To answer your questions about the role of plant life when classifying biomes, and to clarify this point generally, I believe assigning certain biomes based on the species present in a patch is necessary, as a “biome” by definition is a type of ecological community.
I think the simplest approach is a tiered system, where simple (or low biodiversity, low-tier) biomes are assigned based only on patch stats like precipitation and temperature, and more advanced (biodiverse, high-tier) biomes can later be assigned based on the emergence of certain kinds of species.
This may remind you of Spore’s tier system for planet terraforming, which is meant to convey similar concepts.
In T0, before life exists on land, there are only patches of Barrens (not a scientific term), with whatever temperature and precipitation (or other stats) they happen to have.
In T1 the land has experienced primary succession, making land biomes relevant, and Barrens patches get assigned a biome based on their stats. At this early stage, forests and scrublands are not yet possible, so we only have Deserts and Wetlands (which can be defined purely by precipitation/humidity).
In T2 “shrub” organisms have evolved, and scrubland biomes become possible, which are populated in patches with the appropriate stats and presence of the right species.
In T3 “trees” have evolved, and the same occurs with forests.
This does mean we need to define what makes an organism a “shrub” or “tree”, which is a whole other discussion. I am assuming we can arrive at such a definition and thresholds for how many “trees” make a patch a forest, etc.
I think this approach is fairly intuitive and compelling. It means if there is a mass extinction, or deforestation, the simple lack of “trees” that got destroyed will change the biome, just as would happen in real life. A healthy and complex ecosphere will have many different biomes, and a young or struggling ecosphere will have fewer.
Biome types may be pre-defined, but biomes naturally emerge from the simulated climate, terrain, and species which have evolved there, leading to infinite variability.
Right, which is why I tried to specify a category that includes the climate and terrain variables without ecosystems, so that wouldn’t actually be a “biome”.
What I am getting at is that even pre-life a Barrens (tropical flatland), Barrens (Polar hills) and Barrens (Temperate mountains) are different, and will look and feel different. Similar to how our current microbe patches have their own terrain, environment conditions and music, even though they’re really not biomes.
Do we for example want to show these different not-biomes on the map for players to see?
The system you set out in principle makes sense I think.
But what I am wondering, as above, is whether the actual “Biome” (as purely the end result of what the ecosystem is like because of the local conditions) is sufficient as a visualisation and decision making point.
For example, should a flat desert and a mountainous desert use all the same soundtracks?
From the world generator’s perspective, I think we would want to have both the ‘potential biome’ without regard to ecosystem and the fully classified ‘ecosystem biome’ and either of them would be used in different situations.
So, the worldgen would work by partitioning the world into ‘potential biome’ regions, which would then have species propagate across them over time, and the ‘ecological biome’ would be dynamically changing over time, and would be categorized based on the static ‘potential biome’ and the dynamic species populating it.
The ‘potential biome’ regions themselves would be static in the initial implementation (as they are right now) but they could also be changed over time to add in environmental changes. But I think we will wait to have that implemented until later; I at least rank that as a lower priority.
The conditions can also vary drastically over the course of smaller timescales of a year, like for example the rainfall over Africa:
It would be easiest to handle this by just assigning based on average for the entire year. I am not sure if on the timescales of Macroscopic and Aware that we could easily distinguish the differences between seasonal variation and variation over eons without having each game cycle represent an entire year and have the player have to survive through all seasons. This is above however we conceive of implementing the day/night cycle, which would surely be much longer than it currently is in Microbe/Multicellular.
This is somewhat of a tangent, but I think in the 3D world we will need a day/night cycle of around 20 minutes, as any shorter than that in a 3D game would probably be too disorienting, and perhaps nauseating to have the planet rotate much faster.
