Grasslands - Mountains and Plains: The Ecology of Wyoming Landscapes - page 91

table 6.2. estimated energy flow through a prairie ecosystem on the western Great Plains a

Production
consumption ecosystem component energy input Lost by respiration tissue production

SoLAR inPUt
Global radiation

4,155,000

Photosynthetically
active radiation

1,966,000

PRiMARY PRoDUction
Gross b 21, 882 7,4 3 9

net c
Aboveground 2,163

Belowground 12,280

Subtotal 14,443

HeteRotRoPHS
Aboveground
Herbivores
Mammals d 105 92 13 0.13

Macroarthropods e 34 23 11 0.32

carnivores f 8.3 7. 5 0.8 0.10

Subtotal 147 123 25

Underground
Herbivores
Macroarthropods g 127 66 61 0.48

nematodes 50 42 7.9 0.16

carnivores h 20 15 4.6 0.23

Detritivores
Microorganismsi i 12,560 9,632 2,929 0.23

nematodes 72 61 12 0.16

others 9.2 6.7 2.5 0.27

Subtotal 12,838 9,822 3,016

totAL 12,986 9,945 3,041

Source: Adapted from coupland and Van Dyne (1979).
a the units are kilojoules per square meter.
b Gross primary production (GPP), or total photosynthesis (g/m 2 /yr), varies greatly from year to year, depending on water avail-
ability (see fig. 6.4).
c net primary production is calculated as GPP less the amount of GPP used by plants for their own maintenance (respiration).
d Mammalian herbivores include cattle, pronghorn, rabbits, and ground squirrels; cattle grazing in the study area was light (one
yearling steer or heifer per 25-30 acres for 180 days each year).
e Mostly grasshoppers and other insects.
f fAboveground carnivores include the coyote, fox, birds of prey, and snakes.
g Mostly mites and insect larvae.
h Belowground carnivores include mites.
i iBacteria, fungi, and Actinobacteria.