Download 1 - CenTREAD

NAME: ___________________________
1. (2 points) Both stochastic and deterministic factors can shape plant communities.
A. Give an example of a stochastic factor that can be important.
B. Give an example of a deterministic factor that can be important.
2. (3 points) In class we discussed the example of the restoration of Fort Ord, where we were
trying to establish a healthy coastal scrub community dominated by Ceanothus. The first
species to come in is European beachgrass. Imagine that I did the experiment of removing
the beachgrass in 5 experimental plots, with 5 control plots where beachgrass was left. I
found that the Ceanothus came back faster in the control plots.
A) Which model of succession do these data support? ____________________
B) Based on your own intuition and field experience, what might be an explanation for this
relationship between beachgrass and Ceanothus, i.e. describe some plausible mechanism?
3. (2 points) What is the problem with simple additive designs for competition experiments:
What are the two things that you can not distinguish with such a design?
1. _____________________
2.______________________
NAME: ___________________________
4. (3 points) Match the plant to the chemistry, by drawing connecting lines:
Terpenoids
Tan oak (Lithocarpus densiflorus)
N-containing compounds
Mints (e.g. Satureja douglasii)
Phenolics
Coffee (Coffea arabica)
5. (5 points) A young organic farmer grows radishes (Raphanus sativus) in a field near Wilder
Ranch. Wilder Ranch is home to a rare endemic plant in the Brassicaceae (Arabis
satterthwaitii), which only grows in light gaps in forests. There is evidence that genes from
R. sativus have "introgressed" into A. satterthwaitii; that is, that R. sativus hybridizes with A.
satterthwaitii , and radish genes are now part of the genome of the rare plant.
The Monstersanto seed company wants to distribute seeds of a new radish variety ("ReadyGerm") with a phytochrome mutation: in Ready-Germ seeds, the phytochrome molecule is
always in its "PFR" form.
A. Why would this be beneficial in a crop plant?
B. If this mutation were to cross into A. satterthwaitii, what are the potential conservation
consequences? (Explain carefully why.)
6. (2 points) There are four different study design approaches that have been taken to
address the question: Does species diversity influence ecosystem functions? Name or
describe two of these:
1.____________________________
2.____________________________
8. (5 points) Draw the relationship we expect to see between species diversity and
disturbance.
NAME: ___________________________
A. What theory does this pattern describe?
B. Explain the pattern at very high levels of disturbance
C. Explain the pattern at very low levels of disturbance
9. (5 points) One of the ecological ideas behind intercropping or using weedy margins around
crop fields is that plants may reduce their vulnerability to specialist herbivores by blending in
with a lot of other vegetation.
A. Name the theory that is described by this idea: ________________________
B. Design an experiment to test this idea. What are your two treatments (or manipulation and
control)?
C. What do you measure?
D. Draw your expected result if the theory holds (label axes, etc.):
NAME: ___________________________
10. (6 points) A farmer has a grapefruit orchard with two varieties of grapefruit trees. One
variety is resistant to the citrus canker bacteria (Xanthomonas campestris) and the other is not.
The farmer wants to know whether he will be able to harvest any juicy grapefruits this year.
A. Outline the disease triangle for the farmer.
Writ e t he general lab els at each apex.
Writ e t he lab els specif ic t o t his example.
B. Using the gene-for-gene paradigm, describe to the farmer the conditions when the
grapefruit trees will be diseased.
C. Using the gene-for-gene paradigm, describe to the farmer the conditions when the grapefruit
trees will NOT be diseased.
7. (2 points) You graduate from UCSC and get a job with an environmental consulting firm.
Your job is to map out wetlands to make sure that developers don't put buildings on wetlands,
which are federally protected. How do you figure out the boundary between the wetland and
surrounding (unprotected) land by looking at the plant community? Describe a technique (from
Doak's lecture) that you might use to do this sort of work.
NAME: ___________________________
8. (10 pts) This is a real story, although the numbers are made up. The Santa Catalina Island
ironwood, Lyonothamnus floribundus is an extremely unusual and rare tree found only on
Catalina Island. Its adult population appears to be doing fine, but the seedlings and seeds are
a favorite food of marauding exotic pigs and goats.
You do a matrix modeling study of the population dynamics of this species. Assume there is no
seed bank. You do a census every spring, so you don't see new seeds, just the seedlings that
germinated from seeds in the fall. You model seedlings, small trees, and large trees.
8A. Give the matrix that describes this plant's life cycle:
8B. What is the mortality rate of seedlings?
____________
8C. What is the mortality rate of small trees?
____________
8D. You help the Catalina Conservancy do a census of all the ironwood plants in one canyon.
You find 500 large trees, 2 small trees, and 2 seedlings. How many plants in each stage
class do you expect to see in the following year, and the year after that?
STAGE
Seedlings
YEAR O
2
YEAR 1
YEAR 2
NAME: ___________________________
Small trees
2
Large trees
500
SHOW YOUR WORK (you may continue on back of page):
8E. Your first idea for how to save this population is, naturally, to exclude pigs with a
tremendous electric fence. Does this help? You find that seed survival and germination
increase greatly: now large trees are producing 2 seedlings each on average and small trees
are producing 0.2 seedlings each.
Evaluate the conservation value of your management strategy over one year.
STAGE
YEAR O
Seedlings
2
Small trees
2
Large trees
500
YEAR 1
Would a census of the number of adult trees in Year 1 be an accurate way to evaluate your
strategy (compare numbers to previous page)? Explain why/why not.
NAME: ___________________________