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This blog post was also featured in the blog Life in the City 

Hurricanes are powerful storms that shape ecosystems by removing or displacing individuals. Additionally, hurricanes can change habitats due to tree mortality, damage and/or landslides. Ecosystem changes caused by hurricanes can impact species diversity. For example, following Hurricane Hugo, some insects thrived due to higher abundances of new young leaves as the canopy regenerated. On the other hand, canopy openness led to warmer and drier forest conditions which negatively affected other species. While we have several examples of how hurricanes impact species in forest environments, virtually nothing is known about how hurricanes affect urban species..

Hurricane in the city:

Cities can be quite different than non-urban ecosystems resulting in diverging ecological and evolutionary trajectories. Often, green spaces are highly cultivated which directly affects which species are able to exploit city environments. In this study, my co-authors and I evaluated the urban exploiter Anolis cristatellus to contrast population density and species composition in the months following Hurricane Maria.

Anole populations after the storm:

Hurricane Maria was a powerful category 5 storm that made landfall in Puerto Rico in 2017 near the southeastern region of the island. As such, eastern locales experienced stronger winds in contrast to more western regions. We began our study four months after the hurricane and visited sites again eleven and sixteen months after the storm. The main takeaway we found was that irrespective of when we visited, forest sites had nearly double the number of lizards as urban sites. Sites in the east had the lowest population numbers at four months after the hurricane and showed nearly a doubling in population size between four and eleven months afterward. We presumed that this is due to higher mortality at these sites since they experience stronger winds associated with the hurricane.

City humans as ecosystem engineers

An unexpected finding of this study was documenting how new plant growth following the hurricane facilitated the colonization of a bush specialist anole ecomorph at one of our sites. Four months after the hurricane, the forest floor consisted of leaf litter and downed trees and tree branches. However, both eleven and sixteen months afterward, new plants had established exploiting access to light resulting from the open canopies. Access to shrubs and young plants provided the preferred habitat of the grass-bush ecomorph Anolis krugi, a species that was not previously seen within that forest plot. In contrast, urban environments remained relatively unchanged. All of the downed branches and trees were quickly removed. Thus, while forest habitats and the ecosystems they support appear to be altered dramatically by hurricanes, human intervention maintained urban habitats near constant conditions during the extent of our study. Future studies might consider how human intervention in urban habitats affects ecosystems and the species they support.

Read the study

Avilés-Rodríguez, K.J., De León, L.F. & Revell, L.J. Population density of the tropical lizard Anolis cristatellus in urban and forested habitats after a major hurricane. Tropical Ecology (2022).

Featured Image: Anolis cristatellus (K. Avilés-Rodríguez)

From the Facebook page of the Wildlife Resources Division of the Georgia DNR.

The Ogasawara Islands are isolated oceanic islands with a subtropical climate located 1,000 km south of Tokyo. They are very attractive islands with many endemic plants and animals. However, those interested in nature may notice that there are few sounds of insect wings or signs of insects in the forests on Chichijima Island, an inhabited island within the Ogasawara Islands.

It is estimated that the green anole was unintentionally introduced to Chichijima Island in the late 1960s. Currently, there are several hundred to a thousand of them per hectare, depending on location. Predation by the anoles has reduced populations of mainly diurnal insects. Not only that, but disturbance of pollination systems in native flora has been noted due to the decrease in insects. The endemic skink, Cryptoblepharus nigropunctatus, was displaced where anole densities were high.

I first saw the green anole when I was involved in a project to eliminate introduced feral goats in Ogasawara. Wildlife management and conservation is my specialty. In this field, the problems of overabundant mammals such as deer and invasive introduced species are important issues. Researchers and practitioners who love animals frequently discuss the efficient capture of these animals and the eradication of invasive species at academic conferences.

When I attended conferences on reptiles, there were studies on conservation of reptiles that are affected by habitat destruction or non-native species. However, there were only a few studies that were oriented toward taking action against reptiles that cause damage to ecosystems as invasive species. Therefore, I thought I might have something to contribute, even though I am not a herpetologist.

In our first study of anoles published in 2015, we tested in the laboratory and in the field to see if we could attract them with a bait. If the bait could be seen moving, it could attract anoles up to about 2 m, even if it was in a transparent container. However, non-hungry anoles were not interested at all even if there was a bait in front of them. After this study, we wondered if it would be possible to identify their preferred location as a perching tree and capture them intensively. When we studied preference by tree species, they preferred the screw pine.

