AA reader John Thomas questions whether curly-tailed lizards (Leiocephalus carinatus) actually eat anoles, based on his own observations in Florida (see comments on this post). Let’s see proof, he says! Bob Powell rightly points out the scientific literature on this topic and refers to the Schoener et al. paper from 1982 on the diet of curly-tails in the Bahamas. And here’s a photo from that paper! I’ve seen at least two other photos people have taken of such predation–anyone got more?
Anolis chlorocyanus in its habitat. Photo by Jonathan Losos.
Hello All, I’m an ecologist that studies species-habitat relationships, among various other things. I’m presently working on a book that will describe 10 methods of statistically analyzing habitat and also try to provide a conceptual unification of how capital-E ecologists and wildlife ecologists have traditionally viewed habitat and its importance. I’m looking for real empirical datasets to analyze. Data for Anolis species would be great given their importance in testing ecological and evolutionary theory, and their specific habitat preferences. The dataset could be for a single species or multiple species. It could have either microhabitat data (e.g., observations of Anolis individuals at different perch heights and stem diameters, tree species perched on) or macrohabitat data (e.g., amount of vegetation or canopy cover within a 10 m diameter of lizard location). Really any kind of environmental or habitat data would work. Ideally, the dataset would also have environmental data from locations where lizards were not observed (so-called absence points). If you have a dataset that you’d be willing to share please contact me at joseph.veech@txstate.edu. THANKS!
Great news from the conservation group Island Conservation, where this post appeared. Check out all their great work! Also, see Anole Annals posts on this project.
If conservationists had waved a magic wand, the results could hardly have been more spectacular. Within 12 months of starving goats and thousands of ravenous rats being removed from Redonda1, this remote Caribbean island has witnessed a miraculous transformation.
Since the ambitious restoration programme2 was rolled out, the rock of Redonda has been transfigured from an inhospitable lunar landscape to a greener haven. More importantly, the unique plants and animals native to this isolated, uninhabited outpost of Antigua and Barbuda are making a rapid recovery after being freed from an alien invasion.
The evocatively named Redonda ground dragon, a rare black lizard found nowhere else on the planet, has doubled in number – just one of the many fantastic beasts that have been pulled back from the brink of extinction by removing the predatory black rats and plant-devouring goats.
Redonda before restoration. Credit: Ed Marshall
And it doesn’t stop there. In less than a year, numbers of the equally rare Redonda tree lizards have tripled, hundreds of new trees have sprung up, land birds have increased tenfold, and the island’s globally important seabird colonies – including magnificent frigatebirds and several booby species – are having their best breeding year on record.
Speaking on behalf of the Department of the Environment, Dr Helena Jeffery Brown said:
The Government of Antigua and Barbuda considers the return to life of Redonda as a shining beacon in our collective efforts towards ecosystem restoration and biodiversity conservation that will bring us another step closer to attaining some of the Aichi Biodiversity Targets3.”
The project’s coordinator, Shanna Challenger, of the Environmental Awareness Group (EAG) and Fauna & Flora International (FFI), added:
This has been the opportunity of a lifetime – witnessing an island be reborn. Changes forecasted to happen in five years occurred within months. Our conservation efforts really show the benefits of invasive species removal on Caribbean island ecosystems.”
View heading north post-eradication Nov 2017. Credit: ShannaChallenger_FFI
In the field of conservation, where successful outcomes can take years if not decades to materialise, the spectacular results on Redonda appear remarkably swift.
The reality, of course, is that this ‘overnight’ transformation was a long time in the making. It took seven months of blood, sweat, toil and – above all – teamwork to catch dozens of nimble goats and remove over 6,000 rats from every inch of Redonda’s rugged terrain. This Caribbean island makeover involved meticulous planning, ingenuity, and edge-of-the-seat maneuvers that included abseiling down sheer cliff faces to lay down rat bait and, thanks to the skilled pilots of Caribbean Helicopters Ltd, landing equipment in very tight spots.
New Zealand-based Wildlife Management International Limited led the rat eradication team: “We have over 30 years of experience in clearing invasive species from islands,” said ecologist Elizabeth (Biz) Bell, “but having a ground team, rope access team and helicopter team using a combination of bait stations, hand broadcasting and aerial methods to successfully target all of the rats makes the Redonda project unique.”
The British Mountaineering Council (BMC) played a vital role in ensuring that even the steepest cliffs could be reached. Safety was paramount, as CEO Dave Turnbullrecalls:
The volcanic cliffs of Redonda presented an extremely challenging environment for the climbers to operate in; the BMC was very pleased to support this important conservation project and help ensure the safety of the team throughout the work.”
