Zooplankton community structure was examined at five stations in Normandy Reservoir, Tennessee, on six dates from 11 July to 15 September 1980 . Four physical and chemical parameters at three depths at each station were used to discriminate statistically among areas of the reservoir over time ; a similar analysis based on nine taxomonic and ecological categories of zooplankton was also completed . Each of the two multivariate analyses provided a matrix of similarities among station-times (n = 30) in the reservoir . The two similarity matrices were compared by the Mantel test and were found to be not significantly concordant, suggesting that physical-chemical variation among areas in the reservoir during the summer months was not precisely reflected by zooplankton community structure .
The lack of congruence between physically-and chemically-determined reservoir structure and structure implied by zooplankton taxa or functional groups was also observed in the results of a random-effects-model ANOVA of physical and chemical parameters and zooplankton densities . ANOVA of zooplankton densities revealed that spatial variation was generally greater than temporal variation, although most of the spatial variation was ephemeral (station-time interaction) rather than fixed (station effects) . An ANOV A of physical and chemical variables revealed considerable fixed spatial variation over the same time scale .