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The Longer We Live, the More Species We Doom to Extinction

The Longer We Live, the More Species We Doom to Extinction

People are living longer these days. That’s good, right? For us, yes. For species at risk, not so much.

That’s the conclusion of a new study by biologists from the University of California, Davis. Advances in medicine and science now allow humans to live longer than ever before. Unfortunately, human longevity has a direct and decidedly negative effect on endangered and invasive species.

The UC Davis team looked at 15 social, economic and ecological variables to determine their correlation with invasive and endangered species. Although human longevity hasn’t typically been a factor in studies about human impact to the environment, it turns out to be “the key predictor of global invasions and extinctions.”

“It’s not a random pattern,” said the study’s lead author, Aaron Lotz. “Out of all this data, that one factor — human life expectancy — was the determining factor for endangered and invasive birds and mammals.”

The study reviewed data from from 100 countries, spanning 74 percent of the total land area of the earth. This data represented 87 percent of the world’s total population and 43 percent of the world’s gross domestic product (GDP). Biologists focused on the following factors:

  • Per capita GDP
  • Export-import ratio
  • Tourism
  • Life expectancy
  • Adult literacy
  • Pesticide regulation
  • Political stability
  • Female participation in national government
  • Undernourishment
  • Energy efficiency
  • Agricultural intensity
  • Rainfall
  • Water stress
  • Wilderness protection
  • Biodiversity

The results showed in no uncertain terms that the places where people lead the longest lives are also the places with the most endangered and invasive species.

Where is this effect most clearly demonstrated? In New Zealand, which has the highest percentage of endangered animals and birds, the largest number of invasive species, and one of the highest life expectancies of any place in the world.

Conversely, African countries represent 23 of the top 25 countries with the fewest invasive and endangered mammals and birds. They have a closed trade policy and don’t engage in international trade to the extent the rest of the world does. These facts limit the ability of invasive species to hitch a ride into this area and claim a foothold.

The study revealed some interesting facts:

  • As the affluence of a country increased, as measured by the GDP per capita, so did the percentage of invasive mammals and birds in that location.
  • As biodiversity and land area of a country increased, so did the percentage of endangered birds.
  • 25 countries did not have any reported invasive bird species; 13 of those countries did not have invasive mammals either.
  • Sweden, Finland, Trinidad and Tobago, Switzerland and Nicaragua had the smallest percentages of endangered mammals.
  • Cuba, the Dominican Republic, Sri Lanka and India had the highest percentages of endangered mammals.
  • Ireland, Togo, the United Kingdom, Guinea-Bissau and Norway had the smallest percentages of endangered birds.
  • New Zealand, the Philippines, the United States, Indonesia and Japan had the highest percentages of endangered birds.
  • The percentage of invasive and endangered birds and mammals within a country was best predicted by a model that included only life expectancy.

The study concluded that increased life expectancy “means that people live longer and affect the planet longer; each year is another year of carbon footprint, ecological footprint, use of natural resources, etc. The magnitude of this impact is increased as more people live longer.”

“Some studies have this view that there’s wildlife and then there’s us. But we’re part of the ecosystem,” said Lotz. “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.”

Yet again, there’s evidence that humans are the problem. We need to start coming up with ways to be the solution.

Related Stories:

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20 Animals You Didnt Know Are Going Extinct

10 Animals We Thought Were Extinct But Arent

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3:47AM PDT on Jun 22, 2014

interesting article, thanks for sharing

8:06AM PST on Nov 5, 2013

People really destroy everything. We are the ones who should be extinct.

4:35AM PDT on Oct 28, 2013

The current population increase in the human race is unsustainable. How much money is wasted on treating infertility? Yes, infertility is a personal tragedy (my ex and I were told we would never have children - so we stopped after two) but over-population is a global catastrophe. It is not people over-populating the developing countries: their impact on the world is negligible compared to that of our bloated, consumerist lifestyles in the west. The biggest problem in Africa is the unstable nature of the various societies (a western Imperialist legacy) and our willingness to exploit that to destroy forest in the search for minerals, gems and rare metals. Deforestation is driven by our willingness to buy goods with exotic tropical hardwoods, to buy products with palm oil, to use bio-fuels instead of truly sustainable alternative energy sources.
Lifting people out of poverty reduces their need to breed: but Capitalism and globalisation doesn't deliver that: what it delivers is suppressed wages by shifting work to the cheapest, most easily exploited economies leaving increased poverty and societal imbalance in its wake. The UK, a relatively rich country, has the biggest societal imbalance in incomes that it has had since the second world war and our birth rate has just started to increase after decades of falling - and it is not just amongst immigrant families as our home grown racists would argue: it is across the income scale.

4:30AM PDT on Oct 28, 2013

The human species it self is heading straight for extinction for every lifeform it get`s rid off. We can not live without the nature that feeds us, and every singel lifeform in it has a purpose!

3:59AM PDT on Oct 28, 2013

Well said Bev W. The truth of the matter is that humans ARE parasites sucking the earth dry of all other life be it plant or animal. One day, not too far off from now, there'll be nothing left to take .......

6:11PM PDT on Oct 27, 2013

Clara H. Humans are the root of all evil and they will one day suffer for there atrocities they have committed against their own species as well as innocent animals worldwide. And if I guilt trip humans for being human so be it.

9:30PM PDT on Oct 26, 2013

They complain about the foxes in our towns and cities but it is us humans who have built all over their home ,their domain.

12:26PM PDT on Oct 26, 2013

The human species is heading straight for extinction. We are self destructing at an alarming rate and like lemmings we are going over the cliff.

8:05AM PDT on Oct 26, 2013

The real problems lies with the humans killing animals to the point of extinction. If all humans were living in harmony with animals, how many of these animals would still be alive today?

4:42AM PDT on Oct 26, 2013

Can the two be positively related instead?

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