PARENT SESSION
Oral Session #92: Conservation Ecology: Genetics, population viability, interactions.
Presiding: W. Wirtz
Thursday, August 8. 1:00 PM to 3:45 PM. Grand Ballroom West, Radisson.

The use of body mass to estimate quasi-extinction risk.

Hajagos, Janos^*,1, Ginzburg, Lev¹, ¹ State University of New York at Stony Brook, Stony Brook, NY

ABSTRACT- Discrete stochastic models can be used to predict the risk of decline in a biological population. Making an estimate of decline, even with the simplest scalar model, requires detailed information about the population. At the minimum, one needs to estimate the mean rate of population growth, the variation around this mean rate, and, if a model of density dependence is being used, the carrying capacity and the maximum rate of intrinsic increase. Such parameters can be estimated directly from a time-series of population abundances. However, often such series are too short or do not exist, for the population under study. Allometric or scaling relationships between mean adult body mass and an ecological variable can provide a proxy for some parameters in scalar population models, for example, carrying capacity and the maximum rate of intrinsic increase. Currently, there are no published scaling relationships for predicting the variation in the rate of population growth. Using a macroecological database of bird and mammal time series of abundances, predictive upper and lower bounds for the variation in the rate of growth, based on the maximum observed rate of intrinsic increase for a time-series are developed. Combining this finding with other allometric relationships allows a conservative estimation of population decline.

KEY WORDS: quasi-extinction probability, allometry