Not Threatened By Climate Change: Bengal Tigers

Guest Essay by Kip Hansen

 

featured_image_TigersThe Big Cats — lions, tigers, panthers, cougars, leopards —  have always fascinated and frightened mankind.  Tales of tigers and lions — once they have gotten a taste for human flesh — terrorizing villages as they search for another human to eat abound along with tales of the famous hunters hired to kill the man-eaters.  Val Kilmer and Michael Douglas starred in a 1996 movie “The Ghost and the Darkness” which fictionalizes the real story of the Tsavo Man-Eaters — two lions that brought the building of the Kenya-Uganda Railway to a jarring halt as workers became too frightened to work as the lions took man after man from their tents at night,  dragging them off and devouring them.

A female Bengal tiger named Thak man-eater was finally shot and killed in November of 1938 by the world-famous “great white hunter” Jim Corbett who, although colonel in the British Indian Army, was often asked by the government to track down and kill man-eating tigers and panthers that roamed the provinces of  Uttar Pradesh and Uttarakhand, which are in northern India up against the Himalayas.  Overall, big-game hunter and author Jim Corbett, hunted down 33 man-eaters responsible for well over 1,000 deaths. Nobel-prize winner Rudyard Kipling wrote books that featured man-eating tigers and panthers his stories, like The Jungle Book.

Even today, tigers killing people “can lead to intolerance of Tigers by neighbouring communities” which “presents an ongoing challenge to managers to build local support for Tiger conservation and can lead to high rates of retaliatory killing of Tigers. In some areas there have been many human deaths – for example, about 40 people were killed by Tigers in the Sundarbans mangrove forest of Bangladesh and India 2000-2010 (Barlow et al. 2013).” [ source IUCN Redlist ]

It is of the tigers of the Sundarbans mangrove forest of Bangladesh and India that I write today.   It is estimated that 440 tigers live in the Sundarbans Mangrove forests of southwestern Bangladesh and west into India.

SundarbansThe Sundarbans “is a mangrove area in the delta formed by the confluence of Ganges, Brahmaputra and Meghna Rivers in the Bay of Bengal. It spans from the Hooghly River in India‘s state of West Bengal to the Baleswar River in Bangladesh. It comprises closed and open mangrove forests, agriculturally used land, mudflats and barren land, and is intersected by multiple tidal streams and channels. Four protected areas in the Sundarbans are enlisted as UNESCO World Heritage Sites, viz Sundarbans National Park, Sundarbans West, Sundarbans South and Sundarbans East Wildlife Sanctuaries.  …. The Sundarbans mudflats (Banerjee, 1998) are found at the estuary and on the deltaic islands where low velocity of river and tidal current occurs. The flats are exposed in low tides and submerged in high tides, thus being changed morphologically even in one tidal cycle. The tides are so large that approximately one third of the land disappears and reappears every day.  The interior parts of the mudflats serve as a perfect home for mangroves.” [ Wiki ].  Much of Bangladesh is similarly affected by its overall nature as a massive delta.  A little closer up they look like this:

SUNDARBANS_CLOSE_UPThe Sundarbans mangrove forest covers an area of about 10,000 km2 (3,900 sq mi).  Despite mostly being protected lands and nature reserves, the Sundarbans has a population of over 4 million but much of it is mostly free of permanent human habitation. While the math works out to 400 humans per km2, the human population crowds into villages and cities leaving most of the forest unoccupied permanently.  People go into the forest to harvest wild foods and wood, both for building and firewood for cooking.  The people of Bangladesh and this part of India are often profoundly poor thus there is quite a bit of poaching in the protected areas.  It is when people go into the forests to collect wild foods, fire wood, or to poach that some of them fall prey to tigers.

Tigers have been in the news recently:

CNN — Bengal tigers could vanish from one of their final strongholds

Washington Post —  More tigers now live in cages than in the wild.

NY Times — Bengal Tigers May Not Survive Climate Change

The CNN and the NY Times reports are based on a study done by Sharif A. Mukul and a group of Bangladeshi and Australian scientists. Published in Science of the Total Environment, the papers is titled “Combined effects of climate change and sea-level rise project dramatic habitat loss of the globally endangered Bengal tiger in the Bangladesh Sundarbans”.

