Table 1

Properties of empirical and niche model food webs

Food webTaxa S C (L/S2)Observed DModel DError (model SD)
Skipwith Pond35250.321.401.441.10
Little Rock Lake181920.121.901.88−0.94
Bridge Brook Lake75250.171.921.80−1.68
Chesapeake Bay33310.0722.712.55−0.99
Ythan Estuary92780.0612.202.322.06
Coachella Valley30290.311.471.45−0.68
St. Martin Island44420.121.921.980.99
  • Taxa, the original names for groups of organisms found in the primary reference. S, trophic species. The seven food webs address (i) primarily invertebrates in Skipwith Pond (12); (ii) pelagic and benthic species in Little Rock Lake (8), the largest food web in the primary literature; (iii) Bridge Brook Lake, the largest among a recent set of 50 Adirondak lake pelagic food webs (13); (iv) the pelagic portion of Chesapeake Bay emphasizing larger fishes (14); (v) mostly birds and fishes among invertebrates and primary producers in the Ythan Estuary (15); (vi) a wide range of highly aggregated taxa in the Coachella desert (9); and (vii) trophic interactions emphasizing Anolis lizards on the Caribbean island of St. Martin (16). Model D is the mean of 1,000 niche model trials. Errors between the niche model D and observed D are normalized by dividing the difference by the SD of the trial results. Ninety-five percent of normalized errors should be within 2 SD if the model is accurate (5).