# Volume XVIII — biomes 1-4 (theories 1-36), new file
THEORIES = [
# Polar & Sea Ice
{"n":1,"slug":"melt-pond-albedo-tip","field":"Polar & Sea Ice","subject":"Sea ice albedo","title":"Albedo Tips on Ponds","claim":"The ice-albedo feedback tips at a critical melt-pond fraction, not at a critical temperature, so the same warming produces very different ice loss depending on pond coverage.","mechanism":"Ponds absorb where bare ice reflects; once the pond fraction exceeds the percolation threshold, absorbed energy sustains further melting without additional warming.","prediction":"Late-summer ice loss should track pond fraction rather than temperature.","refute":"Loss tracking temperature at controlled pond fraction would remove the threshold."},
{"n":2,"slug":"bear-ice-free-ratio","field":"Polar & Sea Ice","subject":"Polar bears","title":"Body Condition Is a Season Ratio","claim":"Polar bear body condition is set by the ratio of ice-free days to hunting days rather than by total ice extent.","mechanism":"Bears fast when ice is absent and gain when it is present; the ratio of the two periods sets the annual energy balance regardless of the absolute area lost.","prediction":"Condition should track the ratio across regions.","refute":"Condition tracking ice extent would remove the timing term."},
{"n":3,"slug":"ice-thickness-deformation-ratio","field":"Polar & Sea Ice","subject":"Ice thickness","title":"Thickness Is a Balance","claim":"The thickness distribution of sea ice is set by the ratio of deformation to thermal growth, so a thinner pack can be more variable without being warmer.","mechanism":"Deformation creates ridges and leads; thermal growth thickens. Their ratio sets the shape of the distribution, which matters for melt and for navigation.","prediction":"Ridging fraction should track the ratio.","refute":"Thickness distribution tracking temperature would remove deformation."},
{"n":4,"slug":"polynya-heat-flux","field":"Polar & Sea Ice","subject":"Polynyas","title":"Polynyas Need Heat","claim":"Coastal polynyas remain open only while the ratio of ocean heat flux to atmospheric cooling exceeds a threshold, so they close abruptly when cooling intensifies.","mechanism":"Open water loses heat rapidly; the polynya persists only if advection resupplies heat faster than it is removed.","prediction":"Closure should occur at a heat-flux ratio.","refute":"Closure tracking air temperature alone would remove the ocean term."},
{"n":5,"slug":"bottom-water-brine-melt","field":"Polar & Sea Ice","subject":"Antarctic bottom water","title":"Bottom Water Is a Salinity Ratio","claim":"Antarctic bottom water formation is set by the ratio of brine rejection to meltwater input rather than by surface temperature.","mechanism":"Dense water forms where salt rejection outweighs freshwater dilution; the ratio determines whether the shelf water is dense enough to sink.","prediction":"Formation rate should track the ratio.","refute":"Formation tracking temperature would remove the salinity balance."},
{"n":6,"slug":"under-ice-light-threshold","field":"Polar & Sea Ice","subject":"Under-ice blooms","title":"Blooms Need Light","claim":"Under-ice phytoplankton blooms occur only above a threshold in light transmission, set by snow depth relative to ice thickness.","mechanism":"Snow attenuates more than ice per unit depth; the ratio determines whether enough light reaches the water column to support net growth.","prediction":"Bloom occurrence should track the ratio.","refute":"Bloom occurrence tracking ice thickness alone would remove snow."},
{"n":7,"slug":"ice-algae-snow-thickness","field":"Polar & Sea Ice","subject":"Ice algae","title":"Ice Algae Follow the Snow","claim":"Ice algal production is set by the ratio of snow depth to ice thickness, with an optimum where light reaches the bottom of the ice without melting it.","mechanism":"Algae grow at the ice base and need light that penetrates snow; too much snow starves them and too little allows melt pond formation that shades them.","prediction":"Production should peak at an intermediate ratio.","refute":"Production increasing monotonically with light would remove the melt penalty."},
{"n":8,"slug":"arctic-discharge-stratification","field":"Polar & Sea Ice","subject":"Arctic shelves","title":"Stratification Follows Discharge","claim":"Coastal stratification in the Arctic is set by the ratio of river discharge to wind mixing, so a windy year can erase a large freshwater input.","mechanism":"Freshwater stratifies while wind mixes; the ratio determines whether the buoyant layer persists into summer.","prediction":"Stratification should track the ratio.","refute":"Stratification tracking discharge alone would remove mixing."},
{"n":9,"slug":"permafrost-thaw-active-layer","field":"Polar & Sea Ice","subject":"Permafrost carbon","title":"Permafrost Loss Is a Depth Ratio","claim":"Carbon release from thawing permafrost is set by the ratio of thaw depth to active layer depth, not by the absolute area thawed.","mechanism":"Only carbon within the newly thawed zone becomes available; the ratio determines what fraction of the profile is exposed.","prediction":"Release should track the ratio.","refute":"Release tracking thawed area would remove the depth term."},

