Predator/Prey relationships?

[Leigh]

I've been playing for a little while now and I'm still a little confused about how population sizes and resources are handled.

As far as I can tell it food chain operates like this:

Herbivores eat plants. They will reproduce unchecked until all plants are destroyed if left alone. They will then die of starvation.

Omnivores/Carnivores are added. They will reproduce unchecked until all Herbivores are desroyed. They will then die of starvation.

I feel I'm stuck in the game. How do I get these relationships balanced? The carnivores shouldn't reproduce until they destroy all prey in the area should they? Is the game designed around always adding extra plants/animals?

[Immersed Games]

You're not going to be able to get a truly sustained balanced ecosystem.

We've had a lot of debates in our development about this, and definitely had mixed feelings (as you've had) on the outcome. If your ecosystem could be perfectly balanced, then the game would basically just be over.

So yes, the AI is a bit stupid and will keep growing and reproducing until it out-eats an area and dies. In an effort to reduce this, we did enable prey to escape at increasing rates when the ratio gets out of balance, but most of the time after a while the predators will still find them.

This is because we designed each individual animal to be seeking its own best interest of food. Which makes the game fun and responsive as you can see them immediately running to the needed food source, but also means that they tend to voraciously destroy things.

With a large biodome with a lot of biodiversity and reproduction that is mature and at variable rates because of a variety of species, I've had ecosystems that I barely touched except for once every year or so to restock in a few areas. So it is possible to get close to mature and balanced, but given the limited space and the way the AI works, it's going to need a bit of help along. :)

[Leigh]

Thanks for your confirmation.

Can I suggest that perhaps to keep the game going that outside causes of strife would have been better? e.g. like Sim Cities disasters.

As it is I find it unsatisfying, like filling a bucket with a hole in it.

[Leigh]

Additionally, how have you managed to maintain your almost balance? In a biome like the arctic tundra I'm told the Arctic fox has no natural predators. It splits and splits killing everything in it's path. If I were to continue to repopulate the hares and lemmings etc. I would need ever increasing amounts of prey animals which would eat ever increasing amounts of plants so that eventually I must sit there placing down plants without stopping as they're instantly eaten.

[Immersed Games]

Hey there!

While the fox doesn't have any natural predators that prefer to eat it, the Tundra is a rough place and larger predators/carnivores definitely will. You have the Lynx, Arctic Wolf, and even some bears. :)

So the challenge to get things to feel balanced is to get a really good base going first.

If you look at Trophic Levels as an ecological concept, you generally need about 10x more biomass on each lower level.

So:
Plants feed herbivores (need 10x more biomass of plants than herbivores)
Herbivores feed smaller predators (10x more biomass of herbivores than the predators)
Which feed bigger predators (10x more, you know)


We've scaled this back so like 3-5x generally does it since it was way too hard like that, but you get the gist.

If I want to start a good, sustainable biodome, I do nothing but plants and maybe a few herbivores, decomposers, and pollinators. I let that grow out, cover at least a couple zones and start reproducing, before I put in the predators.

You've likely noticed that the large predators can cover pretty much the entire map, so I like to have several zones working well with smaller prey/predators before I add those. The large/apex predators also tend to reproduce more slowly (every 2 years or so), so they make sense to hold down the growth of smaller predators that reproduce more quickly (every year often).


Another note, given the varying reproduction cycles, that's another reason having more biodiversity helps a lot. With an ecosystem with basically every type of plant and animal possible across it, with a lot more herbivores than predators, things are all reproducing at different rates and that helps spread out the eating relationships and growth cycles.

I like to think of it as, "to be balanced, the predators should eat as many prey as are reproducing." Obviously random number generation and if they eat babies vs. adults impacts the reproduction rate, so this isn't going to be perfect, but it's a nice guideline when thinking about predator-prey relationships.

And of course, as you have already noted, there aren't enough limiting factors for the predators bc they will generally succeed in their hunts vs. starving to death, and just kill off all the prey in their area, and then die too, leaving you with just plants, if more prey isn't added. One way to help with this is that because of their territories, one predator territory may not be able to reach the same prey as another territory, so you could potentially place prey in a way that one lives and the other dies. :)

[Leigh]

Thanks for the detailed explanation. I'll keep trying.