BIOL 1107 Module 3
Journal Article:๎
Reich et al.๎ 2004.๎ Species and functional group diversity independently influence biomass accumulation and its
response to CO2 and N.๎๎PNAS.๎101(27):10101โ 110106.๎
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The purpose of this discussion is to evaluate how the authors set up an experiment to test their idea that
species diversity and functional group richness may influence biomass accumulation, thus changes in biodiversity
may change carbon and nitrogen sequestration.๎ Pay careful attention to which variables the authors keep the same
for all the experiments and which variable(s) they manipulate to test their idea.๎ Look at the authors' results and
decide what๎you๎think the answer is to their question.๎
Discussion Questions๎
Introduction ๎
1. What is a functional group? How does that differ from species richness?
Functional group is the specific identity, species richness is the number of functional groups in the
community
2. Why are the authors looking at differences in functional groups and species richness for plant biomass
accumulation?
To identify the effects S and F can have on a community diversity and hoe those effect each other with other
communities
3. What rationale did the authors give for conducting this experiment?
To have a better understanding of how S and F alter diversity
4. What is the authors' research question?๎
What are the effects of S n standardized F on diversity and how do they effect each other?
5.What hypotheses are the authors testing?๎
Biomass increase with CO2 and N increase
6.What specific predictions do the authors make๎from their hypotheses?๎
As CO2 and N levels increase independently, the biomass increases
Materials and Methods ๎
7. The authors had three different experiments. Compare and contrast the experimental design for the three
experiments.
Each experiment has different plots but the same species are tested
8. What dependent variable(s) did they measure?๎How did they measure it/them? Why did they measure so
many different components? Why was this important?
CO2 and N
9. What independent variable(s) did they manipulate?๎How did they do this? Did their approach seem
appropriate?
S and F
10. What four functional groups did the authors select? How do these functional groups differ from one
another? (Hint: think about this at many different scales)
There was 4 C4 gasses (Andropogon gerardii, Bouteloua gracilis, Schizachyrium scoparium, and
Sorghastrum nutans) , 4 C3 gasses (Agropyron repens, Bromus inermis, Koeleria cristata, and Poa
pratensis), four N-fixing legumes (Amorpha canescens, Lespedeza capitata, Lupinus perennis, and
Petalostemum villosum) and four non-N-fixing herbaceous species (Achillea millefolium, Anemone
cylindrica, Asclepias tuberosa, and Solidago rigida). All being presented in each experiment at different
amounts.
Results: ๎ Figure 1. ๎
11. What do the bars show in the three graphs?๎ What do the error bars represent?๎Why does Figure 1B not
have error bars?
They show the effects N and CO2 change has on biomass, the bars indicate any other factrs that might lead
to the deviation
12. What is the difference between parts A, B, and C?๎
