Yale Undergraduate Fiona Reed has designed a website in which you can answer a few question and determine which anole ecomorph you are. Give it a try! And then tell us what you are?
Author: Jonathan Losos Page 13 of 130
Professor of Biology and Director of the Living Earth Collaborative at Washington University in Saint Louis. I've spent my entire professional career studying anoles and have discovered that the more I learn about anoles, the more I realize I don't know.
from the Cayman Compass
Cayman’s island-hopping lizards offer evolutionary insight
Most visitors to Cayman Brac will likely not have noticed one of the island’s now established transplants: the Maynard’s anole.
This non-native lizard spends much of its time just out of eyesight, perched in the tree branches where its bright green colour blends with the foliage. The elusive anole, originally from Little Cayman, has captured the interest of researchers, intrigued by the insight the species can offer about evolution in island ecosystems.
And the Maynard’s anole is not the only island-hopping lizard on the minds of Cayman Islands researchers these days. While far from the invasive status of the prolific green iguana, the brown anole is also creating questions about the potential impact on Grand Cayman’s native blue anole.
Through separate studies – one carried out by Caymanian researcher Vaughn Bodden and another by National Geographic Society grantee Inbar Maayan – biologists are getting a better idea of how invasive species adapt and populate new territories.
Maynard’s anole in Cayman Brac
While the Maynard’s anoles in Cayman Brac are not far from their native home, Little Cayman, the lizard sheds light on how invasive species colonise new habitat.
Fortunately for Cayman Brac, the Maynard’s anole does not appear to pose a threat to the native Cayman Brac anole and has not shown potential for hybridisation.
“Based on similar invasions on other Caribbean islands, we expect the potential for a negative impact to be low. The native anole in Cayman Brac is found low on tree trunks and on the forest floor, while the introduced anole is predominantly found on upper tree trunks and in the canopy so direct interaction between the two species should be limited,” said Bodden, who studied the species while completing his bachelor’s in conservation biology at the University of Plymouth. He is now completing his master’s in biodiveristy and conservation at the University of Glasgow.
“Any impacts on the native anole are more likely to be indirect, such as a shift in habitat use to further avoid interacting with the introduced anole,” he added.
The Maynard’s anole, first spotted in the Brac in 1987, does show signs of adaptation, however, when compared to its counterpart in Little Cayman.
Through fieldwork capturing and analysing the anoles in both Sister Islands, Bodden’s team, assisted by University of Plymouth lecturer Robert Puschendorf, found some interesting differences in their morphology and ecology. While the team hypothesised that the introduced anole might have developed longer hind legs – a trait that can aid dispersal and movement – their findings did not support this. In fact, they found much the opposite. The anole had instead developed longer forelimbs.
“Potential explanations for the rapid divergence could be that the founding individuals of the introduced population had a unique phenotype and these characteristics became exaggerated over time through the process of genetic drift, or that some habitat use characteristics that we did not measure on Cayman Brac are driving the morphological adaptation,” Bodden said.
Another interesting discovery about the introduced anole population was the presence of a parasite not previously recorded in the Sister Islands.
The source of this parasite remains unclear.
“The ectoparasites we found infecting A. maynardi [Maynard’s anole] have not been recorded in the Sister Islands, so this study provides the first evidence of its presence there. It is unclear whether the parasite species is native to both islands, invasive to both islands, or co-introduced from Little Cayman to Cayman Brac with its host,” Bodden said.
“We found that the introduced population [in Cayman Brac] had a reduced ectoparasite prevalence compared to the native population [in Little Cayman].”
The further researchers ventured from long-settled habitats, the lower the prevalence they found of the parasite.
This is something that may have benefited the introduced population and encouraged colonisation.
While the origin of the anole’s introduction to Cayman Brac is unclear, its presence there sends a reminder about the importance of safeguarding borders.
Due to the islands’ prevailing easterly trade winds, Bodden suspects the lizard had human rather than natural assistance in its introduction, possibly as a stowaway in a flight or boat.
“This is a unique situation where we have a species endemic to one of the Cayman Islands being introduced to another one of our islands. Fortunately, this introduction is not a major threat to the ecosystem in Cayman Brac, but it highlights the need for more vigilant bio-security control at our ports,” Bodden said.
“Unchecked cargo transportation provides a route for other invasive species, such as the green iguana, to be transported into or between the three islands.”
