Environmental Engineering Reference
In-Depth Information
Bootstrapping A resampling with replacement method in statistics for drawing
conclusions from data that are subject to random variation.
Bray-Curtis Index An ecological metric that is used to describe the dissimilarity
of different sites using the species number at each site in relation to the total species
number.
Carrying Capacity A population size which does not allow a further increase
because of resource or environmental limitations.
Cause-Effect Chain The philosophical assumption that any effect has an ante-
cedent cause, allows a chain- or net-like arrangement of observed interactions that
are considered for modelling or other forms of description.
Chaotic Dynamics Special behaviour of dynamic systems with strong depen-
dency on initial conditions which can make long-term predictions impossible.
Classical Logic Logic is a subfield of mathematics concentrated on aspects of
reasoning. Classical logic is based on a number of axioms: law of identity (if a
statement is true, then it is true), law of the excluded middle (a statement is either
true or false), law of non-contradiction (a statement cannot be both true and false).
Classical logic is bivalent: the truth value of a statement may only be either true or
false. Statements can be connected by logical operators (and, or, if..then, ...), whose
definition allows to identify the truth value of the resulting statement. There are also
types of nonclassical, multivalued logic, e.g. fuzzy logic, which rejects the laws of
excludedmiddle and non-contradiction, allowing a statement to be both true and false.
Computer Scenarios In computer experiments, different sets of conditions are
grouped into alternative cases and the reaction of the model components to the
variation of these characteristics is assessed through simulation. Scenarios are
widely used to evaluate the outcomes of possible future situations (e.g. global
climate change situation at increased temperatures) on the target variables.
Cybernetics This is an interdisciplinary approach of control and regulation of
complex systems, like machinery or living organisms, founded by Norbert Wiener.
A classic example is the regulation of temperature by a thermostat.
Ecological Niche Describes the position of a species in a formalized multi-
dimensional space of environmental variables and variables describing resource
requirements - e.g. the tolerated range of temperature, salinity, or minimum
quantities of soil nutrients.
Ecosystem Indicators Measurable features in management and conservation
ecology which are used to document certain ecosystem states (like ecosystem
