WIMP Calculator

Abundance-Weighted WIMP

Standard mode uses the booklet formula (Page 6). Weighted mode factors in F/C/A abundance codes so a taxon recorded as Abundant contributes more than one recorded as Few.

Standard mode (booklet formula, Page 6): WIMP Score = average sensitivity of all taxa found. Estimated MCI = WIMP Score × 20. Every taxon counts equally regardless of abundance.

MCI Band

—

WIMP Score

—

avg sensitivity / taxon

Est. MCI

—

WIMP × 20

Taxa — Record Abundance

F = Few (1–4) C = Common (5–19) A = Abundant (20+). Leave blank if not found. Data is shared with the Field Form.

Sensitive Taxa (Sc 7–10)

Sc 10Spiral-cased caddisfly

Sc 9Smooth-cased caddisfly

Sc 6Stony-cased caddisfly

Sc 5Woody-cased caddisfly

Sc 5Free-living caddisfly

Sc 2Oxyethira caddisfly

Sc 9Swimming mayfly

Sc 9Spiny gill mayfly

Sc 8Flat mayfly

Sc 10Stenoperla stonefly

Sc 5Tail gill stonefly

Sc 5Spotty stonefly

Sc 7Archichauliodes dobsonfly

Sc 6Beetle

Tolerant Taxa (Sc 1–6)

Sc 5Pond skater

Sc 5Backswimmer / Water boatman

Sc 6Dragonfly

Sc 5Damselfly

Sc 5Crayfish (Kōura)

Sc 5Shrimp

Sc 5Amphipod / Isopod

Sc 5Water flea

Sc 5Crab

Sc 3Seed shrimp

Sc 6Horsehair worm

Sc 3Leech

Sc 1Oligochaete worm

Sc 3Flatworm

Sc 6Freshwater mussel

Sc 6Latia limpet

Sc 5Fingernail clam

Sc 3Rounded snail

Sc 3Flat spiral snail

Sc 5Dolomedes spider

Sc 5Mite

Sc 5Cranefly

Sc 3Other maggot-like flies

Sc 3Sandfly / Blackfly

Sc 3Mosquito

Sc 2Midge

Formula Reference

Standard (Page 6): WIMP Score = Σ(Sc) ÷ n taxa found · Est. MCI = WIMP × 20

Weighted: WIMP Score = Σ(Sc × w) ÷ Σ(w) · where w = 2.5 (F), 12 (C), 30 (A)

Abundance weights use midpoints of the F (1–4), C (5–19), A (20+) ranges defined on Pages 3–4 of the booklet.