Environmental Engineering Reference
In-Depth Information
what is known without being forced by the abstraction concepts to focus only on
specific properties. This is shown in the following examples.
Eschenbach (2005) attempted to model structural and physiological implications
of plant development jointly. Previous models usually focused on either the structure
or on physiological processes. She defined the typical units as classes and specified
according methods (rules how to change the variables) within the particular classes.
Under certain conditions new class instances are created (e.g. branches, internodes)
- or existing ones could be eliminated (e.g. leaves). This allowed to test whether
certain assumptions about partitioning that cannot be directly measured, but are
important for growth implications were in line with the overall structural develop-
ment that results after many years of growth. (Figs.
4.3
and
4.4
).
The same approach can be used to describe animal interactions. Holker and
Breckling (2002, 2005) applied it to simulate local density heterogeneities of fish
depending on individual behaviour and environmental structures. The model aimed
at investigating the relation between individual bio-energetic characteristics and
population development. It represents individual fish as autonomously acting agents
Fig. 4.4 The repeated iterative application can reveal complex plant-like structures with root
system, stem, branches, leaves and meristems as shown for the model of alder trees (
Alnus
glutinosa
). Two Simulation results of structural development assuming different light intensities
are shown (
left
: optimal,
right
: low light). The tree architecture adapts to the environmental
conditions according to the response pattern of the single components showing the implications
of environmental or physiological differences on the structural development [from Eschenbach
(2005)]
