In the context of invertebrates—specifically aquatic macroinvertebrate biomonitoring—ASPT stands for
Average Score Per Taxon.
It is a water quality index used to assess the pollution levels of rivers and streams, particularly focusing on organic pollution, by analyzing the sensitivity of invertebrate families found in a sample.
Key Details About ASPT
Calculation: ASPT is calculated by taking the total score of a sample (often from the Biological Monitoring Working Party, or BMWP, system) and dividing it by the total number of scoring families/taxa present.
Purpose: It evaluates the overall "sensitivity" of the community. A high ASPT score indicates a cleaner, less polluted site with many sensitive, high-scoring taxa (like mayflies, stoneflies, and caddisflies).
Range: It generally ranges from 0 to 10 (or 0.0 to 6.0 in some specific systems).
Independence: Unlike the raw BMWP score, the ASPT is largely independent of sample size or the total number of families found, making it a more robust, reliable, and consistent indicator.
Context: ASPT is frequently used in conjunction with WHPT (Whalley, Hawkes, Paisley & Trigg) or BMWP systems to comply with environmental quality regulations, such as the Water Framework Directive (WFD).
In the context of invertebrates,
ASPT stands for Average Score Per Taxon.
It is a widely used biological index used to assess water quality in rivers and lakes based on the presence of benthic macroinvertebrates.
Key Features of ASPT
Calculation: It is calculated by dividing the total Biological Monitoring Working Party (BMWP) score by the number of families (taxa) identified in the sample.
Purpose: It measures the average sensitivity of the invertebrate community to environmental pressures, primarily organic pollution and dissolved oxygen depletion.
Scoring: Each macroinvertebrate family is assigned a score from 1 to 10 based on its tolerance to pollution.
High Scores (e.g., 7.0–10.0): Indicate "clean" or "very good" water quality, often characterized by sensitive species like mayflies and stoneflies.
Low Scores (e.g., 1.0–5.0): Indicate "dirty" or "not good" water quality, dominated by pollution-tolerant species like worms (Oligochaeta).
Reliability: Unlike the raw BMWP score, ASPT is considered more robust because it is less affected by sample size or seasonal variations in species richness.
The Average Score Per Taxon (ASPT) is a water quality index calculated by
dividing the total Biological Monitoring Working Party (BMWP) score—the sum of pollution tolerance scores for all families present—by the total number of scoring taxa/families. It represents the average tolerance of the community to organic pollution.
Formula:
ASPT=Total BMWPScoreNumber of Scoring Taxa (Families)
ASPT=Total𝐵𝑀𝑊𝑃ScoreNumberofScoringTaxa(Families)
Total BMWP Score: Sum of tolerance scores (typically 1–10) assigned to each macroinvertebrate family identified.
Number of Scoring Taxa: The count of unique families found that are included in the scoring system.
Key Details:
Range: Generally, ASPT values range from 0 (heavily polluted) to over 6.0 (excellent, clean water).
Purpose: Because it is an average, it is less dependent on sample size or richness than the total BMWP score, providing a more robust measure of pollution.
Context: It is often used alongside the number of taxa (
Ntaxa
𝑁𝑡𝑎𝑥𝑎) to assess ecological quality