Brown anole in Grand Cayman
Theories about how the brown anole, found endemically in Cuba and the Bahamas, arrived in Grand Cayman reinforce the call for careful biosecurity measures at ports. While researchers do not know exactly how the anole arrived here in the 1980s, its prevalence in the western end of Grand Cayman hints that it may have arrived through shipping.
Although Maayan, currently a Ph.D. candidate at Harvard University, did not find brown anoles in the numbers she had expected, she warned of complacency when it comes to invasive species.
“I was expecting them to be more of a problem than I saw, but it speaks to the importance of monitoring introduced and invasive populations,” she said.
Maayan said the brown anole should not be considered invasive in the same sense as the green iguana. But she cautioned that at a time, even the green iguana’s population numbers were much lower than they are now.
Much of the findings of her Grand Cayman research is not ready to share with the public, but she shared a few takeaways from her time on island.
Maayan described Cayman’s native blue anole as an incredibly charismatic and stunningly beautiful animal.
“They are a good ambassador for the Cayman Islands,” she said.
Maayan was interested in whether the presence of the brown anole had led to changes in the native anole’s habitat or physical characteristics. Physical changes in leg and head size, for example, could communicate competition between the species for habitat and resources.
“The reason why these [island] species introductions are particularly useful is they mimic what we would see in evolutionary time,” she said.
“It gives a glimpse in a natural setting of when species come into contact and compete.”
With the help of local researchers, including Vaughn Bodden, Morgan Ebanks and Jane Haakonsson, she scouted out sites where just the Grand Cayman anole lived and sites where both species lived, for comparison.
Finding the brown anole was not as easy as she expected, however. While the lizard is found abundantly in Belize, where it is also an invasive species, this was not what Maayan observed in Grand Cayman.
Researchers sampled two sites heavily, taking data from more than 200 lizards. The team took data on habitat use of both species, and took measurements of the blue anole’s physical characteristics.
Maayan’s next step will be performing DNA analysis on the lizards to determine the level of migration and morphology.
Fortunately for the Grand Cayman anole, Maayan’s initial findings show little impact on how the lizard interacts with its native habitat.
While the brown anoles seemed to prefer perching in lower, sunnier areas, the Grand Cayman anole stuck to shadier natural areas. It would appear the lizards have adapted to separate habitats.
The full findings of Maayan’s research are expected to be released this summer, after the study has been reviewed and published by the National Geographic Society.
Anole Annals‘ woman in Florida, Karen Cusick, has photo-documented more interesting anole behavior (Karen has observed and photographed much interesting green and brown anoles behavior. Search this site for her name or “Daffodil’s Photo Blog” and you’ll find all kinds of interesting observations). oday I saw something I don’t think I’ve seen before, and I’m sending you a few photos. A big male brown anole was sitting in the sun on the upper rail of the fence when a big male green anole approached. He stopped about 6 inches away from the brown anole, and started bobbing his head and displaying his dewlap. The brown anole watched but didn’t react. The green anole moved closer and displayed again while the brown anole watched. Just as I was wondering if there would be a fight, the green anole suddenly ran past the brown anole along the rail and then down off the fence.
Read more about Elaine Powers’ books, including her most recent post, “Stop and Meet the Anole Lizards,” on her author’s webpage.
Up until the mid-1980s, there had never been a recorded sighting of the Maynard’s Anole (Anolis maynardi) on Cayman Brac island despite it being less than 10km from its native territory, Little Cayman.
However, since the species was first discovered on Cayman Brac in 1987 – in what is thought to have been a human-assisted colonisation – its population has spread right across the 39km² island.
For this study, recent graduate Vaughn Bodden and Lecturer in Conservation Biology Dr Robert Puschendorf conducted a detailed analysis of the invasive species.
They wanted to assess whether individuals at the forefront of the invasion have developed distinct biological traits that are advantageous for dispersal, and compared their findings to animals in the area of first introduction and the native population on Little Cayman.
They discovered the Cayman Brac population has diverged morphologically from the native population, and within the invasive range there was trend of increasing forelimb length from the core to range edge areas. This ran contrary to the expected findings that longer hindlimbs would be the trait selected as a dispersal-related phenotype.
They also showed that the introduced population had lower levels of parasite prevalence, and that both males and females were of significantly higher body condition than the native population.
Writing in the Journal of Zoology, they say the results are a perfect example of how a species can colonise a new territory, and the biological adaptations it can make in order to do so.
