Linking Restoration and Ecological Succession (Springer ... - Inecol

Chapter 7 Restoration as a Process of Assembly and Succession Mediated by Disturbance 157
and Keddy 1999), even though there is disagreement among ecologists as to
whether community assembly rules should include or exclude abiotic, environmental
factors (cf. Temperton and Hobbs 2004). As such, dynamic models of
community assembly, such as the dynamic filter model proposed by Fattorini
and Halle (2004), form a very useful link between the focus of community assembly
on biotic interactions within communities and the focus of succession
on temporal dynamics of the biotic and abiotic components of a system after
a disturbance. In summary, succession focuses on what is at a site or able to
colonize while community assembly focuses on what does and does not get
established, but both are concepts of change in communities over time.
Rather than continue with ecology’s traditional propensity to fragment its
subject matter instead of synthesizing disparate approaches, one could argue that
assembly ideas differ very little from succession concepts and hence should not
be considered as a separate entity. Despite the different origin of assembly ideas,
this seems a profitable way to proceed, at least where assembly is considered in
a dynamic context. Indeed, recent studies appear to assume that assembly and
succession can be considered together to help explain observed patterns and
dynamics (Bossuyt et al. 2005).
7.6 Disturbance
Lockwood (1997) and Young et al. (2001) both suggest that succession could
form the core concepts in restoration. We would like to go further and suggest
that disturbance, assembly, and succession together form the key to a better
understanding of concepts in restoration. This may at first sight seem trivial,
as we all know that the main reasons for an ecosystem needing restoration
are usually caused by anthropogenic or natural disturbances, but we propose
to focus particularly on the differential effects of disturbance type, frequency,
and intensity on successional trajectories, on the establishment and extinction
of species within a system, and on assembly rules of community dynamics
under current disturbance regimes. The idea that disturbance is an important
part of succession is, of course, not new (e.g., Pickett and White 1985), but we
suggest that a more coherent combination of ideas from succession, assembly,
and disturbance may be beneficial.
According to Pickett and White (1985), we define disturbance in a neutral
way as a discrete event in time that disrupts the ecosystem, community, or
population structure, and changes the resources, substrate availability, or the
physical environment. Disturbance in a restoration context is far more than just
the event that creates the degradation or change of state. Disturbance can be
an essential tool of management during the restoration process itself, because
it can modify ecosystem dynamics. Disturbances include a wide variety of
events at different spatial and temporal scales, ranging from small-scale animal
diggings through fires and floods to broad-scale storms and tectonic and volcanic
activity. Additionally, disturbance regimes, or the mix of different disturbances
characterized by their size, frequency, and intensity, need to be restored as
such, because they play a crucial role in dynamics of restored sites in many
ecosystems (see Chapters 4 and 6).
Although many restoration ecologists may conceive of disturbance as limited
to the period before restoration begins, disturbance also helps to produce