Increased human life expectancy correlates to increase in species extinction

The introduction of the eastern gray squirrel from North America is blamed for devastating the red squirrel population in the UK.

Sergey Yeliseev

A study published by a team of biologists suggests that as a nation's population life expectancy increases, so does its percentage of invasive and endangered birds and mammals. It suggests that rather than population density alone being the largest threat to wildlife, it's the quality of life that matters most.

The very presence of humans is often blamed for the increasing numbers of extinct species on the planet. But a team of biologists from the University of California-Davis examined 15 economic, ecological, and social variables to judge which factors of that human presence are the biggest contributors to the downfall of species.

Expanding the survey to include the number of invasive species in a country revealed even more interesting results. Introducing a non-indigenous species to any given ecosystem can have devastating effects. Controlling the number of invasive species was identified as the greatest challenge threatening the Galapagos when the World Heritage Committee placed it on its danger list, for instance, and in the UK the introduction of the eastern gray squirrel from North America is blamed for devastating the red squirrel population, now down to under 200,000. What the report found, however, is that a combination of economic and social factors is responsible for this devastation—just as, in reality, deforestation and other factors have contributed to the fall of the red squirrel.