Set the Variables
toggle any lever · run the simulation on the map belowManagement Interventions
Implement clear guidelines for vessels to follow on where and where not to anchor.
Patrols, monitoring and penalties that stop illegal fishing and enforce no-anchor zones.
Submerged concrete modules along the meadow's lower edge that physically block illegal trawling.
Freshwater outflow processing, to remove excess nutrients and pollutants.
Experimental Interventions
Planting entirely new Posidonia patches on suitable bare seabed.
Focus restoration efforts towards naturally cooler, shaded, deeper microsites that survive heat longest.
Select and propagate genotypes that tolerate warm water.
Monitoring plus rapid response to invasive algae and fish.
Investments upfront spend that unlocks effectiveness and credit revenue
Routine surveys and monitoring to track Posidonia.
Invest in verification to meet blue carbon standards and issue credits.
Invest in verification to meet (future) biodiversity outcomes and issue credits.
Revenue levers what the protected meadow pays back
A levy on coastal tourism to support stewardship.
Festivals, sponsorships and school programmes that fund the meadow while building the local mandate to protect it.
Paid fixed moorings that replace anchoring. They earn a fee and remove scarring at the same time, so this lever pays back on both sides of the ledger.
Funding outside capital that de-risks the upfront cost
Public, private and philanthropic capital (EU CRCF, Plan Vivo pilot funding, philanthropy) that covers part of the upfront spend so Pollica does not carry it alone. It does not make the meadow more valuable: it changes who pays, which is what makes the early, cheap moves fundable. Covers ~40% of investment, up to €2.5M.
Systemic trajectory
Whether the water keeps warming on today's path, or on a cooler one.
Time horizon
Cilento coast · Posidonia layer
Yr 0
100% of today
5,100ha living
Year 0 · today
Variables changed. Press Run simulation to update the outcome.
Living meadow
Thinning
Bleached / lost
New growth
The footprint is real, which patches vanish or grow are illustrative.
What it adds up to
grows year by year as the simulation runsCollapse trajectory
Meadow at horizon
-% of today
Blue carbon banked
-ktCO₂e
Cumulative over the horizon
Net position
-
- Total investment-
- Blended finance covers-
- Stacked carbon/biodiversity credits-
- Avoided losses-
- Earned levers-
- Losses vs today's economy-
Revenue + avoided losses − investment
Meadow extent
hectares · your plan vs do-nothing
Your plan
Do nothing
The carbon economy
annual € · revenue vs cost
Stacked credit revenue
Intervention cost
Credit prices here are sourced central values carrying wide bands: carbon €11 to €27/tCO₂e, biodiversity €50 to €500/ha/yr. The whole published blue-carbon price series is mangrove rather than seagrass, and no Posidonia carbon credit has ever been issued anywhere. Read this line as illustrative economics on dated analogs, not as projected revenue.
What showed to be effective
run the simulation, then read what actually moved the meadowTurn on some interventions and press Run simulation to see which ones moved the meadow, ranked by hectares saved at your horizon.
What is driving the decline
the do-nothing losses, by cause, over your horizonRun the simulation to see which pressures drive the meadow's decline.
Model assumptions · every parameter, tagged
These placeholders are calibrated for a decision-framing tool, internally consistent rather than measured, each tagged with the source it leans on. The do-nothing baseline starts from the standard 0.29%/yr Mediterranean Posidonia regression rate (Ifremer 2023) and adds two local pressures for this coast, a localized water-quality / river-outflow load and an emerging invasive front, so Pollica's do-nothing baseline runs above the Mediterranean average and compounds toward ~1.1%/yr by year 30 as warming escalates. Interventions pull it back down. The economics (ecosystem-service value, conservation costs, and the blue-carbon and biodiversity credit framing) lean on the ARTEMIS "Investment Opportunities in Seagrass Restoration" report (Interreg Euro-MED, Oct 2025). You can set any horizon up to 150 years. The escalation was tuned for a 30-year window, so past mid-century (year 40) the warming, acidification and water-quality pressures hold at a plateau rather than compounding forever: a century view shows continued decline, not a runaway to unphysical loss rates, and the warming trajectory still sets the ceiling.
