Revised 4/22/10

Study Questions: biodiversity, resilience, nitrogen saturation, invasive species, and global environmental change.

More on biodiversity:

1.What is the UNDERLYING CAUSAL FACTOR that usually demonstrates a positive relationship between number of species (on x axis) and an ecosystem process? (what is the shape of the relationship and what causes this shape.)

2.Why would we expect variation in ecosystem processes (such as year to year variation in carbon sequestration) to be BUFFERED (reduced) by systems with lots of species?

3.What does it mean if a scientist found “idiosyncratic effects” of species on ecosystem processes? (dictionary definition (as a noun): 1. A structural or behavioral characteristic peculiar to an individual or group.2. A physiological or temperamental peculiarity.

3. An unusual individual reaction to food or a drug.

4.The multimillion-dollar Minnesota study “homogenized” four of the five Jenny state factors (climate, topography, parent material, and time) before conducting the experiment on species richness and ecosystem processes. Now, 20 years after the initiation of the experiment, make a prediction about how soil carbon amounts in soils of these plots. What has happened?

5. Why can’t we consider a species of plant to be a “constant” when talking about ecosystem relationships? (i.e., why isn’t the effect of having two species present twice the effect of having one species present?).

Resilience.

A number of power point slides (e.g. April 16) use the model of the ball (representing an ecosystem) and a simple or complex curved line to represent where this ecosystem can be found in terms of some unspecified landscape configuration. (an x-axis without defined units). How does this model help us understand the concept of ecosystem resilience? How does the concept of historical range of variability (HRV) relate to this model.

What’s it mean when an ecosystem ‘loses resilence’, or exhibits a transformation into a new state?

Nitrogen saturation:

1.If excess nitrogen deposition occurs:

In a forest that has excess ammonium (NH4), why should we expect these soils to become more acidic?

2.What are the main activities or processes that contribute to the excess nitrogen released by human activities?

3.Even if natural terrestrial ecosystems can “get rid of excess nitrogen” why is this a concern?

4. What are the major differences of agroecosystems compared to pristine ecosystems in terms of

a) the source(s) of energy used to grow plants.

b) the amount of nutrients exported from these systems in surface waters or groundwater?

c) the ability of these systems to store carbon in plants and soils

5.List the five major categories of factors associated with global environmental change.

6. Give an example of how a global environmental change factor can interact with another factor (Hint: how does drought (climate change) affect historical fire return intervals?)

7. Why are some ecosystems more invasible (likely to contain higher #s and relative abundances of non-native species?)

8. What factor(s) make agricultural ecosystems perhaps the most invasible ecosystems on earth?

9. What's the argument for stating, "Invasive species are a serious threat to native biodiversity."

9b. What's the opposite argument (specifically, that plant invaders will not exterminate native species)?

10. Give examples where an invader species "changes the biogeochemical rules" for the ecosystem that's been invaded.

Ecosystem management.

1) What's the logic behind the statement, "All ecological management activities are experiments"?

2) What's the logic behind the statement, "If you're not monitoring your management activities, you have no scientific credibility!"

3) Why are scientists so incompetent in getting out their facts about environmental problems? Why isn’t the public responding to the obvious concerns about resource depletion and environmental degradation? (If you haven’t guessed, this is a bonus question)

4) The loss of natural ecosystems – the replacement with ‘synthetic’ or ‘novel’ – is viewed as having two potential effects on biodiversity and ecosystem function. List those effects (see powerpoint).