Even in a single nation, geography can vary wildly. Unless this is the Pokemon equivalent to the Balkan Peninsula, you most likely won't have nearly-identical biomes throughout the country. Considering how these cultures worship specific Legendary Pokemon and said Legendaries seemingly refuse to be anywhere [i]near[/i] a biome not tailored specifically [s]for[/s] by it.

 I'd say if the Pokemon they're worshiping has stuck around the area long enough to [i]be[/i] worshipped, its habitat is fairly specialized. By extension, the surrounding area would be equally-specialized. Beyond that, religion definitely shapes the way a culture works. Just take a look at the difference between Protestantism and Roman Catholicism!