What’s the relationship of diversity and productivity?
David Tilman
Science Oct. 26, 2001, 294:843
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
What’s the relationship of diversity and productivity?
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?
What’s the relationship of diversity and productivity?
1, 2, 4, 8, or 16 native grassland speciesAnnually measured for 7 years:
above-ground biomasstotal biomassnumber or remaining species
What’s the relationship of diversity and productivity?
What’s the relationship of diversity and productivity?
What’s the relationship of diversity and productivity?
What’s the relationship of diversity and productivity?
What’s the relationship of diversity and productivity?
Conclusions?
Importance?
What’s the relationship of diversity and productivity?
… then again …
Peter Adler et al. studied 48 grassland plots around the world.
Sept. 23, 2011Science 333:1750
What’s the relationship of diversity and productivity?
Data for individual sites:
Above ground biomass (g/m2)
Spec
ies R
ichn
ess
What’s the relationship of diversity and productivity?
Pooled Data
What’s the relationship of diversity and productivity?
the real world is a complicated place