This paper makes the following claim:

“Our model predicts that due to the combined effect of climate change and sea-level rise, there will be no suitable Bengal tiger habitat remaining in the Sundarbans by 2070.”  “Our study clearly indicates a rapid decline in the Bengal tiger population and suitable tiger habitats in the Sundarbans area by 2050, and a complete loss of this species by 2070.”

And recommends:

“Enhancing terrestrial protected area coverage, regular monitoring, law enforcement, awareness-building among local residents [are] among the key strategies needed to ensure long-term survival and conservation of the Bengal tiger in the Bangladesh Sundarbans.”

The authors boldly predict that there will be no suitable habitat for tigers in the Sundarbans by 2070 — stating blandly that the tigers will go locally extinct.  Given that prediction, their recommendations for remediation are unlikely to result in long-term survival of the tigers in this ecological niche.   Readers will note that the logic involved in the finding and recommendation leave something to be desired.

The study and its recommendations have to be viewed against the backdrop of history:  Bengal tigers have inhabited the Sundarbans for at least 16,000 years — surviving droughts, failed monsoons, horrific cyclones (one in recent history that killed 300,000 to 500,000 Bangladeshi humans), and continuous hunting of tigers by  the local human population.

So how did they come to this prediction of extinction?  Easy — they used a model.

The model is called Maxent  — a machine-learning technique called maximum entropy modeling.   It is an open source product originally developed at the American Museum of Natural History (AMNH).  It runs in Java on your Windows computer and is available free here.  The Maxent homepage (same link) offers links to the latest “raw ipcc data, as dowloaded from the IPCC Data Distribution Centre.  Also the annual and monthly variables used for the study, extracted from the raw ipcc data and converted into world-wide coverages in .asc format.”

Basically, for non-modelers, the users input the locations (GPS coordinates) of where a species is currently found.  Then, from the Maxent page: “Species models are determined from a set of environmental or climate layers (or “coverages”) for a set of grid cells in a landscape, together with a set of sample locations where the species has been observed.  The model expresses the suitability of each grid cell as a function of the environmental variables at that grid cell.  A high value of the function at a particular grid cell indicates that the grid cell is predicted to have suitable conditions for that species.”

An immediate problem with this approach in this instance — tigers in the Sundarbans — is that the Sundarbans have very little climatic variation from one point to another — there is almost zero change in elevation, zero differences in temperature ranges, etc.   Secondly, Bengal tigers previously occupied almost all of the Indian continent as suitable habitat and have been reduced to their redoubt in the Sundarbans not through climatic changes but through the pressures of burgeoning human population.

The study authors point to Catherine H. Graham and Robert J. Hijmans’ 2006 paper as an example for Maxent use.  Unfortunately, our tiger authors also decided that the bio- and eco- system “parameters” used by Graham and Hijmans in their study were “biologically more meaningful to define the eco-physiological tolerances of most species”.  This is unfortunate as they limited the parameters to  the nine bioclimatic variables used in Graham (2006).  Why is this an error?  Graham was modeling “herpetological fauna of California” — herpts (reptiles and amphibians) usually have narrow ecological niches and California has almost every type of eco-region — deserts below sea level with extremely high temperatures, the High Sierra which includes the highest point in the 48 contiguous states (Mt. Whitney), coastal redwood rainforests, well, the list goes on.  Graham and Hijmans selected a limited set of bioclimatic variables that would best describe the limiting features for snakes, lizards, frogs, toads, newts, turtles, etc., variables that have very wide ranges in California.  Here’s the list, used in the tiger study because it was used in Graham (2006):

table_1

A reasonable set of choices for cold-blooded herpts, but somehow probably not the limiting factors for tigers.  Further, it is difficult to believe that these variables actually vary that much over the small area represented in the Sundarbans mangrove forests of Bangladesh and India.

A great deal of the land surface in the Sundarbans is tidal in nature — submerged at high tide and exposed at low tide.  Very little is more than a meter or so above the highest tides.  This means that sea level rise (SLR) — the kind that RCP6.0 and RCP8.5 project for 2050 and 2070 — will have a very large impact on this delta area.  If those kinds of SLR do come to pass, the Sundarbans will be reduced in size by 50% or so — crowding the tigers and their natural prey into a smaller area.

