The biome that is most at risk due to over-harvest of organisms might be the

Marine biome.  
The marine biome is the greatest biome on the planet as they and cover an extends that can be estimated to be around 70% of the earth. It incorporates five fundamental seas: the Pacific, Atlantic, Indian, Arctic, and Southern, and numerous littler Gulfs and Bays. Marine areas are generally exceptionally salty

Fungi is were it belongs