Biodiversity increases the consumptive value of land, meaning that

ecosystems with low biodiversity consume resources at a higher rate than those with higher biodiversity.
land with lower biodiversity has many more possible uses for humans than land with higher biodiversity.
land that has been cleared for agriculture consumes natural resources at a slower rate and is cheaper to maintain.
ecosystems with higher biodiversity consume more resources than those with lower biodiversity, creating more strain on the environment.
more value can be derived from the more diverse products produced by ecosystems with high biodiversity relative to land that has been cleared for agriculture.