1. What’s the relationship of diversity and productivity?
David Tilman
Science Oct. 26, 2001, 294:843

2. What’s the relationship of diversity and productivity?
168 plots, each 9 m x 9 m
Seeded plots with 1, 2, 4, 8, or 16 native grassland species
Each treatment replicated between 29 – 39 times
Annually measured for 7 years:
above-ground biomass
total biomass
number or remaining species

3. What’s the relationship of diversity and productivity?
1, 2, 4, 8, or 16 native grassland species
Annually measured for 7 years:
above-ground biomass
total biomass
number or remaining species
What are they hypothesizing?
What’s the reasoning (or rationale) behind that hypothesis?
What do they expect to find if the hypothesis is supported?
What do they expect to find if the hypothesis is refuted?
Any trends over the years?

4. What’s the relationship of diversity and productivity?

5. What’s the relationship of diversity and productivity?

6. What’s the relationship of diversity and productivity?

7. What’s the relationship of diversity and productivity?

8. What’s the relationship of diversity and productivity?
Conclusions?
Importance?

9. What’s the relationship of diversity and productivity?
… then again …
Peter Adler et al. studied 48 grassland plots around the world.
Sept. 23, 2011
Science 333:1750

10. What’s the relationship of diversity and productivity?
Data for individual sites:
Species Richness
Above ground biomass (g/m2)

11. What’s the relationship of diversity and productivity?
Pooled Data

12. What’s the relationship of diversity and productivity?
the real world is a complicated place