The safe removal of the malnourished herd of rare-breed feral goats presented an altogether different challenge, as Dr Karl Campbell of Island Conservation can attest:
This project was essential for the wellbeing of the goats and to enable the ecological recovery of the island. The translocation of goats has seen a suite of positive impacts, and further benefits will unveil themselves in time.”
One intriguing consequence of removing the predatory rats is that lizards on Redonda are rapidly changing their behaviour, according to scientists from Harvard University and the Museum of Natural History in Paris. “We measured anti-predator behaviour and found that the ground dragons are becoming fierce and fearless now that the rats are gone, chasing and eating even adult tree lizards”, said Dr Colin Donihue. “This new balance of nature is more in line with what we’d expect of these animals before rats were ever on the island.”
Redonda ground dragon. Credit: Jeremy Holden_FFI
The long list of organisations that cooperated in this mission reflects the complex challenges that had to be overcome. The government of Antigua and Barbuda along with the EAG and FFI joined forces with leading technical specialists from the UK, USA and New Zealand.
Thanks to their collaborative efforts, Redonda has been rat free since March 2017 while the feral goats4 have been rehoused and are being cared for by the government’s Veterinary and Livestock Division on Antigua. Biosecurity equipment and protocols have also been installed to prevent future invasions.
Redonda harbours endemic species that occur nowhere else in the world, including at least five species of reptiles, and globally important colonies of seabirds. Conservationists argue that Redonda’s unique and special wildlife, coupled with the historical remains of one of the region’s largest guano mines, warrants greater protection for the island. They’re not the only ones. A recent nationwide survey revealed that over 96% of Antiguans and Barbudans agree the island should be protected.
Preparations for designating Redonda and the surrounding sea as a reserve are now under way, led by the Redonda Steering Committee, chaired by the Department of Environment.
According to Dr Robin Moore from US-based Global Wildlife Conservation, which has supported this project and is now helping with planning for the protected area, “It’s incredible to see this radical and rapid transformation of Redonda from a bare rock to a carpet of vegetation. As plants and animals continue to rebound, this could truly be a showcase sanctuary for wildlife.”
– END –
High-resolution images are available upon request. For more information and interviews, please contact:
Sarah Rakowski | Head of Communications, Fauna & Flora International | Tel: +44 (0)1223 747 659 | sarah.rakowski@fauna-flora.org
Notes to editors:
Greg Pauly, the world’s authority on the anoles of California [1,2], kindly passed this information along to AA:
Evolution 2018 may have been a week and a half ago, but the fun doesn’t have to stop just yet. Shane Campbell-Staton reports on the talk by Guin Wogan:
As we all know by now, contemporary climate change is expected to cause problems for species across the globe. Understanding the mechanisms that will allow species to cope with these changes, through acclimation and/or adaptation, is one of the most pressing issues of contemporary biology. Reptiles, and lizards in particular, have been a model for studying the effects of climate on extinction, gene flow, performance, and adaptation. Yet, only recently have we really begun to understand the genetic mechanisms associated with survival and persistence in the face of changing environments. In this year’s Epigenetics and Adaptation session of the Evolution Meeting, Guinevere Wogan – a postdoctoral researcher in Ian Wang’s Lab at UC Berkeley – presented a first look at how variation in the epigenome correlates with climate variation with and between anole species.
Wogan et al. used reduced representation bisulphite sequencing to search for epigenomic associations with environment in two wide ranging species – Anolis cristatellus on Puerto Rico and Anolis cybotes on Hispaniola – both species that occur in a wide variety of habitats from cool, wet forests to dry, arid scrubland. They found some indication of convergent methylation profiles under similar climates within species, suggesting epigenetic signals may be important for acclimation and/or adaptation to local climate. However, this association was not perfect potentially due to habitat use differences between populations. Additionally, they found that variation in climate between populations explains a large degree of variation in methylation profiles between popualtions within each species (75.6% in A. cristatellus and 39.1% in A. cybotes), again suggesting an important role of epigenetic modification in contributing to survival in local environments. However, local climate isn’t the only factor effecting variation in epigenetic modification; they also found strong species level differences in methylation, even when populations occurred in similar environments.
As they continue to work on this study, it will be very exciting to see what further patterns emerge. As we collectively seek to better understand the mechanisms involved in environmental adaptation and acclimation, Wogan et al. are exploring an extremely understudied aspect of Anolis biology that is bound to shed valuable light on the subject. I’ll certainly be on the lookout for this manuscript in the near future.
Typical Habitat of Anolis onca, close to the ocean.
Anolis onca
I kept Anolis onca, as a hobbyist, in the late 90s; they were available via European breeders who had obtained them on Isla Margarita, Venezuela. I had some breeding success with them at that time, and have always found them fascinating. I assumed their range was specific to Margarita Island, but only later via Anole Annals saw a photo from Manaure and realized that they were also found in Colombia. I travel frequently to Colombia and know that area of the northeast where the photos were taken, so when I was in the area, I would look for them.