Vaughn, who graduated with a First from the BSc (Hons) Conservation Biologyprogramme in 2018, said:
“There has been a history of lizard studies indicating that longer hindlimbs are an important factor affecting movement ability, so to not find longer hind limbed animals on the range edge was a surprise. For parasites, we found a clear decreasing trend in prevalence within the invasive population from the area of first introduction to the range edge, indicating that the parasites lag behind the host during periods of range expansion.
“We think our findings add to the growing body of literature that demonstrates the complex dynamics of species’ invasions. The results highlight that the animals on the range edge of an invasion are likely to be experiencing different ecological selection pressures that can result in changes in behaviour, morphology, and health for the animals.”
Dr Puschendorf has spent several years researching the consequences of emerging infectious diseases and climate change on biodiversity, with a particular focus on Central America. He added:
“Biological invasions are an important conservation threat across the world. However, every invasion needs to be carefully investigated to identify impacts to native eco-systems and identify potential mitigation strategies.
“In this instance there is likely to be limited overlap with, and therefore a limited threat to, the endemic anole population – the Cayman Brac Anole (Anolis luteosignifer) – because one inhabit the crowns of trees while the other is found closer to the ground. This in some ways highlights the challenges biodiversity managers face when managing species invasions with limited resources, and emphasises the need for greater collaboration among scientific and policy communities.”
Inbar Maayan tells all about her ongoing work in the cover story of this month’s issue of Flicker, the bimonthly bulletin of the Cayman Islands Department of Environment’s Terrestrial Resources Unit. Check it out, and also read about Caymanian fossils and the massive effort to eradicate invasive green iguanas (half a million and counting!).
In a somewhat autobiographical romp through the history of species delimitation, David Hillis, in a recently published article in the Journal of Herpetology, details the state-of-the-field in terms of phylogenetic and species delimitation, detailing both the many advances that have been made over the last few decades, but also pointing out where things are out of whack and need some recalibration. There’s much more to the article than the figure above, but that’s a good place to start!
Anolis landestoyi. Photo by Miguel Landestoy.
As reported by Science Daily:
Elevation matters when it comes to climate change, deforestation and species survival
- Date:
- February 25, 2019
- Source:
- University of Toronto
- Summary:
- A study examining the impact of deforestation on lizard communities in the Dominican Republic demonstrates differing outcomes at different elevations. In the lowlands, deforestation reduces the number of individuals, but not which species occur in an area. In the highlands, it’s the opposite. When the forest is cut down at higher elevations, the newly created pastures become filled with species found in the warmer lowlands. But locally adapted mountain lizards cannot survive as temperature rises.
University of Toronto student George Sandler was shocked to see the rainforest floor suddenly come to life around him, as if in a scene from an Indiana Jones movie.
“The forest floor started rustling around me,” says Sandler, “as dozens of crabs emerged from holes and crevices. Some were huge, the size of dinner plates. I even spotted a hermit crab climbing up a tree, lugging its heavy shell along with it.”
But Sandler wasn’t in the field to study crabs. He was in the Dominican Republic to take a census of the region’s Anolis lizard species for a study on the effects of deforestation being conducted by researchers Luke Mahler, Luke Frishkoff and collaborators. In the Caribbean nation, deforestation is the main form of natural habitat loss as residents cut down rainforest in order to produce charcoal, as well as create pastures for livestock and farmland for crops.
It is no surprise that deforestation has a profound effect on biodiversity; scientists have been studying this problem around the globe for decades. What is surprising is the difficulty they still face in making detailed predictions about which species survive, especially in relation to other factors such as climate change and natural local conditions.
Now, using the data collected in the census, the research team has discovered details about how Anolis lizards are being affected by the loss of their habitat.
“When it comes to predicting the effects of deforestation,” says Mahler, “elevation matters.”
Mahler is an assistant professor in the Department of Ecology & Evolutionary Biology (EEB) in the Faculty of Arts & Science at the University of Toronto. Frishkoff led the research while he was a postdoctoral fellow in Mahler’s lab at U of T and is lead author of the paper describing their findings, published today in Nature Ecology & Evolution; he is currently an assistant professor at the University of Texas at Arlington. Sandler and researchers from the National Museum of Natural History in Santo Domingo were also co-authors.
Mahler and Frishkoff analyzed populations of lizards in both lowland and highland regions affected by deforestation. Generally, the lowlands are warmer than the highlands due to altitude; also, forest canopy blocks direct sunlight, making forests at any altitude cooler than their immediate surroundings.
