An international team of scientists cautions that the loss and decline of animals is contributing to what appears to be the early days of the planet’s sixth mass biological extinction event.
Since 1500, more than 320 terrestrial vertebrates have become extinct. Populations of the remaining species show a 25 percent average decline in abundance. The situation is similarly dire for invertebrate animal life.
And while previous extinctions have been driven by natural planetary transformations or catastrophic asteroid strikes, the current die-off can be associated to human activity, say the researchers.
Across vertebrates – animals with backbones – 16 to 33 percent of all species are estimated to be globally threatened or endangered. Large animals – including elephants, rhinoceroses, polar bears and countless other species worldwide – face the highest rate of decline.
Larger animals tend to have lower population growth rates and produce fewer offspring. They need larger habitat areas to maintain viable populations. Their size and meat mass make them easier and more attractive hunting targets for humans.
Invertebrates are in trouble as well, say the scientists. Human population has doubled in the past 35 years. In the same period, the number of invertebrate animals – such as beetles, butterflies, spiders and worms – has decreased by 45 percent.
As with larger animals, the loss is driven primarily by loss of habitat and global climate disruption.
The research is published in the journal Science.
Eleanor Imster has helped write and edit EarthSky since 1995. She was an integral part of the award-winning EarthSky radio series almost since it began until it ended in 2013. Today, as Lead Editor at EarthSky.org, she helps present the science and nature stories and photos you enjoy. She also serves as one of the voices of EarthSky on social media platforms including Facebook, Twitter and G+. She and her husband live in Tennessee and have two grown sons.