Community Ecology Processes, Models, and Applications

the reliable maintenance of critical ecosystem
services (see Chapters 7, 9 and 10).

14.2 Future directions

Of the various topics emerging from or suggested by
the content of the previous chapters in this volume, I
want to focus on the need for much additional work
in two areas to consolidate what we think we know,
or to resolve ongoing controversies. These future
directions include the problem of invasions by exotic

species as a special case of community assembly

processes, where species traits are likely to predict

community-level effects, and the need to integrate

the full range of ecological interactions into ecologi-

cal networks–complexity beyond food webs.

14.2.1 Biotic invasions

Ecologists recognize that biological invasions and

the biotic homogenization that may consequently

result constitute an enormous problem, comparable

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01020

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Brachionus calyciflorus
(females/ml)
Chlorella vulgaris
(10
6 cells/ml)
120
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Chlorella vulgaris
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Brachionus cal
yciflorus
(females/ml
)
Figure 14.1Predator–prey dynamics for rotifers (solid dots) feeding on single algal clones (a–d); and dynamics for the
same rotifer species feeding on multiple clones of the same algal species (e–i). Note the shift from short period cycles to
ones of longer period with an increase in clonal diversity. Used with permission from Yoshidaet al.(2003).
196 FUTURE DIRECTIONS