#LIVING EARTH WEST KNOXVILLE HOW TO#
Though the numbers may be controversial, since people disagree about how to assign such values, even Wall Street has to admit that nature does a lot of the heavy lifting for us. The Living Planet Report pegs the value of ecosystem services at $125 trillion, just a few trillion shy of the world’s total GDP. Photograph by Joel Sartore, National Geographic Photo Ark Ecosystem servicesįor decades, economists and ecologists have wrestled with how to quantify the value of ecosystem services-the goods and services that nature provides, from bee-assisted crop pollination to water filtration courtesy of mollusks. Local extinction in rural Idaho could mean the loss of only four animals, but since each distinct population makes the species more resilient, it’s still important information for biologists to capture.Ī rare Santa Catalina Island fox, Urocyon littoralis catalinae, at Catalina Island Conservancy. It means that some gray wolf packs have suffered horrific losses, perhaps even local extinction, while others have declined less sharply-but remember, packs aren’t all the same size. That doesn’t mean we’ve lost 60 percent of, say, all individual gray wolves. Or take the example of a single species: Imagine gray wolf populations are declining by an average of 60 percent.
That’s a 60 percent average decline of these three fictitious populations, but only a total decline of 12 percent of the individuals.
And the squirrels drop to 9,000-a 10 percent fall. The second declines 80 percent, to 40 falcons. Let’s say the first population declines by 90 percent, to 5 tigers. Let’s say for example you have 50 tigers, 200 falcons, and 10,000 squirrels. But that’s not the same as saying that we’ve wiped out 60 percent of all animals, which the report makes clear. Stated another way, the report found that populations of vertebrates (animals with backbones) declined by 60 percent on average. But the average represented by the LPI speaks to a catastrophic global trend. Some populations in the study lost far more than 60 percent of their individuals, and some lost far fewer. But a few thousand fewer pygmy shrews is pretty trivial it could be chalked up to a rounding error. The LPI takes into account the fact that one less rhino is, for its overall population, a very big deal. It's not a census in which a Eurasian pygmy shrew-of which there are plenty-would be given equal weight to a critically endangered Sumatran rhinoceros. The Living Planet Index (LPI) combines data on thousands of species with very different lifestyles and very different conservation statuses. The Living Planet Index has taken a sudden nosedive-it’s down 60 percent since 1970, the blink of an eye in evolutionary time. If the global score is steady or increasing, animals are generally thriving, while a falling score indicates a planet-wide problem. The biannual report examined trends in the global Living Planet Index, a biologist’s “stock market index” for the diversity and abundance of animals worldwide. The reality is more nuanced, though still alarming. But it was widely misinterpreted by many outlets, with headlines wrongly insisting that we’ve lost 60 percent of all animals over the course of 40 years. The World Wildlife Fund For Nature’s Living Planet Report released this week describes a catastrophic decline in animal populations the world over.
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