanee salmon Both B and C

Activity: Redraw the food web, adding the shrimp to show what the management team wanted to happen – make sure you consider the strength of interactions (i.e. arrow size)   Use your model to answer the next question. What they wanted to happen!

What the management team wanted Lake Trout Bald Eagles Grizzlies Kokanee Salmon Opossum shrimp Cladocerans Copepods Phytoplankton

Flathead Lake Ecosystem Spend a few minutes here to discuss the connection between salmon, flathead lake, and the connecting rivers. McDonald Creek is the main wildlife viewing area in Glacier National Park. It is connected to the Flathead Lake via the Flathead River.

Did it work? A: Yes, B: No (=shrimps)

Redraw the food web, this time showing what actually happened Activity Redraw the food web, this time showing what actually happened Hint: the food web stays the same, but the arrow sizes (= the strength of species interactions) change Beginning 3rd model here.. Now students are displaying what really happened after the shrimp was introduced.

What actually happened Lake Trout Bald Eagles Grizzlies Kokanee Salmon Opossum shrimp Shrimps ate all the zooplankton, and managed to avoid being eaten by the salmon by migrating down during the day Shrimps also shift the behavior of the zooplankton, who end up migrating too Cladocerans Copepods Phytoplankton

The salmon don’t like to eat the shrimps Why did the management strategy NOT work in the Flathead Lake ecosystem? The salmon don’t like to eat the shrimps The bald eagles ate all the shrimps The shrimps could escape the salmon by migrating to deep waters during the say The salmon died because the water levels became too low Question to discuss, write, or discuss + write. Answers: Flathead Lake is deeper than other experimental lakes Salmon only increased in the short term in the other lakes, but eventually collapsed too. Predation by shrimp on zooplankton populations was higher than anticipated Shrimps migrate up and down to avoid being eaten by salmon

The balance of nature is very delicate and easy to upset strongly agree Agree Neutral Disagree strongly disagree Introduced species only need to be removed if they threaten native species. Ecosystems will eventually adapt to introduced species. The cost of preventing species introductions – or removing invasive species – is too high to consider. The earth has plenty of natural resources if we just learn how to develop them The balance of nature is very delicate and easily upset Humans will eventually learn enough about how nature works to be able to control it Humans have the right to modify the natural environment to suit their needs

Humans have the right to modify the natural environment to suit their needs strongly agree Agree Neutral Disagree strongly disagree Introduced species only need to be removed if they threaten native species. Ecosystems will eventually adapt to introduced species. The cost of preventing species introductions – or removing invasive species – is too high to consider. The earth has plenty of natural resources if we just learn how to develop them The balance of nature is very delicate and easily upset Humans will eventually learn enough about how nature works to be able to control it Humans have the right to modify the natural environment to suit their needs

The amount of grass will increase. The amount of grass will stay the A national park is home to large populations of mountain lions, deer, rabbits, and grass. Recently, park rangers decided to introduce wolves to the park. If the number of deer and rabbits eaten by the mountain lions stays the same, what will happen to the grass after wolves are introduced? Use only the relationships between the plants and animals described above. The amount of grass will increase. The amount of grass will stay the same. C. The amount of grass will decrease.  

The diagram below shows the feeding relationships between populations of organisms in an area. The arrows point from the organisms being eaten to the organisms that eat them. Using only the relationships between the organisms shown in the diagram, what will happen to the number of mice if most of the frogs are killed and why? The number of mice will decrease because the number of individuals in all of the populations of organisms in this diagram will decrease. The number of mice will decrease because there will be more grasshoppers to eat the grass, so there will be less grass available for the mice to eat. The number of mice will stay the same because there will be no effect on the number of individuals in the populations of organisms below the frogs in the diagram. The number of mice will stay the same because frogs and mice are not connected by an arrow in the diagram.