Underdark Ecology

[DM Storn]

Hey folks,

I am a DM working on my first campaign, which has been running for nearly a year now. A quick word about my style - simply put, I am a details nut. My world is created from scratch and is something of a non-stereotypical, non Forgotten Realms(ish) place - no offense intended towards those of you who love Forgotten Realms, but I am just plain sick of that place.

When creating a city, I have to include plenty of (probably unnecessary) details such as when and by whom the city was founded, its geopolitical situation with surrounding cities, its racial makeup, major imports and exports ... and I do this for every city and town I create, no matter how large or small - as I said, I am just a details nut.

Anyways, I am planning on having the players venture to the Underdark shortly and I am trying to think of a way to explain the ecology of the Underdark; for example how does oxygen exist down there? There is no light, so no photosynthesis (right? I'm not a botanist, so I am just assuming this is the case) ... are there enough 'air-holes' in the world to supply the Underdark enough oxygen? My initial thoughts are that there are not, and if that is the case how do they breathe down there (an interesting thing to consider is could an inhabited Underdark exist on a world in which the surface was uninhabitable). Also, what does the food chain look like? How would towns sustain themselves food-wise - would there be fungus farms, maybe some form of herbivore 'cattle' that feeds on mushrooms and supplies towns (and carnivores) with meat ...

This may seem a bit overboard to a lot of you, but this is just how I am - I cannot develop something like this without being able to explain in detail how it would exist in the first place. I have had a difficult time finding some resources regarding this - I don't know if anything has ever been written about what I would belive to be a fairly compelx Underdark ecology. Any guidance would be appreciated!


Storn

 

[VorpalBunny]

Anyways, I am planning on having the players venture to the Underdark shortly and I am trying to think of a way to explain the ecology of the Underdark; for example how does oxygen exist down there? There is no light, so no photosynthesis (right? I'm not a botanist, so I am just assuming this is the case) ... are there enough 'air-holes' in the world to supply the Underdark enough oxygen? My initial thoughts are that there are not, and if that is the case how do they breathe down there (an interesting thing to consider is could an inhabited Underdark exist on a world in which the surface was uninhabitable). Also, what does the food chain look like? How would towns sustain themselves food-wise - would there be fungus farms, maybe some form of herbivore 'cattle' that feeds on mushrooms and supplies towns (and carnivores) with meat ...

This may seem a bit overboard to a lot of you, but this is just how I am - I cannot develop something like this without being able to explain in detail how it would exist in the first place. I have had a difficult time finding some resources regarding this - I don't know if anything has ever been written about what I would belive to be a fairly compelx Underdark ecology. Any guidance would be appreciated!

Even though you said you hate the Realms, I'd suggest taking a look at Underdark. It has an ecology chapter that should definitely help you out. In brief, yes, there's no sun, so photosynthetic plant-life will be scarce. However, fungi don't necessarily need light to survive (they're not photosyntheic) so you'll see a majority of fungal species providing recources normally provided by plant life on the surface.

Regarding air in the Underdark: it makes perfect sense that there should be "air" down there. If there was no air, the Underdark would exist in a vacuum, so either A) there would be no life because nothing can live in a vacuum, or B) the pressure gradient would draw air from the surface down in to the Underdark.

Hope this helps.

 

[Utrecht]

A couple of things that you need to determine for yourself -

How did the underdark even form? Is it some sort of natural phenomena (which is just silly given what we understand about plant formation) - then yes, you will need to develop the ecology that you describe.

Is it a transition realm for to the dead? That implies some sort of mystical/divine connection that gives you a great deal of leaway.

Or has it been created by the Gods? This really gives you ultimate control - for example, there are veins of rock that are able to synthsis O2 from CO2 - does it make alot of sense - not really - but then neither do 200 tonne flying dragons......

 

[Utrecht]

Regarding air in the Underdark: it makes perfect sense that there should be "air" down there. If there was no air, the Underdark would exist in a vacuum, so either A) there would be no life because nothing can live in a vacuum, or B) the pressure gradient would draw air from the surface down in to the Underdark.

Hope this helps.

