Q. Despite having a great biodiversity why is the Amazon Rainforest under risk of desertification?

The natural soil of the Amazon Rainforest isn't very fertile but it is enriched by the vegetal covering made of branches and leaves that fall from the trees. Deforestation decreases this enrichment. In the deforestation zones the rain falls directly on the ground causing erosion, "washing" large areas (leaching) and contributing to make the soil even less fertile. As well that, the deforestation disallows the recycling of essential nutrients for plants, like nitrogen. In this way those regions and their neighboring regions undergo desertification.