BODY MASS-POPULATION DENSITY SCALING AT THE LOCAL SCALE: DOES THE ENERGY EQUIVALENCE RULE HOLD FOR FOREST MAMMALS?

The energy equivalence rule assumes that the scaling of population density with body mass is inversely proportional to the scaling of individual metabolic rate. As a result, the total population energy use, calculated as the product of individual metabolic rate and population density, is independent of body mass. Here we evaluated the validity of this rule at the scale of a single community of mammals. Strong linear dependencies were found between log-transformed individual metabolic rate and log-transformed body mass as well as between body mass and density. The slopes of these relationships are close to the predicted vertical bar 3/4 vertical bar value and, in accordance with the energy equivalence rule, exhibit opposite values. The results however supported this rule only at the scale of the whole community. When small and large species were considered separately, population energy use increased with body mass. Analyzing these two groups separately strongly decreased the range of body mass considered. Body mass range seems to be a critical factor to find support for the energy equivalence rule at the scale of a single community.