This paper introduces a collection of contributions presented at the 8th Workshop of the International Association of Phytoplankton Taxonomy and Ecology. It compares the substance of with what to

In this paper we emphasize that sampling decisions in popUlation and community ecology are context dependent. Thus, the selection of an appropriate sampling procedure should follow directly from considerations of the objectives of an investigation. We recognize eight sampling alternatives, which arise as a result of three basic dichotomies: parameter estimation versus pattern detection, univariate versus multivariate, and a discrete versus continuous sampling universe. These eight alternative sampling procedures are discussed as they relate to decisions regarding the required empirical sample size, the selection or arrangement of sampling units, and plot size and shape. Our results indicate that the decision-making process in sampling must be viewed as a flexible exercise, dictated not by generalized recommendations but by specific objectives: there is no panacea in ecological sampling. We also point to a number of unresolved sampling problems in ecology.

The use of mathematical methods based on Shannon's entropy function is proposed for the evaluation of the consequences of sampling unit size and for the study of vegetation succession. The concept of diversity is extended to sets of phytosociological relev6s under the term florula diversity. It is shown that Shannon's entropy as well as two other related characteristic functions can express the local behaviour and overall relationships of species. Characteristic areas are defined in terms of the maxima and minima of these functions. Several study areas yielded the data which are used in the examples. Some theoretical problems of the methods are discussed and a computer, written in FORTRAN, is described.

No abstract

This paper tries to show some ways and means of simple (binary) modelling, whereby diversity can be interconnected with other attributes of a community. A new type of scaling (called characteristic scaling) is introduced for further use.