Gila Monsters threatened by climate change?

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Fieldherper
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Gila Monsters threatened by climate change?

Post by Fieldherper »

Article alleges Gilas are declining without giving any supporting data. I have seen Gilas in many locales in AZ, some of which (Yuma County) have LONG been brutally hot and dry. There is a big climatic difference between Yuma and Tucson. Gilas seem to be doing very well throughout AZ, based on observations, albeit not formal data. Where is the data to say that they are declining, however? I would like to see more supporting data before such judgments are made. Too easy these days to blame climate change on whatever one wants--expansion of some species and regression/decline of others, but always framed as "bad." But I'm sure it's a buzz word to secure funding.

http://news.nationalgeographic.com/2016 ... te-change/

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Re: Gila Monsters threatened by climate change?

Post by Jeff »

Unfortunately NG seems to have adopted an activist role in issues pertaining to the environment and political events. They have coupled this activism with a writing style that has been crafted for the non-discerning majority.

The present piece announces that Gila Monsters are in trouble due to climate change, which is the take-away message for those who read only headlines. The argument progression is 1) no one knows how many Gila Monsters there are, 2) their populations are declining, 3) they are declining due to sub-urbanization of their optimum habitat, 4) we need to work to control carbon emissions. There is no circle of logic here, and the facts seem to get in the way of themselves. For example, there are Gila Monster populations in the Mohave Desert, so there may be variation in the stated physiological thresholds mentioned in the text. For another example, NG has bracketed a statement that IUCN believes there are "several thousand adults", and Dale avers that he has seen a few thousand Gilas. His observations would include juveniles and adults, and span decades, and a population biologist would infer from those observations that at any time there are, range-wide, probably thousands of these very difficult-to-observe Gilas, not a few thousand adults.

Thanks for posting this Field H

Jeff

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Re: Gila Monsters threatened by climate change?

Post by Richard F. Hoyer »

It would be my guess that perhaps Dr. Dale De Nardo wished he had not given the interview to the journalist. But then again, I am just guessing as I do not know the gentleman’s views about the affect of climate warming.

A few years ago, there was a conference in Boise, Idaho (I believe) in which papers were given dealing with the affects of global warming on Gyrfalcon populations. Being a falconer, I read all of the abstracts and was so disappointed in what I read.

If you approach issues from an objective and impartial position, then as for the affects of the earth’s temperature increasing over time, automatically one should understand there are at least three possible outcomes. That is, for any given species, global warming could be detrimental, could be beneficial, or could have no real affect. Yet as I recall reading those abstracts, all but one paper predicted negative outcomes for the Gyrfalcon. I believe one paper alluded to the point there possibly could be some positive outcomes.

I have no knowledge of the basic biology of the Gila Monster. But what comes to mind is the possibility that perhaps global warming could increase the amount of favorable habitat for the species allowing it to expand its distribution into higher elevations and northward, etc. So any serious analysis of what might occur with the Gila Monster would need to be approached in the same objective manner which for the most part, was not done in this article.

From my vantage point, this is one more example of individuals tending to climb onto the band wagon without really doing any critical thinking. I already mentioned that same scenario has ‘engulfed’ many individuals in conservation circles that have voiced concerns about the negative affects of road kill on a wide range of species including snakes and amphibians.

From June 22nd through the 26th, I was in eastern Calif. and the carnage of jack rabbits (and some cottontails) was very apparent along Hwy. 395. And of course, the first thing that comes to my mind is that the rabbit population must be at or near its peak in that region of Calif. For the life of me, I cannot understand by researchers. conservationists, etc. that encounter a high numbers of snakes and amphibians killed on roads, they too do not immediately realize that the populations of those species are very likely to be quite healthy in the region adjacent to those roads. Instead, the only thought that seems to comes to their minds is that road mortality is causing a negative impact on the populations of such species.

The night (6/24), we road cruised for snakes at lower elevation in the Mojave Desert east of Hwy. 395 confirmed a rather large population of the Black-tailed Jackrabbit. A very good number of hares crossed the road in frong to us and on the way back, we finally hit one of them. As a falconer that hunts rabbits with a Harris’s Hawk, I know if my female HH had seen all of those hares that night, she would have gone bonkers.

Richard F. Hoyer

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Kelly Mc
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Re: Gila Monsters threatened by climate change?

Post by Kelly Mc »

So with difficult to observe and impossibly hidden by habitat physics herps, it seems that analysis of populations will not ever be possible.