“It turns out that deforestation changes lizard communities in fundamentally different ways in the lowlands as compared to the highlands,” says Mahler. “In the lowlands, deforestation reduces the number of individuals, but not which species occur in an area. In the highlands, it’s the opposite.”
“When the forest is cut down at higher elevations,” says Frishkoff, “the newly created high elevation pastures become filled with species we saw down in the warmer lowlands. But, the locally adapted mountain lizards cannot survive.”
The invasion into the highlands by lowland-dwelling lizards was made possible by a combination of human activity and natural factors; i.e. deforestation and elevation respectively. Thanks to the altitude, the temperature of deforested fields in the highlands was comparable to the temperature of forested lowlands.
As it is in many regions around the world, the problem of deforestation in the Dominican Republic is dire. In 2016, Mahler announced the discovery of a previously unknown chameleon-like Anolis lizard on the island of Hispaniola. In the paper describing the discovery, Mahler and his co-authors recommended that the new species, dubbed Anolis landestoyi, be immediately classified as critically endangered because the lizard was threatened by illegal clear-cutting in the region.
Unlike the crabs that crowded around Sandler in the rainforest, the lizards were more elusive and difficult to survey. In order to obtain accurate counts, the students employed a technique known as mark-resight.
“We hiked out to our designated plots,” says Sandler, who was an undergraduate student while conducting the field work and is currently an EEB graduate student at U of T. “Then we walked around looking for lizards. We carried a paint spray gun filled with a non-toxic, water soluble paint — a different colour for each of the six observation periods. If we saw a lizard we would note the species, if it had any paint on it already, and the colour of the paint. Then we would spray the lizard with the paint gun we were carrying, a task that was a little tricky with some of the more skittish species!”
Paint on a lizard indicated that it had already been counted; and the number of unpainted lizards that were observed during each period allowed the researchers to calculate how many lizards were going uncounted.
“It’s not your typical summer job,” says Mahler. “Each survey is essentially a game in which you try to find all the lizards in an area and zap them with paint. It’s a messy affair, but we get great data from it.”
“Our results help us better understand the likely consequences of climate change and how it will interact with human land-use,” says Frishkoff.
For lowland forest Anolis lizards, deforestation just means a decline in abundance or relocating to the highlands. But for highland species, the situation is more critical. Unlike their lowland cousins, they have reached high ground already and in the face of deforestation have nowhere to go — a situation facing more and more species around the world.
“Our data suggest that while many lowland Anolis species might not be seriously affected by deforestation and the gradual warming brought about by climate change,” says Frishkoff, “the opposite is true for the unique mountain lizard species which do not tolerate land-use change well, and which are already on the top of the island.
“Land-use and climate change are a double whammy for these species. If we cut down the mountain forests these lizards have nowhere left to go. Gradual warming might push species up slope, but when you’re already at the top of the mountain, you can’t move any higher.”
Story Source:
Materials provided by University of Toronto. Note: Content may be edited for style and length.
Journal Reference:
- Luke O. Frishkoff, Eveling Gabot, George Sandler, Cristian Marte, D. Luke Mahler. Elevation shapes the reassembly of Anthropocene lizard communities. Nature Ecology & Evolution, 2019; DOI: 10.1038/s41559-019-0819-0
Lourdes Rodriguez Schettino with Ada Chamizo and Rich Glor in 1999.
Our recent mention of Richard Etheridge’s death reminded us that we’d never noted the passing of Lourdes Rodriguez Schettino nearly two years ago, in March of 2017.
Lourdes was an expert on the lizards of Cuba, particularly the iguanid lizards, about which she truly wrote the book. She also was the lead author on a lovely book on Cuban herpetology (below).
Sadly, I am unaware of any obituaries of Lourdes in English, but the Instituto de Ecología y Sistemática, where she worked for many years, has a nice summary of her life’s work, and there is a brief notice in Revista Colombiana de Ciencia Animal.
Lourdes Rodriguez Schettino in 1995.
Word has belatedly reached Anole Annals’ ears that, sadly, Richard Etheridge passed away last month at the age of 89. Richard was not only a titan of lizard systematics, but the founder of anole systematics. Amazingly, the classic worked that is the foundation of all that has followed in anole systematics was his never-published PhD dissertation. Bobby Espinoza and Kevin de Queiroz wrote a biography of Richard’s career that was published a decade ago in Copeia and that, happily, is freely available.