‘Sixth extinction’ of wildlife faster than feared
The sixth mass extinction of life on earth is occurring faster than scientists have warned fear.
More than 30% of animals with vertebral column – fish, birds, amphibians, reptiles and mammals – decrease both in variety and population, according to the first comprehensive analysis of these trends.
“This is the case of a biological annihilation occurring all over the world,” said Stanford professor Rodolfo Dirzo, co-author of a study published Monday in the US journal Proceedings of the National Academy of Sciences (PNAS) .
There are about a decade, experts fear that a further global deceleration of the species has been threatened.
Today, most agree that it is ongoing – but the new study suggests that the course is already stuck.
It provides the long-awaited data on the threat to wildlife, mapping of the lower areas and populations of 27,600 species. For 177 mammals, the researchers painted data for the period 1900-2015.
Mammals under supervision have lost a third of their original habitat, the researchers showed.
Forty percent of them – including rhinoceroses, orangutans, gorillas and many large cats – survive 20% or less of the land they have traveled before.
Biodiversity loss has accelerated recently.
“Several species of mammals were relatively safe there one or two decades are now in danger of extinction,” including the cheetahs, lions and giraffes, the study showed.
Globally, massive deaths – considered the sixth in the last five billion years – is the worst since three quarters of life on Earth, including non-avian dinosaurs were exterminated out there 66 millions of years ago by The impact of a giant meteorite.
Tropical regions experienced the highest number of declining species. In southern and southeastern Asia, large mammal species have lost more than four-fifths of their historical ranges.
While fewer species disappear in temperate zones, the percentage is as high or higher.
Up to half the number of animals that have shared our planet are no longer here, a loss that the authors describe as “a massive erosion of the greatest biological diversity in the history of the earth.”
There is no mystery as to why: our own species of growth – which has more than doubled in number from 1960 to 7400000000 – to eat, obstruct and pollute their planetary cohabitants of existence.
In comparison, there are less than 20,000 lions in the wild, less than 7,000 cheetahs, 500,000 giant pandas and approximately 250 Sumatran rhinos.
The main factors behind the decline of wildlife are habitat loss, over consumption, pollution, invasive species, disease and poaching in the case of tigers, elephants, rhinoceroses and other large animals. Its parts of the body.
It is expected that climate change to become a major threat in the coming decades, some animals – polar bears more – are already in decline due to rising temperatures and changing climatic conditions.
“The massive loss of populations and species reflects our lack of empathy for all wildlife species that have been our partners and our origins,” said lead author Gerardo Ceballos of the National Autonomous University of Mexico.
Beyond any moral imperative, there are practical reasons to disconcert the eclipse of animals, whether a megafauna or less charismatic creatures, the researchers warned.
The disappearance of a carnivore or a high herbivore level can have a cascade effect on the food chain, disrupting entire ecosystems.
Other species directly provide the “services” to humans, such as bees bee pollinating crops and birds that provide pest control.
Previous studies show that ecosystems subjected to stress, while lasting, have a breaking point – a rapid change can cause a collapse.