But this paper states in its conclusion “We have found that climate change always had a greater effect than that of only sea level rise alone on suitable Bengal tiger habitats.”  How so?  They don’t say — that is, they offer no biologically plausible explanations for their conclusion.  They simply say, in effect, “because the model says so (after 500 iterations).” Remember, the model has been established with the bioclimatic parameters for reptiles and amphibians.

Let’s try something a little more real.  Where do tigers live today?

tiger_range_Wapo

It is clear that tigers historically (the tan background color) have lived all throughout Asia.  Today, they live wherever they are not being hunted and killed — either in retribution for preying on the livestock of humans or preying on the humans themselves or for the never ending Chinese Folk Medicine market, which demands tiger parts of all sorts.  Tigers have very few restrictions for habitat as long as there is adequate prey.

 

Bottom Line:

  1. The Bengal Tiger is threatened — just not by climate change. Sea Level Rise may eventually (100-300 years) push the tigers of the Sundarbans to higher land to the north, where human-animal conflict will ramp up — to the detriment of the tigers.  The real threats for these tigers stem from human-animal conflict (tigers attacking and eating people) leading to retribution tiger killings and from human-animal competition for the same prey — deer and other forest animals.
  1. The tiger study by Mukul et al. is flawed and has arrived at a scientifically unsupportable, biologically implausible conclusion.
  1. The IPCC bioclimatic projections under RCP8.5 have been found to be extremely unlikely to impossible and should not have been used to project the future survival of Sundarbans tigers.
  1. Tigers will continue to live and thrive wherever their human neighbors cease killing them and their natural prey, and where enough of their natural habitat is allowed to remain unharmed by human development.

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Author’s Comment Policy:

Readers interested in this topic should read the Mukul et al. paper in its entirety to see just how this study failed. [If you are unable to access a full text copy, email me — my first name at i4 dot net].   It is a good example of several scientific errors that are rampant in science today — and not just CliSci.  The authors depend on a previous study, Graham and Hijamns (2006) which they don’t seem to have understood yet they follow its lead in using Maxent and IPCC bioclimatic parameters inappropriate for their Sundarbans tigers study. They don’t seem to have considered the biological plausibility of their findings —  what future bioclimatic changes would harm the tigers?  How would it harm them? Also,  I very much doubt that Maxent can be used in any sensible manner over such a small and homogenous geophysical area.

 

Let us hope that the Conservation agencies of India and Bangladesh don’t read this paper and decide that they should do nothing for the Sundarbans tigers because they are all going to be extinct in 50 years.

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50 thoughts on “Not Threatened By Climate Change: Bengal Tigers

  1. Tiger, tiger, burning bright
    In the forests of the night.
    You’ve lost so much of former range,
    But not because of climate change.

    (apologies to Wm. Blake)

  2. The threat to Big Cats is a real environmental challenge.
    They are dangerous and compete with farmers for livestock. So they are hunted.

    We must be careful not to hunt them to the point where they are no longer viable.

    Trace gasses in the atmosphere are of negligible impact compared to bullets.

    • M Courtney ==> quite right….like almost all species loss, human killing of the species is often the largest threat and the easiest to change. Polar bears recovered after hunting was banned, and the same is true for many African species.

      For the Bengal tigers of the Sundarbans, the tigers don’t leave the forest and attack humans in their villages — the humans go into tiger territory after bush meat or firewood or honey — and the tigers see them as prey. Once a man-eater is active in an area, they send hunters in after them.

    • The Bengal tiger is doomed. It’s CITES I listing guarantees its demise.

      Same with the cheetah.

      Hunters will pay for the preservation of species. CITES I ends hunting. Converting tigers and cheetahs into nuisances, no different than marmots or magpies.

      I have two different friends who while hunting in Africa were asked by farmers to shoot the damn cheetahs. Madison Avenues’ embrace will be their demise.

      Kenya banned hunting lions 30 years ago. Current population of lions in Kenya:
      double ought zero.

