|SREL Reprint #0562|
A Potential Measure of the Effects of Environmental Stress Upon Wildlife
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.