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
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