Defining the scales of interest

Abstract

We saw in Chapter 2 that equilibrium theory could only be applied to small closed universes that were, in all probability, rarely found in the real world. The world of the field ecologist is one of ‘patches’ in space and in time and, while some of the patches may be sufficiently distinct to be classed as closed systems for the purposes of theory, there is much migration between patches. Some of the patches are clearly the result of external physical and chemical influences on the populations of organisms and some of the patches arise from internal biological interactions such as grazing. How important are the two influences? What constitutes a patch and how are they formed? Are there any patches that are sufficiently closed and persistent for the competitive equilibrium to be achieved? I will now attempt to describe the ‘patchiness’ to be found in lakes and the oceans and to show how this patchiness influences the ecology of the species in those systems. In later chapters I will look at distinct spatial and temporal scales as they influence certain aspects of the ecology of the organisms, so our job here is to sketch the outline of the processes and to broadly define the scales of interest.