Historic genus extinction intensity and modern predictions for marine molluscs and vertebrates. Extinction intensity has generally not exceeded 10 percent for either molluscs or vertebrates since the end-Cretaceous extinction. The proportion of modern genera with near-threatened species exceeds background extinction rates in most data treatments. Upper estimates approach the magnitude of the end-Cretaceous mass extinction. For future predictions, closed symbols indicate results from a pessimistic scenario based only on genera containing IUCN-assessed species; open symbols indicate results from an optimistic scenario in which genera lacking assessed species were included and assumed to be nonthreatened. Both scenarios include only living genera with fossil records to maximize comparability with extinction intensity for ancient events. Graphic: Payne, et al., 2016 / Science

By Ker Than
14 September 2016

(Stanford University) – An unprecedented pattern of extinction in the oceans today that selectively targets large-bodied animals over smaller creatures is likely driven by human fishing, according to a new Stanford-led study.

“We’ve found that extinction threat in the modern oceans is very strongly associated with larger body size,” said Jonathan Payne, a paleobiologist at Stanford’s School of Earth, Energy & Environmental Sciences. “This is most likely due to people targeting larger species for consumption first.”

In a new study, to be published in the Sept. 16 issue of the journal Science, Payne and his colleagues examined the association between extinction threat level and ecological traits such as body size for two major groups of marine animals – mollusks and vertebrates – over the past 500 years and compared it with the ancient past, stretching as far back as 445 million years ago and with a particular emphasis on the most recent 66 million years.

“We used the fossil record to show, in a concrete, convincing way, that what is happening in the modern oceans is really different from what has happened in the past,” said study co-author Noel Heim, a postdoctoral researcher in Payne’s lab.

Specifically, the authors found that the modern era is unique in the extent to which creatures with larger body sizes are being preferentially targeted for extinction. “What our analysis shows is that for every factor of 10 increase in body mass, the odds of being threatened by extinction go up by a factor of 13 or so,” Payne said. “The bigger you are, the more likely you are to be facing extinction.”

The selective extinction of large-bodied animals could have serious consequences for the health of marine ecosystems, the scientists say, because they tend to be at the tops of food webs and their movements through the water column and the seafloor help cycle nutrients through the oceans.

Judy Skog, program director in the National Science Foundation’s Division of Earth Sciences, which funded the research, said the findings should be incorporated into decisions about how we manage ocean resources like fisheries. “These results show that larger marine animals are poised to disappear from the seas faster than smaller ones,” Skog said. “Studies of the fossil record indicate that this trend didn’t exist in the past – it’s a new development in today’s world.”

While Payne and his colleagues did not directly examine why large modern marine animals are at higher risk of extinction, their findings are consistent with a growing body of scientific literature that point to humans as the main culprits. “It is consistent with the tendency for fisheries to first exploit larger species and subsequently move down the food web and target smaller species,” said study co-author Matthew Knope, a former postdoc in Payne’s lab who is now an assistant professor of biology at the University of Hawai‘i at Hilo.

It’s a pattern that scientists have seen before. On land, for example, there is evidence that ancient humans were responsible for the massacre of mammoths and other megafauna across the globe. “We see this over and over again,” Heim said. “Humans enter into a new ecosystem, and the largest animals are killed off first. Marine systems have been spared up to now, because until relatively recently, humans were restricted to coastal areas and didn’t have the technology to fish in the deep ocean on an industrial scale.”

If there is one silver lining in the troubling new findings, it’s that there is still time for humans to change their behavior, Payne said. “We can’t do much to quickly reverse the trends of ocean warming or ocean acidification, which are both real threats that must be addressed. But we can change treaties related to how we hunt and fish. Fish populations also have the potential to recover much more quickly than climate or ocean chemistry,” Payne said. “We can turn this situation around relatively quickly with appropriate management decisions at the national and international level.”

Other co-authors on the study, titled “Ecological selectivity of the emerging mass extinction in the oceans”, include Andrew Bush of the University of Connecticut and Doug McCauley of the University of California, Santa Barbara.

Contact

Ker Than, Stanford School of Earth, Energy & Environmental Sciences: (650) 723-9820, kerthan@stanford.edu

Jonathan Payne, Stanford School of Earth, Energy & Environmental Sciences: (650) 721-6723, jlpayne@stanford.edu

Noel Heim, Stanford School of Earth, Energy & Environmental Sciences: naheim@stanford.edu

Larger marine animals at higher risk of extinction, and humans are to blame, Stanford-led study finds


ABSTRACT: To better predict the ecological and evolutionary effects of the emerging biodiversity crisis in the modern oceans, we compared the association between extinction threat and ecological traits in modern marine animals to associations observed during past extinction events using a database of 2497 marine vertebrate and mollusc genera. We find that extinction threat in the modern oceans is strongly associated with large body size, whereas past extinction events were either nonselective or preferentially removed smaller-bodied taxa. Pelagic animals were victimized more than benthic animals during previous mass extinctions but are not preferentially threatened in the modern ocean. The differential importance of large-bodied animals to ecosystem function portends greater future ecological disruption than that caused by similar levels of taxonomic loss in past mass extinction events.

Ecological selectivity of the emerging mass extinction in the oceans

3 comments :

  1. Anonymous said...

    Watched the Netflix movie series about long-line tuna fisherman in Australia. Pretty bloody obvious after a single episode how severely depleted the oceans are. 50 miles of long lines can return zero fish at times. The fisherman killed lots of sharks at other times and took whatever and everything that they can from the oceans.

    Not blaming the fisherman, but the entire population. We are to blame for the rapid depletion of life on this planet. Our species is f'n evil as it gets, rapacious, destructive, warring and indifferent. The planet is dying and it is our fault, and yet, nobody really cares enough to put a stop to any of it.

    In many ways, we can't. Civilization is not only a heat engine, it's a devouring monster with an insatiable appetite for virtually everything, doesn't even have to be organic life, it can anything and it will consume it all until there is nothing left.

    We need to go extinct. We need to be removed from the place and from the Universe. We do not have the right to destroy everything else so that we can continue our gluttony, because that is exactly what it is. We are total gluttons in all that we think and do. Our appetites are not just for other creatures, but for the elements themselves, which we fully intend to consume until there is nothing else.

    Nature made a HUGE mistake with our species, but not for much longer. When they die, we die, our gluttony will be our undoing.  

  2. Anonymous said...

    "Nature made a HUGE mistake with our species" Nature IS a huge mistake!! The Gnostics are right, matter itself is evil! If matter is evil, then biological life is super evil. Biological life feeds on other life, without regard to the welfare of what's being consumed. Humans are just better at this hideous game than every other creature. Give them a large brain, written language, opposable thumbs and they too would become monsters!  

  3. Anonymous said...

    Without humans to project arbitrary value onto everything, whether the value is "yummy" or "pretty," why does anything need to exist? Do squirrels care if fish exist or vice versa? The real problem with humans is that they value things at all. Buddhism tells us that you can only miss what you possess. Whether we like it or not, all biological life will end.  

 

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