---
title: the same acre is not the same acre
canonical_url: https://ensurance.app/guide/the-same-acre-is-not-the-same-acre
markdown_url: https://ensurance.app/guide/the-same-acre-is-not-the-same-acre.md
subtitle: "extent, character, condition: how one polygon gets its number"
category: natural-capital
---

# the same acre is not the same acre

*extent, character, condition: how one polygon gets its number*

**Ecosystem condition** is, in the words of the UN's ecosystem accounting standard, the quality of an ecosystem measured in terms of its abiotic and biotic characteristics: its physical and chemical setting, the species in it and how they are arranged, the processes running through it, and the landscape it sits in, read against a reference state. In plainer words: not what kind of place this is, and not how big, but how well it is working.

Two inland wetlands, forty acres each, a mile apart in the same county. One was ditched sixty years ago and drains by March; the other holds water into summer, with the sedges and the frogs and the muck to show for it. Each is a stock: a living system with an extent, a character and a condition. What each does in a year is its flow, and RealValue makes that flow legible in dollars beside what the stock costs to hold. Both are Inland Wetlands. Both draw on the same row of the value table, where a year of a wetland's flood storage, filtration and habitat has been valued per acre. They do not do the same work, and the account has to say so. Condition is how it says so. The wet one is wet whether or not anyone scores it. [Ensurance](/?from=guide) funds the stock, and the work that keeps its condition. It is not the score.

:::johnson
**extent says how much. condition says how well.** — The borrowed dollar per acre per year comes from studies of places in whatever condition they were in. The condition score is how the framework scales that figure to this place.

[what a valuation counts →](/guide/what-ecosystem-valuation-counts?from=guide)
:::

## the polygon has four parts

RealValue values an ecological polygon: a boundary, usually the property's legal description, drawn around the living systems inside it. The polygon has four components. The Field Manual asks for best efforts on each, and for the data and the method to be stated and disclosed with the number rather than for perfection before a number exists.

| Component | What it records | Where it comes from |
|---|---|---|
| Extent | The acres of each ecosystem type present; past and planned composition where known | The parcel survey, land cover data, the delineation |
| Characteristics | Which of the fifteen stocks each area is; and finer reads where useful, the IUCN functional group, the One Earth bioregion, the Resolve ecoregion | [Every acre is one of fifteen things](/guide/every-acre-is-one-of-fifteen-things?from=guide); the typologies behind it |
| Condition | How well each ecosystem present is working, ranked 1 to 10, applied to each ecosystem separately | A site assessment; the indicators below |
| On and off record data | What the public record holds (title reports, appraisals, prior studies) and what is private (leases, the owner's own knowledge, local sentiment) | The county, the deed, the owner |

Extent and characteristics say what and how much. Condition says how well. The fourth part is where the valuation says what it knew and what it did not.

## what the score does to the number

The condition score is a multiplier. A stock's borrowed value per acre per year comes from studies of ecosystems of that kind, in whatever condition those study sites were in. The framework ranks each ecosystem in the polygon from 1 to 10, with 10 as the reference state, undisturbed and fully functioning, and scales the borrowed figure by that rank. The lower the score, the less of the row's work this place is credited with. The scale is BASIN's own ranking; it is not calibrated to an external standard, and each valuation discloses how the score enters the number.

One multiplier across every flow is a simplification for comparison, not a model of each flow. The flows come out of the same living system together, so a drained wetland loses most of them together: the flood storage, the filtration, the habitat and the carbon fall with the water table. But some flows move differently, and a few can rise as others fall. The score says how well the system is working; the indicators behind it say which parts. [One stock, nineteen flows](/guide/one-stock-many-flows?from=guide) makes the joint-production case; [what ecosystem valuation counts](/guide/what-ecosystem-valuation-counts?from=guide) says why condition matters more than area. This post is about where the score comes from.

This is the part of the account that moves. Extent changes when land is cleared or restored. Characteristics rarely change. Condition changes with every season of management or neglect, and it is the part a steward can act on. For a risk reader, an insurer or a lender, it is also the evidence that would be asked for: not that a wetland exists above the town, but that it is in the condition that holds a flood.

## where the score comes from

What makes a 1 to 10 defensible is the evidence it is built on, and the framework points at two sources for that evidence.

The first is the SEEA Ecosystem Condition Typology, the UN standard's own structure for condition. It sorts condition indicators into three groups and six classes, and where time and budget allow, the framework asks for it to be applied to the polygon:

| Group | What it covers | An example from the indicator survey, assigned to the group here |
|---|---|---|
| A: abiotic | Physical and chemical characteristics; the water, the soil, the air | Water quality; sediment and soil quality |
| B: biotic | Compositional, structural and functional characteristics; who is there, how they are arranged, what they do | Abundance and distribution of selected species; annual net primary production |
| C: landscape and seascape | The pattern around the polygon; connectivity, fragmentation | Ecosystem connectivity; extent of suitable habitat |

The second is the indicator library behind the framework: more than 250 ecological indicators and metrics compiled from condition, integrity, characteristics, services, biodiversity, biocomplexity, wildlife, habitat, species and climate frameworks, set beside one another in a survey, among them CICES, the JRC indicator list, the SEEA condition typology, the SEED biocomplexity index, essential biodiversity variables, the Ecosystem Integrity Index, mean species abundance, Swiss Re's index, IPBES's selected indicators and the essential climate variables. Any of them can be paired with the financial figures, so that a dollar value per year sits beside the thing in the field that moved it.

