Hii!
Habitat destruction is the most significant threat to biodiversity, because it can wipe out an entire population and then, in turn the ecological chain related to that species and dependent on it.
Habitat destruction can lead to death of a large number of species residing in that area, it can eradicate the endemic species, it can result in reduction of gene pool and genetic diversity, in turn production of infertile individuals, inbreeding depression, generation of a  completely different species, not suitable for ecosystem etc.,
Ultimately, the whole global biodiversity can be disturbed.
Hope this helps.
Good luck!