        • From your link:

          ‘In 2012 the Kenya Wildlife Service said therev were 1,700 lions in Kenya. Based on no real surveys.’

          I concede that the number today is probably not zero. But the trend to extinction is clear:

          “There is no doubt that the numbers are in freefall. I’d be surprised if they even last as long as 20 years.” – Laurence Frank, project director of Living With Lions, a Kenya-based conservation organisation.

          Again, hunting brings value to wildlife. If a farmer can get something from hunters, he will accept some depredation from lions, cheetahs and elephants. Otherwise, he wants them gone. CITES I listing means they’ll be gone.

      • tom ==> Thanks for the full Blake poem. Blake understood something that Darwin missed.

        All the cats (large and small) have that same fire in their eyes and in their minds. Thus my support for policies for restricting pet (owned) cats to their owners property and the elimination of feral (freeroaming) cats.

      • Most of the large mammal extinction problems stem directly from “intentional killing” (hunting for sport or threat reduction — protecting humans or their herds and flocks).

        The Big Cats come right back when we quit killing them. Same for bears.

        The problems arise when there are Human-Animal Conflicts. These Big Cats and Bears can consider animals of human size to be prey — nobody likes to be eaten — and certainly our cattle, sheep, goats etc. look like prey to the Big Cats — people don’t like having their animals (which are humans meal tickets) killed.

        Thus the solutions come when large tracts of habitat are set aside for these species and hunting is sharply restricted to protective measures.

  3. This information ? which is now data, is being processed by a model
    which is using data from a IPCC model. What could possibly go wrong.

    Its obvious what is the problem, too many people with less and less useable
    land.

    The only hope for the big cats is for special areas to be created by
    Western nations, such as the magnificent one at Monato in
    South Australia. A sort of modern Noas Ark.

    Unless the Asian nations can be persuaded to limit their populations, there
    is no long term hope for the tigers in the wild.

    Such protection worked to save the American Bisons, so it can work to
    save any truly at risk species.

    MJE VK5ELL

    • Michael ==> There are three reserves in the Sundarbans — which, according to population density maps (humans) — are pretty human free. But this part of India and Bangladesh are very densely populated and the Sundarbans offer “free” food (bush meat, honey, fish) and fuel (firewood for cooking and building materials) that are almost irresistible.

      The UN has declared the Sundarbans a World Heritage site, which has helped with funding and some control.

  4. Everyone realizes that without an alarmist narrative to write climate change porn stories to the naive public, climate change itself is a big nothing-burger.

    And researchers in diverse fields of ecology and biology need positive results in studies to get published in decent journals. The IPCC and and climate scam community figured this out in the 1990’s, and into the early 200’s as public sentiment and concern just wasn’t budigng and staying CC way down on list of concern in polling.

    So RCP 8.5 in CMIP5/AR5 was specifically intended to be the alarmist, worst case, over-the-top scenario for diverse fields to show climate change impacts in their areas of study. They know they can get away with this because of both consensus acceptance and an un-critical reporting of studies to the public.

    And CMIP6 and AR6 has an even more improbable emissions scenario cooked up to make for even more “impact.” As in, “Its getting worse,” media story headlines.

    The intellectual dishonesty of uncritical use of RCP8.5 by so many diverse fields is just another reason climate change scam needs to be ignored.

  5. This paper makes the following claim:
    “Our model predicts “.

    Well that was enough reading for one evening.

    • Its probably a really good thing that the tigers cannot read – they might become frightened and need counseling in a safe space! Grrrr!

  6. Of the top two animals I would not want to run into in the wild, the second would be a tiger – the first would be a polar bear.

        • Without the Anopheles species the malarial protozoans would be extinct or at leat very obscure. I think Javert is more correct. Not sure why Anopheles are such good vectors, but we should be grateful that species in other mosquito genera are not competent vectors of human malaria (sad that Culex can transmit avian malaria and is helping to exterminate native Hawaiian birds – Hawaii having been, once, a true paradise without mosquitoes).

    • manbearpig tops my list.

      After that, anything that outweighs me by twice and is wanting to eat me gets equal billing on the list.

  7. ~~~~~~~~~~
    The Tiger

    TIGER, tiger, burning bright
    In the forests of the night,
    What immortal hand or eye
    Could frame thy fearful symmetry?