There’s been some interesting points raised here. I’ve typed a long response, so let me break it into several parts:
Biome Soundtrack Design Philosophy
In my opinion, yes. Or rather, there should be a desert theme which plays in deserts, and perhaps a mountains theme, and both can play in desert mountains. As the player becomes more familiar with the soundtrack, this should create a greater tonal variety while still fitting the gameplay environment, if that makes sense.
If you’re in the desert mountains and hear the desert theme, it may invoke memories of time you spent wandering the dunes, and when you then hear the mountains theme, it may invoke memories of time you spent scaling snowy mountain cliffs, both of which provide different and rich context to the current gameplay experience.
I think themes should strike a balance between specific and broadly applicable, while specific locations can be given a sonic identity using a combination of multiple themes and ambient tracks.
Biome Parameters & Exobiomes
I never responded to this, but a biome map something like this is what we should develop. Holdridge has 3 axes, but I for the simplified simulation we’re going for in Thrive, two parameters (temperature and humidity) ought to suffice, modulated by altitude. I may take a shot at defining parameters on a map like this in a way that Hadron and other people can reference.
Also, I’ve thought more about how to represent non-Earth biomes, and my intuition is that not much change is really necessary. I see no reason an alien planet with plant-analogs wouldn’t have analogs to deserts, scrublands, grasslands, and/or forests. With our two parameters, temperature and humidity, what kind of biomes might inhabit the extremes that we don’t see on Earth? An even hotter desert? An even wetter wetland? I think that such environments can be represented as unique subtypes of biomes we already have.
I’d like to direct attention to a source that’s been very inspirational for me when thinking about this topic, and that’s the work done by Nikolai Hersfeldt for his Worldbuilding Pasta blog. It’s quite well-researched, and he’s developed his own climate classification system which can handle biomes beyond what we find on Earth. Allow me to quote some of his work here. I highly recommend giving the whole blog post a read if anyone’s interested, I won’t be able to do it justice.
Based on our previous sources and other work, here’s a range of potential tolerance limits for minimum temperature encountered for more than a brief period in a typical year, for a range of life forms—do note that some of these are very approximate:
18 °C: tolerance limit for shallow marine coral.
10 °C: tolerance limit for some particularly warm-adapted tropical plants.
0 °C: the frost point, when ice formation may damage exposed soft tissues; tolerance limit for tropical plants; minimum growth temperature for even cold-adapted plants.
-15 °C: tolerance limit for frost-tolerant broad-leaved evergreens
-40 °C: tolerance limit for many non-boreal plants.
-60 °C: tolerance limit for needle-leaved evergreens; approximate freezing point of water-H2O2 mix.
-80 °C: minimum temperature with observed metabolic activity; potential atmospheric freezeout in CO2-rich atmospheres.
-97 °C: freezing point of water-ammonia mix.
-180 °C: atmospheric freezeout in N2/O2-rich atmospheres; freezing point of Li-ammonia brines.
There is some literature exploring the absolute limits of temperature at which plants are irreversibly damaged even in moist conditions that we can go off of here:
35 °C: bleaching temperature of even heat-tolerant corals.
40 °C: tolerance limit for aquatic and undergrowth plants.
50 °C: tolerance limit for most plants with exposed leaves.
70 °C: tolerance limit for desert-adapted plants, and complex life generally.
100 °C: water boiling point at 1 atm; tolerance limit for any life on land.
374 °C: boiling/critical point of water even at high pressure.
Conveniently, complex Earth life simply isn’t able to thrive (get it) at temperatures much higher or lower than we already have on Earth. Without delving into literature, I would wager that’s no coincidence, as Earth’s biosphere is a self-regulating system deeply connected with the planet’s climate. Given that life in Thrive is pretty Earth-like (even with LAWK off), I would argue we simply don’t have much to worry about here.
Still, Hersfeldt has neatly classified some exoclimates. These are exclusively hotter than Earth, because Earth temperatures already get colder than the absolute limits for complex Earth life.
