“Local Extinction”: The Climate Crisis Term for a Shift of Species Range

Flatback Turtle

Flatback Turtle. By Lyndie MalanOwn work, CC BY-SA 3.0, Link

Guest essay by Eric Worrall

Apparently we now need to shut down industrial civilisation to prevent “local extinction” events, scary short distance migrations to more favourable territory.

Climate change could make flatback turtle population be born all female or die out, scientist warns

By Jane Bardon

The members of one of the Northern Territory’s largest flatback turtle populations could all be born female in less than 15 years if rising temperatures continue unabated, a leading Australian turtle scientist says.

The Honorary Fellow of Charles Darwin University and head of AusTurtle has used sand probes to monitor the rise in nest sand temperatures over the decades on the island and at other sites, including Ashmore Reef.

The sex of hatchlings is determined by the sand temperature of their nests, and in 2016 all the Bare Sand Island nests were too hot to produce any males.

“If the temperatures are below about 29.5 degrees [Celsius] we have a male turtle, if it’s above 29.5C you’re going to have a female turtle,” Dr Guinea said.

“And if you have a rise above about 33C to 34C, you start getting into lethal temperatures.”

Dr Guinea said by 2030, all of Bare Sand Island’s flatback hatchlings could be born female.

But he still hoped some nesters would seek out cooler beaches.

We might find that further south, the turtles are actually having better success there, they could be the saviours for the population,” he said.

Read more: https://www.abc.net.au/news/2018-11-12/climate-change-turtle-born-all-female-die-out-scientist-warns/10483790

I live near a flatback turtle nesting site, at the right time of year the beaches are thick with hatchlings – around 1,500 miles south of the “endangered” colony. Somehow I suspect the strategy of moving south a little in response to global warming is working out.

Update (EW): Deleted a redundant sentence in the last paragraph

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50 thoughts on ““Local Extinction”: The Climate Crisis Term for a Shift of Species Range

  1. As that species of sea turtle is probably at least several glacial cycles old , they have survived much more pronounced changes in temperature.
    It looks like yet another booga booga story.

    • Yes this ”study” is just more total nonsense to add to the rest. IMO what needs to be looked at more closely is not temperature shifts but estrogen-like chems in the environment.

      • The danger of us producing estrogen-like compounds from our various agricultural chemicals never came to be because, although indeed some estrogen-like compounds are produced by bacterial action on such chemicals, bacteria do not stop just there and continue to break down the chemicals further. Thus, estrogen-like chemicals are transient and very low concentration as well as randomly distributed and do not have any detectable effects.

    • Actually the penchant of the turtle to have females in warmer climes is a sign that the species likes warmer conditions, as more females means more young and warmer conditions means more food. There are indeed males out there in the ocean waiting for the bevy of females.

      Colder conditions, which favor less food also causes more males and fewer females, thus preserving the food supply for the fewer turtles.

      This species is clearly signaling its preferences for warmer conditions.

    • It seems that my region of the world is experiencing a huge amount of ‘Local Extinction’ as it has been decades, nay centuries!, since the last hippopotamus, elephant, giraffe, or any number of other creatures has been seen in the wild in my neighborhood. I would expect that many regions of the world are also experiencing ‘Local Extinctions’ too.
      Some how I do not think recent climate change is a factor in this regard, but I suspect it certainly played a roll in the distant past. It probably is also responsible for all the aquatic creatures inhabiting the ocean regions as well.

  2. From https://www.amnh.org/our-research/science-news2/2008/revealing-the-evolutionary-history-of-threatened-sea-turtles

    Naro-Maciel and colleagues confirmed that one major group of sea turtles includes sister species flatback and green turtles (one carnivorous and the other herbivorous), while another clade is formed by the hawksbill, loggerhead, Kemp’s Ridley and Olive Ridley turtles. The leatherback is confirmed as the most basal of all the sea turtles, and the Eastern Pacific green turtlethought by some to be a separate speciesfalls within other green turtles. The branches of this evolutionary tree can be calibrated with time using the new phylogeny and DNA data: Even though the ancestor of all sea turtles arose over 100 million years ago, the separation between the flatback and green turtles happened about 34 million years ago.

    IMO these creatures have already survived quite a few larger threats to their existence. What is happening now with the climate is trivial compare to what their ancestor survived. Does the author of this over alarmist piece truly feel that these turtles have no coping mechanism? That they are some kind of aquatic robot unable to adapt to this planet’s ever changing environment?
    No doubt during their very long run of being on this planet there has been many occasions when they became ‘locally extinct’ from a few places on earth and mattered little.

  3. “But he still hoped some nesters would seek out cooler beaches.”

    As far as I know, they nest in damp sands which stay relatively stable with minor variability (That 0.5c). How long have turtles been doing this, and were SUV’s around all those years ago?