So without that data, it can be repeated over and over that there is no data, and recreationally motivated individuals press on with an incessant wave of anti scientists critique as well, to bend opinion amongst their fellows, many who practice leave as you find it in their nature activities.

Those whom are Leave As Find individuals, introducing themselves and their interests - will be more reluctant to disclose that they dont collect - for fear of "looking like they are an activist" to a group they wish acceptance and inclusion with.

Clever.

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Re: Gila Monsters threatened by climate change?

Post by scottriv »

The reason gilas appear to be "scarce" is because they spend the vast, vast majority of their time underground.

If you know when and how to see them in the wild, they suddenly begin to appear plentiful.

I have been pulled over by AZ game and fish three times and each time I asked the warden, "Do you think gilas should be fully protected or should there be a bag limit on them?"

All three wardens said that they thought there were plenty of gilas and that there should be a bag limit on them.

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Re: Gila Monsters threatened by climate change?

Post by Richard F. Hoyer »

Kelly Mc.
If anyone would spend time thinking about the issue of ‘demand’ (collecting for personal reasons), eventually they should reach the conclusion (as I did long ago), that recreational collecting of herps, by and large, is a self regulating and self limiting activity. I urge you (and others) to give this some thought and then see if you can reason why I came to that conclusion.

As for what you mention in your first sentence, that also requires some thinking. You might recall, that a number of professional herpetologists and perhaps others in 1970 all considered the Southern Rubber Boa to be rare or very scarce at best. That including Dr. Glenn Stewart, the co-author on the two papers we published in 2000 on the SRB in the J. of Herpetology. Our study demonstrated that all, including Glenn, who considered the SRB to be rare were wrong.

It is my view that the reason some species seem impossible to assess is due to the lack of imagination and creativity of researchers. I have been a long time advocate of the use of artificial cover in order to acquire research samples. For quite a long period time, the professional herp community rejected or refused to use A/C. But eventually, the ice began to melt. I have likewise been an long term advocate of making search other than when it is warm and sunny.

So with the advent of using innovative methods such as the use of A/C and conducting searches other than when sunny and warm, species that were once considered as ‘rare’ have now been discovered to be far more common. I urge you review the following paper. “Perceptions of Species Abundance Distribution, and Diversity: Lessons from Four Decades of Sampling on a Government-Managed Reserve. J. Whitfield Gibbons and others. Environmental Management Vol. 21, No. 2. pp. 259 – 268. 1997 Springer-Verlag New York Inc.

With respect to what you mention in your last paragraph, that does not resonate with me. One of the major facets of my studies of the Rubber Boa and Common Sharp-tailed Snake involves mark / recapture. As such, except for a few specimens I have donated as voucher to institutions, all specimens of both species have been released where found. I have retained one captured Rubber Boa that was given to me by someone else. And the reason she has not been released is that I do not know the exact locality where she was captured somewhere near Banks, Oregon west of Portland.

I can only speak for myself, but I have never had any reservations about broadcasting the point that I release all of the snakes I capture. I am not intimidated in the slightest by those that may wish to retain specimens. I would be very surprised if others that choose to just observe and photograph specimens would be intimidated by those that wish to collect specimens now and then.

Kelly, do you really feel intimidated by individuals that sometimes collect specimens?

Richard F. Hoyer

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Kelly Mc
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Re: Gila Monsters threatened by climate change?

Post by Kelly Mc »

Richard Hoyer it does not appear that you were fully present in reading the actual content of my post.

Also I'm trying to wrap my mind around "feeling intimidated by people who collect"

I'm not intimidated by a whole bunch, Mr Hoyer, thats been made pretty clear I think, and no, I can definitely say that I myself am not intimidated by people collecting.
What a strange comment...?


However, I have posted openly about an F1 animal I keep that is bare bones proof of my unbiased objectivity.

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Re: Gila Monsters threatened by climate change?

Post by VanAR »

Perhaps it would help to explain the interview to those apparently unwilling to comprehend it. To be clear, Dale DeNardo is the foremost expert on gila monster physiology. He's made a career out of studying their ability to retain water in a harsh desert environment, which is very important to understand within climate change scenarios.

1) He says up front nobody knows what current gila population status really is. Title notwithstanding, nobody is necessarily saying that they are rare, just that they are at risk of several major threatening processes.