Typical Habitat with Milkweed
I first saw them about 4 years ago, during a day trip near Rioacha, the Departmental Capital of La Guajira. The first ones I saw were very small juveniles which were sunning themselves in very thick piles of discarded branches, and so were difficult to catch, handle and photograph. In a subsequent trip in 2017, I enlisted the help of some of the local Wayuu (the indigenous group that is predominant in that area of the country). They called them the “lizard that doesn’t move,” which is a very apt description of their habits.
The habitat in the region is characterized as being dry Chaparral (though with very few trees), and is very windy. While looking for Anolis onca, we would find nests of the local dove species, which choose to nest on the ground versus in the low lying trees probably due to the wind. The main shrub is a species of Milkweed, and animals were found within yards of the Ocean.
I am no newbie to looking for Anolis, but A. onca really is very different in its behavior compared to many of the anoles I had previously observed in the wild. While you often find them on the ground in the midst of thickets of vegetation on the beach, they are very slow and deliberate in their movements and as you approach them. They only seldom move when approached, even when you are very close to them. They are almost twig anole-like in their behavior and obviously rely on camouflage as their first line of defense.
Despite the sparse nature of vegetation in their habitat, ground dwelling habitats and relatively large size for an anole (about 4-5 inches SVL and 6-7 inches in TL), they are a challenge to find. I would estimate that we saw only one animal every 1.5 hours of searching (there were three of us actively looking). We probably saw nine over about 12 hours of searching.
I would be very curious to hear from others who have observed them in the wild, and if Anolis annectens, which is closely related, is similar in its habits.
A. onca male flaring Dewlap on Capture
Cities were hot at this year’s Evolution meeting because they provide valuable petri dishes for asking myriad evolutionary questions. For example, cityscapes tend to create and retain heat–the so-called urban heat island effect–resulting in significantly elevated temperatures in urban areas relative to nearby undeveloped landscapes. Hot cities thus provide scientists an opportunity for asking questions about how plants and animals adapt to tolerate high temperatures. These questions are especially relevant as the built landscape continues to creep into less-developed surroundings and the globe as a whole experiences year after year of record temperatures.
Dr. Shane Campbell-Staton and colleagues used steep thermal differences between cities and nearby forests in four municipalities in Puerto Rico to determine whether, and to what extent, lizards may have adapted to warmer temperatures in the city. First, they found that operative temperature does change: lizards in cities use warmer perches and they operate at higher body temperatures than their forest counterparts. When brought back to the lab, however, those city lizards did not continue to function better at higher temperatures than their forest counterparts.
So what might be underlying this thermal plasticity?
Campbell-Staton and his collaborators then brought lizards back to the U.S., bred them, and raised the offspring in common conditions. Surprisingly, they found that the differences they observed in the wild populations disappeared in the next generation, an indication that this thermal ability is a plastic response to the thermal environment.
This thermal plasticity observation generated another question: Is thermal plasticity the target of natural selection in urban heat islands? To investigate this, Campbell-Staton isolated and analyzed transcriptomes of skeletal muscles in lizards from the hot city and cool(er) forests. Indeed, after the lizards were subjected to controlled heat treatments in the lab, they found a suite of candidate genes that were expressed at different levels between the populations. More genomic wizardry is planned for the very near future.
The work is ongoing and a very exciting paper is coming together. Keep your eyes peeled because it will certainly make a splash. Additionally, if you’re interested in this kind of work, Campbell-Staton has just started a lab at UCLA and is actively recruiting new lab members. Shoot him an email here.
The anole dewlap is a powerful visual signal to attract sexual partners and repel rivals and predators. The diversity of dewlap color has fascinated researchers for decades, environmental lighting and species competition being among the potential drivers of its evolution. At the Evolution meeting in Montpellier, Winter Beckles, PhD student at the University of Miami, presented his great study on the bark anole. Anolis distichus invaded Miami through multiple introductions events. Intriguingly, these little lizards occupy a range of habitats and present polymorphisms in their dewlap color within populations.
For his PhD, Winter and his colleagues measured the reflectance spectrum of the habitat and of the dewlap of 20 to 25 males per population. They found a strong positive correlation between the relative abundance of habitat UV light and the UV light reflected by the dewlaps. But that was before Hurricane Irma hit Miami in September 2017. And what a destruction it was: the trees, the canopy, the plants and by consequence the habitat lighting, were affected by this catastrophic event.
