Snag Wildlife HSI

Aggregate caller independently calibrated snag-habitat component scores by weighted geometric mean, retaining limiting zero components; not species presence probability or validated habitat suitability.

Description

A weighted geometric habitat index lets a zero component limit the whole modeled score.

A weighted geometric habitat index lets a zero component limit the whole modeled score. This differs from an arithmetic average that can hide that zero.^[1]

When to use Snag Wildlife HSI

Use this tool to aggregate caller independently calibrated snag-habitat component scores by weighted geometric mean, retaining limiting zero components; not species presence probability or validated habitat suitability.

Gather the tree inventory, plot measurements or model parameters. Check diameter, area, time and moisture conventions; keep paired observations aligned.

How to use Snag Wildlife HSI and understand its results

Gather the tree inventory, plot measurements or model parameters. Check diameter, area, time and moisture conventions; keep paired observations aligned.
Enter habitatComponentSuitabilityScores, componentWeights using the field table and calculation rules, then run the tool.
Read weightedGeometricHabitatIndex, limitingComponentScore. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
habitatComponentSuitabilityScores	Habitat component suitability scores	list of number	Required
componentWeights	Component weights	list of number	Required

Pair scores in [0,1] with positive weights. Return their weighted geometric mean and minimum component; handle zeros before logarithms.

Paired lists must be nonempty and have equal lengths.

index=exp(Σweight log(score)/Σweight); any zero score gives index zero

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
weightedGeometricHabitatIndex	Weighted geometric habitat index	number
limitingComponentScore	Limiting component score	number

json

{
  "input": {
    "habitatComponentSuitabilityScores": [
      0.25,
      1
    ],
    "componentWeights": [
      1,
      1
    ]
  },
  "output": {
    "weightedGeometricHabitatIndex": 0.5,
    "limitingComponentScore": 0.25
  }
}

Limitations and assumptions

Scores must be independently calibrated. The index is not species-presence probability or validated habitat suitability.

Numeric inputs and returned numeric values must be finite; an unrepresentable returned value produces an error. Numeric lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Snag Density: Pool unequal-area snag surveys with caller differential detection and independent Poisson count error; unlike existing fixed-plot tree expansion, correction/uncertainty require extra measured assumptions. For a complementary task, use Interior Forest Edge Ratio From Patch Size: Evaluate rectangular patch interior/edge areas under a caller uniform inward edge-depth model; no coordinate buffers, patch shape inference or biodiversity outcome; absent interior makes edge/interior ratio undefined.

References

Snag Wildlife HSI — tool.io

Similar or alternative tools

Snag Density
Pool unequal-area snag surveys with caller differential detection and independent Poisson count error; unlike existing fixed-plot tree expansion, correction/uncertainty require extra measured assumptions.
Interior Forest Edge Ratio From Patch Size
Evaluate rectangular patch interior/edge areas under a caller uniform inward edge-depth model; no coordinate buffers, patch shape inference or biodiversity outcome; absent interior makes edge/interior ratio undefined.