2) He says that urbanization is likely the biggest cause of declines (tacitly assuming that they are occurring). This ain't rocket science folks. You're not going to find a gila in much of downtown Phoenix... you might get them in the suburbs, but habitat destruction is likely to affect them as much as it is any other reasonably large reptile.

3) He explains that gilas have a very poor ability to retain water, especially compared to other desert species. He's demonstrated this repeatedly in a number of lab studies (look up on google scholar), and most of you with gila experience will probably concur with those results. Why do you think gilas are most easily found during the wetter, cooler parts of the year in most of their range? That is when they are most active because they are at least risk of desiccating.

4) The question then, in NG, is- how will gilas be affected by climate change? Well, assuming it gets hotter and drier, or that rainfall becomes less synchronized with the biological timing of some of their behaviors and physiology (ex, reproduction), then they're probably going to suffer a bit.

That's all it says here. It has nothing to do with herping, bag limits, collection, possession, etc. Take your chill pills.

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Kelly Mc
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Re: Gila Monsters threatened by climate change?

Post by Kelly Mc »

I for one thank you for the above. The interview read to be a non inflammatory, measured presentation.

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Re: Gila Monsters threatened by climate change?

Post by Fieldnotes »

hmmm, that's interesting.

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VanAR
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Re: Gila Monsters threatened by climate change?

Post by VanAR »

So sorry, I misspoke. Please take your crazy pills :crazyeyes:

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Re: Gila Monsters threatened by climate change?

Post by Kelly Mc »

I dont want to slide to off the track of Gilas but as I was sitting in a little knoll today I was thinking about you Richard and the things that you have done.

A lifetime of meticulous, unabated passion that has contributed to the body of knowledge, especially about two species that are so fascinating, and make me wonder about their hidden lives in the earth.

I would hope nothing - most especially anything invalid or badly founded ever gets in the way of your studies.

If a grafting of circumstances can be imagined, causing a sudden restriction of resources that are integral to many of our own varied and special interests - especially where study is involved, imagine how terrible that would be.

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Re: Gila Monsters threatened by climate change?

Post by Richard F. Hoyer »

“Colorful, Venomous Lizard Is Declining Due to Climate Change”
Van,
Just reading the above headlines of the National Geographic article immediately told me that the journalist, editor, or someone at National Geographic, took journalistic liberties. No responsible professional would have written such a headline without having solid evidence in support of such a claim. And of course, the is no such evidence. So my assessment of the story is much the same as that mentioned by Dr. Jeff Boundy of Louisiana (second post in this thread.Jeff).

Note that the headline is stated as if it were fact. Also as if fact, the author wrote, “But these charismatic animals are in trouble, scientists warn, due to climate change.” Not he did not name the "scientists" which is a red flag of sorts.


At any rate, with respect to your advice, I went one step further. Last night, I sent an email to Dr. DeNardo and received a reply this morning. Dr. DeNardo essentially confirmed my assessment and mentioned he had not read the article. I sent him the link to the article. From my vantage point, the NG article represents another example of the type of sleaze that has infiltrated the field of conservation.

Below are some point to consider (with my comments).
1) It can be noted in the article, it asks, “How many Gila monsters are there now? Then it answers, “Nobody knows.” So if baseline data does not exist on current (and likely historical) abundance of the species, explain how the ICUN can state, as if fact, that the species "is probably in significant decline...”?

2) As for the loss of habitat, a general estimate in loss of numerical abundance can be determined by comparing the area of lost habitat to the area of a species’ total distribution. If 50 % of a species’ habitat has been converted to other uses, then on the average, it has lost about 50 % of his original numerical abundance. So comparing the amount of area taken up by urbanization of Gila Monster habitat and comparing that to the total area of the Gila Monster’s distribution would give a general idea in lost numerical abundance of the species due to urbanization. Whether such loss in a species’ population is of concern is dependent on a number of other variables.

3) If the evidence indicates the Gila Monster has been in existence for 100,000 years or perhaps into the millions of years, then the argument about the dire affects of climate change would seem to be tenuous It is my understanding that historically, the North Am. continent has undergone a series of ‘cold’ and ‘hot’ spells. And if such cooling and heading up took place from below the Mexican border on north, that suggests that the Gila Monster was able to withstand past fluctuations in cold and hot climate conditions. But I am quick to add, my understanding of this particular issue is marginal at best so I could be off base. I just put it out for something else to possibly consider.

