What is the major cause of diminishing wildlife number?

Explanation

Wildlife refers to all living organisms (terrestrial, aquatic and aerial) living in all possible natural habitats of their own, other than the cultivated plants and domesticated animals. Thus "wildlife" does not exist only in jungles and are hunted down but wildlife includes even the migrating birds, turtles, coral reefs, microorganisms, insects, fishes, etc. Several hundred organisms are endangered or on the verge of extinction. The reasons are deforestation, pollution, killing, over exploitation etc. The destruction and fragmentation of natural habitats due to urbanization, agriculture, deforestation, and infrastructure development are major factors affecting wildlife. As humans expand their activities, they encroach on and alter the natural environments that wildlife depend on.