SEED is the one the framework singles out. It is a standardized biodiversity index from the Crowther Lab at ETH Zürich, and the Field Manual says BASIN hoped to be a beta tester. The contrast is the point: a standardized index puts every site on the same scale; a 1 to 10 ranking does not, and says so. Where an index like SEED is available for a polygon, it belongs in the record beside the rank.

## a blank is not a zero

Measurement grows the count. The closer you look at a living system, the more there is to measure, and no survey finishes. Two consequences for the account. Where a flow in a stock has no value record, the table cell is blank, and the valuation carries the blank, not a zero; zero is a claim, and a blank is an admission. And where the condition evidence is thin, the record says so, naming what was observed and what was not. A score with no indicators behind it is an opinion. A score with several, disclosed, is a reading.

## what condition is not

Condition is not a credit. A carbon credit is a receipt for a measured change in one flow; a condition score is a reading of the whole system the flows come from. Condition is not a label; "pristine" and "degraded" are the ends of the scale, not the scale. And condition is not something you can buy. It is what the steward's work produces and the account reads. The money that goes to the stock funds that work; [what a natural capital certificate actually holds](/guide/what-a-natural-capital-certificate-actually-holds?from=guide) says what the funding instrument is and is not.

## frequently asked questions

### what is ecosystem condition?

The quality of an ecosystem measured in terms of its abiotic and biotic characteristics, read against a reference state: its physical and chemical setting, its species and their arrangement and function, and the landscape around it. The SEEA Ecosystem Condition Typology organizes condition indicators into three groups and six classes. In a parcel valuation, condition is ranked for each ecosystem present and scales the borrowed value of its flows.

### how is ecosystem condition measured?

With indicators chosen for the ecosystem and the question: water quality, species abundance, net primary production, connectivity, soil carbon, and hundreds of others in the published frameworks. RealValue ranks each ecosystem in a polygon from 1 to 10 on a site assessment, records the indicators behind the rank, and discloses how the rank enters the number.

### is an ecosystem condition score a credit?

No. A credit is a receipt for a measured change in one flow, issued to be sold. A condition score is a reading of the whole living system the flows come from, kept in the account so the borrowed values can be scaled to this place. It is not issued and it is not for sale.

## next

The one number: [flows over stocks](/guide/flows-over-stocks?from=guide).

If you steward a place and want the condition you are producing to be legible, [land stewards](/solutions/land-stewards?from=guide&topic=stocks-and-flows) shows what we do with a parcel. If you can name a place whose condition you can document, [tell us which](/contact?from=guide&topic=stocks-and-flows).

## sources

[BASIN Field Manual, Ecological Polygon](https://docs.basin.global/realvalue/the-realvalue-of-natural-capital/ecological-polygon) — the four components, the 1 to 10 condition multiplier, the SEEA ECT groups, SEED, and the data-quality stance.

[BASIN Field Manual, Ecological Indicators & Metrics](https://docs.basin.global/appendix/ecological-indicators-and-metrics) — the 250+ indicators and the invitation to collaborate on them.

[BASIN Metrics & Indicators worksheet](https://docs.google.com/spreadsheets/d/1_IrNH_HgoqE8OfxI7wEH-0O-OLZpkb-2cdkIW5C-iKM/edit) — the survey tab setting RealValue beside CICES, JRC, the SEEA condition typology, SEED, EBVs, EII, MSA, EECs, SBEI, the Swiss Re index, IPBES and the ECVs; the indicators named in the table above.

[United Nations et al. 2021. System of Environmental-Economic Accounting, Ecosystem Accounting (SEEA EA), chapter 5: ecosystem condition.](https://seea.un.org/ecosystem-accounting) — the definition of condition and the Ecosystem Condition Typology.

## the series

1. [the stocks and flows of natural capital](/guide/the-stocks-and-flows-of-natural-capital?from=guide) (read first)
2. [every acre is one of fifteen things](/guide/every-acre-is-one-of-fifteen-things?from=guide)
3. [nineteen things a place does](/guide/nineteen-things-a-place-does?from=guide)
4. [where the dollar per acre comes from](/guide/where-the-dollar-per-acre-comes-from?from=guide)
5. [the same acre is not the same acre](/guide/the-same-acre-is-not-the-same-acre?from=guide)
6. [flows over stocks](/guide/flows-over-stocks?from=guide)