This is the last of five chapters in which I describe patterns observed in phytotelm food webs. In this chapter I move away from the theme of variation at various spatial scales and examine variation that is primarily a response to the passage of time.

There are a number of time scales of importance in considering food-web structure. The expanses of geological time and the processes of plate tectonics and resulting biogeographic change determine the basic set of organisms ‘available’ for invasion of a habitat unit. In addition, this geological time scale is the scale of evolution and speciation in response to environmental change. I revisit these very extended time scales again in one of my concluding chapters (Chapter 13). For the moment though, it is time scales spanning months and years that are of more concern. Not surprisingly it is over these more modest time scales that we have data to illustrate ecological processes and their impact.

I describe in this chapter three processes.

• First is the complex of factors usually referred to as seasonality: in other words the changes which we may observe in community structure within a habitat unit which persists for one or many years. To illustrate this class of change I re-present data from Kitching (1987a) on variation through time in food webs in water-filled tree holes in the subtropical rainforests of south-east Queensland and compare these with earlier results from British tree-hole communities. […]