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Commerce · VII.03 · MMXXVI · daylight

La Bourse  /  Volume VII  /  Nº VII.03  /  Workbook — the student

WORKBOOK — THE STUDENT

Chapter VII.03 · Biodiversity as Infrastructure

For the personal student. A term of practice, a term project, and a self-assessment. The subject is a productive input with a measurable marginal product, and the skill you are acquiring is the ability to price one before you argue about it.

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WHY THIS WORKBOOK IS DIFFERENT

Most environmental coursework asks you to describe a loss. This one asks you to compute a marginal product, and the difference is not tone — it is what you can do afterwards.

By the end of a term you will be able to walk onto a piece of ground, draw a service radius, count what is inside it, compute a leverage ratio, price a hectare at three commodity prices, state your attribution assumption out loud, and say the price at which your answer flips. That is a skill perhaps a few thousand people in the world currently have, and every one of the numbers you need is in the published literature.

You do not need a farm. A community orchard, an allotment site, a hedgerow along a school field, a city park beside a market garden — any of these will carry the whole exercise. The arithmetic does not care about scale.

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PART ONE — DISCOVERY

Weeks 1–4: find the service and draw its shape

Exercise 1.1 — The decay map (3 hours)

Take any satellite imagery tool that lets you measure. Find a piece of cropped ground near a piece of uncropped ground — an orchard by a wood, a field by a railway embankment, a garden by a churchyard.

1. Outline the uncropped parcel. Record its area in hectares.
2. Treat it as a disc and compute its radius: r = √(area in km² ÷ π).
3. Draw a one-kilometre buffer outward from its edge.
4. Measure the crop area inside that buffer.

Worked, from the chapter: a 46-hectare wood is 0.46 km², so r = 0.383 km. The ring of crop within one kilometre of its edge is π(1.383² − 0.383²) × 100 = 554.6 hectares.

Write down both numbers. You have just drawn an asset's catchment.

Exercise 1.2 — Your first leverage ratio (1 hour)

  L  =  crop hectares inside the buffer  ÷  habitat hectares

Compute it for your site. Then do the thing that matters: compute what L would be if the same habitat area were redistributed as strips through the cropped ground instead of sitting in one block at the edge. At Finca Santa Fe the measured L was 2.07 against a geometric ceiling of 7.9 — a gap of 3.8 times, produced entirely by placement.

Write one paragraph on what you found. This is the chapter's central finding and you have now reproduced it on ground you can walk to.

Exercise 1.3 — Read three papers properly (6 hours)

Ricketts et al. (2004), Garibaldi et al. (2013), Moreno-Mateos et al. (2012). For each, write half a page answering four questions:

1. What was the treatment and what was the control?
2. What is the effect size, with its unit?
3. What did the authors say they could not conclude?
4. What is the denominator — how many sites, crops, years, continents?

Question four is the habit this workbook is really teaching. A number without its denominator is a rumour, and you will spend the rest of the term noticing how often one is offered to you.

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PART TWO — THE ARITHMETIC

Weeks 5–8: price it, three ways

Exercise 2.1 — The marginal hectare, by hand (2 hours)

        V  =  L · Y₀ · Δ · P · φ

Compute V for your site. You will have L from Exercise 1.2. For the rest, use published figures and say where each one came from:

• Y₀ — a national or regional average yield for the crop, from a statistical agency. Cite the table.
• Δ — a measured uplift from the pollination literature for that crop or the nearest analogue. Ricketts measured 0.20 for coffee.
• P — a farmgate price with a date on it.
• φ — your attribution. Start at 0.70 and justify it in one sentence.

Then run P at a low, a mid and a high value from the last twenty-five years. From the chapter, for coffee at L = 4.0:

  $1,320/t  →  V = $  739 /ha/yr    capitalised at 7%   $10,560
  $3,000/t  →  V = $1,680 /ha/yr                        $24,000
  $6,000/t  →  V = $3,360 /ha/yr                        $48,000

Exercise 2.2 — The flip (45 minutes)

Find the price at which your habitat hectare stops beating the crop that would replace it:

  P*  =  crop net margin  ÷  (L · Y₀ · Δ · φ)

The chapter's answer: 800 ÷ (4.0 × 1.0 × 0.20 × 0.70) = $1,429/t, which is sixty-five cents a pound — a price arabica has seen in one window since 1975.

Now find the historical price series and mark on it every year your site's habitat was worth less than the crop. This is the exercise that changes how you think about land-use decisions, because you will see that the decisions get made in exactly the windows where the answer is about to reverse.

Exercise 2.3 — Attribution sensitivity (30 minutes)

Recompute V with φ = 1.00. From the chapter's mid case, V moves from $1,680 to $2,400 — a 43 per cent swing produced by an assumption nobody measured. Write two sentences on what you would have to observe to defend a φ above 0.80.

Exercise 2.4 — Divide the big number (30 minutes)

Take the largest ecosystem-service figure you can find in the popular press and divide it by the relevant area, population or output. The chapter's example: $4.5 billion of US pest control across 160 million hectares is $28.12 per hectare per year — below a single insecticide pass.

Do this once a week for the rest of the term. It is the cheapest intellectual discipline available to you.

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PART THREE — DREAM AND DESIGN

Weeks 9–12: build the instrument

Exercise 3.1 — Write the royalty (3 hours)

Draft a one-page habitat service royalty for your site. It needs six things:

1. The term — fifteen years minimum.
2. The measure — paired blocks, matched on cultivar, age and management, with three seasons of baseline.
3. The royalty — a percentage of the measured differential. The chapter uses 25 per cent.
4. A floor at the land's documented alternative use, and a cap — the chapter suggests 40 per cent of the differential.
5. φ, stated as a number with a review date.
6. The verifier, named.

