‘Sixth extinction’ of wildlife faster than feared
The sixth mass extinction of life on Earth is developing faster than previously feared, scientists warned.
Over 30% of animals with a backbone – fish, birds, amphibians, reptiles and mammals – are declining in both the range and population, according to the first comprehensive analysis of these trends.
“This is the case of a biological annihilation occurring globally,” said Stanford professor Rodolfo Dirzo, a co-author of a study published Monday in the US journal Proceedings of the National Academy of Sciences.
About a decade ago, experts feared a new planetary extinction of species would be in sight.
Today, most agree that it is under way, but the new study suggests that death is already increasing.
It provides much needed data on the threat to wildlife, mapping the decline in ranges and populations of 27,600 species. For 177 mammals, the researchers collected data covering the period 1900-2015.
The mammal species that were monitored have lost at least a third of their original habitat, the researchers found.
Forty percent of them – including rhinoceros, orangutans, gorillas and many large cats – survive on 20% or less of the land they once wandered.
Biodiversity loss has accelerated recently.
“Several species of mammals that were relatively safe one or two decades ago are now in danger,” including cheetahs, lions and giraffes, the study showed.
Around the world, mass death, considered the sixth in the last 500 million years, is the worst since three-quarters of life on Earth, including non-avian dinosaurs, was annihilated 66 million years ago By a giant Impact of meteors.
On average, two species of vertebrates disappear each year.
Tropical regions have recorded the highest number of declining species. In South and Southeast Asia, large-bodied mammal species have lost more than four-fifths of their historical ranks.
Loss of habitat
While fewer species are disappearing in temperate zones, the percentage is as high or higher.
Up to half the number of animals that once shared our planet are no longer here, a loss that the authors described as “a massive erosion of the greatest biological diversity in Earth’s history.”
There is no mystery as to why: our own constantly expanding species – which has more than doubled in number since 1960 to 7.4 million – is eating, crowding and polluting its planetary peers of existence.
By comparison, only 20,000 lions remain, less than 7,000 cheetahs, 500-1,000 giant pandas and about 250 rhinos in Sumatra.
The main causes of declining wildlife are loss of habitat, over consumption, pollution, invasive species, disease, and poaching in the case of tigers, elephants, rhinos and other large animals appreciated for their body parts.
Climate change is poised to become a major threat in the coming decades, with some animals – the most famous polar bears – already declining due to rising temperatures and changing weather patterns.
“The massive loss of populations and species reflects our lack of empathy with all the wild species that have been our partners since our origins,” said lead author Gerardo Ceballos of the National Autonomous University of Mexico.