Sufficiently high temperatures may then inhibit growth even among heat-tolerant plants, creating a period of interrupted growth in summer similar to that in winter for cold climates, and so a parallel sequence of increasingly growth-restricted climates:
Supertropical (HT), with only brief growth interruptions, allowing for evergrowth plants, named as the converse to subtropical zones.
Swelter (HD), with longer growth interruptions potentially favoring a more deciduous lifestyle.
Parch (HF), with a brief growing season to short for large vegetation.
Hot Barren(HG), with a growing season too short for almost any vegetation.
These zones can then be subdivided based on additional thermal tolerances, in particular the 70 °C and 100 °C boundaries:
Hot Summer (Hxa) climates have summers within the range of survival for complex life on Earth.
Torrid (Hxb) climates have summers beyond Earth’s complex life tolerances, requiring extreme adaptations to survive.
Boiling (Hxc) climates reach temperatures above boiling, fatal for all exposed life incapable of surviving total desiccation.
Because we’re trying to go for a pretty simple system, I don’t see the need for specificity like “Torrid Parch”, but we can definitely borrow some of this terminology.
My decisions here are somewhat arbitrary, but here’s the exobiomes I’ve devised for Thrive:
Biome type is on the left and Subtype is on the right. (Exo) indicates it’s a biome not found on Earth.
’Supertropical’ environments have brief interruptions to the growing season due to the extreme heat, and this term would indicate that. I would think they othwerwise can still support any tropical biome from Desert to Rainforest, though organisms in any of these environments would require special adaptations.
‘Torrid’ and ‘Boiling’ environments have summer or year-round temperatures beyond the tolerances of complex life. As such, I think these terms can only be fitting for superhot deserts.
Torrid deserts are only survivable to extremophile organisms. Boiling deserts are for our purposes not survivable, and no gameplay can take place there.
‘Parch’ environments can support vegetation, but not large vegetation, so this term works well for superhot Scrubland.
‘Swelter’ environments can support large vegetation, but with interruptions to the growing season in the summer. This term works well for superhot Forests and Dry Forests.
You could simplify this by only using the ‘Supertropical’ subtype to indicate temperatures higher than Earth, though I think using these several terms provides useful context to the player as well as flavor.
I’ve also added a ‘Hot’ and ‘Cold’ Barren subtype here, indicating that there is no life here because of inhospitable temperatures, rather than a lack of primary succession. These two biomes could populate worlds where there is no life, or where life can exist in water or underground somewhere but not on the surface.
I didn’t dive into the suite of Extraseasonal biomes in Hersfeldt’s system and how they may apply to Thrive (think a biome with swings into boiling and freezing temperatures but brief habitability), as I’m not sure how we’re going to handle seasons in Thrive.
Grasslands
Finally, coming back to Earth, there’s been some discussion on the community forums about how grasslands fit into this system. For posterity, I’ll copy my takeaways from that discussion here.
Actual grasslands are shockingly recent. Depending on your source and how they’re defined, grasslands as we know them today didn’t appear until after the Cretaceous, maybe even as recent as 5 million years ago.
Around 5 million years ago during the Late Miocene in the New World and the Pliocene in the Old World, the first true grasslands occurred.
I think for educational purposes it would be nice to make it somewhat difficult for grasses to evolve in Thrive, making it take a while after trees. Once they evolve and the conditions are right, then like on Earth, they should be able to dominate much of the planet.
As for biomes, I was going to suggest Grassland should be a subtype of Scrubland biomes, I just realized I’ve already got Steppe, which is a type of grassland. Prairie and Savanna are the other types. So, I could replace Steppe with Grassland, which can replace Scrublands once grasses evolve, and have Steppe, Savanna and Prairie be subtypes.
Edit: Grasslands can replace forests, scrublands, or even deserts, depending on the right conditions. Grasslands replacing forests was a major reason humans evolved to walk on two legs.
Here’s the layout of all the terrestrial biomes. I’ve added a T4 for post-grass, which I said I wouldn’t do, but the evolution of grasslands is a pretty major milestone.