    They will, don’t worry Dr. nature always finds away…and it’s it’s only half a degree (Will the turtle know?) or will she settle for “Humm, that feels just about right for males this time around”…

        • With extinctions happening at such a slow rate, scientists have begun to ask the awful question: are there any species left?

          “Twenty, 30 years ago, when the climate issue first appeared on our radar, the big question was: can we name a single species killed by global warming?” recalls scientist and serial reef obituarist Ove Hoegh-Guldberg.

          “Today it’s become: can we name a single species?”

          It’s harder than you might think, notes the University of Queensland professor, who opens all his public presentations on the climate tragedy by challenging the audience for the full Linnaean name of the last species they saw in the wild.

          “A lot of umming and awwing ensues,” he says with a chuckle. “After a minute I let them off the hook. Relax, I say—there’s a reason you’re struggling to think of one.

          “Species have been extinct for years. If my team is right,” explains the newly-appointed director of UQ’s $45m Centre for Excellence in Extinction Modelling, “then the planet ran out [of them] sometime in the mid nineties.”

          In fact—believes Guldberg—species may already have been a thing of the past by the late 1980s in many parts of Australia.

          It’s a disturbing thought. But it’s backed by the latest math, and Guldberg assures me it’s passed muster on the fastest computers taxpayers’ money can buy.

          “The proof [that species are extinct] is straightforward,” says David Karoly, the Winthrop Professor of Climate and the Climate Sciences at ANU.

          Using the same equations that describe the exponential decay of radioactive material, Karoly explains, we can see that the rate of extinction should be proportional to the absolute number of species.

          “But the rate is zero per annum, which means there are zero species.”

          Efforts by zoos and conservation parks to save species in the latter years of the 20th century ended in disappointment, says Karoly.

          “For some reason, species [in captivity] didn’t want to mate with each other. It turned out that you can’t just put two of them in a cage and hope for the best.”

  4. It appears the turtles are able to adapt to global warming a whole lot better than researchers give them credit for.

    It could explain why turtles have been on earth for a whole lot longer than climate researchers.

    • Berple, if you redo that first sentence to this: “…turtles are able to adapt to global warming a whole lot better than researchers can adapt to anything at all….” it will make a lot more sense.

      I’m more and more convinced that these “researchers” are sideshow barkers trying to lure the gullible into the tent to see the bearded lady turtle and the half electric eel boy, and poke the visitors for even more cash just to have a chance to pet a dogtoothed violet shark.

    • I often wondered about the incubation temperature sex determination thing, as it seemed inefficient and arbitrary. Now I see what an effective system it is for adapting to a changing temperature. The populations will swing north or south with the temperature. The outliers will be mostly male or mostly female and will not reproduce as effectively.

      • Contrariwise. If it gets warmer there will be fewer more “heat-resistant” males which will each get to fertilize more females and have more little turtle kids, which will mean that the “thermostat” for the 50/50 sex ratio will be nudged up a little bit.

        These researchers have apparently never wondered why there are 50% males and 50% females produced in almost all species despite the fact that rather few males are usually enough to fertilize all the females. The reason is that parents of those few males would have a huge evolutionary advantage and those “male breeders” will therefore very rapidly increase in number. So you always end up with 50% males and 50% females. It is biologically inefficient but it is the only ESS (Evolutionary Stable Strategy).

      • Reproduction is not affected as much as you might think, Peterg, because turtles travel long distances from their birthplace. The females return to where they were born to lay eggs, but could have been impregnated a 1000km away. And if you watch David Attenborough, you will have seen video of half a dozen male turtles spending an entire day competing to mate with a single female.

        When food is plentiful in warm periods, more females are born, which results in a rising population. In colder periods, when food is scarcer, you get more males being born, so the population starts to dwindle – an evolutionary version of birth control.

  5. Giving data access to eco-hystericals is like giving a combined CT/MRI/PET diagnostic suite to a hypochondriac. It really has no good ending.

  6. You know, we all ought to get used to the idea that human activity does indeed have an impact on our planet. Someone coined the term anthropocene, well no kidding, eons from now the footprint of human activity is going to be very prominent in the geologic record. And furthermore, nobody can do anything about it. We all ought to get used to the idea. Curtailing the use of fossil fuels won’t do anything.

    • ‘Anthropocene’ proponents seem to be suggesting humans are capable, for the first time ever, of literally affecting the objects around them. Ha! I’ve never witnessed such a miracle. We’re not beavers, dam it!

  7. “If the temperatures are below about 29.5 degrees [Celsius] we have a male turtle, if it’s above 29.5C you’re going to have a female turtle,” Dr Guinea said.

    And if the temperature is 29.5 C exactly, we have a LGBT turtle.

  8. So much negativity. Look at the bright side. Think of how much fun the few males around will have. Just like the end of “Dr Strange Love”.

