Learning target: I can write a claim, evidence and reasoning argument that evaluates competing farm designs for how well they maintain biodiversity and ecosystem services while meeting economic and social needs.
Read the scenario and the four criteria the cooperative agreed on. The trial results are a teaching dataset. Complete Parts A and B first, because your argument in Part C must use them. Your claim may depend on a condition (for example, 'if the cooperative gets a buyer's contract'); if it does, say so clearly. There is more than one defensible answer, but every claim must be backed by the evidence.
You will need: This worksheet, Pencil, Calculator
Las Nubes is a coffee cooperative of 40 families in the mountains of Central America (the cooperative is invented for this worksheet). Each winter, black-and-white warblers and other songbirds that nest in North American forests and parks fly south and spend the winter in forests and shaded farms like these. The cooperative must replant 50 hectares of old coffee and is choosing among three designs. Design A, full sun: coffee plants alone in rows, with more fertilizer and pest control. Design B, light shade: coffee under one kind of planted shade tree, Inga, a fast-growing tree that adds nitrogen to the soil. Design C, diverse shade: coffee under several kinds of native trees in layers, like a thinned forest. Only Design C can earn a bird-friendly certification, which pays a higher price, but only if a buyer signs a contract.
| Measurement | A: Full sun | B: Light shade | C: Diverse shade |
|---|---|---|---|
| Coffee harvested (kg of beans) | 1600 | 1250 | 950 |
| Standard price ($ per kg) | 2.50 | 2.50 | 2.50 |
| Certified price after the certification fee ($ per kg, only with a buyer's contract) | not eligible | not eligible | 3.20 |
| Other products sold: fruit, firewood, timber ($) | 0 | 250 | 450 |
| Yearly costs: fertilizer, pest control, labor ($) | 1900 | 1250 | 1150 |
| Bird species counted | 10 | 28 | 52 |
| Wintering warblers seen per survey | 0 | 3 | 9 |
| Soil washed away in the rainy season (tonnes) | 18 | 7 | 3 |
| Bee visits to coffee flowers (per 10 minutes) | 5 | 11 | 16 |
| Families willing to farm this way (out of 40) | 31 | 27 | 21 |
| Coffee income ($) | + Other products ($) | − Costs ($) | = Net income ($) |
|---|---|---|---|
| A: Full sun | |||
| B: Light shade | |||
| C: Diverse shade, standard price | |||
| C: Diverse shade, certified price |
| 1. Income at least $2,000? | 2. 25+ bird species and warblers? | 3. Soil under 10 t and 10+ bee visits? | 4. At least 20 families willing? |
|---|---|---|---|
| A: Full sun | |||
| B: Light shade | |||
| C: Diverse shade |
Claim: 'Las Nubes should choose Design ___ (if ___).' Evidence: 'Design ___ earned $___ per hectare, which is above/below the $2,000 criterion. It had ___ bird species compared with ___ for full sun. Soil loss was ___ tonnes...' Reasoning: 'Shade trees give birds places to feed and shelter, their roots and fallen leaves hold soil in heavy rain, and flowering trees support bees, so ___. Design ___ fails criterion ___, so ___.'
Shade trees keep coffee plants cooler, and arabica coffee grows poorly when it gets too hot. Suppose models predict the region will warm by about 1 to 2 °C over the coming decades. Write a paragraph explaining how this new information should change how the cooperative weighs its criteria, and whether it strengthens or weakens the case for each design. Then propose one measurement the cooperative should add to its trial plots.