In the latest paper, I re-tabulated the data from the tree species preference study by trunk diameter. Anoles avoided tree trunks thinner than 1 cm in diameter, but had no preference by diameter for trunks larger than 2 cm. Except for very thin trunks, this means that trunks of any thickness are used according to their frequency of occurrence.

These behavioral traits may be a disadvantage when trying to capture green anoles and reduce their numbers. They are not attracted to dead, immobile baits; they are not interested in baits unless they are hungry themselves; they prefer the screw pine, but use other trees as well. Conditions for high-frequency use of sites are not clearly limited. Controlling lizard populations may be more difficult than for mammals.

On the Ogasawara Islands, where there are many endemic species, chemicals such as insecticides cannot be used easily. Also, consideration must be given to the bycatch of non-target species. We must improve our measures step by step to break through this difficult challenge.

Or perhaps we need to think differently from the way we capture mammals and insects. I assume that there would not have been many occasions in human history when we would have wished to capture a large number of reptiles in an efficient manner. It would be a great help if researchers in various fields are interested in controlling reptile numbers. In this regard, it is fortunate for those of us involved in anole control in Ogasawara to publish an article on the subject in Anole Annals, which attracts many people interested in lizards.

The latest research is available open access.

 

While green anoles may be a pleasant sight throughout their native range, they’ve become cause for concern in Japan–just one region of the Pacific where this species has invaded and become successfully established. The arrival of these anoles initiated a decline of several endemic arthropods, propelling a handful of subsequent studies on the invasion biology of this species. The most recent contribution to Anolis carolinensis ecology and biology in Japan is from Mitani (2022), who collected and analyzed perch ecology data on the Ogasawara Islands–check it out!

New literature alert!

Selectivity of Perch Diameter by Green Anole (Anolis carolinensis) for Trapping in Ogasawara

I can’t call myself a herpetologist, let alone an anologist, these days – now I mostly work on freshwater fish in Aotearoa/New Zealand, though I have dabbled in collaborations on native NZ geckos and skinks. Nonetheless, I was pleased to recently publish a paper on Puerto Rican anoles that was a decade in the making.

My one proper field season with anoles was back in 2012 when I was a postdoc with Jonathan Losos. I tried some experimental enclosures that didn’t ultimately work out, and took some pictures that contributed to a macroevolutionary study of dewlap size. In between these projects, I decided to pull together a dataset of several niche dimensions in the anole community around the El Verde Field Station. My undergraduate assistant Tanner and I collected data from 200 anoles of six species (Anolis pulchellus, A. krugi, A. cristatellus, A. gundlachi, A. stratulus, A. evermanni) in three ecomorph classes, with the idea to measure how niches were partitioned among ecomorphs, species, and sexes. We measured the usual perch characteristics and body temperature, and also collected diet samples non-lethally using gastric lavage (stomach flushing).

Nothing much happened for some time, as I had moved on to a second postdoc and then my current job at the University of Otago. A few years ago when Jonathan was clearing out his former lab, I put out a call for interest in the stomach samples that were still sitting in a drawer, and was lucky enough to spark Sean Giery’s interest in a collaboration. Sean, now at Penn State, has plenty of experience counting terrestrial invertebrate samples, and he made quick work of processing the stomach contents.

Now that the data set was complete, I just had to find some time to revisit it. Last summer I had study leave on Rēkohu/Chatham Island, and made use of the down time between fieldwork days to get the analysis done and written up. We used hierarchical analyses to estimate how much of the variation in perch characteristics*, body temperature, prey size, and prey composition was partitioned among ecomorphs, species, and sexes.

*I used perch curvature rather than diameter as the second measure, along with perch height. Curvature is just the reciprocal of the radius, assuming a cylinder, but it allows missing data (anoles perched on walls or the ground, for which a measure of diameter is meaningless) to be included assuming that these have effectively zero curvature. It made sense to me, but I’d be interested to hear if other practitioners find this intuitive or not.