In his above post, Dr. Jeff Boundy wrote, “Unfortunately NG seems to have adopted an activist role in issues pertaining to the environment and political events. They have coupled this activism with a writing style that has been crafted for the non-discerning majority.”

I encourage everyone on this forum to try and become an ever increasing minority that is not automatically taken in by what occurs in print. Over the years, I endeavor to approach issues from impartial and objective position. So with respect to the warming of the earth, an objective approach would indicate that such warming could have no affect on some species, a negative affects on some species, or a positive affects on some species. Everyone can then apply that type of analysis to what may or may not happen to the Gila Monster population during the current warming trend.

Richard F. Hoyer (Corvallis, Oregon)

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Re: Gila Monsters threatened by climate change?

Post by Richard F. Hoyer »

Kelly Mc.,
With respect to your post yesterday, I posted a response on the thread I started on July 1st.

Richard F. Hoyer

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Re: Gila Monsters threatened by climate change?

Post by VanAR »

You guys are still reading far more into this than is actually written.

Specific quibbles:
1) It can be noted in the article, it asks, “How many Gila monsters are there now? Then it answers, “Nobody knows.” So if baseline data does not exist on current (and likely historical) abundance of the species, explain how the ICUN can state, as if fact, that the species "is probably in significant decline...”?
I agree- note that Prof DeNardo didn't make any of those claims.
) As for the loss of habitat, a general estimate in loss of numerical abundance can be determined by comparing the area of lost habitat to the area of a species’ total distribution. If 50 % of a species’ habitat has been converted to other uses, then on the average, it has lost about 50 % of his original numerical abundance. So comparing the amount of area taken up by urbanization of Gila Monster habitat and comparing that to the total area of the Gila Monster’s distribution would give a general idea in lost numerical abundance of the species due to urbanization. Whether such loss in a species’ population is of concern is dependent on a number of other variables.
That's a pretty coarse way to look at landscape ecology and population dynamics. Species tend not to be equally distributed throughout their range irrespective of microhabitat. Particular regions/habitats can have major variation in species occupancy, and that variation can change over time. For example, let's say you put a major highway through the middle of a species' migratory path between hibernacula and summer foraging grounds. It might destroy less than 1% of that species' total habitat, but road mortality is going to severely impact that species' population, far out of proportion to the actual destruction of habitat. I have no idea if Gilas would be affected by this, but I suspect in some places, some small populations could be.
3) If the evidence indicates the Gila Monster has been in existence for 100,000 years or perhaps into the millions of years, then the argument about the dire affects of climate change would seem to be tenuous It is my understanding that historically, the North Am. continent has undergone a series of ‘cold’ and ‘hot’ spells. And if such cooling and heading up took place from below the Mexican border on north, that suggests that the Gila Monster was able to withstand past fluctuations in cold and hot climate conditions. But I am quick to add, my understanding of this particular issue is marginal at best so I could be off base. I just put it out for something else to possibly consider.
Read up on water relations in gila monsters before you make a strong opinion on their physiological tolerances to drought and high temperatures. Those biophysical constraints (and their inter-population variation) are what determine the habitats the animals can actually occupy. Selection can certainly tune their physiological sensitivities to a degree, but remember that the animals in nature don't exist in a bubble. During those historic fluctuations you refer to, there weren't roads, etc. to block their migratory responses to climate change (which likely were more rapid than physiological adaptation), and there weren't dams blocking 90% or more of the river flows from certain areas, making some areas drier than they normally would be. Little patches of human development- golf courses, etc. provide huge water subsidies to animals like gilas and may be potential "islands", but figuring out how much this benefit helps them in the face of other negative factors is pretty tricky.

I agree that the sky probably isn't falling, but these are warning signs reasonable to consider/act on BEFORE we get to a major crisis.

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Re: Gila Monsters threatened by climate change?

Post by Richard F. Hoyer »

vanAR;
You have interpreted comments made by myself and others as being critical of Dr. DeNardo. That is not the case. Even without ever having viewed any of Dr. DeNardo’s publications on the Gila Monster, I automatically assumed his research results were valid.

My criticism was solely directed at the National Geographic and the journalist that wrote the article which contains
an unmistakable bias or agenda in the manner the article was written.

From the reply I received from Dr. DeNardo, it is quite clear he would never have written the headline of that story. (“Colorful, Venomous Lizard is Declining Due to Climate Change”) That headline was the creation of the journalist and worse, was approved by the editors of National Geographic. That is what I consider as sleaze. I hope you are able to see the difference.

