The increasing human life expectancy may be good news for homo sapiens, but not so much for every other species on the planet.
A new study found that as human lives get longer, the percentage of "invasive and endangered species" grows as well, a University of California, Davis press release reported.
The study looked at 100 countries which contained about 87 percent of the world population.
Researchers factored in 15 different social and ecological variables including tourism and water stress to make their conclusion.
The team looked at how specific human activities affected the percentage of invasive and endangered birds and mammals. Some of the other factors the researchers took into account included: "agricultural intensity, rainfall, pesticide regulation, energy efficiency, wilderness protection, latitude, export-import ratio, undernourishment, adult literacy, female participation in government, and total population."
The researchers included a factor in their study that is not typically associated with what conservationist Aldo Leopold called "land sickness." That factor was human life expectancy, and it turned out to be the "key predictor of global invasions and extinctions," the press release reported.
"It's not a random pattern," lead author Aaron Lotz, a postdoctoral scholar in the Department of Wildlife, Fish and Conservation Biology which hosted the study, said. "Out of all this data, that one factor - human life expectancy - was the determining factor for endangered and invasive birds and mammals."
The team found the U.S., New Zealand, and the Philippines were at the top of the list of countries with the most endangered and invasive birds.
New Zealand was also found to have the highest rate of invasive and endangered species overall, although it has a low rate of "native terrestrial land mammals." African countries were found to have the lowest percentage of endangered and invasive species, this could be partially due to the low rate of international trade in the region.
"Some studies have this view that there's wildlife and then there's us," Lotz said. "But we're part of the ecosystem. We need to start relating humans to the environment in our research and not leave them out of the equation. We need to realize we have a direct link to nature."
