Species abundance proportions calculator
Counts of 40, 30, 20 and 10 trees give a total of 100 and shares of 0.4, 0.3, 0.2 and 0.1: the calculator turns raw tallies into the proportions that Shannon, Simpson and evenness indices need. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Community ecology reduces a field sample to relative abundances before Shannon entropy, Simpson dominance, or Pielou evenness can be computed.
What proportional abundance is and why diversity work starts here
Relative abundance is the share of a community sample that belongs to one taxon. Working from raw counts without dividing by N mixes sample size into the next index and makes two plots incomparable when one walk was longer than the other. This calculator performs only that normalisation: it does not compute a diversity index, so it remains a dedicated landing for the search species abundance proportions rather than competing with a Simpson or Shannon page.
Counts may be integers from a point-count or non-negative reals from biomass, basal area, or percent cover; the algebra is the same. An all-zero sample has no N and is rejected.
What you enter and what the results show
At most ten thousand rows are allowed on this free parse path. Parallel arrays proportions and percents match input order so a Shannon or Simpson script can consume the p-vector without parsing names. Formula and method strings are included for display and audit.
Numeric fields are rounded to twelve significant digits for stable goldens across runtimes. Classic check: forty, thirty, twenty, and ten individuals of four named trees give N equals one hundred and shares 0.4, 0.3, 0.2, and 0.1.
Who relies on relative abundances
Environmental impact assessments and restoration scorecards need reproducible relative abundances when arguing that a post-disturbance stand is still dominated by a few opportunistic taxa—the Berger-Parker share and the ranked cumulative column make that claim checkable. Teaching labs and online ecology courses use a live calculator so students can type named counts from a bird point-count or a vegetation quadrat and see percents and ranks update without installing R or vegan.
Research notebooks that already compute diversity indices can standardise the p-vector once, then reuse it for several indices without re-dividing by N in each cell.
FAQ
How do I convert species counts to proportional abundances?
Send a species array of { name, count } rows.
Does this calculator compute Shannon or Simpson diversity?
No. It only builds the p-vector those indices consume. Use a dedicated Shannon or Simpson capability on the returned proportions array if you need the index itself.
What happens if every count is zero?
Empty lists and missing names are also rejected and are not billed.
Can I use biomass or percent cover instead of head counts?
Yes. Any non-negative finite abundance measure works: individuals, biomass, basal area, or cover. Each row is still divided by the sum of all rows.
What is the Berger–Parker share?
It is the proportion held by the most abundant species. In a sample of 40, 30, 20 and 10 trees, the dominant species has 0.4 of the total, a quick sign of how strongly one taxon dominates.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/bio/species-abundance-proportions \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"species":[{"name":"Quercus alba","count":40},{"name":"Acer saccharum","count":30},{"name":"Fagus grandifolia","count":20},{"name":"Pinus strobus","count":10}]}'const res = await fetch("https://api.kit.forhosting.com/bio/species-abundance-proportions", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"species": [
{
"name": "Quercus alba",
"count": 40
},
{
"name": "Acer saccharum",
"count": 30
},
{
"name": "Fagus grandifolia",
"count": 20
},
{
"name": "Pinus strobus",
"count": 10
}
]
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/bio/species-abundance-proportions",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"species": [
{
"name": "Quercus alba",
"count": 40
},
{
"name": "Acer saccharum",
"count": 30
},
{
"name": "Fagus grandifolia",
"count": 20
},
{
"name": "Pinus strobus",
"count": 10
}
]
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/bio/species-abundance-proportions", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"species":[{"name":"Quercus alba","count":40},{"name":"Acer saccharum","count":30},{"name":"Fagus grandifolia","count":20},{"name":"Pinus strobus","count":10}]}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"species":[{"name":"Quercus alba","count":40},{"name":"Acer saccharum","count":30},{"name":"Fagus grandifolia","count":20},{"name":"Pinus strobus","count":10}]}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/bio/species-abundance-proportions", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"species": [
{
"name": "Quercus alba",
"count": 40
},
{
"name": "Acer saccharum",
"count": 30
},
{
"name": "Fagus grandifolia",
"count": 20
},
{
"name": "Pinus strobus",
"count": 10
}
]
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "bio.species_abundance_proportions",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Limits
max_items | 10000 |
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
Those indices all consume p_i equals n_i over N, not the raw head counts from a quadrat, transect, or mist-net. This species abundance proportions calculator accepts a list of named taxa with non-negative counts—or any non-negative abundance measure such as biomass, basal area, or percent cover—divides each value by the sample total N, and returns proportions, percents, ranks, a running cumulative share, and the Berger-Parker dominant share. Empty lists, missing names, negative counts, and an all-zero sample fail with invalid_input so you never publish a hollow p-vector.
What proportional abundance is and why diversity work starts here
If species i was recorded with abundance n_i and the sample holds N equal to the sum of every n_i, the proportional abundance is p_i equals n_i divided by N. Those p_i values—not the raw tallies—are the actual inputs to Shannon entropy (minus the sum of p_i times the natural log of p_i), Simpson lambda (the sum of p_i squared), inverse Simpson (one over lambda), Pielou evenness, and rank-abundance or Whittaker plots. Zero-count rows are kept with p_i equal to zero and do not add to richness. The dominant taxon is the row with the largest count; its p_i is the Berger-Parker dominance index, a compact companion to the full p-vector that many monitoring reports print beside the table of shares.
Input contract, response fields, and validation errors
POST a JSON body with a required species field: a non-empty array of objects, each with a non-empty name string and a finite non-negative count number. Aliases taxa, abundances, community, and rows are accepted for the list; on each row, count also accepts n, abundance, or individuals. Missing field, empty list, non-object rows, blank names, non-numeric tokens, negative values, and an all-zero total fail with invalid_input and are not billed. On success the body returns species as an array in input order, each row carrying name, count, proportion p_i, percent, rank (one is most abundant; ties keep earlier input order), and cumulative_proportion (the running sum of p values along that rank order, useful for dominance curves). Summary fields are species_count (richness: rows with count greater than zero), row_count, total_individuals N, dominant_name, dominant_count, dominant_proportion, dominant_percent, berger_parker (equal to the largest p_i), and sum_of_proportions (should be one after rounding).
Where a species-abundance-proportions API earns its keep
Biodiversity monitoring programs reduce each plot’s raw tallies to a p-vector before storing time series or feeding Shannon, Simpson, or evenness calculators; automating p_i equals n_i over N removes spreadsheet drift when technicians copy a SUM formula down a sheet and forget to lock N. Mobile field apps can call the same parse endpoint from offline-synced count lists once connectivity returns, billing only successful tasks at the published $0.002 base price with no model tokens and no outbound network from the worker.
Integration use cases
Plot and transect p-vectors
Turn named counts from a vegetation plot, bird point-count, or quadrat into p_i, percents, and ranks before Shannon or Simpson.
Impact and restoration tables
Document whether a few taxa still dominate after disturbance by reporting Berger-Parker max(p_i) beside the full share table.
Teaching labs and field apps
Let students or technicians paste a named community sample and read proportions that match the API path used in later analysis.
Technical questions
What does the species abundance proportions calculator cost?
The browser tool is free. API requests use prepaid KIT balance at $0.002 per successful call; invalid input is not billed.