Diversity Indices and Standards
Ecology – study of the interrelationships between plants and animals
and their abiotic environment.
Species – individuals that interbreed freely to produce fertile
Population – all the individuals of the same species in a defined
area. All the Micropeterus salmoides in Lake Ray Roberts.
Community – all the populations in a defined area, or all the fish in
Lake Ray Roberts.
Ecosystem – Lake Ray Roberts, the surrounding watershed and all
the organisms there in.
Watershed – the area of land that catches precipitation that then if
transported along the surface drains to a common point.
Historically pollution and organic enrichment problems were
synonymous. Engineers and chemists used physical and chemical
surveys to tell them about the “health” of a system.
Measured parameters like: pH, dissolved oxygen, and BOD5
Why can’t you use physical/chemical measurements alone to tell you
about the “health” of an ecosystem?
When biologists became significantly involved they tended to
provide lists of species they found in a survey.
Species Lists…. Head of chironomid… dichotomous key
Eventually developed a belief that organisms living in a system are
probably the best indicator of their health.
In the discussion that follows the letters used in the listing of
organisms represent species A = a species, B = a species, etc.
The indices that are used in the following series of slides are examples
of the kinds of indices that have been developed. There are many
variations of these indices and each has its own inherent strengths and
If you are using diversity indices you would never
represent your data by a single index!
CCC criteria continuous concentration
CMC criteria maximum concentration
The State criterion in Texas for a given river might look like
the formula below where the 0.960 accounts for the acid
soluble function and the 1.60 for the water effects ratio
assigned to a particular receiving system.
For the chronic value for 100 mg/L hardness as CaCO3
Answer is: 29.5 ug/L copper; without the 0.960 and
the 1.60 the standard would be 19.2 ug/L