A bit a physics here - not necesarily - yes there would be gases - but not necessarily breathable air. Denser gases tend to hug the ground (Bournuli's Law IIRC) - so the underdark would be populated with toxic gases - at least to surface dwellers.

The cool thing about this is that you could have an entire - say methane based - ecology in the underdark - and treat the underdark as a hostile area that needs a spell similar to breathe water to even interact with.

 

[DM Storn]

Wow, thanks for the quick replies!

I am thinking that the Underdark began as something of a natural phenomena - at least the cave structures - that was 'colonized' and gradually expanded. The races that colonized it would have had to find ways to sustain themselves ... maybe they had cattle that didn't mind an all-mushroom diet, for example. I know that ultimately I can have magic be the driving force behind that sustainability, but I would like to begin with as much reality (odd word, I know, for a fantasy world) as I can. One thing I am actually considering is something like 'sun stones,' which would be a magical stone that gave off the equivalent of sunlight, allowing green plantlife to be cultivated nearby ... so you would create a greenhouse, place the sunstone inside and grow your greens.

Thanks for the recommendation, by the way - I don't necessarily 'hate' the Forgotten Realms, I am just a bit worn on them; I like to try new things now and again and this is one of those times

Thanks again!


Storn

 

[Utrecht]

Actually, your sun-stones are not a bad approach - In this cases we can borrow very heavily from ideas being thought of for space travel/planet colonization. I would look to what NASA or some other space exploration think tank has to say.

You could end up haveing some sort of mage prestegie class that specializes in the survivability of the city - and in some cases, there would be entire religions springin up around them - after all they are the ones providing life in a world of death.

Another thing to consider are a new breed of arobic (or anarobic) bacteria who is able to consume - say Ferrous Oxide and release Oxygen - making iron rare in the underdark. (if this is not practicle - perhaps some other oxidized metal)

 

[Vaxalon]

**sigh**

If you want a science-based game, unfortunately, your caves are going to be inhabited by a few tiny cave fish and maybe some bats. Not too much room for adventure when there's no available nutrients.

If you want a FANTASY game, however, you can set up the ecology any way you like. For my part, I based the ecology on green slime.

IMC green slime is a naturally occurring substance. While it's inimical to most forms of life, it is the primary nutrient source for fungi aside from dead flesh.

 

[Nightchilde-2]

Even though you said you hate the Realms, I'd suggest taking a look at Underdark.

I'll second this. There's a bunch of info that can be incorporated into any campaign. A large portion of the book concentrates on rules for fighting in the underdark, what flora and fauna you'll find there, what dangers you might run into while spelunking and so on.

However, a large portion of the book details the cities and features of the Underdark as it pertains to the Realms as well. But no problem, eh? So you tell the characters that they go to Plenzoberranzan rather than Menzoberranzan, they'll never know the difference.

 

[Snapdragyn]

One of the classic problems with Underdark ecology is a source of nutrients. People frequently try to get around this with the 'fungus' solution, but fungi still have to be getting nutrients from somewhere -- IRL, it's typically decaying matter which ultimately traces back to photosynthetic plants. When you have a shroom patch miles below the surface, that's not really a practical solution for the diversity & size of ecology you want, even in the typically resource-poor Underdark.

IMC, I'm planning to instead have a group of organisms which use the radiation-like energy described in "Underdark" as an energy source, much as RL plants use light radiation. Many of these organisms will have shapes resembling typical fungi (& will probably be called 'fungi' or 'mushrooms' by the inhabitants of the world), but they will in fact be an entirely different form of life. 'Sunstone' type caverns will also exist in some places, so that green plants will not be completely unknown (though they will be rare & much coveted).

I'm even planning that one region of the surface world which is perpetually cloaked in darkness (due to a tenuous separation from the Plane of Shadow) will have an extensive forest of these fungus-like organisms, since green plants in the area died off centuries ago.

 

[jgbrowning]

In our upcoming book, A Magical Society: Ecology and Culture we've postulated that tiny (microscopic) magic feeding creatures (magiovores) turn pure magic energy into flesh. Solves the problem nicely.

joe b.