But I will add that a commercial grower of venus flytraps once got curious, and took a few thousand cloned plantings, growing them in a variety of conditions. As soon as the soil became nourishing, the plants would die. Post mortem seemed to indicate their roots were fungally attacked.
So: plant adapts to living in a food desert (not an actual one, of course; it has to be wet for the carnivory to work, as the article points out). Plant gains weirdo digestion abilities, but at the same time, it no longer needs expensive anti-fungal defences - because the ground isn't rich enough to support parasitic fungi.
Then: human adds the nutrients back in. Boom! The ordinary fungus in the air, which has a tough time invading grass or tree or tobacco or pepper roots (because they have extensive defences, like capsaicin), lands in the rich soil of pretty-much helpless flytrap roots, and has a buffet.