Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

THERMAL AND ENERGETIC CONSTRAINTS ON ECTOTHERM ABUNDANCE: A GLOBAL TEST USING LIZARDS

THERMAL AND ENERGETIC CONSTRAINTS ON ECTOTHERM ABUNDANCE: A GLOBAL TEST USING LIZARDS Population densities of birds and mammals have been shown to decrease with body mass at approximately the same rate as metabolic rates increase, indicating that energetic needs constrain endotherm population densities. In ectotherms, the exponential increase of metabolic rate with body temperature suggests that environmental temperature may additionally constrain population densities. Here we test simple bioenergetic models for an ecologically important group of ectothermic vertebrates by examining 483 lizard populations. We find that lizard population densities decrease as a power law of body mass with a slope approximately inverse to the slope of the relationship between metabolic rates and body mass. Energy availability should limit population densities. As predicted, environmental productivity has a positive effect on lizard density, strengthening the relationship between lizard density and body mass. In contrast, the effect of environmental temperature is at most weak due to behavioral thermoregulation, thermal evolution, or the temperature dependence of ectotherm performance. Our results provide initial insights into how energy needs and availability differentially constrain ectotherm and endotherm density across broad spatial scales. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Ecology Ecological Society of America

THERMAL AND ENERGETIC CONSTRAINTS ON ECTOTHERM ABUNDANCE: A GLOBAL TEST USING LIZARDS

Buckley, Lauren B.; Rodda, Gordon H.; Jetz, Walter
Ecology , Volume 89 (1) – Jan 1, 2008
Download PDF
8 pages

Loading next page...
 
/lp/ecological-society-of-america/thermal-and-energetic-constraints-on-ectotherm-abundance-a-global-test-Aw630choso

References (44)

Publisher
Ecological Society of America
Copyright
Copyright © 2008 by the Ecological Society of America
Subject
Reports
ISSN
0012-9658
DOI
10.1890/07-0845.1
Publisher site
See Article on Publisher Site

Abstract

Population densities of birds and mammals have been shown to decrease with body mass at approximately the same rate as metabolic rates increase, indicating that energetic needs constrain endotherm population densities. In ectotherms, the exponential increase of metabolic rate with body temperature suggests that environmental temperature may additionally constrain population densities. Here we test simple bioenergetic models for an ecologically important group of ectothermic vertebrates by examining 483 lizard populations. We find that lizard population densities decrease as a power law of body mass with a slope approximately inverse to the slope of the relationship between metabolic rates and body mass. Energy availability should limit population densities. As predicted, environmental productivity has a positive effect on lizard density, strengthening the relationship between lizard density and body mass. In contrast, the effect of environmental temperature is at most weak due to behavioral thermoregulation, thermal evolution, or the temperature dependence of ectotherm performance. Our results provide initial insights into how energy needs and availability differentially constrain ectotherm and endotherm density across broad spatial scales.

Journal

Ecology – Ecological Society of America

Published: Jan 1, 2008

Keywords: ectotherms ; energetic constraints ; energetic equivalence rule ; environmental temperature ; lizards ; metabolic theory ; population density

There are no references for this article.