Richard F. Hoyer

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Re: Gila Monsters threatened by climate change?

Post by WSTREPS »

Unfortunately NG seems to have adopted an activist role in issues pertaining to the environment and political events. They have coupled this activism with a writing style that has been crafted for the non-discerning majority.

The present piece announces that Gila Monsters are in trouble due to climate change, which is the take-away message for those who read only headlines. The argument progression is 1) no one knows how many Gila Monsters there are, 2) their populations are declining, 3) they are declining due to sub-urbanization of their optimum habitat, 4) we need to work to control carbon emissions. There is no circle of logic here, and the facts seem to get in the way of themselves.
Jeff
'

There's seems to be quite a bit of that found in todays scientific world.
) It can be noted in the article, it asks, “How many Gila monsters are there now? Then it answers, “Nobody knows.” So if baseline data does not exist on current (and likely historical) abundance of the species, explain how the ICUN can state, as if fact, that the species "is probably in significant decline...”?


Significant decline along with climate change . That's the catch phrase with everything. You can say that due to habitat destruction there are fewer Gilas today then in 1602. But the real question isn't how many there were or will be but how many is enough. There's enough Gilas. Their not going to be leaving us anytime soon. Not that anyone straight out said that but they certainly want the idea planted in unsuspecting readers minds. The Gila monster is found in portions of the Mohave Desert in southwestern Utah, southeastern Nevada, southeastern California, and northwestern Arizona; in the Sonoran Desert in southwestern Arizona and Sonora, Mexico; and in small portions of the Chihuahuan Desert in southeastern Arizona and southwestern New Mexico. Its fully protected everywhere.
At any rate, with respect to your advice, I went one step further. Last night, I sent an email to Dr. DeNardo and received a reply this morning. Dr. DeNardo essentially confirmed my assessment and mentioned he had not read the article.
Maybe. DeNardo might be an alright guy. I don't know. But. Yeah, I've been down this road a few times. With these guys its always golly gee wiz I had no idea. That darn media. The reason someone does an interview with National Geographic is to get the attention. Everyone knows how their going to play it up and that's what they want. No one ever makes outright claims they just lead readers on, power of suggestion. Its gives them plenty of outs if needed. My few dealings with NG, they are the National Inquire with good pictures.
Perhaps it would help to explain the interview to those apparently unwilling to comprehend it. To be clear, Dale DeNardo is the foremost expert on gila monster physiology. He's made a career out of studying their ability to retain water in a harsh desert environment, which is very important to understand within climate change scenarios.
That's friggin great. But being the foremost expert on gila monster physiology is useful.....how in practical application? Besides being used to speculate, ponder on how a species might react to a hypothetical set of environmental conditions in an uncertain future. How is all this gila monster physiology useful in any workable way that will actually help Gila monsters. My 25 years old Gilas are dying to know.

Ernie Eison

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VanAR
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Re: Gila Monsters threatened by climate change?

Post by VanAR »

VanAR wrote:You have interpreted comments made by myself and others as being critical of Dr. DeNardo. That is not the case.
I apologize. I've become used to the forum being a hotbed of science discontent and my perspective may be a bit warped as a result. To be clear, I don't mind people being critical of science or scientists, but I would prefer their criticisms to be reasonable.
That's friggin great. But being the foremost expert on gila monster physiology is useful.....how in practical application? Besides being used to speculate, ponder on how a species might react to a hypothetical set of environmental conditions in an uncertain future.
Case in point.... :crazyeyes:

If what I've typed already doesn't explain it well enough for you, and you can't begin to understand how water physiology is important to know for managing an animal that lives in the desert, in the face of a changing climate, extremely altered hydrology, and pockets of major habitat disruption, then there's not really any point in discussing it further.

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Re: Gila Monsters threatened by climate change?

Post by WSTREPS »


If what I've typed already doesn't explain it well enough for you, and you can't begin to understand how water physiology is important to know for managing an animal that lives in the desert, in the face of a changing climate, extremely altered hydrology, and pockets of major habitat disruption, then there's not really any point in discussing it further.


Case in point. The basic principles sound all well and good. On paper. In hypothetical theory based on uncertain predictions and guess's. That ultimately don't mean much in real world application. Maybe in the lab the gilas benefit, De Nardo can figure out when to give his animals a drink.

