University of Minnesota
University of Minnesota
College of Biological Sciences


Experiment 123 - The Small Biodiversity Experiment

Biodiversity I (E123), also called the ?small biodiversity experiment,? was designed to determine how the number of species affects the dynamics of ecological processes at the population, community, and ecosystem levels. By experimentally manipulating the number of species and the kinds of species, the amount of plant growth and the change from year to year that result can be examined. Also, the effects of number of species on carbon and nitrogen in the soil and on the ability of other species to invade can be studied. The experiment contains 147 3 x 3m plots that were randomly allocated 1, 2, 4, 6, 8, 12 or 24 plant species. The particular species in a plot were randomly selected from a set of 24 prairie-grassland species which included seven warm-season (C4) grasses, four cool-season (C3) grasses, four legumes, nine non-legume forbs. Each level of number of species has 20 to 24 replicates. In this experiment not all of the species are in monocultures. The study was established in 1994 by lead investigators David Tilman, David Wedin, Peter Reich, and Johannes Knops. Experiment 123 is similar to Experiment 120, but it uses smaller plots and did not categorize by type of plant species prior to randomizing species to plots. This size of plot in Experiment 123 means that the soils are relatively more homogeneous and the desired number of species can be more easily maintained by frequent hand weeding than with larger plots. However, the small size of plots limits sampling and the nesting of other studies within the plots.

Methods for e123


Dataset IDTitleRange of Years (# years with data)
nle123Litter carbon and nitrogen1998-1998 (1 year)
lpe123Percent light penetration1996-1999 (3 years)
nbe123Plant aboveground biomass carbon and nitrogen1996-1998 (3 years)
ple123Plant aboveground biomass data1996-2005 (8 years)
pce123Plant species percent cover data1995-2005 (7 years)
rbe123Root biomass data1997-2004 (4 years)
nre123Root carbon/nitrogen data1996-1998 (3 years)
nohe123Soil nitrate and ammonium1997-2005 (5 years)
nme123Soil nitrate, ammonium, moisture and nitrogen mineralization1996-1996 (1 year)
ne123Soil nitrogen1996-1998 (2 years)
adhe123Vac Sampling arthropod community1996-1996 (1 year)

Compiled data is also available in these pre-formatted files.

Compiled Arthropod Data
Descriptions of Data FieldsTABJMPEXCEL

Compiled Biomass, Plant Cover, and Soil Data
Descriptions of Data FieldsTABJMPEXCELEXCEL