Hot and Cold Running Lizards: Threatened by Climate Change or not?

The great majority of lizards prefer to live in places where daytime temperatures exceed 30 degrees Celsius. If you want to see a lot of lizards, or a great variety of species, head into the tropical and subtropical regions of the Earth. In the face of increasing global warming you wouldn't expect lizards to be especially vulnerable, right? As it so happens, opinions on the subject are mixed.

Back in 2009 a team of well-respected physiologists and herpetologists sounded an alarm: Global warming was coming fast, and with it many lizards would become extinct (University of Washington. "Tropical Lizards Can't Take The Heat Of Climate Warming."ScienceDaily, 5 Mar. 2009. Web. 18 Jun. 2013). That research team's leader was Raymond Huey, one of the intellectual powerhouses of reptile physiology. If Huey makes a claim in print, you'd better take it seriously.

But a few years later another team published a paper that presented the exact opposite case: in an ever-warming environment, most lizards would do better than they do now (Wiley. "Some like it hot: Cold-blooded tropical species 'not as vulnerable' to climate change extinction." ScienceDaily, 16 Aug. 2012. Web. 18 Jun. 2013.). The proposition that warmer climates will not threaten the majority of lizard species was supported by a separate study, also published in 2012 (Duke University. "Rapid changes in climate don't slow some lizards." ScienceDaily, 26 Nov. 2012. Web. 18 Jun. 2013.).

In March 2012 yet another study was published, this time supporting Huey's team and its conclusions (University of Lincoln. "Lizards facing mass extinction from climate change." ScienceDaily, 6 Mar. 2013. Web. 18 Jun. 2013.). That study's leader, , believes that warmer climates will drastically and negatively affect species that live at higher altitudes, especially those that produce live young instead of laying eggs. Then, on 17 May, another study concluded that climate change will barely affect lizards (Dartmouth College. "Climate change may have little impact on tropical lizards: Study contradicts predictions of widespread extinction."ScienceDaily, 17 May 2013. Web. 18 Jun. 2013).

This is how science is done. Scientists pick questions, seek answers, and often get conclusions that seem oppositional or totally unexpected. How, then, shall we choose which of several competing hypotheses to become our "truth"? We don't. Science is not democracy or hocus-pocus. We don't say something like, "well, three groups say that climate change will devastate lizards and two say they won't; let's go with the former." Scientists may come to consensus on many things, but should not do so on the basis of the number of published studies on a given topic. Too many studies provide excellent insight into a very tiny part of a question, but give us little or nothing from which to realistically extrapolate to, say, all organisms in a class.

In the studies mentioned above I see a few important limitations. Each study used only species from one genus (Anolis or Liolaemus). In the case of Anolis we have small species with short lifespans. Species with short lifespans tend to reproduce prodigiously, and in each generation may contain minute genetic modifications that could allow for greater thermal tolerance. Would the studies have gotten appreciably different results if a wider range of species been examined? Would size affect the results--say by comparing those tiny Anolis with 2m long iguanas?

The work being conducted is worthwhile, and is providing information that may become extremely important as the climate changes. However, I do not feel that the presentation of results based upon a very small sample of the species and environments concerned presents an accurate picture. Not all lizards might be so vulnerable, and maybe they are, but as of today there is no justification for claims that link any effect of climate change to the majority (or even a significant fraction) of the 4,500 species of living lizards.

Writing once more

It has been quite a while since I last kept a (fairly) regular work schedule. As my dear wife often says, "life is what happens while you're making plans", and that message has really been the description of life since... well, a few years now. I've been through several surgeries of the spine and eye, moved a few times, and been bogged down with either visiting doctors and physical therapists or making appointments to see them.

ENOUGH!

Whatever the new limits, which include entering my 60th year, I've regained a considerable level of my old "normal" and am determined to get back to work doing what I most love: studying and writing about animals. THIS blog will now be my link with readers and potential readers, to keep you informed of what I am working on and to give me some sense of there being deadlines.

Here's what's hot here! Besides the awful, muggy east-coast weather.

UPCOMING BOOK: I AM KING
See the picture above? That is yours truly and his late, very dear dog, King (King is the good-looking one). Yes, I used to read to King, especially the brief news pieces in Science magazine and Herpetological Review. He was a very important part of my life from 1998 until 2009, and from him I learned that we (humans collectively) and I (specifically) may have underestimated or dismissed the intelligence of animals because we didn't know HOW to understand their languages. Initially, even though I could often only guess at what King was saying, I was fairly certain it had nothing to do with mathematics, prime integers, or any of the other things SETI people seem to think will dominate the first conversations between humans and – if they are out there – extraterrestrials. Think about it for a moment: which of these opening lines do you think would really get an interplanetary relationship off to a good start: 

a.      “Wow! I love the way you guys can moderate sub-angstrom wave oscillations,” or

b.      “Welcome to Earth! Let’s get a pizza and some beers and get to know each other!”

Fact: You’d get me hooked with option b. King, too.

