The Kolyma River Basin is a river basin ecosystem, featuring mountain and lowland tundra interspersed with forested river valleys. The major biodiversity values of the area include a high diversity of valuable freshwater fish species (mainly whitefish), habitat and nesting ground of numerous waterfowl, including rare and endangered species, and unique relic larch forests. Threats to the ecosystem come from illegal logging of old-growth valley forests, wildlife poaching, and local habitat destruction from gold-mining.