Rodolfo Dirzo

Stanford Biologist Warns: Early Signs of Earth’s 6th Mass Extinction in Progress ·

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Those who keep taking our biodiversity for granted: dumping corporate waste, spraying copious amounts of herbicides and pesticides, contaminating our water with fluoride, arsenic, and other industrial chemicals while generally ignoring the environment at large, have another thing coming. According to a Stanford biology professor, Rodolfo Dirzo, the earth has begun its 6th mass extinction cycle – and it’s our fault.

More than 3.5 billion years of biodiversity hang in the balance. According to lead author Dirzo, we have reached a tipping point. In a recently published review of scientific literature and an analysis of data published in Science, an international team of scientists cautions that the loss and decline of animals is contributing to what appears to be the beginning of the planet’s sixth mass biological extinction event.

While 320 terrestrial animals have died off since 1500, populations of the remaining animal species show a recurring decline of 25 percent. There is a similar dire prophecy for invertebrate life.

What’s alarming is that previous extinctions were caused by planetary transformation or asteroid strikes, and the current die-off is entirely due to human error.

Humans are Causing the Deaths of Many Species

Professor Dirzo is calling our time an era of “Anthropocene defaunation.” Human ignorance and greed are its causes. According to the study:

“Across vertebrates, 16 to 33 percent of all species are estimated to be globally threatened or endangered. Large animals – described as megafauna and including elephants, rhinoceroses, polar bears and countless other species worldwide – face the highest rate of decline, a trend that matches previous extinction events.

 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.”

What people seem to misunderstand is that while these species represent a fairly small number in representation of all animal life, they inherently represent a failure of our global ecosystem to support life. Their loss imposes a trickle-down affect that would eventually eradicate other species, and possibly even human beings.

For example, when zebras, giraffes, and elephants were removed in a Kenyan landscape, the areas quickly became over-run with rodents. The soil compaction also decreased, and more shrubs and grasses grew, causing the rodent population to increase even further – doubling, in fact, in a  very small time period. This means that the diseases rodents carried, including various parasites, also became more prevalent, posing a threat to human health.

“Where human density is high, you get high rates of defaunation, high incidence of rodents, and thus high levels of pathogens, which increases the risks of disease transmission,” said Dirzo, who is also a senior fellow at the Stanford Woods Institute for the Environment. “Who would have thought that just defaunation would have all these dramatic consequences? But it can be a vicious circle.”

While human populations have doubled in the past 35 years (and our abominable environmental practices along with that), invertebrate species are dying off. This includes spiders, butterflies, worms, and bees.

The scientists observed a 45% decrease in the same period that humans have flourished. Loss of habitat and the defamation of ecosystems was primary in the loss of these animals. Since insects pollinate roughly 75% of the world’s food crops, it is obvious that the loss of further invertebrates would further negatively impact modern civilization.

“We tend to think about extinction as loss of a species from the face of Earth, and that’s very important, but there’s a loss of critical ecosystem functioning in which animals play a central role that we need to pay attention to as well,” Dirzo said. “Ironically, we have long considered that defaunation is a cryptic phenomenon, but I think we will end up with a situation that is non-cryptic because of the increasingly obvious consequences to the planet and to human wellbeing.”

Meanwhile, corporations given personhood are absolved from any responsibility for ruining our planet. Glyphosate is still used, our water is still polluted by corporations as diverse as Walmart, Monsanto, Bayer, Dow, Syngenta, and BP Oil or Exxon, and our governments tend to look the other way while worshipping the almighty dollar. I’d like to see them try to eat a $5 bill when there is nothing green or living left on this planet.

References:

http://news.stanford.edu

http://www.sciencemag.org

https://woods.stanford.edu/ 

http://www.independent.co.uk

Earth is headed for its sixth mass extinction.

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The rapid depletion of Earth’s biodiversity indicates that the planet is in the early stages of its sixth mass extinction of life since becoming habitable 3.5 billion years ago, according to a new study published in Science.

Human activity, including a doubling of its population in the past 35 years, has driven the decline of animal life on Earth, the researchers concluded.

AFP Photo / NASA

There has been a 25 percent average decline rate of remaining terrestrial vertebrates, and a 45 percent decline rate in the abundance of invertebrates. These losses will continue to have innumerable impacts on species that depend on the delicate balance of life on Earth for their own survival.

“We tend to think about extinction as loss of a species from the face of Earth, and that’s very important, but there’s a loss of critical ecosystem functioning in which animals play a central role that we need to pay attention to as well,” said Rodolfo Dirzo, lead author of the study and a biology professor at Stanford University.

“Ironically, we have long considered that defaunation is a cryptic phenomenon, but I think we will end up with a situation that is non-cryptic because of the increasingly obvious consequences to the planet and to human wellbeing.”

The “Anthropocene defaunation,” as some researchers have dubbed this era, is hitting large animals such as elephants, polar bears, and rhinoceroses the hardest, as these megafauna are the subject of some of the highest rates of decline on Earth. This trend matches previous mass die-offs of the Big Five extinction periods.

Megafauna usually have lower population growth rates that need larger habitat areas to maintain their populations, thus they are particularly affected by human growth and desire for their meat mass. Losses among these animals often mean dire impacts for other species that depend on them within an ecosystem.

Past studies have found that the loss of larger animals means a spike in rodents, as grass and shrubs proliferate and soil compaction decreases, all while the risk of predation also declines, Futurity.org notes. As rodent populations increase, so do the disease-transporting ectoparasites that come with them.

“Where human density is high, you get high rates of defaunation, high incidence of rodents, and thus high levels of pathogens, which increases the risks of disease transmission,” said Dirzo.

“Who would have thought that just defaunation would have all these dramatic consequences? But it can be a vicious circle.”

About 16 to 33 percent of all vertebrate species are considered threatened or endangered, the review found.

Invertebrate loss also has far-reaching ripple effects on other species. For example, the continued disappearance of vital honeybee populations across the globe will have bleak consequences for plant pollination, and thus on the world’s food production, as RT has previously reported.

Insects pollinate about 75 percent of the world’s food crops, according to Futurity.

Overall, of the world’s more than 71,000 species, 30 percent of them are threatened, according to the International Union for Conservation of Nature. Based on this assessment – and without drastic economic and political measures to address the current die-off – the sixth mass extinction could be cemented by 2400 A.D., University of California, Berkeley geologist Anthony Barnosky told Harper’s magazine.

Solutions to the die-off are complicated, the study posits, as reducing rates of habitat change and overexploitation of lands must come through regional and situational strategies.

“Prevention of further declines will require us to better understand what species are winning and losing in the fight for survival and from studying the winners, apply what we learn to improve conservation projects,” said Ben Collen, a lecturer at the University College of London and a co-author of the study.“We also need to develop predictive tools for modelling the impact of changes to the ecosystem so we can prioritize conservation efforts, working with governments globally to create supportive policy to reverse the worrying trends we are seeing.”

Researchers from University of California, Santa Barbara; Universidade Estadual Paulista in Brazil; Universidad Nacional Autonoma de Mexico; the Natural Environment Research Council Centre for Ecology and Hydrology in England; and University College London are coauthors of the new study.