# Boreal Forest
{"n":10,"slug":"treeline-degree-frost","field":"Boreal Forest","subject":"Treeline","title":"Treeline Is a Degree-to-Frost Ratio","claim":"The boreal treeline is set by the ratio of growing degree days to frost damage rather than by temperature alone.","mechanism":"Trees establish where warmth permits growth and frost does not kill seedlings; the ratio determines the establishment niche.","prediction":"Treeline position should track the ratio.","refute":"Treeline tracking mean temperature would remove frost."},
{"n":11,"slug":"boreal-fire-fuel-decomp","field":"Boreal Forest","subject":"Fire regime","title":"Fire Interval Is a Fuel Ratio","claim":"The boreal fire return interval is set by the ratio of fuel accumulation rate to decomposition rate rather than by climate alone.","mechanism":"Fire requires accumulated fuel; cold, wet soils slow decomposition and let fuel build, so the interval is a balance of the two rates.","prediction":"Interval should track the ratio across sites.","refute":"Interval tracking temperature would remove the fuel balance."},
{"n":12,"slug":"peat-production-decay","field":"Boreal Forest","subject":"Peatlands","title":"Peat Is an Imbalance","claim":"Peat accumulation occurs only where the ratio of plant production to decay exceeds one by a margin set by waterlogging.","mechanism":"Anoxic conditions suppress decay; accumulation is the residual after decomposition, which is why a small change in water table flips the sign.","prediction":"Accumulation should track the ratio.","refute":"Accumulation tracking production alone would remove decay."},
{"n":13,"slug":"boreal-outbreak-drought-defense","field":"Boreal Forest","subject":"Insect outbreaks","title":"Outbreaks Need Stressed Hosts","claim":"Boreal insect outbreaks occur when the ratio of drought stress to host defence exceeds a threshold, not when insect populations are large.","mechanism":"Defence depends on resin and carbon reserves, which drought depletes; outbreaks begin when defences fail, and populations follow.","prediction":"Outbreaks should track the ratio.","refute":"Outbreaks tracking insect counts would remove the defence term."},
{"n":14,"slug":"lichen-recovery-grazing","field":"Boreal Forest","subject":"Reindeer lichen","title":"Lichen Needs a Rest","claim":"Lichen recovery after fire requires a threshold in the ratio of recovery time to grazing pressure, so heavy grazing can prevent recovery entirely.","mechanism":"Lichens grow slowly and are grazed; recovery requires growth to outpace removal over years, and the ratio determines whether that is possible.","prediction":"Recovery should track the ratio.","refute":"Recovery tracking time since fire would remove grazing."},
{"n":15,"slug":"boreal-carbon-winter-threshold","field":"Boreal Forest","subject":"Forest carbon","title":"Boreal Carbon Tips in Winter","claim":"The boreal forest carbon balance tips from sink to source above a winter warming threshold, because soil respiration responds while photosynthesis does not.","mechanism":"Winter photosynthesis is negligible while soil respiration continues under snow; warming raises respiration without a compensating uptake.","prediction":"The sink should weaken above a winter temperature threshold.","refute":"The balance tracking annual temperature would remove the seasonal asymmetry."},
{"n":16,"slug":"moss-light-moisture","field":"Boreal Forest","subject":"Forest floor","title":"Moss Follows Light and Water","claim":"Moss dominance on the boreal forest floor is set by the ratio of light transmission to moisture, so a thinned canopy can reduce moss despite more light.","mechanism":"Mosses need light but desiccate without cover; the ratio determines whether growth exceeds desiccation.","prediction":"Cover should track the ratio.","refute":"Cover tracking light alone would remove moisture."},
{"n":17,"slug":"lake-co2-import-processing","field":"Boreal Forest","subject":"Boreal lakes","title":"Lakes Emit What They Cannot Process","claim":"Boreal lake carbon emission is set by the ratio of terrestrial carbon import to in-lake processing rather than by import alone.","mechanism":"Imported carbon is either respired or buried; the ratio sets how much leaves as gas, which is why similar imports give different emissions.","prediction":"Emission should track the ratio.","refute":"Emission tracking import would remove processing."},
{"n":18,"slug":"treeline-seedling-herbivory","field":"Boreal Forest","subject":"Treeline advance","title":"Advance Needs Survivors","claim":"Treeline advance is set by the ratio of seedling establishment to herbivory, so a warmer climate without reduced browsing produces no advance.","mechanism":"Establishment above the treeline requires seedlings to survive; herbivores remove them before they can form a cohort.","prediction":"Advance should track the ratio.","refute":"Advance tracking warming would remove herbivory."},

