Which conditions are possible reasons for declining genetic diversity of a species? loss of habitat

Loss of habitat results in reduced genetic diversity.

Explanation:

Loss of habitat due to any natural or man-made reason leaves the animal species to shelter less and makes them more prone to extinction due to lack of space, food and other required factors for survival.  

Deforestation is one of the causes of loss of habitat which removes a large number of trees at once. All the inhabitant species face the danger of extinction due to lack of resources.