Then test it against the chapter's decision inequality:

      royalty per hectare of habitat
   ------------------------------------------   >   1
    opportunity cost  +  monitoring cost

At L = 4.0, a $150 pasture opportunity cost and $60 of monitoring, the royalty covers 0.88× at $1,320/t, 2.00× at $3,000/t and 4.00× at $6,000/t. It clears above $1,500 a tonne — sixty-eight cents a pound.

Exercise 3.2 — Price the same hectare as a permit (90 minutes)

Now price your hectare in England's biodiversity net gain market. Medium distinctiveness, good condition, low strategic significance: 4 × 3 × 1.0 = 12 units at baseline. Created, with a difficulty multiplier of 0.67 and a temporal multiplier near 0.50, that is 4.02 units per hectare. At £25,000 a unit: £100,500 a hectare, one-off, against a thirty-year obligation — £6,538 per hectare per year at a five per cent annuity.

Write one paragraph explaining to a non-specialist why that is 11.2 times the measured service value at trough prices and 2.47 times at peak, and why the two numbers are not supposed to agree.

Exercise 3.3 — Reconcile the saturation curve (2 hours)

Reproduce the chapter's reconciliation in a spreadsheet:

  species required  =  147 · (1 − (1 − 12/147)^c)

Plot it for c from 1 to 40. Mark where it crosses 84 per cent — the chapter finds c ≈ 21.5. Then write half a page on why a curve that saturates after three species and a finding that 84 per cent of 147 species matter are the same result seen through two different denominators.

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PART FOUR — DESTINY AND DELIGHT

Weeks 13–15: make it hold, and go and look

Exercise 4.1 — The delivery audit (3 hours)

Find one real offset or net-gain site near you — the public registers make this possible in England, and permit records make it possible in much of the United States. Answer four questions:

1. What was promised, in what units?
2. Who holds the obligation, and for how long?
3. What financial assurance exists?
4. When did somebody qualified last visit?

If you cannot answer question four, that is the finding. The number that matters in this market is not the price of a unit — it is the proportion of secured sites visited by someone qualified in the last thirty-six months.

Exercise 4.2 — Stand next to it (1 hour, and it is not optional)

Go to a flowering margin in its second or third week, early, and stay ten minutes. Write four sentences about what you heard. This exercise has no analytical purpose and it is the reason people keep doing this work.

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THE TERM PROJECT

One site, priced three ways, defended

The deliverable: eight pages on one piece of ground.

1. The site. Location, area, habitat, crop, and a map with the service radius drawn.
2. The leverage ratio, computed, with the redistributed alternative computed beside it.
3. The marginal hectare, priced at three commodity prices, with every input sourced and dated and every assumption labelled.
4. The flip price, with the historical series behind it and the years marked.
5. The same hectare as a permit, priced in the nearest compliance market.
6. The instrument — a one-page royalty with floor, cap, attribution and verifier.
7. The honest negative. One place your own analysis is weak, with the sensitivity computed rather than described.
8. What you would do on the ground on Monday, in under two hundred words.

The grading standard. A project that produces a confident number without stating its denominator scores below one that produces a wide range and says exactly why it is wide. The discipline is the deliverable.

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SELF-ASSESSMENT

Score yourself one to five, honestly, at the start and at the end.

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CARRYING IT FORWARD

Three habits survive the term and they are the whole of it.

Divide every large number by something. A national aggregate is a claim about a policy, never about a field. Four and a half billion dollars became twenty-eight dollars a hectare in one division, and everything downstream changed.

Ask what the denominator was. Most apparent contradictions in ecology are two honest results measured over different universes. The saturation curve and the eighty-four per cent are the same data.

Price it before you argue it. You will be more persuasive, and — this is the part that surprises people — you will also change your own mind more often, which is the point of doing arithmetic at all.

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THE FOUR MISTAKES THIS FIELD KEEPS MAKING

Learn to name these and you will read the literature — and the press coverage of the literature — with a confidence that has nothing to do with how much ecology you know.

The undivided aggregate. A national total offered as a reason to do something on one farm. It is always large and it is almost always irrelevant at the scale of the decision. The test is one keystroke: divide it by the area, the population or the output it is spread across, and see whether the answer is still an argument.

The claimed whole. An uplift produced by four things, attributed entirely to the one the author is interested in. The fix is a stated attribution term with a review date, and the reason to state it yourself is that the discount costs you less than the dispute.

The single-context curve. A relationship measured on one function, in one year, in one place, and then reported as though it described the world. Almost every apparent contradiction in this literature dissolves the moment somebody asks what the denominator was.

The price mistaken for a value. A market price treated as evidence of what a thing is worth, when the price is set by the cost of the buyer's alternative. It is the most seductive of the four because the number is real, public and verifiable — and it is measuring something else entirely.

Write these four on a card. For the rest of the term, when you meet a claim about the value of nature, put it against the card before you put it against your notes. You will find that most published claims fail one of them and the good ones fail none.

And one habit that is not a mistake but a stance. When your own arithmetic disagrees with your prior, say so in writing on the day it happens, with the number. That is the entire method of this edition compressed into a sentence, and it is the reason the chapter you have just worked through could be written at all: somebody divided before they wrote.

APPRECIATIVE QUESTIONS FOR YOUR SEMINAR

1. When has a piece of ground near you been kept for reasons nobody could price, and turned out to be earning something?
2. What is the most useful number you have computed this term, and what made it useful — its size, or the fact that you could show your working?
3. If every student here priced one hectare properly, what would the room be able to do that it cannot do now?
4. What would have to be true for the instrument you drafted to still be running in twenty years?