at the larger spatial scales that are relevant to
managers.
Community-level management is described in
Chapter 10 forsalt marshesin North-West Europe.
It deals with interactions among sedimentation,
nutrient availability, plant growth and herbivores.
Natural succession in these systems results in the
dominance of a single tall grass species to the detri-
ment of the natural herbivores such as geese and
hares. Introductions of large herbivores can reverse
succession to facilitate geese and hares. Without
this management, these systems would develop
into low-diversity systems of reduced value.
Finally, we considerfuture directions of community
research. These chapters include the study of the
evolution of community processes and patterns,
ranging from local dynamics to large-scale diversity
gradients, and focus on the role of mutualisms in
community ecology. Chapter 11 focuses onevolu-
tionary processes in community ecologyto try to bridge
the gap between community and evolutionary ecol-
ogy by considering the reciprocal effects of individ-
ual trait variation and community characteristics.
Central principles from evolutionary biology are
used to extrapolate the consequences of genetic
diversity to community level and illustrate the ef-
fects of genetic variation on community properties
and vice versa. It is stated that more studies have
been performed on the effects of genotypic and
phenotypic diversity on community properties
than on the effects of community diversity on ge-
netic and phenotypic diversity of single species.
This fascinating new field of integrative evolution-
ary community ecology is still in its infancy, but
holds great promise. Chapter 12 deals with the
emergence of complex food web structure in community
evolution modelsand aims at synthesizing how evo-
lutionary dynamics may help the understanding of
food web structures and dynamics. Community
evolution models incorporate both the dynamical
components of food webs and the complexity nec-
essary to understand empirical food web data. It is
shown how this model matches topological proper-
ties of empirical data, while giving information on
the dynamics of the food web. It also discusses the
relevance of the allometric theory of ecology to the
debate on the relationship between stability and
diversity, as well as the evolution of niche breadth
and non-trophic interactions. Another promising
line of research involves mutualisms. Chapter 13
deals with the role ofmutualisms and community
organization.Key evolutionary events, such as the
origin of the eukaryotic cell, the invasion of land by
plants and the radiation of angiosperms, are linked
to mutualisms. Mutualism probably brings order to
the organization, structure and function of commu-
nities by regulating the acquisition of resources and
ameliorating stresses. Finally, Chapter 14 specu-
lates aboutemerging frontiers of community ecology.
Among various emerging areas, a focus on the im-
portant topic of biotic invasions seems crucial, since
they alter the world’s natural communities as well
as their ecological character. Further emerging
areas concern questions surrounding the linking
of the structure of ecological networks to empirical-
ly measured community dynamics.INTRODUCTION 3