SREL Reprint #0562




Growth Curve Analyses:  A Potential Measure of the Effects of Environmental Stress Upon Wildlife Populations

T. T. Fendley and I. L. Brisbin, Jr.



Recent advances in the development of mathematical procedures for the qualitative and quantitative analyses of sigmoid growth curves have provided a new tool for assessing the impacts of environmental contaminants upon populations of game birds and possible other forms of wildlife.  Because derived sigmoid growth parameters are usually based upon mathematical fits to a relatively large number of data points for each individual, they should be relatively free from biases introduced by random measurement errors.  Such growth parameters, moreover, can also provide an integrative assessment of the health or condition of an animal over its entire period of growth and development.  The use of growth curve analytical techniques are illustrated with data for laboratory-reared wood ducks (Aix sponsa) hatched from eggs laid by birds inhabiting a swamp delta contaminated with nuclear reactor effluents, principally radiocesium.  Using the logistic growth model, the birds from this contaminated habitat showed significantly accelerated growth rates and earlier points of inflection than those of birds from an uncontaminated area.  Only sex, irregardless of habitat contamination, affected the asymptotes of the growth curves, those of males being greater than those of females.


SREL Reprint #0562

Fendley, T.T. and I.L. Brisbin Jr. 1977. Growth curve analysis: a potential measure of the effects of environmental stress upon wildlife populations. p. 337-350. In Thirteenth International Congress Game Biologists, edited by T.J. Peterle. Atlanta, GA.

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