What evidence do scientists offer to support their idea that the african elephants are two different species?

to this answer it would be edge enhancement

yes. we have only a limited amount of land and space, and every plant is adapted to its own environment. through gene manipulation, we could perhaps create plants that can grow in a wide variety of environments, grow taller or wider, or be more resistant to diseases.

(this is the exact answer provided by the system)

the principle of competitive exclusion basically relates when two species cannot continue in the same niche habitat, one will be outcompeted and will be better modified to the habitat. the principle could never be functional when the species fluctuate in their competitive capabilities.