# Temperate Forest
{"n":19,"slug":"diversity-intermediate-disturbance","field":"Temperate Forest","subject":"Diversity","title":"Diversity Peaks in the Middle","claim":"Temperate forest diversity peaks at an intermediate disturbance frequency because both competition and mortality limit diversity at the extremes.","mechanism":"Too little disturbance lets competitors exclude; too much prevents establishment. The peak is where both pressures are moderate.","prediction":"Diversity should peak at an intermediate frequency.","refute":"Monotonic diversity with disturbance would remove the peak."},
{"n":20,"slug":"mast-seeding-resource-threshold","field":"Temperate Forest","subject":"Mast seeding","title":"Masting Needs Reserves","claim":"Mast seeding occurs only when stored resources exceed a threshold, so masting years follow years of high photosynthesis rather than years of warm weather.","mechanism":"Seed production is expensive; trees build reserves and spend them in a single year, which is why masting is synchronised and intermittent.","prediction":"Masting should track prior reserves.","refute":"Masting tracking current weather would remove the reserve term."},
{"n":21,"slug":"deer-browse-regeneration","field":"Temperate Forest","subject":"Deer browsing","title":"Regeneration Tips on Browse","claim":"Forest regeneration collapses above a threshold in browse pressure, and the threshold depends on light availability rather than on deer density alone.","mechanism":"Seedlings need to reach a height escape; browsing holds them below it, and shade makes growth slower and the escape harder.","prediction":"Regeneration should track the ratio of browse to growth.","refute":"Regeneration tracking deer density would remove light."},
{"n":22,"slug":"soil-carbon-root-turnover","field":"Temperate Forest","subject":"Soil carbon","title":"Soil Carbon Balances Roots and Microbes","claim":"Temperate forest soil carbon is set by the ratio of root input to microbial turnover rather than by litter input.","mechanism":"Roots deposit carbon directly into mineral soil where it is protected; litter is processed at the surface and lost more readily.","prediction":"Soil carbon should track the ratio.","refute":"Soil carbon tracking litter would remove root input."},
{"n":23,"slug":"leafout-chilling-forcing","field":"Temperate Forest","subject":"Phenology","title":"Leaf-Out Needs Both Cues","claim":"Spring leaf-out occurs when the ratio of accumulated forcing to remaining chilling requirement exceeds a threshold, so warm winters delay rather than advance leaf-out.","mechanism":"Budburst requires chilling to break dormancy and warmth to drive growth; a short winter leaves chilling unmet, which raises the forcing needed.","prediction":"Leaf-out should be delayed after warm winters.","refute":"Leaf-out tracking spring temperature alone would remove chilling."},
{"n":24,"slug":"edge-effect-height-fetch","field":"Temperate Forest","subject":"Edge effects","title":"Edges Penetrate by Geometry","claim":"The depth of forest edge effects is set by the ratio of canopy height to the fetch of the opening, so a small clearing has a shallower edge than a wide one.","mechanism":"Wind and light penetrate from the edge until the canopy closes; the aspect ratio of the opening sets how far that is.","prediction":"Edge depth should track the ratio.","refute":"Edge depth tracking edge length would remove geometry."},
{"n":25,"slug":"oldgrowth-gap-threshold","field":"Temperate Forest","subject":"Old growth","title":"Old Growth Needs Gaps","claim":"Old-growth structure develops only above a threshold in gap formation rate, because large trees and deadwood require repeated small disturbances.","mechanism":"Gaps create the heterogeneity that supports large trees and coarse woody debris; below the threshold the stand remains even-aged.","prediction":"Structural complexity should track gap rate.","refute":"Complexity tracking stand age would remove gaps."},
{"n":26,"slug":"shrub-canopy-openness","field":"Temperate Forest","subject":"Understory invasion","title":"Invasion Tips on Light","claim":"Invasive shrub dominance occurs above a threshold in canopy openness, so a thinned forest can be invaded without any change in propagule pressure.","mechanism":"Shrubs need light to establish; below the threshold they persist but do not spread, above it they outgrow regeneration.","prediction":"Invasion should track openness.","refute":"Invasion tracking propagule pressure would remove light."},
{"n":27,"slug":"drought-mortality-hydraulic-depth","field":"Temperate Forest","subject":"Drought mortality","title":"Drought Death Is Depth Against Risk","claim":"Temperate forest drought mortality is set by the ratio of rooting depth to hydraulic risk, so deep-rooted species survive droughts that kill shallow-rooted ones at the same site.","mechanism":"Access to deep water determines whether the canopy can be supplied; vulnerability to embolism determines the cost of running dry.","prediction":"Mortality should track the ratio.","refute":"Mortality tracking drought severity would remove rooting depth."},

