10 Ecology and Applied Environmental Science
exerted on the ecosystem. Examples of these parameters, called external
factors, are temperature, incoming solar energy, and trophic inflows.
A mathematical model of an ecosystem consists of functions that mainly
connect the external factors and the state variables. These functions result,
firstly, from the application of fundamental laws governing the physical,
chemical, and biological phenomena of the functioning of the ecosystem.
The process during which sets of values of external factors are determined and, based on the functions of the model, the values of the state
variables are calculated over time is called a mathematical simulation of the
functioning of the ecosystem.
Usually, when studying ecosystems, the set of values of external factors in
general is called input, and the resultant set of values of the state variables
is called output.
The process of constructing a model generally includes the following stages:
• Determination of objective
• Selection of the necessary parameters for the given level of description, given that some information will be lost when moving up to each
higher level
• Simplification of the system by omitting unimportant elements
• Formulation of hypotheses to facilitate the study
• Extraction and control of results
Present-day problems of protecting the environment have placed particular emphasis on ecology as an applied science. Mathematical simulation is
a useful tool of ecology, in the effort to solve problems in relation to human
management of ecosystems. As a rule, however, the results of a mathematical simulation do not lead to full, precise solutions to problems, for the
following reasons, inter alia:
• Many ecological phenomena, particularly phenomena with a long-term
evolution, have not been sufficiently investigated, and quantitative
approaches to them are usually inadequate and/or superficial.
• Ecosystems are characterised by a complex interconnection, not only
internal but usually also external. Thus, the separation of the biosphere into ecosystems is artificial, and therefore the realism of the
ecosystem models is reduced. The input of the ecosystem includes
elements that constitute output of other ecosystems, which influence,
and are also influenced, by the one being examined.
Therefore, although mathematical models are a very useful tool for study,
they are usually approximate, even rough, depictions of the functioning of
natural ecosystems.
exerted on the ecosystem. Examples of these parameters, called external
factors, are temperature, incoming solar energy, and trophic inflows.
A mathematical model of an ecosystem consists of functions that mainly
connect the external factors and the state variables. These functions result,
firstly, from the application of fundamental laws governing the physical,
chemical, and biological phenomena of the functioning of the ecosystem.
The process during which sets of values of external factors are determined and, based on the functions of the model, the values of the state
variables are calculated over time is called a mathematical simulation of the
functioning of the ecosystem.
Usually, when studying ecosystems, the set of values of external factors in
general is called input, and the resultant set of values of the state variables
is called output.
The process of constructing a model generally includes the following stages:
• Determination of objective
• Selection of the necessary parameters for the given level of description, given that some information will be lost when moving up to each
higher level
• Simplification of the system by omitting unimportant elements
• Formulation of hypotheses to facilitate the study
• Extraction and control of results
Present-day problems of protecting the environment have placed particular emphasis on ecology as an applied science. Mathematical simulation is
a useful tool of ecology, in the effort to solve problems in relation to human
management of ecosystems. As a rule, however, the results of a mathematical simulation do not lead to full, precise solutions to problems, for the
following reasons, inter alia:
• Many ecological phenomena, particularly phenomena with a long-term
evolution, have not been sufficiently investigated, and quantitative
approaches to them are usually inadequate and/or superficial.
• Ecosystems are characterised by a complex interconnection, not only
internal but usually also external. Thus, the separation of the biosphere into ecosystems is artificial, and therefore the realism of the
ecosystem models is reduced. The input of the ecosystem includes
elements that constitute output of other ecosystems, which influence,
and are also influenced, by the one being examined.
Therefore, although mathematical models are a very useful tool for study,
they are usually approximate, even rough, depictions of the functioning of
natural ecosystems.