Despite the obvious negative consequences of the hurricane, this event gave a great opportunity to test the effect of extreme habitat change in the variability of dewlap color in the bark anole. Thus, after Irma, Winter and his colleagues immediately returned to each field site to collect reflectance data of the habitats and dewlaps: Irma altered the light profiles across sites and the correlation between dewlap and ambient light disappeared. In order to track how the relationship between dewlap color and habitat lighting develops over time, Winter plans to collect data in 2018: maybe the correlation will be back. Looking forward to seeing the paper.
Two of the authors (Colin Donihue and Raphaël Scherrer) with their poster at Evolution 2018
How do new species form? At ESEB 2018, Colin Donihue uses Anolis lizards to answer this fundamental question in evolutionary biology.
Anoles are known for their adaptive radiation in the Carribean and the corresponding diversification into distinct “ecomorph” categories. Each ecomorph is associated with distinct morphologies and behaviors that allow it to live easily in a different habitat. This pattern is repeated across the Greater Antillean islands, but what we see is the end result of an adaptive radiation – each ecomorph corresponds to a separate species.
Donihue and his co-authors embarked on an ambitious project to capture the beginning of an adaptive radiation. To do so, they turned to the ubiquitous brown anole, Anolis sagrei. As Anolis sagrei is found across the Bahamas in a variety of different habitats, you might expect to see them adapting to those different habitats through changes in morphology; in other words, looking at the early adaptation of Anolis sagrei populations in different habitats is a natural experiment reflecting the early stages of ecomorph development. And since Anolis sagrei is on islands across the Bahamas, there isn’t just one experiment, but several replicated ones. Donihue et al. could therefore also question the role of contingency vs deterministic evolution though their study.
The authors captured 20 individuals from coastal scrub, mangrove, and primary coppice forest habitat across 11 islands in the Bahamas, and measured a suite of morphological traits for all individuals; these traits include the “usual culprits” of ecomorph differentiation, such as forelimb length, hindlimb length, and lamella count. This effort resulted in an enormous data set that the authors could use to test whether brown anoles had adapted to the different habitats across all the islands.
So are the Bahamian brown anoles adapting along early ecomorph lines? Well…sort of. On any given island, lizards living in different habitats have different morphological characteristics. But, looking across islands, Donihue et al. observe different patterns of morphological specialization on each island. This suggests that contingency, in this case represented by the island of origin, is playing a large role in how the lizards adapt to the three different habitats.
In an interesting twist to the project, Donihue et al. used supervised machine learning to test whether lizards could be assigned to the correct habitat categories based on morphology. They found that this algorithm could assign lizards to their habitat correctly based on the input of their morphological measurements across islands. This result implies that determinism is playing a role in the specialization of these brown anoles, but may only be detectable when looking at a lizard’s holistic phenotype rather than any individual trait measurement. Looking forward to seeing the paper on these results!
Anolis gundlachi, Photo taken by Johann Crespo Zapata
Disturbance events can be important drivers of population dynamics for many different species. Puerto Rico, an island in the Caribbean, experienced two major disturbances over the course of a few years – a drought in 2015 and a hurricane in 2017 – that caused stress to the herpetofauna living in the region. The yellow-chinned anole, Anolis gundlachi, is particularly susceptible to disturbance events because it is a thermoconformer and vulnerable to dehydration. Johann Crespo-Zapata and his team wanted to track the population of yellow-chinned anoles in the tropical mountain forest of Sierra de Cayey during and after these disturbance events to determine how the population would change.
Johann and his collaborators counted A. gundlachi along four 30-meter transects to determine population size. The crew split its groups into adults (> 45 snout to vent length, SVL), large juveniles (20-45 SVL) and juveniles (<20 SVL). The team also collected precipitation levels using a local weather station to determine if each month had less rain than average, which is called a rain deficit. Following the population subsets over the last four years allowed Johann to understand how the population responded to hydric stress. He recorded a decrease in juvenile abundance as rain deficit increased (r = -0.352, p < 0.0482, n = 32), which suggests a decrease in recruitment. There was no overall trend for large juveniles in response to the drought. Adults displayed a similar pattern to that of juveniles, as they experienced a decrease in abundance with increased deficit. After a time lag, adults experienced an increase in abundance when the drought lifted (r = 0.4469, p <0.0024, n = 44) that could be attributed to increased mortality during the drought events.
Sierra de Cayey forest after Hurricane Maria, photo taken by Johann Crespo Zapata
Following this study period, hurricane Maria struck Puerto Rico, causing structural changes to the forest canopy and decreases in humidity. Immediately following the hurricane, Johann saw the anole abundance decrease to its lowest point. Johann plans to continue to follow this population for the foreseeable future to observe population dynamics in A. gundlachi populations following major hurricane disturbances. Understanding the population dynamics of these anoles is critical to comprehending how this species and others like it will cope with increased disturbance events that will become more frequent according to current climate change projections.
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