In the first such global evaluation, Stanford biologists found more than 30 percent of all vertebrates have declining populations. They call for curbs on the basic drivers of these losses. See video here.
No bells tolled when the last Catarina pupfish on Earth died. Newspapers didn’t carry the story when the Christmas Island pipistrelle vanished forever.
Two vertebrate species go extinct every year on average, but few people notice, perhaps because the rate seems relatively slow – not a clear and present threat to the natural systems we depend on. This view overlooks trends of extreme decline in animal populations, which tell a more dire story with cascading consequences, according to a new study that provides the first global evaluation of these population trends.
“This is the case of a biological annihilation occurring globally, even if the species these populations belong to are still present somewhere on Earth,” said co-author Rodolfo Dirzo, a professor of biology.
A 2015 study co-authored by Paul Ehrlich, professor emeritus of biology, and colleagues showed that Earth has entered an era of mass extinction unparalleled since the dinosaurs died out 66 million years ago. The specter of extinction hangs over about 41 percent of all amphibian species and 26 percent of all mammals, according to the International Union for Conservation of Nature (IUCN), which maintains a list of threatened and extinct species. This global disaster scene has the fingerprints of habitat loss, overexploitation, invasive organisms, pollution, toxification and climate change.
The new analysis, published in Proceedings of the National Academy of Sciences, looks beyond species extinctions to provide a clear picture of dwindling populations and ranges. The researchers mapped the ranges of 27,600 species of birds, amphibians, mammals and reptiles – a sample representing nearly half of known terrestrial vertebrate species – and analyzed population losses in a sample of 177 well-studied mammal species between 1990 and 2015.
Using range reduction as a proxy for population loss, the study finds more than 30 percent of vertebrate species are declining in population size and range. Of the 177 mammals for which the researchers had detailed data, all have lost 30 percent or more of their geographic ranges and more than 40 percent have lost more than 80 percent of their ranges. Tropical regions have had the greatest number of decreasing species while temperate regions have seen similar or higher proportions of decreasing species. Particularly hard hit have been the mammals of south and southeast Asia, where all the large-bodied species of mammals analyzed have lost more than 80 percent of their geographic ranges.
The study’s maps suggest that as much as 50 percent of the number of animal individuals that once shared Earth have disappeared, as have billions of animal populations. This amounts to “a massive erosion of the greatest biological diversity in the history of Earth,” the authors write.
“The massive loss of populations and species reflects our lack of empathy to all the wild species that have been our companions since our origins,” said the new study’s lead author, Gerardo Ceballos of the National Autonomous University of Mexico. “It is a prelude to the disappearance of many more species and the decline of natural systems that make civilization possible.”
Why does the loss of populations and biological diversity matter? Aside from being what the scientists call a prelude to species extinction, the losses rob us of crucial ecosystem services such as honeybees’ crop pollination, pest control and wetlands’ water purification. We also lose intricate ecological networks involving animals, plants and microorganisms – leading to less resilient ecosystems and pools of genetic information that may prove vital to species’ survival in a rapidly changing global environment.
“Sadly, our descendants will also have to do without the aesthetic pleasures and sources of imagination provided by our only known living counterparts in the universe,” said Ehrlich.
In the meantime, the overall scope of population losses makes clear the world cannot wait to address biodiversity damage, according to the authors. They call for curbs on the basic drivers of extinction – human overpopulation and overconsumption – and challenge society to move away from “the fiction that perpetual growth can occur on a finite planet.”
The Latest on: Human impact on Earth’s animals
Humans linked to current mass extinction
on June 13, 2018 at 11:18 pm
Equated one year with one centimetre, we've taken a 45,400-kilometre long trip through the Earth's history ... to consider the impact we have had. 25.8 km of our trip. It is a very short component of the history of our planet. Modern humans - homo sapiens ... […]
The First Animals That Could Go Extinct Due to Climate Change
on June 13, 2018 at 7:30 pm
The resulting increase in Earth’s temperature is raising sea levels ... organization that works to preserve wilderness and reduce human impact on the environment. Click here to see list of animals likely to go extinct due to climate change. […]
Human Activity Has Been Chemically Changing the Earth Since Well Before the Industrial Revolution
on June 13, 2018 at 11:00 am
It’s some of the earliest evidence of humans having lasting a environmental impact on planet Earth. “This is a new lens on one ... certain nitrogen isotope associated with crop growing in animal bones from the middle and late Bronze Age, around 2,000 ... […]
How to save Antarctica (and the rest of Earth too)
on June 13, 2018 at 10:11 am
"To avoid the worst impacts, we will need strong international cooperation and effective regulation backed by rigorous science. This will rely on governments recognising that Antarctica is intimately coupled to the rest of the Earth system, and damage ... […]
For good of the planet, humans must show restraint
on June 7, 2018 at 11:13 pm
About half the Earth’s animals are thought to have been lost in the last 50 years. The transformation of the planet by human activity has led scientists to the brink of declaring a new geological era – the Anthropocene. Our impact on the natural world ... […]
Pacific rats trace 2,000 years of human impact on island ecosystems
on June 4, 2018 at 12:13 pm
The Earth has entered a new geological epoch called the Anthropocene, an era in which humans ... profound impacts on island ecosystems. Pacific rats hunted local seabirds and ate the seeds of endemic tree species. Importantly, commensal animals like ... […]
Patricia Randolph's Madravenspeak: Earth's mammals: 96% humans and livestock, just 4% wild
on June 3, 2018 at 2:53 am
Winston Churchill, who predicted humans would stop eating animals by the 1980s ... who led the study of Earth’s biomass, is quoted in The Guardian article as saying, “But our impact on the natural world remains immense, particularly in what we choose ... […]
Megafauna Doomed: Early Humans Drove Biggest Animal Species On Earth To Extinction
on April 20, 2018 at 7:34 am
More than a 100,000 years ago, planet Earth hosted megafauna in big numbers. Animals like wooly mammoths ... could make through time were the smaller ones. "It wasn't until human impacts started becoming a factor that large body sizes made mammals more ... […]
Oldest Evidence of Humans’ Impact on Geological Processes Found in Israel
on June 5, 2017 at 9:45 am
What is being reported as the earliest indication of humans’ impact on the Earth’s geology and ecosystems has been ... “Natural vegetation was replaced by crops, animals were domesticated, grazing reduced the natural plant cover, and deforestation ... […]
We will lose two-thirds of our wild animal populations by 2020 due to human impact on the Earth, new study finds
on October 27, 2016 at 12:14 pm
The study predicts what many environmentalists refer to as a "sixth extinction," or the disappearance of animal populations within our current geological age. The Earth has transitioned ... to intentional policies to human impact on nature," but rather ... […]
via Google News and Bing News