In this book, we have grouped the various chap-
ters into several areas: (1) community shape, struc-
ture and dynamics, (2) communities over space and
time, (3) applications of community ecology and (4)
future directions of community research. We start
with shape and structure, with a focus on thetopolo-
gyof networks of interacting organisms in ecological
systems. Chapter 1 deals with subsets of the full
network of interactions: competition networks, mu-
tualistic networks and consumption networks (food
webs). It involves recent studies and important ques-
tions about the structure and the processes or me-
chanisms that may result in their structure. Chapter
2 follows with dynamics, dealing with thetrophic
dynamics of communities. The focus is on types of
dynamics that can be distinguished, the dynamics
of simple and complex interactions and the internal
and external determinants of food web dynamics.
Chapter 3 considersmodelling of the dynamics of com-
plex food webs, with a focus on whether embedding
simple modules in complex food webs affects the
dynamics of those modules. The dynamic analysis
of complex food webs is organized around the rela-
tionships between complexity and stability and
diversity and stability. Body-size-dependent scaling
of biological rates of populations emerge as a possi-
ble solution to the instability predicted for complex
food webs. Chapter 4 forms a bridge between
dynamics and the next section on space and time.
The subject of this chapter iscommunity assembly
dynamics in space, with a focus on three elements of
assembly dynamics: the rate of immigration to local
communities, the degree to which the species pool is
external to local community dynamics and the
amount of variation in immigration history among
local communities. The hypothesis is that these ele-
ments together determine the degree of historical
contingency. Chapter 5, onincreasing spatio-temporal
scales: metacommunity ecology, discusses whether a
metacommunity perspective can be helpful in
synthesizing community ecology across spatial
scales, and whether it can provide insights into the
spatial mechanisms causing variation in species co-
existence, strengths of species interactions and pat-
terns of local and regional diversity. Chapter 6 deals
withspatio-temporal structure in soil communities and
ecosystem processes, and highlights the complexity
exhibited by soil communities at different scales.
Community ecology has many real-world appli-
cations deriving from the fact that the abundance of
species strongly depends on competitive and pred-
atory interactions. These interactions are major dri-
vers of ecosystem processes, and they are the key to
the delivery of ecosystem goods and services.
Chapter 7 focuses on applications of community
ecology approaches in terrestrial ecosystems: local
problems, remote causes. In terrestrial ecosystems,
there is a clear link between belowground and
aboveground subsystems, which is to be compared
with benthic–pelagic coupling in aquatic or marine
systems. These above/belowground linkages influ-
ence many major processes, such as ecosystem res-
toration following land abandonment or the fate of
introduced exotic alien species. Some examples of
above/belowground interactions in relation to
changing land usage and biological invasions are
discussed and related to climate warming. Chapter
8 reviews the consequences of industrial-scale
fishing on marine communities and is entitledsea
changes: structure and functioning of emerging marine
communities.Growing evidence from models and
empirical time series suggests that fishing pressure
can cause relatively rapid regime shifts into distinct
semi-stable states that resist change even after fish-
ing has been relaxed. Although theory predicts that
a preponderance of weak interactions stabilizes
food web dynamics, these weak interactions may
be unlikely to buffer marine ecosystems from the
impacts of intense exploitation by humans. Thus,
the systematic reduction in average food chain
length documented in oceanic and coastal ecosys-
tems can initiate regime shifts to alternate semi-
stable states, and is already affecting the provision
of marine ecosystem services to society. In Chapter
9, which focuses onapplied (meta)community ecology:
diversity and ecosystem services at the intersection of
local and regional processes, several expectations
from metacommunity theory on the effects of land
use intensification are suggested, based on the fact
that both local and regional processes are important
for diversity and ecosystem functioning. Examples
drawn from research on organic farming and
biological control illustrate that metacommunity
theory combined with good knowledge of the sys-
tem under management is useful to understand
how human-dominated ecosystems can be managed2 INTRODUCTION