A biome is a biotic area with homogeneous features, characterized by distinctive plants, animal species and climate. A biome will also contain only one set of stone layers, though these usually expand beyond a single biome. Your dwarves will find different resources depending on which biomes you select when starting a fort.
 Selecting a biome
Biomes are important when choosing a fortress location in order to understand your surroundings. Individual biomes, which form at least one map-tile of your embark location, can be cycled with the -keys; for example, an area with 3 biomes present can be cycled using , and . The selected biome will be highlighted with flashing Xs on the Local Map, and the biome's information will be displayed on the right side of the screen.
 Characteristics of biomes
Selecting different biomes gives you some ability to influence the difficulty of your game. Each biome has a different set of resources; the availability of trees, sand, certain plants or animals, and sometimes water is specific to a particular biome, and different biomes may have different stone layers containing flux, coal or useful ores. Mountains have a lot of ore, but no soil.
Generally it is advantageous to plot your embark location at the convergence of multiple different biomes, the more the better (within reason) - which is made easier if you enlarge your starting embarkation area. However, it is not usually too hard to find three or four biomes using the default size.
Note: Making the starting plot larger will slow your game down considerably; likewise, a small embark area can dramatically increase framerate. One embark square translates to 48x48 ingame tiles
By making use of several biomes you can provide more resources for your fort. Making sure one of your biomes contains either a broadleaf or conifer forest will provide you with an ample supply of trees, even if the rest of your plot extends into badlands and desert.
All biomes also have some kind of "alignment" -- good, neutral, or evil -- and a degree of "savagery", which essentially measures how relatively peaceful the biome is. The combination of alignment and savagery is referred to as the biome's surroundings. However, a named region (which is a contiguous area of one category of biomes, such as forests or wetlands) will be either good, neutral, or evil. It is not uncommon to see a large mountain range with one alignment and a few mountains, disconnected from the main mountain range by a single region tile, with a different alignment. Therefore, the more biomes you have, the more likely it is to have combinations of different alignments and savageries, if so desired.
If your plot contains only ocean, lake or mountain biomes you will not be able to embark. The dwarves would have difficulty parking their wagon on water, while mountains are too barren and remote to reach.
 Available Biomes
- Temperate Freshwater Swamp
- Temperate Saltwater Swamp
- Temperate Freshwater Marsh
- Temperate Saltwater Marsh
- Tropical Freshwater Swamp
- Tropical Saltwater Swamp
- Mangrove Swamp
- Tropical Freshwater Marsh
- Tropical Saltwater Marsh
- Temperate Coniferous Forest
- Temperate Broadleaf Forest
- Tropical Coniferous Forest
- Tropical Dry Broadleaf Forest
- Tropical Moist Broadleaf Forest
- Temperate Grassland
- Temperate Savanna
- Temperate Shrubland
- Tropical Grassland
- Tropical Savanna
- Tropical Shrubland
- Tropical Ocean
- Temperate Ocean
- Arctic Ocean
- Temperate Freshwater Pool
- Temperate Brackish Pool
- Temperate Saltwater Pool
- Tropical Freshwater Pool
- Tropical Brackish Pool
- Tropical Saltwater Pool
- Temperate Freshwater Lake
- Temperate Brackish Lake
- Temperate Saltwater Lake
- Tropical Freshwater Lake
- Tropical Brackish Lake
- Tropical Saltwater Lake
- Temperate Freshwater River
- Temperate Brackish River
- Temperate Saltwater River
- Tropical Freshwater River
- Tropical Brackish River
- Tropical Saltwater River
- Subterranean Water
- Subterranean Chasm
- Subterranean Magma
Certain creatures and plants use special biome tokens to encompass several similar environments.
- "Not Freezing" includes all land biomes excluding mountains, glaciers, and tundras.
- "Any Temperate Broadleaf" includes temperate broadleaf forests as well as grasslands, savannas, shrublands, swamps, and marshes.
- "Any Tropical Broadleaf" includes tropical dry/moist broadleaf forests as well as grasslands, savannas, shrublands, swamps (including Mangrove), and marshes.
More information can be found in the Biome token list.
 Generating a Biome
When using advanced world generation to attempt to create the "perfect" starting location, it helps to understand how biomes are created. A region's biome is a factor of elevation, drainage, rainfall, and temperature, as explained in this old forum thread for 40d.
Elevation comes first. Any terrain with an elevation of 0-99 is ocean. Any terrain with an elevation of 300-400 is mountain terrain. All other biomes lie in between these two extremes.
Drainage and rainfall determine the next division.
Finally, temperature. Glaciers seem to form at a temperature of around 0. Just above that temperature, forests become taiga, and all other terrain becomes tundra. Unfortunately, temperature is harder to affect directly in world gen because according to Toady One, it's affected by both latitude and elevation. At the other end of the temperature scale, biomes become tropical at around 65+; generally speaking you'll need Hot and Scorching temperatures.
|World Generation (Basic/Advanced) - Regions - Climate - Surroundings - Map legend|
|Civilizations - Sites ( Cave - Town - Fortress - Ruin ) - Calendar|
|Aquifer - Brook - Island - Tunnel - Volcano - Waterfall|
|Biomes|| Chasm/Caverns - Desert - Forest - Glacier - Grassland - Lake - Mountain|
Murky pool - Ocean - River - Savanna - Shrubland - Tundra - Wetland