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been declining at an alarming pace [Myers and Worm (2003); Worm et al. (2005);
Heithaus et al. (2008)]. Moreover, recent empirical and theoretical studies have
demonstrated that top predator removal often induces large-scale cascading eects
[Bascompte et al. (2005)]. Many developed nations have made progress in better
shery management [Grith (2008)]. However, nearly 20% of sh stocks in the
United States, for example, remain over-shed or are shed unsustainably [National
Marine Fishery Service (2008)]. The problem is more dire in developing countries,
many of which rely upon shing as an important economic activity [United Nations
Food and Agriculture Organization (2006)].
There are numerous ecological, environmental, economic, and social aspects to
the problems which stand before us. In order to remedy them, and avoid recreating
such problems in the future, we must develop eective environmental policies which
are rmly based on current environmental and ecological research. Reecting upon
the recent past and prospective future, research in the eld of ecological networks
is a strong candidate to successfully lead us in this direction.
In more traditional ecology, studies are restricted to an analysis of one to a few
species within an ecosystem or of one habitat patch within a landscape. In the study
of food webs or mutualistic networks, in contrast, the focus is upon understanding
the properties of the entire ecosystem [Bascompte et al. (2003); Pascual and Dunne
(2006)]. Similarly, in the study of spatial networks, the focus is upon understand-
ing the properties of the entire landscape by applying the network formalism to
problems in spatial ecology [Urban and Keitt (2001)].
The network approach in ecology has the longest tradition in community ecology
and food webs, where it has been utilized over the last thirty years [Cohen (1978);
Pimm (2002)]. Even so, the static and structural properties of food webs are only
recently becoming better understood partly because a recent acquisition of more
resolved data [Pascual and Dunne (2006)]. This leaves open a number of impor-
tant questions regarding food-web dynamics and stability. Similar conclusions are
reached when reviewing the mutualistic and spatial network literature.
If we wish to transform ecology, and in particular ecological networks, from a
descriptive to predictive science, we must move beyond static characterization to the
topic of dynamics upon these network structures. Consider, for example, the issue
of overshing. The eect of overshing of a single species cannot be considered
in isolation; it is imperative that the dynamics be viewed as a component of a
far larger and more complex system. To eectively manage sheries, then, we must
understand the dynamics of the complete ecosystem and the inuences of individual
species upon all others. Similarly in spatial networks, we understand that species
cannot be managed from the perspective of isolated local processes but through a
combination of local and regional dynamics and exchanges across the system.
We will cover the topic of ecological networks in three separate sections which
focus on the most developed sub-elds: food webs, mutualistic networks, and spatial
networks. In this chapter, we authors shall not provide comprehensive reviews of
