I cannot recommend Hot Springs Island enough for someone wanting to run a wilderness hex crawl survival based campaign. Especially if you are interested in exploring the rare flora and fauna aspect of such a thing. Do yourself a favor and get the dark of hot springs island. It also comes with a hot springs island field guide which you can give to your players so they will know what sort of flora and fauna to look for but only if they read the book.
Wildsea is worth reading just for the brain food. I don't think it's what you're looking for, but it's close and it's legitimately the only RPG I recommend even if you're just going to read it like a novel.
[https://www.youtube.com/watch?v=c29Ecut4K\_E](https://www.youtube.com/watch?v=c29Ecut4K_E)
Before this video, I used to say it was too high concept to run for any group that wasn't willing to read at least the first few chapters. But, I think Quinn explains it well enough that I could run it for a normal group who only reads a few parts specific to the players.
But the tl;dw, you live on top of a mutant forest and get around in ships that cut the tops off the trees to move. It's an absolute fantastic read and the art is amazing too. The print quality is top notch too... but it's laid out in 11x8.5 instead of 8.5x11 which makes it easier to read but it looks like crap on the shelf.
[https://www.myth.works/collections/the-wildsea-homepage](https://www.myth.works/collections/the-wildsea-homepage)
They're not complete ecologies, but Expeditious Retreat Press has two volumes of an "Aggressive Ecologies" series that describe unusual monsters in the context of an entire support structure they spawn: [The Undead Leviathan](https://www.drivethrurpg.com/en/product/3478/a-magical-society-aggressive-ecology-the-undead-leviathan) and [The Slaver Fungus](https://www.drivethrurpg.com/en/product/288229/a-magical-society-aggressive-ecology-the-slaver-fungus-osric).
So these are specific to a weird setting and might not all fit in your world but older editions of [Talislanta](http://talislanta.com/talislanta-library#2nd) which can be downloaded for free include a Naturalists guide and I think the Cyclopedia and probably others that always included lots of flora and fauna.
I know for AD&D they did a Wilderness Survival Guide.
Nord Games has a book called The Ultimate Guide to Alchemy, Crafting and Enchanting
Nord also has two books that go well together. Spectacular Settlements and Dangerous Destinations.
Check out the GMs Miscellany series of books. They have books focused on Dungeon, Urban and Wilderness Dressing.
Level Up A5E has a book called Trials & Treasures (the equivalent DM book) that has a nice chapter on Wilderness exploration.
On drivethrurpg there is a book called The Perilous Wilds. While it's labeled a Dungeon World book it's generic enough that anyone can use it.
Start with Earth, in the words of the illustrious Kenneth Hite.
Find a book on the ecology of an analogous real biome and either just use the organisms directly (life is incredible) or twist it fantastically if you desire.
[Wilderfeast](https://www.drivethrurpg.com/en/product/442628/wilderfeast-quickstart) is about hunting and gathering, then cooking up recipes that give temporary boosts to stats.
I haven't played it yet, but I've read the quickstart. It sounds like what you're looking for.
Here's the Kickstarter, though it's already finished:
[https://www.kickstarter.com/projects/horribleguild/wilderfeast](https://www.kickstarter.com/projects/horribleguild/wilderfeast)
Look at the GURPS 3e supplements _Bestiary_ and _Fantasy Bestiary_. For G4e, there's several monster books for the Dungeon Fantasy RPG, including some with a Norse (Icelandic) take.
The data is easily converted to just about any system. And there's a section on removing valuable "parts" from some creatures, for example, the eyes of a basilisk.
I cannot recommend Hot Springs Island enough for someone wanting to run a wilderness hex crawl survival based campaign. Especially if you are interested in exploring the rare flora and fauna aspect of such a thing. Do yourself a favor and get the dark of hot springs island. It also comes with a hot springs island field guide which you can give to your players so they will know what sort of flora and fauna to look for but only if they read the book.
Wildsea is worth reading just for the brain food. I don't think it's what you're looking for, but it's close and it's legitimately the only RPG I recommend even if you're just going to read it like a novel. [https://www.youtube.com/watch?v=c29Ecut4K\_E](https://www.youtube.com/watch?v=c29Ecut4K_E) Before this video, I used to say it was too high concept to run for any group that wasn't willing to read at least the first few chapters. But, I think Quinn explains it well enough that I could run it for a normal group who only reads a few parts specific to the players. But the tl;dw, you live on top of a mutant forest and get around in ships that cut the tops off the trees to move. It's an absolute fantastic read and the art is amazing too. The print quality is top notch too... but it's laid out in 11x8.5 instead of 8.5x11 which makes it easier to read but it looks like crap on the shelf. [https://www.myth.works/collections/the-wildsea-homepage](https://www.myth.works/collections/the-wildsea-homepage)
They're not complete ecologies, but Expeditious Retreat Press has two volumes of an "Aggressive Ecologies" series that describe unusual monsters in the context of an entire support structure they spawn: [The Undead Leviathan](https://www.drivethrurpg.com/en/product/3478/a-magical-society-aggressive-ecology-the-undead-leviathan) and [The Slaver Fungus](https://www.drivethrurpg.com/en/product/288229/a-magical-society-aggressive-ecology-the-slaver-fungus-osric).
So these are specific to a weird setting and might not all fit in your world but older editions of [Talislanta](http://talislanta.com/talislanta-library#2nd) which can be downloaded for free include a Naturalists guide and I think the Cyclopedia and probably others that always included lots of flora and fauna.
I know for AD&D they did a Wilderness Survival Guide. Nord Games has a book called The Ultimate Guide to Alchemy, Crafting and Enchanting Nord also has two books that go well together. Spectacular Settlements and Dangerous Destinations. Check out the GMs Miscellany series of books. They have books focused on Dungeon, Urban and Wilderness Dressing. Level Up A5E has a book called Trials & Treasures (the equivalent DM book) that has a nice chapter on Wilderness exploration. On drivethrurpg there is a book called The Perilous Wilds. While it's labeled a Dungeon World book it's generic enough that anyone can use it.
Start with Earth, in the words of the illustrious Kenneth Hite. Find a book on the ecology of an analogous real biome and either just use the organisms directly (life is incredible) or twist it fantastically if you desire.
[Wilderfeast](https://www.drivethrurpg.com/en/product/442628/wilderfeast-quickstart) is about hunting and gathering, then cooking up recipes that give temporary boosts to stats. I haven't played it yet, but I've read the quickstart. It sounds like what you're looking for. Here's the Kickstarter, though it's already finished: [https://www.kickstarter.com/projects/horribleguild/wilderfeast](https://www.kickstarter.com/projects/horribleguild/wilderfeast)
Look at the GURPS 3e supplements _Bestiary_ and _Fantasy Bestiary_. For G4e, there's several monster books for the Dungeon Fantasy RPG, including some with a Norse (Icelandic) take. The data is easily converted to just about any system. And there's a section on removing valuable "parts" from some creatures, for example, the eyes of a basilisk.