    In what distant deeps or skies
    Burnt the fire of thine eyes?
    On what wings dare he aspire?
    What the hand dare seize the fire?

    And what shoulder and what art
    Could twist the sinews of thy heart?
    And when thy heart began to beat,
    What dread hand and what dread feet?

    What the hammer? what the chain?
    In what furnace was thy brain?
    What the anvil? What dread grasp,
    Dare its deadly terrors clasp?

    When the stars threw down their spears,
    And water’d heaven with their tears,
    Did He smile His work to see?
    Did He who made the lamb make thee?

    Tiger, tiger, burning bright
    In the forests of the night,
    What immortal hand or eye
    Dare frame thy fearful symmetry?

    ~~~~~~~~~~
    William Blake (1863)

  8. ” … there will be no suitable Bengal tiger habitat remaining in the Sundarbans by 2070.”

    Is the writer of that even vaguely aware that tigers not only can swim, but love to play in water? They groove on it. In regard to “suitable habitat”, if food runs out in one area, the tigers will move some place where there is food. They’re considerably smarter than the individual who wrote that forecast. In fact, I’d lay odds that any tiger now in existence will still be around long after he’s gone.

    • Sara ==> Yes, it appears to me that the authors of the study failed to give any consideration to the biological plausibility of their findings. The larger of the range maps in the essay shows that tigers found almost all of India and what is now Bangladesh as suitable habitat. Whatever small changes in temperature, precipitation, or Sea Level the future holds for the Sundarbans, it will still be good habitat for tigers — they are not that fussy.

  9. Anybody that has taken on his sisters fully clawed alley cat (intentionally provoked), learns things about cats.
    Even with the leather gloves.

    • uk ==> When I was a child, we had a cat named “Blackie” (guess what color he was?) that did not allow any dogs in our unfenced yard. The neighborhood dogs respected him after one or two run-ins. He was all claws and teeth with ears shredded by too many battles. 65 years later I still miss him.

      • When I got it really mad, it would clamp on to my arm, front claws out and dug into my flesh,
        but it seemed to know we were playing, cus when it raked its back feet along my forearm the claws were retracted (usually).

  10. Even if there is SLR, are we 100% sure that the area of the mangrove forest will decline? I was under the impression that mangroves trap silt and sediment. Might they influence their own environment enough to keep up with sea level rise, like corals seem to?

    • Shaun ==> Of course, you are absolutely right. If the sea rises to flood and tide- inundate land further inshore, the mangroves will colonize the new delta swamps, along with the tigers. So many of these so called climate effect projections fail to take into account that as climate things change the biota will change with it. This is especially true of deltas — there is no hard line in the sand of where the land ends and the delta begins — and at a few millimeters rise per year, that line slowly moves taking with it the transitional biota of the delta.

  11. I’m thinking why are there so many cows and chickens and pigs and horses and dogs etc? Well, perhaps because they are all privately owned. The bison was hunted almost to extinction by the Native American tribes plus some old white guys. The bison returned in force after farmers were allowed to own them. Now you can get bison steak and hamburger etc. at you local grocery store.
    I’m thinking it would be the same with elephants, lions, tigers, and anything else that is “threatened” with extinction. Governments owning these animals never seems to work, lets try private ownership.
    If I want to market elephants for parts, it would be in my best business not to kill every elephant I had. In a few years, with careful herd management, I could have many hundreds of elephants. Whatever it is that poachers want, they could simply buy now and sell instead of hunt and steal.

  12. Kip, I’ve been trying to counteract this sea level rise and loss of deltaic habitat. Before all this foolishness published regularly, it was certainly well known by geologists ( of which I am one), that deltas rise with sea level rise. The mechanism: a rise in sea level causes distributaries of rivers near the sea to slow their flow as the sea water moves upstream. This causes the river borne sediments to settle out ‘early’ thereby building up the delta level. If sea level drops, the unconsolidated sediments that make up the delta begin to be eroded deeper by the increased flow rate of the steam and wave action from the sea erodes the margins back taking away habitat.

