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Multi-trophic interaction, levels of trophic cascade, direct effects,…
Multi-trophic interaction
Linear combinations of linked trophic interactions (plant>herbivore>carnivore)
energy transfer (depends on taxonomic group)
Assimilation efficiency
Production efficiency
Consumption efficiency
Testing the Energy-Flow Hypothesis
(Pimm, S. L. (1982) Food Webs. Chapman and Hall, London)
3 level
top predator reduces abundance of intermediate (meso-) predator,
– abundance of prey increases,
– decrease in prey’s resource
removal experiement-Inter-tidal rocky shore (Wootton, J.T. (1992) Ecology 73, 981-991)
Predatory birds like gulls and oystercatchers feed on limpets.
Limpets graze on algae
Birds feed on goose barnacles.
Barnacles and mussels compete for space
cascade caused by bird predation
Birds directly limit density of competing limpets
• Grazing pressure by limpets reduced.
• predation indirectly cascades down to algae.
• Birds directly limit number of goose barnacles.
• predation indirectly leaves more space for competing mussels
cryptic habitat
selection = organisms choose habitats that make them less visible or detectable to predators, competitors, or prey
(Nugent et al., 2022)
Bottom-up control by competition
Plants limited bottom-up by competition for their resources
Herbivores limited by competition for plants
Predators limited by competition for herbivores
levels of trophic cascade
4 level
predator reduces prey abundance
increase in abundance of prey’s resource
Trophic cascade across ecosystems
(Knight, T.M. (2005) Nature 437, 880-883)
direct effects
(Ripple, W.J. (2016) Trends Ecol. Evol. 31, 842-849)
All trophic levels subject to bottom up control
