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).