The results aren’t going to blow your mind, and they confirm a lot of what is already understood about Greater Antillean anole communities. As expected based on decades of previous work, variation among ecomorphs explained the largest share of perch height and curvature, and variation among species nested within ecomorphs explained by far the most variation in body temperature. Perhaps the more surprising results were that ecological sex dimorphism explained little of the variation in any niche dimension, and that a large fraction of most dimensions was unexplained.

My feeling is that this approach to measuring multidimensional niche diversity in communities is more interesting than any particular result of this study. An idea I quite like is using this hierarchical approach for a comparative study of different communities. For example, one could ask how the partitioning of variation at each level changes over time as communities assemble, or how it changes across some natural or anthropogenic gradient. There is also room to do analyses that properly incorporate variation among individuals – we did include individual diet variation in a version of the analyses (using multiple items in one stomach as replicates), but the same individuals should be sampled repeatedly over time to see how consistent their foraging patterns really are.

All in all it has been fun thinking about anoles again after a long break. Our paper is available to read for free in the Journal of Zoology.

Eminent anole researcher Robin Andrews was recognized by the Herpetologists’ League with the 2021 Distinguished Herpetologist Award for her contributions to advancing scientific and public understanding of herpetology through research, teaching, and service. Her essay in Herpetologica chronicles the incredible, 50-year-long research program she, Stan Rand and others have conducted on Anolis apletothallus on Barro Colorado Island in Panama.

Here’s the Abstract:

I present the results of 50 yr (1971–2020) of annual censuses of Anolis apletophallus on Barro Colorado Island, Panama. The main objectives were to assess why abundance in end-of-the-year censuses varied substantially from year to year and why it declined over time. Abundance was negatively correlated with annual rainfall, 90% of which occurs in the wet season when eggs are laid. Lizard abundance is indirectly linked to rainfall through the interaction between Anolis eggs and their major predator, Solenopsis ants. More eggs are killed by ants when rainfall is relatively high because ants are more active and encounter more eggs than when rainfall is relatively low. While rainfall accounts for variability in abundance, it has not changed over time and thus may not account for the overall decline in abundance. Model selection of AICc analyses identified two other factors correlated with abundance. Abundance was positively correlated with the Southern Oscillation Index (SOI) lagged by 1 yr. High SOI (and high abundance) is associated with cool and wet La Niña conditions and low values with dry and warm El Niño conditions. The prediction that low abundance is associated with dry and warm El Niño conditions (low SOI) conflicts with the negative correlation between abundance and rainfall where low abundance is associated with high rainfall. Moreover, abundance was negatively correlated with Tmin (minimum annual temperature). The mechanism by which increasing Tmin during the census period is linked to declining abundance is unknown. Three climatic factors are correlated with lizard abundance, but none of them explain why abundance has declined. A third objective was to examine the relationship between species richness and species dominance of Anolis communities with respect to rainfall patterns. Tropical forests typically have a maximal richness of 7–8 species. Our study sites in Panama have high species richness, but Anolis apletophallus individuals made up 96% of all records, an unexpected level of species dominance. Comparisons among sites suggest that the number of Anolis species in a community is related to annual rainfall, and dominance is related to seasonality of rainfall. Dry forests have few Anolis species and wet forests have as many as 7–8 species. Forests with short wet seasons (months with .100 mm rainfall) have a high likelihood that individuals of one species will dominate the community.

 

As the abstract reveals, the paper summarizes an extraordinary amount of fascinating research. But there are also some great stories. This is my favorite:

My trip to Panama to conduct the Christmas lizard count with Stan was normally a very special and much anticipated annual treat. One such year, however, was far different from the treat I had anticipated. I had taken my Boston Whaler, on what was to have been a quick trip to our remote AVA site to replace fallen flagging tape that marked transects. This was a boat trip of some 9 km from the BCI boat dock on the canal (northeastern) side of the island to the AVA boat tie up on the back (southwestern) side of the island. My mission accomplished, I left AVA midafternoon and was close to the half-way point when the motor of the Boston Whaler quit. Not only was I alone on the back side of BCI, but the strong dry season wind was pushing the boat away from BCI. To stop the boat from drifting farther, I used its single oar to steer it to the nearest channel marker where I tied up. I had faint hopes of rescue because boat traffic was infrequent; the most likely scenario was that I would sit in the boat until nightfall when the wind would die down and I could start to paddle. This is exactly what happened. Progress around BCI was very slow because I had to sit on the prow of the Whaler and pull the boat forward with the oar while alternating strokes from one side of the boat to the other to maintain a somewhat straight course. It was thus quite dark when I saw the first of many waves of large, low-flying aircraft pass overhead. I heard the steady drone of the air traffic and felt extremely isolated in my small boat in the dark. I did not know until the next day that, in the early hours of 20 December, I witnessed the beginning of the 1989 US invasion of Panama!

