Although many researchers have stressed the importance of among-specie
s variation in plant response to elevated CO2, none have quantitativel
y tested whether variation exists among biomes. I compiled data from t
he literature and found that, although C-3 plants did respond more tha
n C-4 plants (as predicted), biome origin was a better predictor (acco
unted for more of the variation) of plant response to elevated CO2 tha
n mode of photosynthesis, Variation in plant response among biomes was
found both between and within latitudinal zones, with plant species f
rom tropical and temperate biomes responding more than plant species f
rom a polar biome. Within the temperate zone, species from forested bi
omes responded more than species from a grassland biome, and this prov
ides further evidence that forests are acting as major sinks for incre
asing levels of atmospheric CO2. A more than 4-fold difference was fou
nd among ecosystems in coefficients of variation (calculated across me
an species response within each ecosystem). Based on this difference,
I suggest that ecosystems may vary in the amount of change in species
composition in response to elevated CO2.