    • Exactly. Doesn’t it trouble their conscience?

      How do they sleep with themselves?

      A: on piles of money surrounded by beautiful vimmin. (Rainier Wolfcastle, The Simpsons)

  9. ” Depending on the area of the nesting site, the nesting season can go from November to January or can last the entire year.”
    https://en.wikipedia.org/wiki/Flatback_sea_turtle#Reproduction

    So for a large part of their range they can only breed in the hottest summer months of November to January.
    This indicates that the breeding season could increase with warming, along with their southern range.
    More turtles, not less.

    • November to January is usually the wet season in the Northern Territory…But being nature at work as per usual, sometimes the wet season is late and that would lead to higher temperatures in the nesting sites of the turtles..

      Also it’s pretty dry from April till November…And that may be an important constraint on the breeding season

  10. I read that ‘story’ on the ABC’s website this morning…..

    Ummmmm ?

    The ABC and the ‘researcher’ seems to believe that these poor turtles have never evolved and cannot evolve further to adapt the temperature at which male 7 female are determined…

    Now that is NOT science..

    It’s just BS

    And by the way, in case there are any ABC bureaucrats reading this blog, “its not my ABC…Ownership has passed into the hands of some dopey ideocrats with almost no science in their heads at all”

  11. I just finished reading a presentation made in 1952 where the movement of animals and plants was documented all over the northern hemisphere as a result of increasing temperatures. The increased number of shipping in Arctic waters was also mentioned. It would seem that some of these people need to do a bit of digging if they are interested in learning about how our climate has changed and perhaps obtain some perspective on how it may change in the future. I cannot find where I saved the link to the presentation or I would provide it. Stuff like this seems to be happening with more frequency lately.

  12. I don’t know much about turtles so maybe an expert or two will correct me, but as someone grounded in evolutionary biology, the concern expressed by the head of ‘AusTurtle’ seems to me unjustified and shallow.

    The interesting question (indeed, the first that should be asked) is, why is this extreme sensitivity to incubation temperature perpetuated down through the generations? It’s just assumed that an ideal temperature is REQUIRED for a balance of gender in the population, and any change therefore poses a threat of extinction. Not so. The AusTurtle people see high temperatures as a weakness/handicap when it clearly is not.

    My guess is that it is very useful for mixing up the gene pool, and preventing too much inbreeding between turtles born in the same area or on the same beaches. They’ll find most animals of local origin to be of the same sex, whereas those from further afield, born under different incubation conditions, and with a different suite of genes, are more likely to be mateable.

    Surely the turtle people have studied this?

  13. I honestly can’t see why Turtles would not easily adapt to a supposed temperature change well within the bounds of what their species has already experienced. There are multiple routes – move breeding grounds, adapt behaviour to bury eggs deeper, pick shadier sites, dominance of genetic pool from remaining occurring males that will be less prone to temperature influence on sex determination……………

  14. Sea turtles are a pelagic species with preferred nesting beaches, usually their beach of hatching. The turtles do not “live” where they dig their nests and deposit their eggs. As soon at the female turtle finishes laying the eggs she covers the them with sand and drags herself back into the ocean, leaving her offspring to incubate, hatch, and then make their own arduous journey back into the nearby water. In the short crawl from nest to water many of the little turtles will be eaten by raccoons, sea birds, and other land predators. As soon as they enter the water aquatic predators will also feast. But the ones that survive will take off into the world ocean, only females returning at some point in time to repeat the cycle.

    Sea turtles do not haul out of the water except to lay eggs, the rest of their life is spent cruising around eating whatever they prefer and just enjoying their long lives. The very notion that there could be a gender imbalance just because one beach might produce more males than females and vice-versa is totally numbyheaded! The life of a sea turtle is like one long pub crawl, they are constantly meeting other turtles from other beaches and the genders tend to equalize.

    This person claims to understand sea turtle life cycles? Hogwash, wonder if this so-called scientist has ever spent hours walking beaches at night looking for nests or releasing new hatchlings to the ocean, like I and many others have done.

  15. “the genders tend to equalize”

    It is almost inevitable that they will equalize. If there is a gender imbalance the individuals producing more of the scarcer gender will have an evolutionary advantage and increase in numbers until things even out.

  16. One could assume that turtles are about to increase in number. Turtles normally have a higher ratio of females to males. Turtle sexual acts are also a bit violent. Often scars are left on the female as a result of sexual encounters. More females being born will mean more partners for the males meaning more turtles. This is just another case of an unexplained annomoly which requires more research and linking it to global warming will increase chances of funding.

