Stress tolerance is the organism's ability to withstand a certain amount of anthropogenic influences. The
index range for each category is based upon a (0-10) scale. For example, invertebrates with a low tolerance
need adequate dissolved oxygen and chemical and physical stability, while those with a high tolerance can
survive for a period of time when dissolved oxygen levels are less than adequate or other disturbances may
be present.
Note: There are some types that are undetermined (U) or unknown.