How this physiology information can actually be applied to something useful to preserving the gila monsters future in the wild. That at this time is solid. It cant and isn't necessary.

You don't need to understand water physiology in detail to "manage" gila monsters ithe wild. If that actually is a possibility. A detailed analysis of their physiology is completely useless in managing wild populations because you cant control anything in a detailed manor. Basic understanding is all that's needed and at best its all that can be applied. Things have to be done in a generalized manor. This isn't 12 condors on an isolated mountain top or a herd of goats running around a restricted range. Where every detail can be useful. Its a thriving wide ranging secretive species whos population cant be accurately monitored. Its hard to manage animal's you can find no matter how well you understand their water physiology.

Their not complicated in their needs. Yes, if a gila monster doesn't get a drink now and again it will die eventually. So they need a water source of some kind at least periodically . It doesn't matter if they can go a week or 81 days they are going to need water. Everybody knows that. All the requirement's for gila monsters to complete their life goals are known. A gila monster can eat like a snake. They don't have to eat often and can swallow a big rat. Like a snake . Gila monster's don't need a specialized habitat. They can live anywhere that provides them with food, water and the ability to thermal regulate.

What's need to preserve gila monster populations is very simple and common sense based.


Climate change predictions , I guess if the Everglades is going to be underwater lets scrap the 8 billion dollar restoration project and use that money to buy Gila monster habitat and irrigate it before its to late.

Ernie Eison

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Re: Gila Monsters threatened by climate change?

Post by Bryan Hamilton »

Thanks Van for taking the time to make those posts. Very good points and remarkably civil. I wish I could communicate scientific thought as concisely as you.

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Re: Gila Monsters threatened by climate change?

Post by scottriv »

Because of the evolutionary adaptations that gilas have made toward living in hot, dry desert conditions, I would say they are uniquely qualified to survive global warming and drought.

If we start reading about quail populations declining or quail being put on the endangered species list, then we can start worrying about gila populations.

Until then, I wouldn't worry one iota about gilas surviving climate change.

Actual global warming would likely cause more rain to drop in Arizona which would make it easier for gilas to find the food they require.

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Re: Gila Monsters threatened by climate change?

Post by Bryan Hamilton »

Because the only thing that matters for a reptile species is that its main food is abundant. And gilas only feed on quail. And quail will certainly respond well to climate change. And gila monsters only occur in Arizona. And rainfall will certainly increase under every climate change projection. And gilas are actually extremely poorly adapted to the desert. This isn't really fun anymore.

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Re: Gila Monsters threatened by climate change?

Post by jonathan »

Richard F. Hoyer wrote:3) If the evidence indicates the Gila Monster has been in existence for 100,000 years or perhaps into the millions of years, then the argument about the dire affects of climate change would seem to be tenuous It is my understanding that historically, the North Am. continent has undergone a series of ‘cold’ and ‘hot’ spells. And if such cooling and heading up took place from below the Mexican border on north, that suggests that the Gila Monster was able to withstand past fluctuations in cold and hot climate conditions. But I am quick to add, my understanding of this particular issue is marginal at best so I could be off base. I just put it out for something else to possibly consider.
No, I think that's a really bad assumption.

One example I can think of are the Foothill Yellow-legged Frogs of southern California. They used to exist all the way down to Baja, including all over the San Gabriels, and now you can't find them south of Fresno.


I saw someone claim once on this forum that the reason they had become extirpated in LA County was because of flooding in 1969, and that it had nothing to do with people at all. He was repeating an opinion that other educated people apparently shared.

However, it made little sense. They'd been in the San Gabes thousands of years and had obviously experienced flooding before. However, their disappearance did appear tied to the flooding event.


The answer, of course, is that man-caused changes AND climate extremes combined to make continued existence impossible where once it would have been. Humans had made a lot of changes to those streams, including water being held in different places and released in different ways, which may have made the flooding events worse. But more importantly I think, development had choked off virtually every water body in the LA Basin and lot of the water bodies across the mountains. As a result, when one aspect of their habitat became inhospitable, there wasn't a remnant safety area to repopulate from. There weren't a few frogs making due in the valley or the foothills, because all those possibilities had been wiped out. There was no chance of newer, smaller streams in the wet times or larger bodies become hospitable small streams in the dry times. The frogs were only left in their single, most ideal habitat, and when temporary changes in climate caused a shift, there was no way for the populations to shift accordingly. And it's not just the FYLF - we could lose Southern Mountain Yellow-legged Frogs and Arroyo Toads in the San Gabes for similar reasons.


