5 100THE MAXIMUM TROPHIC POSITION IS THE TROPHIC POSITION (FCL + 1)...

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The maximum trophic position is the trophic position (FCL + 1)

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of the species with the highest average trophic position in each of

Productivity (TP,

g l

)

the lake food webs. (After Post et al., 2000.)

If available energy is found ultimately to have no effect on

food chain length, it should perhaps be borne in mind that species

richness is usually significantly higher in productive regions (see

Chapter 21), and that each consumer probably feeds on only a

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limited range of species at a lower trophic level. Hence, the

amount of energy flowing up a single food chain in a productive

region (a large amount of energy, but divided amongst many sub-

systems) may not be very different from that flowing up a single

food chain in an unproductive region (having been divided

amongst fewer subsystems).