BODY-SIZE SPECTRA OF PRODUCTION AND BIOMASS AS SYSTEM-LEVEL INDICATORS OF ECOLOGICAL DYNAMICS

In ecosystems both production per unit biomass and biomass per unit area are functions of the individual body size of the organisms. Comparison of the properties of body-size spectra based on these two functions leads to their interpretation in energetics terms as reflections of three underlying mechanisms: the metabolic energy requirements of individuals, their aggregate food consumption, and the consequent dependence of organism number density on body size. The mean level of biomass observed over the whole body-size-range reflects the energy levels in particular ecosystems, while the succession of domes within the biomass spectrum expresses the trophic organization. Different shapes of these domes in different ecosystems may reflect the specific character of the predator-prey interactions in them. © 1991 Academic Press Limited.