Allometric scaling of rate, age and density parameters in ecological models

Over 100 allometric regressions on rare [kg kg(-1) d(-1) = d(-1)], age [d] and density [kg km(-2)] parameters often used in ecological models were collected in a literature review. For each parameter, typical coefficients and exponents that covered most of the correlations found were selected. The parameters were checked for consistency by comparing them to each other, e.g. mortality versus age and to independent data, e.g. production and respiration rate constants versus production efficiency. Exponents for consumption, production and respiration rates on the one hand and slopes for maturation. average and maximum age on the other, scale to size with an exponent of the same magnitude but opposite sign. Most values are between +/- 0.25 and +/- 0.33. No consistent differences between parameters and species were found. Coefficients for production and respiration were largely consistent with those for ingestion and with independent data on assimilation and production efficiencies. The same was concluded for production versus mortality. for mortality versus age as well as maximum versus average production and consumption. Warm-blooded animals consume, produce and respite at rates about 10 times higher than equally sized cold-blooded species. The reverse uas noted for age and possibly density. Population density of individual species and biota density of geometric size classes are nearly independent of size for regressions that span a wide size range. The coefficients for density vary up to two orders of magnitude. depending on local conditions. Most allometric regressions reported apply to aquatic invertebrates or terrestrial birds and mammals of the biophageous food chain. Yet, the rate and age regressions that include other species do not indicate substantial deviations for bacteria, micro-and macrophytes and for terrestrial (saprophageous) invertebrates. The set of typical values derived may facilitate parameter estimation for generic models. For specific models, the regressions collected in the literature review may provide initial values for parameters.