I agree with you on all points, but I do think this still supports the point I was initially trying to make:
Classification of “patches” into biomes (in the true ecosystem sense) is in my opinion necessary but by itself insufficient for Thrive’s purposes. In order play a mountain theme in mountain “patches”, we do need to categorise which patches are mountains. This means we need a terrain classification either baked into biomes (as is the case in microbe stage) or a new separate system entirely parallel to the real ecosystem-based biome. So that would respectively be “Biome: Desert (mountains)“ or “Biome: Desert + Terrain: Mountains”.
The same goes for hills, plateaus, presence of rivers maybe, etc.
It’s the thing that keeps making me wonder if it would be better to have a microbe-stage-style patch classification determined purely by terrain + climate conditions as a “base layer”. The actual biome classification would then be a layer on top decided by the actual species present and ecosystem.
That would be in place of the multi-tier biome system where you define then “end biome”, with lower tier biomes replacing them if the right type of plants are not available. So this is also in response to HH:
The end result will probably be similar, since as @HyperbolicHadron mentioned, we’d be using the generator’s basic outputs to determine either the “potential biome” or the “non-biological patch classification“. And in the end a “tropical high-temperature high-precipitation” patch is still most likely going to end up with a “Rainforest” biome built on top of it, same as if you defined it as “potential biome: Rainforest”.
But mechanically, I feel more comfortable with a “bottom-up” definition than a “top-down” definition. It seems inherently more flexible to me. The top-down system of potential biomes with conditional downgrades seems a bit too rigid and linear. For example:
I agree designing this to be likely is probably a nice thing to do. But this is Thrive, so likely does not mean guaranteed. It’ll likely be at least possible for something grass-like to evolve before something tree-like does. What happens to the succession tier pattern when grasses exist but trees do not?
And do we really want to make it impossible for there to be a possibility of a “tree” species to evolve a way to compete more effectively against the “grasses” (for example, poisoning the soil with something the grasses have not evolved resistance to), thereby having forests displace some of the grasslands?
Another possible factor affecting biomes could be the fauna available. For example, I know that the presence of grazing animals is a major factor in maintaining grass/scrubland by preventing the growth of forests.
So again: I think your list of biomes is so far a very good one, but I don’t think it’s a good idea to define patches by their end-point “potential biome”, with a linear set of lower tier biomes leading up to it. I can imagine some potential problems already with just having earth-like life evolving in a different order, or with different competitive effectiveness. But what concerns me more is the problems we are not foreseeing right now.
So I would greatly prefer a system that at the base level defines patches by their geography and climate. Then let auto-evo decide based on those characteristics and the inter-play between species what type of vegetation actually ends up dominating. Then based on those results, we can select from your list of biomes. This seems more flexible to me, since I expect each “climate-geographical zone” to have more of a “tree”, “field” or “list“ of potential biomes, rather than a linear list leading up to a final ultimate biome, based purely on available plant species.
Seems like here you’re primarily talking about the climate-side (which makes sense since that is also what your (very interesting!) source is talking about! But I’m still thinking more about the biological side. Since ultimately, biomes to me seem defined by the ecology. Which is very strongly influenced, but not entirely determined, by climate.
Some things that still stand out to me:
You seem to assign all pre-shrub scrubland as (cold) desert. Now, shrubs are actually defined as still pretty decently sized woody plants. And as far as I can tell from a quick wiki search, those are a middle-Devonian development. But in the early Devonian (and later Silurian?), there were still a lot of small herbaceous plants. Rather than desert, I think this would be visually more similar to (alpine) tundra, rather than desert? (Please ignore the Prototaxites, they’re… weird)
Going even earlier into the Silurian and late Ordovician, we’re probably moving into seeing only moss and lichen (and algal/bacterial mats). Still tundra? Or is that Barrens? To us maybe, but to the arthropods we know were crawling around, probably not.
