Causal Analysis/Diagnosis Decision Information System (CADDIS)

Predicting Environmental Conditions from Biological Observations

• Biological inferences
   
   
• Using existing
  models to infer
  env. conditions
• Estimating
  taxon-environment
  relationships
• Inferring env.
  conditions from
  biological data
• R scripts
   
   

Can the biota at a site tell us the environmental conditions at the site?

This module provides statistical tools for predicting environmental conditions from biological observations, and provides some of the ecological and statistical theory that underlie this method.

Probabilities of occurrence of Heterliminus and Malenka along a temperature gradient. Each symbol represents the average frequency of occurrence within approximately 20 samples around the indicated temperature.  Horizontal axis in units of °C.

Different taxa require different environmental conditions to persist. From the figures shown above, we can see that the riffle beetle, Heterlimnius, is most frequently found in streams that are approximately 8°, while the stonefly, Malenka, prefers warmer streams (~12°). If we knew the environmental preferences (i.e., the taxon-environment relationships) of many different taxa, we might be able to infer the environmental conditions at a site only from the biota that are observed at the site.

Inferring environmental conditions from biological observations can be very useful for stressor identification because they provide a biologically-based measure of environmental conditions at a site. Thus, these inferences can often provide another, alternate line of evidence that can strengthen a case made with other measurements.

Introduction:   Home    Next