It was well after midnight when, to my great relief, I was intercepted by BCI guards on their regular island patrol just as I saw the buoy lights of the canal; the guards towed me the last several kilometers of what had been a physically and mentally challenging journey. The next day BCI was deemed unsafe and all scientists, guards, cooks (and their food supplies), etc. were ordered to leave the island by the Smithsonian. For the first time in its history as a nature reserve, the island’s biota was left to its own devices. All the island boats were commandeered to take the residents of BCI to Gamboa (Fig. 3), one of the initial targets for US military action. When we were allowed outside, we visited the remains of a Panama Defense Forces building and saw what automatic rifle fire could do to the simple wooden walls and floors of standard issue Panama Canal Company buildings. That memory became especially vivid on that evening when our group was taking shelter in the concrete stairwell of just such a building because of nearby sniper fire. Panama City and rural areas were so chaotic that the Panamanian evacuees could not go home to their families, not even to know, in some cases, if they were safe. Despite these challenges, the cooks continued to produce great meals for us, including a turkey dinner on Christmas Day. At the end ofDecember, we were allowed to return to BCI. The Anolis team completed the scheduled censusing of four sites, but what remained of my vacation time was too short to conduct planned experimental studies. I was on the first commercial flight to the United States after the invasion, and, for the very first time, I was happy to leave Panama.

Read all about it in Caribbean Herpetology, freely available online. Here’s the Abstract:

Green anoles of the Anolis carolinensis group are divided into the carolinensis and isolepis subgroups according to a consensus of molecular phylogenies. Species in the Anolis isolepis subgroup (A. altitudinalis, A. isolepis, A. oporinus, and A. toldo) are endemic to Cuba and the highest diversity is concentrated in forested areas of eastern Cuba. Here, we describe a new species of this subgroup from western Cuba based on genetic and morphological differences from other species. Our phylogenetic analysis, based on DNA sequences, includes all of the known species and suggests that the new species is more closely related to A. altitudinalis, A. oporinus, and A. toldo than to the widespread A. isolepis. In addition, we provide a new hypothesis on the taxonomic status of A. incredulus and recommend that it no longer be considered as a species in the A. carolinensis group. Due to the lack of a diagnosis, and poor condition, of the only available specimen, we consider A. incredulus as a species inquirenda. New morphological and genetic data of recently collected specimens of A. oporinus and A. toldo will provide complementary information about these species known from one or a few specimens.

And here are some similar Cuban species:

This important herpetological updated appeared in the Miami Herald today.

Dave Barry: Fellow Floridians, beware of toilet lizards and rising iguana aggression

BY DAVE BARRY UPDATED JULY 15, 2022 2:47 PM

We need to talk about the lizards. I think they’re up to something.

Here in South Florida we’re accustomed to lizards, of course; they’re everywhere. When I moved here decades ago, the lizards were one of the things I had to adjust to, along with the hurricanes, the 250 percent humidity, and the fact that Miami drivers actually speed up for stop signs.

But the lizards didn’t bother me, because even though there were a lot of them, they were small and cute and non-threatening. They seemed to spend most of their time just standing around doing nothing, like members of a miniature highway-repair crew.

The most aggressive lizard behavior I’d see was the occasional male lizard trying to attract a sex partner by displaying the skin flap under his chin, which is called a “dewlap.” Apparently it is a strongly held belief among male lizards that the chicks really go for a guy with a big dewlap. It’s kind of like weight-lifter human males who believe human females are attracted to large biceps and consequently wear tank tops everywhere, including funerals.

But I was not threatened — nor, for the record, attracted — by the dewlap displays. I left the lizards alone, and the lizards left me alone. If I encountered lizards, say, on a sidewalk, they always respectfully skittered out of the way, in recognition of the fact that I was, compared to them, Godzilla.

But lately the lizards are different.

