The scaling of abundance in consumers and their resources: implications for the energy equivalence rule.
The negative scaling of plant and animal abundance with body mass is one of the most fundamental relationships in ecology. However, theoretical approaches to explain this phenomenon make the unrealistic assumption that species share a homogeneous resource. Here we present a simple model linking mass and metabolism with density that includes the effects of consumer size on resource characteristics (particle size, density, and distribution). We predict patterns consistent with the energy equivalence rule (EER) under some scenarios. However, deviations from EER occur as a result of variation in resource distribution and productivity (e.g., due to the clumping of prey or variation in food particle size selection). We also predict that abundance scaling exponents change with the dimensionality of the foraging habitat. Our model predictions explain several inconsistencies in the observed scaling of vertebrate abundance among ecological and taxonomic groups and provide a broad framework for understanding variation in abundance.
Carbone
Chris
C
Institute of Zoology, Zoological Society of London, Regent's Park, London NW1 4RY, United Kingdom. chris.carbone@ioz.ac.uk
Rowcliffe
J Marcus
JM
Cowlishaw
Guy
G
Isaac
Nick J B
NJ
D000818:Animals; D001481:Basal Metabolism; D018533:Biomass; D049628:Body Size; D017753:Ecosystem; D005502:Food; D005518:Food Preferences; D008954:Models, Biological; D063245:Plant Development; D011156:Population Density; D014714:Vertebrates / Q000502:physiology