3.1 WHAT DO WE MEAN BY ‘STABILITY’

20.3.1 What do we mean by ‘stability’?

to invasion, etc.). Now, however, it is clear his assertions were

mostly either untrue or else liable to some other plausible inter-

Of the various aspects of stability, an

pretation. (Indeed, Elton himself pointed out that more extensive

resilience and

analysis was necessary.) At about the same time, MacArthur (1955)

initial distinction can be made between

resistance

the resilience of a community (or any

proposed a more theoretical argument in favor of the conventional

wisdom. He suggested that the more possible pathways there

other system) and its resistance. Resilience describes the speed with

were by which energy passed through a community, the less likely

which a community returns to its former state after it has been

it was that the densities of constituent species would change in

perturbed and displaced from that state. Resistance describes the

ability of the community to avoid displacement in the first place.

response to an abnormally raised or lowered density of one of

the other species.

(Figure 20.7 provides a figurative illustration of these and other

aspects of stability.)

The second distinction is between