Abstract
AbstractTo detect spatial heterogeneous distributions it is necessary to delimitate quantitatively the sum of all errors caused by methods from sampling to counting. This is possible by the coefficient of variation, since it constitutes also a measure of the counting error and since its dependence on the counted number or the mean density of the population is clearly defined. In the investigations the error caused by methods (reproducibility of sampling and counting) does not exceed the theoretically permitted maximum counting error (at p = 0.05). Accordingly, all results of investigations for which the coefficient of variation lies above this counting error limit can be interpreted as actual spatial heterogeneous distributions. During the full circulations of autumn and spring as well as the summer stagnation period, in the Saidenbach storage reservoir no significant differences of the phytoplankton were observed within the range of horizontal distances of appr. 100m for 50% of the cases. For zooplankton. 45% of the investigations indicated a homogeneous distribution. The evaluation of data by the patchiness‐index according to Lloyd (L), the Morisita index (M) as well as the graphical comparison between variance and mean value (82/x) do not show any remarkably different results.
Published Version
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