It's easy to imagine a similar thing with Gilas. Do humans populate and utilize the desert randomly? No, they focus on the water bodies, the oasis's, the most hospitable spots, and they change those the most. It's easily possible that the places which would have been survivable reservoirs for remnant Gila populations in the tough times of the past are now inhospitable due to human interference.

In the Imperial Desert in SoCal, we've already lost all known populations of Lowland Leopard Frogs, Sonoran Desert Toads, and Desert Mud Turtles in California (as well as Arizona Toads further north). There's still lots of desert out there, but that suggests that we've made an entire type of habitat inhospitable for a lot of species. That's not the only livable habitat for every species, but it's possible that those same habitats were the reservoirs in the tough times before, and now they're gone.


I recommend Jared Diamond's "Collapse" for thinking about this issue more. He looks at why the Anastazi of the SW desert, the Norsemen of Greenland, the Mayans of the Yucatan Peninsula, and the Polynesians of Easter Island all saw their civilizations collapse. In at least three of those cases, possibly all four, the primary issue was that they had ended up in a lifestyle that was close to the edge of what the habitat could tolerate, and when local climate or environmental changes made the situation shift, they were pushed past their edge.

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VanAR
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Re: Gila Monsters threatened by climate change?

Post by VanAR »

scottriv wrote:Because of the evolutionary adaptations that gilas have made toward living in hot, dry desert conditions, I would say they are uniquely qualified to survive global warming and drought.
ll
If we start reading about quail populations declining or quail being put on the endangered species list, then we can start worrying about gila populations.

Until then, I wouldn't worry one iota about gilas surviving climate change.

Actual global warming would likely cause more rain to drop in Arizona which would make it easier for gilas to find the food they require.
Please read up on Prof Denardo's (and others) work on Gila water physiology and see if you still hold the opinion that they are well adapted to deserts. They are actually supremely well-adapted (in terms of their sensitivity to water loss only) to seasonally monsoonal climates, preferably those with high humidity- very similar to the habitats beaded lizards are found in. They tolerate drier parts of the American southwest mostly because they are good at hiding in cool spots in the dry periods, can utilize nocturnal cool/humid conditions at certain times of the year to forage, and can be fairly explosive in most of their behaviors/biology during a brief wet monsoon. Much of the American southwest actually hasn't been all that dry for very long- the Sonoran desert in particular isn't even a "true" desert based on total rainfall accumulation, and less than a million years ago it was much more a humid scrub forest more similar to beaded lizard country in central Mexico. Gilas thrived back then, and are in many ways, by comparison, hanging on by the skin of their teeth in regions where water is just available enough for them to have continued surviving. Sure, they've almost certainly adapted to drier conditions to some extent, but they're nowhere near as resistant to drought as many sympatric reptiles. Things like Desert tortoises, Chuckwallas, and Desert iguanas are FAAAR more resistant to water loss than are gilas.

Assuming the climate in that region continues to dry (and it is drying, by all published measures), gilas are going to be one of the first reptiles that will exhibit an impact.

Richard F. Hoyer
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Re: Gila Monsters threatened by climate change?

Post by Richard F. Hoyer »

The Rubber Boa tends to dehydrate more readily that many other species of snakes. Yet, a sizeable amount of the Rubber Boa’s distribution occurs in desert scrub type habitat far from any free sources of water ---- but invariably at higher elevations.

I have speculated that during the warmer parts of the year, condensation may occur in subsurface cavities when temperatures dip at late night–early morning hours. In that manner, the boa can remain hydrated by taking condensed moisture off of rocks, roots, or its own body when underground.

Does anyone else know whether or not if condensation occurs underground in some parts of the Sonoran Desert?
If so, the same scenario might apply to other underground dwelling species in desert habitats -- including the Gila Monster.

Richard F. Hoyer

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Bryan Hamilton
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Re: Gila Monsters threatened by climate change?

Post by Bryan Hamilton »

Interesting though RIchard. Thanks for sharing.

I'm not even sure that condensation is necessary as long as the relative humidity is high in the burrows. For example, a lot of water is lost during breathing. Kangaroo rats and other heteromyid rodents maintain positive water balance partially by spending the hottest driest portions of the day underground in burrows. This way they minimize water loss from respiration. Reptiles lose less water from breathing (because ectotherms don't respire as much) but being in a humid burrow still helps with water balance, independent of loss through the skin. Directly drinking condensed water in burrows is intriguing. Condensed atmospheric water ha a very distinct isotopic signature. If it contributes significantly to the water budget, potentially it could be tracked indirectly.