Speaking of algal/bacterial mats, which make for example stromatolites, they’re also around during some of the timeframes above, and before then. Afterwards, the evolution of other flora and grazing fauna prevented them from defining the ecosystem anymore. How would you classify a biome where just this stuff is covering everything?
Another problem could be that the plant-analogs may not be super plant-like? With the way auto-evo is going, you could just as easily end up with a main photosynthetic phylum that is built on soft-body cells or cells individually encased in silicate or carbonate rocks instead of the the cellulose-walled plants we all know and love.
I would expect that will change the calculus on for example growing tall, and how different climates affect different types of growth.
Which still all brings me back to “categorise areas based on geographic-climatic conditions,define biome from dominant species“.
I see what you’re saying, and I think the latter option is better, having a separate biome and terrain classification. Terrain is too complicated of a factor to bake into our biome classification scheme in my opinion. Some biomes, like wetlands, can only exist with highly specific terrain, while others like desert can exist anywhere with certain parameters, in this case little rain.
I think I was slightly misleading with my “tier system”. There is no built-in progression for biomes, and biomes are only defined by what is there in the patch, a.k.a the humidity, temperature, and species. If one generation there’s enough trees, it’s a forest. If next generation they are outcompeted by grass due to changing conditions, it’s a grassland. If the planet then freezes over, it’s a polar desert. The tiers were initially meant to represent higher biodiversity, but I jumped the gun on that when I added T4 for grassland, as a grassland will have lower biodiversity than a forest.
You’re right about this, and the answer would simply be, there are grasslands but no forests. A “succession pattern” for biomes is only relevant when totally uninhabited rock is being colonized for the first time by life.
So these are some good weird cases to think about, and I think these can be addressed by clarifying some sub types of Barrens and Desert.
Inhospitable barrens don’t have life, even microbes, because they cannot support it.
Abiotic barrens can support life, but have none yet.
Pioneer barrens have life, but no soil yet. They are still undergoing primary succession. There notably is rainfall. If there’s a lack of rainfall/humidity, this is instead a desert.
Deserts are defined entirely by lack of rainall/humidity.
It’s worth noting, many deserts actually have quite a lot of vegetation. I’ve added Arid, Semi-arid and Coastal desert, with Semi-Arid being typically the most lush subtype. The line between desert, steppe, scrubland, etc. gets pretty blurry and in my opinion arbitrary, but for Thrive, I think environments with “plants but not grasses or shrubs” generally qualify as either Pioneer barrens or Semi-arid desert, depending on the extent of soil development.
You can see I’ve redone the tiers, which are only meant as a tool to indicate present key species, and correspond loosely to biodiversity levels. Some types of Tundra could perhaps be T1.
I’ve also deleted the table showing examples of various biomes’ succession, as it’s perhaps a little misleading. Instead, I’ve created an example scenario of how a single patch might develop over time, to highlight the range of possibilities.
As for Prototaxites… Let’s just throw it in the Pioneer Barrens bucket! But seriously, I think that’s the best solution for weird organisms like that. Same for bacterial mats, stromatolites, and any weird alien things that we can’t classify as shrubs, grass or trees. I’m sure auto-evil (I meant to type auto-evo just now, but I’m leaving it) will mock our attempts at classifying plants and biomes, but we gotta draw the lines somewhere.
As a side note, I revisited wetlands, because I had a Saltwater Wetland and Freshwater Wetland biome under Marine and Freshwater biomes respectively, and that felt wrong to me. The whole point of wetlands is they’re a transitional zone between land and sea, so I’ve created a special transitional biome category just for them. You win, wetlands.
If that is the case, one thing to keep in mind is that probably the world would be divided into regions based on those abiotic factors of terrain and climate? Because I think the distribution of species in auto-evo would need those region “patches” to already be settled. So whatever size these regions are, they would get “filled in” with whole uniform biomes. But that makes sense if we deliberately create these regions based on those factors that should decide what life can live there. I think @HyperbolicHadron already discussed this before.