I don’t know what’s causing it. Maybe it’s global climate change. Maybe there was a leak from some kind of top-secret Chinese lizard laboratory. Whatever the cause, there seem to be a lot more lizards around than usual. But what’s really disturbing is that many of these appear to be a new kind of lizard: They’re bigger, and they’re uglier. They’re not the cute li’l Geico Gecko types. They’re more along the lines of junior-varsity velociraptors.

And they have an attitude. More and more, when I encounter sidewalk lizards, they do not skitter away. At best they casually saunter off in an insolent manner. I suspect they may also be vaping.

Sometimes these lizards don’t move at all: They just stand there defiantly, giving me that beady lizard eyeball, clearly conveying, by their body language, the message: “Why should I fear YOU? You have a small dewlap!”

Which, much as it pains me to admit it, is true.

Perhaps you think I’m overreacting. Perhaps you’re thinking, “OK, maybe the lizards are getting bigger and more aggressive. But why should I care? I spend most of my time indoors anyway, so this issue doesn’t really affect ME.” Oh really? Let me ask you a question: While you’re indoors, do you ever have occasion to use a toilet? I ask because of an alarming report I saw July 8 on NBC6 TV news. The report begins with a camera shot looking down into a toilet bowl, which contains a large iguana. As we’re seeing this, news anchors Jawan Strader and Jackie Nespral have the following exchange:

STRADER: Imagine walking into your bathroom at home and seeing this! An iguana in the toilet!

NESPRAL: OK, I don’t want to imagine that.

This exchange introduces a report concerning retirees Janet and Bruce Bleier, who, since moving to Hollywood from Long Island, have encountered not one, but TWO commode iguanas

The first time was in October, when Bruce went to use the bathroom late one night.

“I yelled to my wife, ‘There’s an alligator in the toilet!’ ” he recalls.

Janet discovered the second iguana. She offers this advice to NBC6 viewers: “Look before you sit.”

In both cases, the Bleiers called Harold Rondan, proprietor of a company called Iguana Lifestyles, who came and took the iguana away. (Iguana removal is a major industry in South Florida.)

Perhaps at this point you’re thinking, “OK, so this one couple had two iguanas show up in their toilet. It’s probably just a fluke. It’s not like it’s an epidemic.”

Oh really? Well perhaps you would be interested to know that on July 10, just two days after the NBC6 report about the Bleiers, another local station, WSVN 7News, carried a report about another Hollywood resident, Michelle Reynolds, who came downstairs one evening and looked into her toilet. Guess what she found?

That’s right: Rudy Giuliani.

No, that would be pretty great, but that’s not what happened. She found an iguana. A LARGE iguana.

“He took up most of the toilet bowl,” she tells 7News. There’s video of the iguana being removed, again by Harold Rondan of Iguana Lifestyles, who identifies it as a Mexican spiny-tailed iguana. Even by iguana standards, this is an ugly animal, and it does not look happy. You can tell by its facial expression that its goal in life is to grow much bigger so that one day it can come back and eat Harold Rondan of Iguana Lifestyles.

And that’s not the end of our story. On July 11, one day later, the Bleiers were once again on the local TV news. It turns out they had yet another toilet iguana. This was their THIRD.

So please don’t try to tell me this isn’t an epidemic.

I spoke by phone with Janet Bleier, who said she and her husband are trying, with the help of Hollywood authorities, to figure out how the iguanas are getting in, but so far they’ve had no luck.

I asked her if they ever encountered toilet iguanas when they lived in Long Island.

“Nope, nope, nope,” she said, adding, “nope.”

I asked her if they had considered moving back to Long Island, and she said they had not, but she added this: “We never, ever, walk into one of our bathrooms any more without checking. Even if we’re not going to use the toilet, we look.”

In case you think this epidemic is confined to Hollywood, I urge you to Google “toilet lizards.” You’ll discover that this has been going on for a while now, and not just in Florida; it’s happening in warmer climates all over the world.

So I repeat: The lizards are up to something. But what? Are they planning some kind of coordinated attack? Are we going to find ourselves in a real-life version of the classic Alfred Hitchcock thriller movie “The Birds,” in which suddenly, out of nowhere, a peaceful California village is terrorized by a huge, mysterious flock of violent toilet iguanas?

