Taxonomic variation in size-density relationships challenges the notion of energy equivalence
Isaac, Nick J.B.; Storch, David; Carbone, Chris. 2011 Taxonomic variation in size-density relationships challenges the notion of energy equivalence. Biology Letters, 7 (4). 615-618. 10.1098/rsbl.2011.0128Before downloading, please read NORA policies.
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The relationship between body mass and abundance is a major focus for research in macroecology. The form of this relationship has been suggested to reflect the partitioning of energy among species. We revisit classical datasets to show that size-density relationships vary systematically among taxonomic groups, with most variation occurring at the order level. We use this knowledge to make a novel test of the ‘energy equivalence rule’, at the taxonomic scale appropriate for the data. We find no obvious relationship between order-specific exponents for abundance and metabolic rate, although most orders show substantially shallower (less negative) scaling than predicted by energy equivalence. This finding implies greater energy flux among larger-bodied animals, with the largest species using two orders of magnitude more energy than the smallest. Our results reject the traditional interpretation of energy equivalence as a predictive rule. However, some variation in size-density exponents is consistent with a model of geometric constraints on foraging.
|Item Type:||Publication - Article|
|Digital Object Identifier (DOI):||10.1098/rsbl.2011.0128|
|Programmes:||CEH Topics & Objectives 2009 - 2012 > Biodiversity > BD Topic 1 - Observations, Patterns, and Predictions for Biodiversity > BD - 1.4 - Quantify and model interactions to determine impacts ...|
|Additional Keywords:||metabolic ecology, metabolic theory, scaling, allometry, energetic equivalence, Damuth's rule, population density|
|NORA Subject Terms:||Ecology and Environment|
|Date made live:||19 Oct 2011 11:34|
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