I think those are good additions, trying to cover as much as possible without bloating the list too much.
One thing I am still really looking at is that potential early Devonian scenario of “no shrubs, but plenty of herbaceous small plants and probably soil“. That seems like it would be a likely enough scenario?
It doesn’t match Pioneer Barrens, because soil. If Deserts are defined by rainfall, it can’t be a Desert (and visually/mechanically, I think it would not fit). Not scrubland, because no shrubs. In types of vegetation, I still think it visually looks like a Tundra, but that can’t be it if those are defined by permafrost. I guess it’s like a Grassland, just that the herbaceous plants are not grass-like? On the community forums, Herblands was suggested? It’s not any official widely used term as far as I can see, but I did see it used in a few published papers where they probably couldn’t find any existing word to describe what they meant.
Or maybe we’re being a bit too strict on requiring grassland biomes to have herbaceous plants that are actually grass-like? Sure, on earth they’re a late development because before then small herbaceous plants were not displacing shrubs and trees. But where does that leave us when shrubs and trees just don’t exist (yet)?
Very small nitpick here: Pioneer to me explicitly says this is a first step before the establishment of other life (either evolving later, or colonising from elsewhere later), which is actually unusual compared to the other names. Maybe we can use a term that is more prediction-neutral? Random grab: Biotic Barrens, Sparse, Simple, Basic, Crust?
Actually something that also the early Devonian not-grassland made me think about:
Maybe for the purpose of classifying plants in order to classify biomes we want to look more purely at the plant’s more obvious and basic characteristics that matter for moving around and living near it?
Sessile species with an 8 meter tall trunk? That’s a tree.
It’s not a plant but a giant lichen in symbiosis with algae? Cool, but still a tree.
It’s actually growing from detritus it’s sucking out of the soil instead of photosynthesis? Weird, but still a tree.
Made with rock instead of wood? Still tree!
It’s actually using radio-synthesis from the open nuclear reactor you put next to it? Tree!
Taking this to the extreme end, that early Devonian landscape would be described as a “grassland” with occasional “trees”, but not enough to make it a “forest”. If we ignore climate, Savannah?
In fact:
Have you considered taking this a step further?
We could classify and divide regions/patches first based purely on a combination of the a-biotic terrain and climate variables.
Then the “biome” classification (probably renamed to vegetation type?) is purely a description of the type and distribution of “vegetation”, without any regard for or reference to why (terrain and climate) those species ended up dominating there.
I realise this is a big shake-up but I guess it could cut down on the number of different biomes, and make it easier to avoid edge-cases where we don’t have a name for that particular combination of vegetation and climate?
I want to note here that your wetland biomes here actually are a purely geographical/terrain description, without taking into account present biology (other than being Coastal if there is no life at all). That for example combines Marshes and Swamps into one thing.
Link for Spreadsheet 1: Dropbox
Link for Spreadsheet 2: Dropbox
(you can click on the link and go to “File” → “Download” to interact with it. Doing this for Spreadsheet 2 is more important, as it has an explorer tool)
Here is an interpretation of this conversation based on some things I’ve noticed. Not really convinced it’s better than what anyone has proposed, but maybe it could be a different point to consider.
First Spreadsheet
First, I tried to parametrize three values: Temperature, Vegetation, and Rainfall (below found on “new matrix” sheet).
Not that we’d need to actually quantify biomass and give that a number range, I just am not smart enough to give an estimate of biomass within a specific area
I then condensed things into six larger “buckets” of biomes.
Forest - An environment with a substantial presence of tall biota. Now includes rainforests.
Desert - An environment with sparse vegetation and arid/semi-arid conditions, which has a yearly average temperature above 1 Degrees Celsius. This notably excludes polar deserts, which I consider a type of Barren here.
