Extrapolation from Individual-Level Responses to Population Growth Rate Using Population Modeling

Authors: Hanson, Niklas; Stark, John D.

Source: Human and Ecological Risk Assessment, Volume 17, Number 6, 1 November 2011 , pp. 1332-1347(16)

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Abstract:

Ecological risk assessments of chemicals are often based on simple measurements of toxicity in individuals. However, the protection goals are often set at the population and community levels. Population models may be a useful tool to extrapolate from individual-level measurements to population-level endpoints. In the present study, the population growth rate (λ) was calculated for three sets of full life-cycle data (Tetranychus urticae exposed to agrimek, and Daphnia pulex exposed to spinosad and diazinon). The results were compared to λ from population models, where survival and/or reproduction were adjusted according to 4 d of data from the same life-cycle data. This was done to determine whether truncated demographic data can give results similar to that obtained with full life-cycle data. The resulting correlations were strong when both effects on survival and reproduction were included in the model (p < .001, 0.93 < R₂ < 1.00). There were also strong correlations in several cases when only effects on survival or reproduction were considered, although the total risk to the population tended to be underestimated. The results of the present study show that population models can be useful to extrapolate truncated data on the individual level to more ecologically relevant population-level endpoints.

Keywords: ecological risk assessment; extrapolation; population modeling; population level; life tables

Document Type: Research article

DOI: http://dx.doi.org/10.1080/10807039.2011.618421

Affiliations: 1: Washington State University,Puyallup Research and Extension Center, PuyallupWA, USA

Publication date: 2011-11-01