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Kelly Mc
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Re: Gila Monsters threatened by climate change?

Post by Kelly Mc »

Lung mechanics and respiratory moisture loss are probably Much different in a gila than a rubber boa.

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Bryan Hamilton
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Re: Gila Monsters threatened by climate change?

Post by Bryan Hamilton »

Possibly different but lots of similarities. In almost all terrestrial vertebrates, respiratory moisture loss is a big part of their water budget. That's controlled primarily by the difference in humidity between saturated respired air and the environmental air. Gilas have two lungs, boas one functional lung. But in terms of water budget, we would look at them the same way. Both species use shelters to minimize water loss. I remain intrigued by the idea of condensation in underground burrows. Kind of like a natural flowmaster.

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scottriv
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Re: Gila Monsters threatened by climate change?

Post by scottriv »

Van,

The Reticulated gila in South Eastern AZ definitely gets the benefits of the Summer Monsoons, but the Banded gilas in the western and northern areas get almost no summer rains and the rainfall totals for the year in these areas are bleak and very "desert" like.

The weeks of peak activity in these two different sub species of gila are drastically different, yet gilas in both different areas are thriving.

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WSTREPS
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Re: Gila Monsters threatened by climate change?

Post by WSTREPS »

Lets see,

Climate change is going to create an environment that is to hot and arid for the survival of a relatively small burrowing lizard that is well adapted to desert life but........will create an environment that is favorable for a giant tropical terrestrial constrictor that is so strongly tied to water scientist refer to it as semi aquatic. All across the Gilas range. Hum...that seems a bit strange. Talk about contradiction.

The links , One map shows where the pythons could live today, an area that expands when scientists use global warming models for 2100. Junk science anyone?

http://ww1.hdnux.com/photos/11/24/11/24 ... 28x471.jpg

https://www.nps.gov/ever/learn/news/up ... _color.jpg

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scottriv
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Re: Gila Monsters threatened by climate change?

Post by scottriv »

That is funny!!

The idea that Burmese pythons are going to make it even 100 miles further north into Florida is borderline preposterous.

My friends who live down there said that the very cold winter we had a few years back wiped out close to half the Burms.

We are gonna need an awful lot of global warming to get Burms all the way to AZ. :lol: :lol: :lol: :lol:

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jonathan
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Re: Gila Monsters threatened by climate change?

Post by jonathan »

VanAR wrote:Please read up on Prof Denardo's (and others) work on Gila water physiology and see if you still hold the opinion that they are well adapted to deserts. They are actually supremely well-adapted (in terms of their sensitivity to water loss only) to seasonally monsoonal climates, preferably those with high humidity- very similar to the habitats beaded lizards are found in. They tolerate drier parts of the American southwest mostly because they are good at hiding in cool spots in the dry periods, can utilize nocturnal cool/humid conditions at certain times of the year to forage, and can be fairly explosive in most of their behaviors/biology during a brief wet monsoon. Much of the American southwest actually hasn't been all that dry for very long- the Sonoran desert in particular isn't even a "true" desert based on total rainfall accumulation, and less than a million years ago it was much more a humid scrub forest more similar to beaded lizard country in central Mexico. Gilas thrived back then, and are in many ways, by comparison, hanging on by the skin of their teeth in regions where water is just available enough for them to have continued surviving. Sure, they've almost certainly adapted to drier conditions to some extent, but they're nowhere near as resistant to drought as many sympatric reptiles. Things like Desert tortoises, Chuckwallas, and Desert iguanas are FAAAR more resistant to water loss than are gilas.

Assuming the climate in that region continues to dry (and it is drying, by all published measures), gilas are going to be one of the first reptiles that will exhibit an impact.

That sounds like it could fall right in line with the issue that I was speaking about.

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lateralis
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Re: Gila Monsters threatened by climate change?

Post by lateralis »

...nobody mentioned the fact that this author claimed to have seen "thousands of them". If that's the case monsters must be doing pretty well lol. Climate models in the Imperial and Coachella Valley have predicted many species will just move upslope to higher elevations. With Fringe-toed lizards the models showed little to no shift at all...

it is sad to see this type of bonehead journalism in an otherwise noteworthy journal like NGS.

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