I don’t have the answers. As a journalist, all I can do is raise questions, in hopes of getting internet clicks and creating widespread panic. It’s up to the authorities to take whatever steps are necessary to end this crisis, even if that ultimately means relocating the entire population of South Florida to Long Island.

But for now we all need to do our part. This means keeping our toilet lids down, of course, but it also means standing up to the lizards and letting them know we’re not afraid of them, even though we actually are. The next time you encounter a lizard, either on the sidewalk or, God forbid, in your bathroom, look it straight in whichever eyeball is closest to you and tell it, in a firm, clear voice: “We know what you’re up to.“ If it’s a Mexican spiny-tailed iguana, you should say this in Spanish.

Also, if you have a dewlap, you should display it. They respect that.

Read more at: https://www.miamiherald.com/living/liv-columns-blogs/dave-barry/article263508388.html#storylink=cpy

Dr. Phillip Smith of Georgia wrote to Anole Annals:

“For the past several days one of my anole friends has appeared at my back door windows at about 12:30 PM.  I have studied and played violin as a pastime since about 1947, and play a bit every day. I had happened to choose that time on the first day and after a few minutes my attention was drawn to this little guy poking his nose farther and farther in a jabbing way into the window as he “moon-walked” along the side of each pane.  He had glided down to the bottom of the door window when I really began to watch, and it was so in synch with the music that I kept playing for a bit.  

He kept up his activity, sometimes appearing almost completely, always making a rocking, jabbing movement with his body, gradually moving to his right and the other side of the window.  When he got there he really took off upward with his head always extending onto the glass and “slid” to nearly the top of the door, then gradually worked back down.  By then I had been watching for several minutes, and realized this was no accident (or at least so I projected).  

I got my iPhone and began to try to capture his activity.  Of course this meant the music stopped, and the activity diminished pretty quickly.  When this became obvious I hustled back to my violin and began to play.  Within a very short time he was back at it, and he stayed for at least a half hour.

The door opens on a small slab, about ten feet square as is common in condos, with grass around its two sides and a shed along the left side.  I have quite a few large potted plants including a nine-foot yellow pine and a climbing rose on my back fence, many of which have been there for years.  The eave overhangs the back wall and door until about 1:30 at this time of year, so is shaded when he comes, and he has come for several days in a row, always with similar interaction.  I don’t even know how or what anoles (If he is indeed one) hear and was a little surprised he could hear through the glass, but then it occurred to me he might be sensing the vibration through his feet.  

I am a retired physician and very interested in this phenomenon, and experienced enough in scientific literature to know it would take me “forever” to ferret out information truly relevant to this interaction and my little friend, which is why I thought to contact you in this way.”

Dr. Smith then provided two videos, which he describes (see videos at bottom):

“The “screen” for the interaction is a French door with five apparent panes of glass, facing due west with a shading, overhanging eave above it, which becomes sun-exposed at about 2:20 PM.  The videos and photos were all taken in the period after 11 AM, when the anole appeared only once—all other “visits” were between 12:50 and 1:30.  

Sadly the reason the anole attracted my attention on the first interaction was that he/she moved very actively around the lower 1/3 of the door glass frequently making jabbing, bobbing up and down movements along the bottom and once “moon-walking” almost all the way up the left side and back down.  These movements were almost continuous for more than 30 minutes, and did not suggest hunting.  But because I could not photograph this and play the music at the same time, and I had not previously used the “selfie stick” I had, the later videos don’t show much of this.  

There are periods of activity and some fairly long periods of simply “freezing” in place, sometimes off the edge of the glass out of view.  

In the longer video I couldn’t get both the very top and bottom of the glass in the frame where I could anchor the camera stand, and the anole really doesn’t appear until just after 5 minutes.  From the start his primary attention seems to be the insect life on the outside of the door.  He moves up and down the right side of the glass often looking toward the middle of the door and from time to time scratching his head with his back foot (I think usually his left) as @ 16 minutes 59 seconds.  

There is a fairly active section from 23:30 to the end of this video, especially a dart downward to nail a bug @ 27:09.

The overall impression of the 11 and a half minute video is similar. The anole is present from the beginning with movements up and down from one pane to another, and his intent seems to be to get something to eat.  

I don’t think there is a particularly convincing relation of his movements to the music in either of these.”