    • Gary Pearse ==> True for rivers that are not subject to human intervention. Much of Bangladesh is river channels that have been dredged and boldered, restricting the flows in between — thus the flow speeds up and takes the sediment out to sea. See my earlier essay on Bangladesh.

      We see this in the Mississippi delta.

      Not sure how this will all play out in the future. as for coastal wetlands, I believe they will simply replace themselves as the sea rises millimeter by millimeter.

  13. I grew up in Central India. When cattle became too old to be economical, they were taken to the jungle on the north side of the Narmada river and left for tigers or starvation – after all you could not kill a cow.

    Tigers in the jungle area between the Narmada and Bhopal attracted a lot of big game hunters. To get a permit, an official was bribed to declare a tiger a ‘man eater’. Then the mighty hunter tethered a goat and got up on a machan (platform) and waited in the night.

    I have very little faith in the stats from Indian conservation agencies. For an example of Indian stats for 2018 say 50,000 snake bite deaths. Well, when I was growing up, it was well known that villagers reported embarrasing deaths as ‘snake bite’ to the DC’s office – someone hit his wife too hard; fights, etc. Between 1952 and 1965, I know of one confirmed snake bite death – a little girl who flung her hand out of the bed at night.

  14. If anyone was frightened by a fictionalised version of the man-eaters of Tsavo I recommend they try The Man-eating Leopard of Rudaprayag by the great Jim Corbett – they will never sleep without a light again!

    • Susan ==> Yes, Corbett is one of Indian history’s larger-than-life figures. Most of his tales are true! (or at least, basically true….)

  15. Hi Kip – Interesting as all of your essays are. I sometimes wonder if all mathematical models in the biological sciences aren’t inherently evil. Well, some do work pretty well (e.g. day degree models for predicting plant growth, bud burst, insect attack, etc.) and some seem to be almost useful if the system is very simple (predator prey oscillations for example – but what system consists of one predator and one prey?). But most are so unrealistic but seductive that even people who one would think were competent biologists can’t see the world around them for the model. I remember the optimal foraging fad, the food web ‘science’ fad, and others where the ‘science’ became ‘well we have our model, so let’s cram the data into it’. And those were only perverting sub-disciplines, not trying to predict the behaviour of the entire world for centuries to come.

    Anyway, the way we interact with large predators today is strangely interesting. I knew someone whose daughter was killed and partially eaten by a cougar, but maintained that her daughter would not have wanted anyone to hunt down the cougar (possibly other people with daughters may have had a different opinion). Have you seen Werner Herzog’s film ‘Grizzly Man’? Herzog always comes across as an Alien scientist observing human nature in an objective way, and he does a fine job with this tragedy.

    • DaveW ==> I haven’t seen Grizzly Man, but look forward to it. I see that it is available on Amazon Prime Video.

      I admit I tend to be put off a bit by these quirky (and inevitably tragic) characters — along the lines of Christopher McCandless (idealized in the book/film “Into the Wild”.

      I’ve had my quirky days, I admit (running off to sea in my early twenties, after University life became impossible due to crazies like me protesting everything, shutting down the Uni, shutting down the war in Viet Nam, etc etc and then returning to the sea at 55 with my wife to do humanitarian work in the Caribbean for a dozen years).

      But not near-suicidal….(at least I didn’t think so — anyway, survived and now land-locked and limited to mostly intellectual adventures).

      Thanks for the tip on Grizzly Man.

      • Hi Kip – I read some of the arguments about legume toxins doing in McCandless. I have an interest in bush tucker and there was a time when I might have done something similar (I certainly spent a lot of time wandering alone in the bush), but I don’t think I could stomach a Sean Penn film even when it has great reviews. However, I did watch a very nicely done doco on Richard Proenneke (‘Alone in the Wilderness’ I think) and felt the lure of the wild again, although I would have probably ended up like McCandless. I’m pretty good with microscopes, but generally not very handy with anything else and a terrible shot.

        Surprising election results in Australia yesterday. Preferences are still being assigned, but it looks like the Coalition will hang on handily. A climate crazy did whoop former PM Tony Abbott, but the winner is a former Olympic medalist, better looking than Tony, and never ate a raw onion without peeling the skin in front of a news camera. I was always a bit leery of him after that.

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