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Stepping in Elton’s footprints: a general scaling model for body masses and trophic levels across ecosystems
Author(s) -
Riede Jens O.,
Brose Ulrich,
Ebenman Bo,
Jacob Ute,
Thompson Ross,
Townsend Colin R.,
Jonsson Tomas
Publication year - 2011
Publication title -
ecology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.852
H-Index - 265
eISSN - 1461-0248
pISSN - 1461-023X
DOI - 10.1111/j.1461-0248.2010.01568.x
Subject(s) - trophic level , predation , predator , ecology , apex predator , food web , ecosystem , ectotherm , biology , ecological stability , invertebrate , trophic cascade , food chain
Ecology Letters (2011) 14: 169–178 Abstract Despite growing awareness of the significance of body‐size and predator–prey body‐mass ratios for the stability of ecological networks, our understanding of their distribution within ecosystems is incomplete. Here, we study the relationships between predator and prey size, body‐mass ratios and predator trophic levels using body‐mass estimates of 1313 predators (invertebrates, ectotherm and endotherm vertebrates) from 35 food‐webs (marine, stream, lake and terrestrial). Across all ecosystem and predator types, except for streams (which appear to have a different size structure in their predator–prey interactions), we find that (1) geometric mean prey mass increases with predator mass with a power‐law exponent greater than unity and (2) predator size increases with trophic level. Consistent with our theoretical derivations, we show that the quantitative nature of these relationships implies systematic decreases in predator–prey body‐mass ratios with the trophic level of the predator. Thus, predators are, on an average, more similar in size to their prey at the top of food‐webs than that closer to the base. These findings contradict the traditional Eltonian paradigm and have implications for our understanding of body‐mass constraints on food‐web topology, community dynamics and stability.