# Grassland & Savanna
{"n":28,"slug":"savanna-fire-rainfall","field":"Grassland & Savanna","subject":"Tree-grass balance","title":"Savanna Is Fire Against Rain","claim":"The tree-grass balance in savanna is set by the ratio of fire frequency to rainfall, so a wet savanna with frequent fire has the same cover as a dry one without.","mechanism":"Rain favours trees and fire kills their recruits; the ratio sets the equilibrium cover, which is why cover is not a simple function of rainfall.","prediction":"Cover should collapse onto the ratio.","refute":"Cover tracking rainfall alone would remove fire."},
{"n":29,"slug":"grassland-season-grazing","field":"Grassland & Savanna","subject":"Productivity","title":"Productivity Is Season Against Grazing","claim":"Grassland productivity is set by the ratio of growing season length to grazing pressure rather than by rainfall.","mechanism":"Growth accumulates over the season while grazing removes it; the ratio determines standing biomass at the end.","prediction":"Biomass should track the ratio.","refute":"Biomass tracking rainfall would remove grazing."},
{"n":30,"slug":"migration-quality-risk","field":"Grassland & Savanna","subject":"Migration","title":"Migration Follows Quality Against Risk","claim":"Migratory herds move when the ratio of grass quality to predation risk falls below a threshold, not when grass is exhausted.","mechanism":"Animals trade nutrition against danger; they leave before the resource is gone because the risk rises faster than the benefit falls.","prediction":"Departure should track the ratio.","refute":"Departure tracking grass biomass would remove predation."},
{"n":31,"slug":"grassland-carbon-root-fire","field":"Grassland & Savanna","subject":"Soil carbon","title":"Grassland Carbon Is Root Against Fire","claim":"Grassland soil carbon is set by the ratio of root turnover to fire loss, so frequent burning can offset a productive system.","mechanism":"Carbon enters through roots and leaves through fire and respiration; the ratio determines the net balance.","prediction":"Soil carbon should track the ratio.","refute":"Soil carbon tracking productivity would remove fire."},
{"n":32,"slug":"encroachment-grazing-threshold","field":"Grassland & Savanna","subject":"Shrub encroachment","title":"Encroachment Follows Grazing","claim":"Shrub encroachment occurs above a threshold in grazing removal, because grass competition is what keeps shrubs from establishing.","mechanism":"Grasses compete for water in the surface layers; when grazing reduces them, shrubs escape the competitive filter.","prediction":"Encroachment should track grazing pressure.","refute":"Encroachment tracking rainfall would remove competition."},
{"n":33,"slug":"savanna-rooting-rainfall","field":"Grassland & Savanna","subject":"Tree cover","title":"Tree Cover Is Rooting Depth","claim":"Savanna tree cover is set by the ratio of rooting depth to rainfall seasonality, so deep-rooted trees persist where rainfall is strongly seasonal.","mechanism":"Deep roots access water through the dry season; the ratio determines whether trees can stay active while grasses senesce.","prediction":"Cover should track the ratio.","refute":"Cover tracking rainfall would remove rooting depth."},
{"n":34,"slug":"recovery-seedbank-tillers","field":"Grassland & Savanna","subject":"Drought recovery","title":"Recovery Needs Reserves","claim":"Grassland recovery after drought is set by the ratio of seed bank to surviving tillers, so a system with few tillers and no seed bank recovers slowly.","mechanism":"Recovery starts from surviving meristems and from germination; the ratio determines which pathway dominates and how fast.","prediction":"Recovery rate should track the ratio.","refute":"Recovery tracking rainfall would remove the reserves."},
{"n":35,"slug":"bison-patchiness-diversity","field":"Grassland & Savanna","subject":"Grazing diversity","title":"Grazing Needs Patchiness","claim":"Grazing maintains grassland diversity only above a threshold in grazing patchiness, so uniform heavy grazing reduces diversity despite high pressure.","mechanism":"Diversity requires some patches to escape grazing; patchiness sets the fraction that does, and the ratio to pressure determines whether it is enough.","prediction":"Diversity should track the ratio.","refute":"Diversity tracking grazing intensity would remove patchiness."},
{"n":36,"slug":"savanna-fire-decomp-carbon","field":"Grassland & Savanna","subject":"Carbon emissions","title":"Fire Emissions Balance Decomposition","claim":"Savanna carbon emissions are set by the ratio of fire to decomposition, so fire-prone systems emit more than decomposition alone would predict.","mechanism":"Both pathways release carbon; the ratio determines the partitioning, and fire releases it faster and more completely.","prediction":"Emissions should track the ratio.","refute":"Emissions tracking productivity would remove the partitioning."},
]