So I am now chest-deep in the writing of the manuscript (translation: at 11 chapters, 31 000 words and going) with a self-set goal of completing the book by Christmas, 2013. Seems like a long time, doesn't it? The difficulty with it being an easy target (besides my vision thing) is that the research covers an incredibly broad swipe of the sciences. I've got pertinent data concerning intelligence and relationships in mammals, birds, reptiles, and octopuses, and each of those groups has amazing stories -- uh, data -- that supports the argument for their considerable mental faculties. No spoiler alerts yet. If you'd like to be a reviewer, someone who gets to read the rough drafts and then make suggestions for clarification and other improvements, please a) join this Blog and b) let me know of your interest. If I get responses, I'll post draft excerpts here on my Blog.

Cheerio for now, and good reading!

Invasive Species? (Published June 2010)

Bite of the Bandy-Bandy,

and other tales from the world of a herpetologist

There’s been a lot of talk about unwanted visitors. I’m not talking about in-laws or college students on an extended return from school. The visitors to which I refer have gone under a suite of pejorative titles: tramp species, non-native species, introduced species, and injurious wildlife. If you’ve been reading the herpetological magazines this past year, you are aware that Hawaii is now hip-deep in a campaign against such animals. There are few places that aren’t concerned, to at least a small degree, about preserving the “natural” order of local Nature. Noble efforts, in some cases, but a bit confusing in concept and confused in practice.

We have all been exposed to the stories about the invasion of Guam by brown tree snakes (Boiga irregularis), voracious “tramps” that have decimated much of Guam’s native bird populations. Considerable expertise and expense has been paid to eradicate the snakes, to limited effect. The biological fall of Guam became a rallying point for preservationist actions. How justified are such eradication stances?

Certainly we have witnessed unwise (and this a charitable choice of words) introductions around the world. Mongooses were brought to Caribbean islands that lacked venomous snakes in order to eliminate perceived venomous snakes. They decimated poultry and small native animals and contributed to increased diseases. Australians imported rabbits to provide some “familiar” European animals. Crop damage by rabbits is now almost legendary. As is the damage done by cane toads. Poor Australia; even when it didn’t import the troublemaker, it helped increase the threat’s population size. Unaware that cut-up sea stars (“starfish” to some) will grow into new sea stars, Australian fishermen and (?) biologists captured crown-of-thorns sea stars, hacking them to bits, and tossing the still viable remains back onto the reef!

I thought California led the pack in released wildlife paranoia until the Hawaiian issue came along. Does anyone with herpetocultural experience believe that Jackson’s chameleons are a threat to bird populations? Granted that an adult lizard might take a fledgling, how rare is this event? My gray cells hurt when trying to conceive of day geckos as “injurious.” Sadly, almost nothing of “native” lowland Hawaii is still in place. Humans long ago annihilated the few true natives, replacing them with agricultural lands, ornamental plant (non-native) farms and tourist facilities. Certainly Hawaii should conserve its remaining native wildlife, but few native species dwell near cane fields and swimming pools.

The preservation of natural areas, if intelligently conceived and enacted, should be given highest priorities. What is so often overlooked is the reality of the number and degree of invasiveness of so many “foreign” species. Herpetoculturists may cringe when told Jackson’s chameleons will devastate Hawaiian birds, or that alligators may proliferate and become a threat in San Francisco, but does anyone consider that the most destructive animals—barring the all too obvious humans—are domestic cats, rats, and assorted plants? Goats were a big problem, but they have been culled from islands ranging from Round Island to New Zealand. Round Island, a tiny mound in the Indian Ocean, has had its goats removed in a so-far successful effort to preserve the rare and endemic gecko, skink, and boa species. Too late, alas, for one of the boas, now considered extinct. Cats are pets, and few people really consider how much damage they do to small animals, native or not. There are many more critical battles to wage than those against questionably influential species.

In my “natural” California neighbourhood, I am surrounded by eucalyptus trees (Australian imports, brought over by some genius who incorrectly thought they would provide a good source of lumber), and Mediterranean ice plants covering the fragile sand dunes. Ice plants have broad, fine roots that effectively take all the water in the soil, crowding out native plants and insects. Many streams are filled with the large tadpoles of non-native eastern bullfrogs (imported as a food commodity), which have steadily been eliminating the native frogs. English sparrows are common here. Mediterranean fruit flies periodically threaten (mostly non-native) crops. If I want to see a “native” coastal community, I have to go to a State Preserve, where I must stay on the designated path. Natives are now rare and often threatened.

We are told that humans are the main movers of animals and plants, to the detriment of native species. Geological facts dispute this assertion; how can humans compete with events such as the ramming of North and South America to allow hitherto unprecedented exchanges of species? Winds, rafts, and temporary bridges also contribute to the colonization of islands and continents. To use Hawaii as an example again, how else did the volcanic islands—never connected to or even located near a continental mass—obtain its flora and fauna? Long before human colonization, rafts, winds and sea birds brought seeds, insects, spiders, and a few lizards. Humanity has merely accelerated the rate of species transport. As a biological species, humans must be seen as a natural—albeit very rapid and effective—factor altering the global biogeography.

Maybe it is time to take a different view of “non-native” species. Looking at the paleontological record, few species alive today were “native” to their present distributions in times past. Biogeography is the study of distribution and dispersal of species. The dispersal we see today is “natural,” unless we can truly see humans as separate from everything else on Earth. Maybe the preservation of diversity should be more focused on defensive actions in largely uninvaded habitats rather than offensive actions against new colonizers.