What are the factors responsible for depletion of wildlife?

Question

What are the factors responsible for depletion of wildlife?

Answer 1

Number one is habitat loss, this is everything from rain-forest destruction to urban sprawl.

Number two is toxic consumerism, and this is everything from Ag chemicals that produce conventional food and the mis/overuse by zealous homeowners wanting that perfect lawn, but also that c**p that is under your kitchen sink all help poison ecosystems.

Number three is over exploitation, everything from the useless fur trade to over finishing.

Answer 2

I say there is only one factor. The increasing human population. There is not room enough on the planet any more for all the people and all the animals too.

Answer 3

The factors most responsible for biodiversity loss change over time and vary from one place to another.  For much of human history, and well into the twentieth century, one of the leading causes of wildlife depletion was direct exploitation for human use or consumption.  This is the factor that brought many species of great whales, big cats and crocodilians to the brink of extinction in the 1960s and 1970s, and it remains the most significant factor in the depletion of commercially-harvested fish species--from cod to tuna to swordfish to sharks.  Since the worst excesses of international wildlife trade were brought under control in the 1970s, the two biggest drivers of biodiversity loss have been habitat loss (which is actually a whole suite of problems rolled into one, ranging from illegal logging in tropical forests to coastal development in the US) and invasive species.  As the world continues to warm, however, global warming is certain to supplant habitat loss as the leading driver of species loss, if it hasn't already.  In its most recent assessment of climate change impacts, the nobel-winning Intergovernmental Panel on Climate Change estimated that up to 30% of all species could vanish in the coming decades as a result of global warming.

Answer 4

People, People and people.

Answer 5

Whenever environmental pressures increase, biodiversity decreases.  This is because some species are dying (going extinct), and others hybridize in an attempt to broaden their gene pool and have a greater chance at surviving the stressing event.  For example, the finches in the book "the beak of the finch."  

Humans are a big environmental stressor for many species right now.  The good news is, when the pressure decreases biodiversity will once again increase.