Do you mean *Sahara* sands? I've heard that too, but I have no information on how important it is for plant growth in the Amazon, so I was hesitant to mention it.
I'm not too fond of big geological or environmental changes in regards to AH but this one sounds interesting to me. What if there is no Amazon rainforest? The forest is gone but Earth's O2 levels unaffected. Other forests are bigger to make up for it but its spread evenly. At least that's one butterfly I can think of.
Do you mean *Sahara* sands? I've heard that too, but I have no information on how important it is for plant growth in the Amazon, so I was hesitant to mention it.