4.2 Changing order of biomass and complexity of communities
during the succession process
Jorgensen et al. (2000) has put forward three types of growth
patterns for communities: growth of reserves (Type I), growth
of flows (Type II), and growth of structural complexity (Type
III), which, when used in this research, corresponded to growth
of biomass, growth of network structure, and growth of information,
respectively. Jorgensen et al. (2000) suggested that, in
the ecological succession process, the early stage of succession
gives priority to the storage of exergy (Type-I growth), which is
shown by the structural construction of communities, for which
the important feature is the quick accumulation of exergy by the
communities and the low output of entropy. In the middle stage
of succession, there is an increasing relationship among the
species in the communities, which means there is a growth in
exergy flows (Type-II growth). In the final stage of succession
(i.e., the mature stage of the communities), circulation becomes
the main feature of the communities and reflects the highly
structured complexity of the communities (Type-III growth).
These three types of growth can be reflected in the growth of
structural order or information content, although the practical
application of community growth is often expressed by biomass,
biodiversity, and other quantitative indicators (Marques
and Jorgensen, 2002). Jorgensen and Mejer (1979) suggested
that exergy reserves could be used to measure community
complexity. They proposed that: (a) systematic complexity becomes
more relevant as more complex species appear, that is, it
is more relevant as the information content increases, and (b)
the development of the ecological system optimizes the systematic
exergy reversals under some circumstances. The exergy
reversals clearly indicate the distance between the system and
the thermodynamic equilibrium and reflect the developmental
degree of systematic structure (Jorgensen, 2002).