  17. 1 : The temperature on the turtle nesting beaches is dependent on sunlight and rainfall. As in more rainfall means less sunlight; and less rain means more sunlight.
    2 : The Northern territory in Australia has wet season/dry season climate.The wet season normally starts building up in September, early October. However this year because of the impact of the positive Indian Ocean Dipole and the start of an El Nino in the Pacific, the wet season has not yet really started in Northern Australia. Check here for more info : http://www.bom.gov.au/climate/rainfall-onset/#tabs2=Observations
    I suggest that means that the turtle nesting beaches this season are hotter than usual. And so maybe there will be more female turtles hatched..But next year when the IOD is negative, the wet season will start earlier and the temperatures of the sand on the nesting beaches a tad lower; and more hatchlings will be male..

    3 : Something else being missed in all this : pelagic turtles are very long lived animals; 70-80 years and longer. And they do not reach sexual maturity for 8-9 years. So there are plenty of mating opportunities for turtles of different years which evens out the male/female ratio over the long term.

  18. “Climate change could make flatback turtle population be born all female or die out, scientist warns: By Jane Bardon”

    “Mick Guinea has been researching the nesting of flatback turtles on Bare Sand Island, 50 kilometres from Darwin, since the 1980s.”

    “And if you have a rise above about 33C to 34C, you start getting into lethal temperatures.”

    Not research!
    Personal speculation by someone deeply committed and involved; who ignores the success rates while claiming future imaginary disasters.

    Ignored is the amazing reproductive design of this evolution step.
    With turtles that live over a hundred years, one male amongst a plentitude of females is a far more successful trait than one female amongst a plentitude of male turtles.

    “If”, “start”, one single location and an alleged researcher speaking “off the cuff”.

    “The Honorary Fellow of Charles Darwin University and head of AusTurtle has used sand probes to monitor the rise in nest sand temperatures over the decades on the island and at other sites, including Ashmore Reef.”

    “Has used”?
    Obviously, he has not installed or implaced temperature instruments to monitor sand temperatures 24/7 throughout the nest cycle.
    The wording appears to describe a portable “stick in the sand” temperature probe; and does not monitor the temperature of the eggs.
    Temperatures are dependent upon “how deep” Mick Guinea sticks the probe. Slight differences of angle and pressure make the sand temperature location different, even for the same nest.

    No mention is made whether night temperatures are cooler. All focus is still on Mick Guinea’s probe hand stuck into some poor turtle’s nest.

    “Dr Guinea said by 2030, all of Bare Sand Island’s flatback hatchlings could be born female.

    Utter speculation.
    Guinea’s speculation is generically applied to all flatback turtles, based on Guinea’s imagination regarding one location.

    But he still hoped some nesters would seek out cooler beaches.”

    We might find that further south, the turtles are actually having better success there, they could be the saviours for the population,” he said.”

    Is this an indication of how little Mick Guinea actually knows about his one location’s turtles?
    N.B. Guinea’s reference to “better success” after he claims his one location has “95%” success.

    Rising temperatures could cause ‘local extinction’
    Bare Sand Island is one of the most successful turtle nesting sites in Australia, Dr Guinea said, with more than 95 percent of beach tracks resulting in a nest.

    In other parts of Australia, that figure is closer to 50 per cent “because the turtles are easily disturbed, or they’re not happy with the area”, Dr Guinea said.”

    Sloppier and sloppier research and speculation as this article predicts future disasters based on today’s successes.
    No wonder alleged “climate change” researchers claim to be depressed.

  19. There was an anthropogenic climatic warming event of nearly 1 degree C from 1975 to 1998. This was caused by chlorine photodissociated from CFCs, and it caused climate zones to shift poleward. There is no evidence of any other climatic warming event over the past 70 year interval. CO2 is incapable of causing warming in the Earth context because its emissions (13 to 17 microns; MODTRAN6) are incapable of increasing the molecular vibrations of Earth’s warmer surface, and hence are simply reflected and not absorbed.

  20. Turkeys studying turtles!
    Those celibate male turtles that survived without female company all alone; throughout the +/- 100 thousand years of the last glacial minimum are really to be pitied.
    Makes one wonder if these turkeys/researchers have any common sense at all!!!

  21. “Local extinction” is a neologism that has no meaning overall, since every organism and plant on the planet is “locally exrinct” in thousands and thousands of places, now, and will be in more places for a variety of reasons.

    • Yes, I want this applied to HUMAN populations, too. If people move, it has to be due to climate change. Can’t be due to local jobs, better opportunities elsewhere, moving closer to family, etc. It must be climate change and until we get humans NOT to move away from where they are, we must work day and night to save the local populations.

      /s if I need one.

  22. I doubt that every female member of the species lays eggs that have the exact same temperature response. Some will have males at higher temperatures than claimed while others will have the divide be at lower temps. If temps continue to rise the eggs with the male/female divide at a higher temp will make up a disproportionate amount of the males, causing the male/female divide temp to rise throughout the species.

    This is basic evolutionary theory. I would have thought scientists (especially biologists) would know this.

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