| Starting extent / carrying capacity | 5,100 ha today · 6,630 ha historical ceiling · illustrative |
| Baseline regression (do nothing) | warming + acidification + mechanical core = 0.29%/yr at year 1 (warming 0.13% + acidification 0.06%, now escalating ~2%/yr + mechanical 0.10%, split anchoring 0.06% + trawling 0.04%) · Ifremer 2023. With the local water-quality (~0.04%/yr) and emerging invasive pressures added, Pollica's full do-nothing baseline compounds to ~1.1%/yr by year 30 |
| Warming trajectory | current ×1.0 (escalating ~5.5%/yr) · reduced ×0.55 (held flat) · strong ×0.28 (declining) |
| Heat-resilient strain (unproven) | each run rolls the outcome: 50% delivers a 40% cut · 35% only ~10% · 15% backfires (+12% warming bite). Expected ≈22% cut · €300k/yr programme |
| No anchor zones | mechanical loss ×0.55 partial · ×0.22 full · €35/ha/yr fee (partial = half) · within the Mediterranean conservation-cost range of 38-58 €/ha/yr (ARTEMIS SOTA, Balearic Islands) |
| Protection enforcement | extra ×0.80 on the anchoring share of mechanical loss, plus ×0.75 on the trawling share (patrols deter illegal fishing), when on · €75/ha/yr, near the upper Mediterranean conservation-cost range (ARTEMIS SOTA) |
| Restoration planting | +0 / +20 / +50 ha planted per year · €2.5M/ha one-time active restoration, per the ARTEMIS SOTA report (reported €250/m² of Posidonia) · restoration is slow: ~40% transplant survival and a multi-year establishment lag (survivors become living meadow ~30%/yr), so realized new meadow runs well below the planted rate while you pay for the full rate |
| Natural regrowth | logistic, up to 0.2%/yr, suppressed under stress |
| Blue carbon banked | 1.45 tCO₂e/ha/yr gross sequestration × 28% long-term burial = 0.41 tCO₂e/ha/yr durable, on living area · plus a one-time 110 tCO₂e/ha avoided sediment release for each hectare kept from loss · illustrative |
| Stacked carbon/biodiversity credits | carbon 0.41 tCO₂e/ha/yr × €24/tCO₂e (≈€9.7/ha/yr) + biodiversity €150/ha/yr = ≈€159.7/ha/yr on protected area · each stream only counts once its verification is funded (no verification = no credit revenue, one = partial) · sourced centrals with wide bands (carbon €11 to €27/tCO₂e, biodiversity €50 to €500/ha/yr), see docs/BLUE_CARBON_CREDIT_PRICES.md |
| Ecosystem-service value | €86,000/ha/yr · the value of Posidonia ecosystem services per the ARTEMIS SOTA report (Interreg Euro-MED, Oct 2025) · drives both avoided losses (area protected vs do-nothing) and losses vs today's economy (area below today's extent) |
| Revenue levers | sustainable tourism tax €150k/yr · cultural events €45k/yr · mooring balls + fees €70k/yr, which also cut ~35% of the anchoring share of mechanical loss by replacing anchoring · placeholders |
| Assisted migration | focuses restoration on naturally cooler, shaded, deeper microsites that survive heat longest: cuts the warming-driven share of loss ×0.92 (~8% meadow-wide-equivalent, since only the cooler-microsite fraction benefits) when on · €65k one-time mapping study to locate cooler microsites · placeholder pending calibration |
| Blended finance | outside capital (EU CRCF, Plan Vivo, philanthropy) covers 40% of investment up to €2.5M · de-risks who pays the upfront cost, does not add meadow value · illustrative |
| Anti-trawling reefs | cut the trawling share of mechanical loss ×0.20 (~80%, Gulf of Cadiz precedent) · €1.5M one-time project-level deployment · trawling is operator-reported at Pollica (ledger N3) |
| Water-quality remediation | freshwater-outflow nutrient and pollutant removal, cuts nutrient-driven loss ×0.35. The open Cilento meadow is oligotrophic (ARPAC WFD), but localized river / freshwater-outflow loads are a real local pressure, and nutrient stress on Posidonia is exacerbated as the water warms (Mutalipassi et al. 2021) · modeled nutrient share ~0.04%/yr, rising with warming · placeholder pending local calibration · €4.5M one-time + €150k/yr |
| Invasive species control | monitoring plus rapid response to invasive algae and fish; detection-timing-dependent, so each run rolls the outcome: 45% early detection (80% cut) · 35% partial (45% cut) · 20% already established (no gain). Not yet established at Pollica, but the nearest Caulerpa cylindracea population is ~45 km north (Gulf of Naples) and dense meadows lose their resistance as they degrade (Bernardeau-Esteller et al. 2015), so it is modeled as an emerging pressure that rises from near-zero today toward a ~0.12%/yr ceiling (about half reached by year 5, saturating rather than runaway) · placeholder pending local calibration · €50k/yr |
| Monitoring network | routine surveys that make interventions land: without it every management and experimental lever delivers only 60% of its modeled effect · €250k one-time + €120k/yr · does not lower loss on its own, it lifts what the other levers achieve |
| Carbon capture verification | MRV to meet blue-carbon standards · unlocks the carbon share of stacked credits (≈€9.7/ha/yr on protected area); off = that stream earns €0 · €300k one-time + €40k/yr |
| Biodiversity verification | surveys/verification for (future) biodiversity credits · unlocks the biodiversity share of stacked credits (€150/ha/yr on protected area); off = that stream earns €0 · €250k one-time + €30k/yr |
| Effectiveness report | after each run, every enabled intervention is re-simulated with that one lever removed; the hectares it saves at the horizon is its ranked contribution |