Tundra - A polar or cold region with ground-cover, semi-arid conditions, and a lack of tall biota.
Grassland - A temperate, tropical, or warm environment with ground-cover, a lack of tall biota, and atleast semi-arid conditions.
Barrens - An environment with no or an extremely minimal presence of biota. Similar here, but includes polar-desert-esque environments like ice shelves and frozen environments.
Heathland - A sparse environment with atleast moderate amounts of rainfall. A new category to catch environments which might not last long and aren’t included conveniently in other categories. I particularly was motivated by the idea of a biome which isn’t dry enough to be a desert, but has sparse vegetation.
I then made some sort of matrix describing when an environment is possible, seen above (found on “new matrix” sheet). X with a red box indicates that the biome cannot exist in this category. This is a bit difficult to read through, and is expressed better in a later part. Just know that I used this as a reference to an index I created, and just shows if a biome can possible exist in a given condition.
This matrix also effectively means that if parameters are in the ranges/categories listed below, they can only be the given biome. And, put another way, these different biomes can only exist on these conditions (found on the “qualifiers” sheet):
Now to the meat of this interpretation: a combination of the biome name/type and the category of each parameter possible for the biome can result in us giving more unique names to different combinations. In other words - a forest that is cold, with moderate rainfall, and towering vegetation is X name; a forest that is cold, with moderate rainfall and forested vegetation is Y name; a forest that is warm, with semi-arid rainfall and forested vegetation is Z name; etc.
I created an index (“index” sheet) of all the different possibilities of each biome: a forested, semi-arid temperate forest, a forested, semi-arid, tropical forest, etc. Column B is the name of the Biome, and Columns C - R indicates which category of each parameter this specific environment is - X indicating a chosen range. So the first “Forest” biome row shows a forested, temperate, semi-arid forest.
I combine these in Column AI (Named ID) - “ForestedTemperateSemi-Arid” in the first row” - and give that specific ID a name. For example, I called ID “ForestedTemperateSemi-Arid” a “Dry Forest”. This name doesn’t have to be unique for every single possibility - I call numerous things a “Rainforest” as seen in the snip above. It just is a way to more conveniently refer to a type of environment. I did this for every possible combination of every biome: this results in 113 combinations, which I gave 49 unique names to.
The “patch identifier explorer” spreadsheet uses this index to give you the name of a particular combination of parameters. Move the Xs around on each parameter, and it will return the name of the patch and the biome type this name is. This lets you walk out a potential story of a specific piece of land, and review whether you agree with the biome classification and patch-name of these parameters: what if a cold environment goes from sparse, to ground cover, then warms up to temperate, increases rainfall, etc?
This Interpretation Summarized
I’m honestly not fully sure how useful this is or how much it assuages any concerns, but I guess this is the essence of it.
Six types of “Biomes” exist.
Three parameters are influential in the naming of a patch, interacting with a biome. A specific combination of these biomes plus the biome name results in a regional biome name.
So a larger region might be “Barren”, but specific areas within that region could be a “Frozen Wasteland”, then “Badlands”, then “Mudlands”, etc.
Caveats
How we measure the amount of biota should be a purposeful decision. I think biomass would be a decent proxy, but we still need to be sure. Maybe if X% of biomass is represent by biota which are above X feet, the category changes to forested and towering?
Rainfall should also be purposefully discussed. I had an inconsistent treatment of rainfall in cold and polar regions. In some cases, snowfall counted in my head; but tundras are unique in that not much actual rainfall occurs, but permafrost and ice can make water accessible.
The index doesn’t have any say on how realistic different possibilities of parameters are. Can there be an arid environment with ground cover? Can there be a sweltering temperature environment with massive trees? It doesn’t have a say on this - I just gave names to different things.
