Synoptic Limnology: The Analysis of British Freshwater Ecosystems

Surveys of various fresh waters in Great Britain have been carried out in the past, ranging from detailed studies of one particular water body to broader surveysof a large number of waters (often with reference to only one group of organisms). Although individual studies have been of value, the more extensive surveys have proved of greater and longer — lasting worth. Outstanding among such is the study of 562 lochs in Scotland carried out by Murray & Pullar (1910). This work is still used widely among those concerned with freshwater research in Scotland, though it is very incomplete biologically. The normal disadvantage with such accounts is that, within any one study, only a limited number of parameters were described, 'while, among several studies, not only were different parameters measured, but a wide range of methods may have been used to measure them. The synoptic value of such works is therefore greatly reduced, and, for this and other reasons, 'surveys' are often regarded as having little other than descriptive value in ecology.' This account illustrates the importance of a synoptic approach to the study of British fresh waters and outlines how it has been initiated. The primary aim of the research described is to provide a scientific background for the interpretation and classification of aquatic ecosystems in Great Britain — particularly for conservation and management purposes. The synoptic data bank will also be a major source of autecological information. Apart from the descriptions arising from survey data, their potential predictive worth is something which is often ov-erlooked. The normal experimental approach to predictive problems in fresh waters is difficult both in execution and interpretation. The prediction of the nature of new or modified aquatic systems can also be investigated using simulation models. Experience at a number of IBP sites has demonstrated the difficulties associated with using models developed at a single site as a means of general prediction — absurd results often occurring if the assumed ecosystem dynamics are in error. Without elaborating the topic of mathematical modelling, it is fair to say that. the practical use of models demands comparative data on freshwater systems of a quality which is not yet available. In particular, the information obtained through extensive survey can often complement the development of specific site models.