This assumes Rainfall, Temperature, and Vegetation Amount to exist, and no other parameters. I’m not sure what the full list of parameters will be, as well as how they will interact with each other. My intuition tells me that we should make only a few parameters influential for things like naming, and have derived parameters which might further diversify gameplay, but don’t alter the name. I’d assume these “secondary parameters” would have a relationship with our larger parameters, so that “Rainfall”, “Temperature”, and “Vegetation Amounts” (assuming those are the primary parameters) strongly effect the derived parameters.
This currently doesn’t have any sort of interaction with special patch features, like wetlands, rivers, hills, mountains, etc. I have some sort of an idea for how those can be handled that I can can be demonstrated here, but I didn’t write them down here yet.
Numbers of parameter ranges are completely open to change, as well as the name for any biome.
Excellent work paramaterizing these terms. I broadly support all of this, and I like the system you’ve established of assigning Biome IDs special names where it’s relevant. Natural language doesn’t much care for rigid classification schemes, and names can sound akward as a result, so giving biomes nicknames may “feel” better for the player. I think if we go with this system, then for clarity the player should always be able to see the biome ID in a tooltip or info panel, and be able to understand that many biomes are referred to with nicknames.
I don’t know enough to comment on most of your parameters, and they look good to me. As a nitpick, I want to say re: discussion about exoclimates earlier in this thread, you could perhaps extend the temperature scale to account for hotter exoclimates.
Since ‘Swelter’, ‘Parch’ and ‘Torrid’ were defined as hot enough to interrupt the growth season for part of the year, and we’re working with yearly averages, it’s gonna be really hard to figure out the proper thresholds.
I would argue that ‘Supertropical’ is supposed to represent regular hotter-than-earth climates, so ‘Sweltering’ shouldn’t begin until growth becomes interrupted/impossible for part of the year. Rather than defining it on a yearly average, this should be applied based on the yearly high, since an average of 40 C might mean swings up to 80 C or it might mean it never changes more than a few degrees. From earlier:
50 °C: tolerance limit for most plants with exposed leaves.
70 °C: tolerance limit for desert-adapted plants, and complex life generally.
So perhaps Sweltering is defined as a yearly high temperature above 50 C. Hot enough that plants struggle, but survive.
Parch and Torrid are just different terms for the same thing (in the way that I’m using them). They are purely for flavor and are alternate terms based on humidity. Torrid Desert sounds better than Sweltering Desert. Flavorful terms like these can be used in the biome nicknames as long as it’s descriptive.
This would go until Boiling, which is hot enough that at some parts of the year, water boils. It is therefore defined as a yearly max temperature at or above boiling point (100 C, but hotter at higher pressure). These are the hottest temperatures where microbes might sustain themselves permanently. Taking a quick look at Wikipedia:
At a yearly high above 122 C, or when a biome is hot enough that no life survives, biome classification is irrelevant, and it is Inhospitable Barrens.
My thoughts on some of your Caveats:
I would argue we shouldn’t measure biomass, but rather the abundance of key species (“trees”) in either population or energy consumption. For bizarre edge, cases biomass might be misleading. If the trees are all made of light material and held up with helium balloons, and don’t have a ton of sunlight to produce biomass, meanwhile there is dense undergrowth that has some other energy source conducive to abundant biomass, the calculation might be off.
In my opinion this is fine. In practice, not every combination of values can exist:
We may not be able to predict what odd edge cases will and won’t appear in game, but if each of them has a systemitized name, it doesn’t matter which combinations can’t exist because the player will never encounter them.
If we weren’t in the business of naming things that can’t exist, we wouldn’t have named the latter stages of Thrive. /s
I’ll have to check out your spreadsheet later when I get time, but for the biomass density parameter I can at least say that if we do end up wanting to use that it should be an available statistic to use. The world generator will have accurate plant count and distribution statistics in order to place the flora in the 3D world so converting that to biomass distribution would just require multiplying that flora population density for each species in the patch by a biomass per species member number, however we calculate that.
And it should be biomass density, not absolute biomass volume because patches will vary in size.
