Climate change threatens Komodo dragons


This 2019 video says about itself:

The Raw Nature crew observe Komodo dragons hunting in the wild during a visit to Rincah Island in Indonesia. They then demonstrate the effect of the powerful Komodo venom on a piece of raw meat.

From the University of Adelaide in Australia:

Climate change threatens Komodo dragons

September 17, 2020

The world’s largest lizard, the Komodo dragon, could be driven to extinction by climate change unless significant measures to intervene are taken soon.

A new international study, led by the University of Adelaide and Deakin University, has found that the impact of both global warming and sea-level rise threatens the extinction of Komodo dragons, which already have restricted habitats, and this must be better incorporated into conservation strategies.

“Climate change is likely to cause a sharp decline in the availability of habitat for Komodo dragons, severely reducing their abundance in a matter of decades,” says lead author Dr Alice Jones from the University of Adelaide’s School of Biological Sciences. “Our models predict local extinction on three of the five island habitats where Komodo dragons are found today.”

The Komodo dragon, Varanus komodoensis, is the world’s most iconic lizard species which has existed on Earth for more than a million years, but only an estimated 4000 individuals survive in the wild. They are endemic to five islands in southeast Indonesia: Komodo, Rinca, Nusa Kode and Gili Motang which are part of Komodo National Park, and Flores, the fifth and largest island which has three nature reserves.

“Current-day conservation strategies are not enough to avoid species decline in the face of climate change. This is because climate change will compound the negative effects of already small, isolated populations,” says Dr Jones.

“Interventions such as establishing new reserves in areas that are predicted to sustain high-quality habitats in the future, despite global warming, could work to lessen the effects of climate change on Komodo dragons.

This study, which is published in the journal Ecology and Evolution, is the result of many years of fieldwork on the ecology and conservation status of Komodo dragons.

“Using this data and knowledge in conservation models has provided a rare opportunity to understand climate change impacts on Indonesia’s exceptional but highly vulnerable biodiversity,” says co-author Dr Tim Jessop, School of Life and Environmental Sciences, Deakin University.

Importantly, the research project involved close collaboration with the Komodo National Park and the Eastern Lesser Sunda Cen¬tral Bureau for Conservation of Natural Resources.

“The severity and extent of human actions impacting Komodo dragon populations, especially on Flores Island, are only just being realised,” says co-author Deni Purwandana, Coordinator of the Komodo Survival Program.

“Having an insight into future impacts of climate change provides new possibilities to work with conservation agencies and local communities to find on-ground solutions that will limit climate and other threats to Komodo dragons and their habitats.”

The researchers say climate-change-informed decisions should be a common part of conservation practice.

“Our conservation models show that Komodo dragons on two protected large islands are less vulnerable to climate change. However, even these island habitats might not provide an adequate insurance policy for the survival of the species,” says Associate Professor Damien Fordham from the University of Adelaide’s Environment Institute.

“Conservation managers in coming decades may need to consider translocating animals to sites where Komodo dragons have not been found for many decades. This scenario can be tested easily using our approach.

“Our research shows that without taking immediate action to mitigate climatic change, we risk committing many range-restricted species like Komodo dragons to extinction.”

Threatened Caribbean iguana born in Rotterdam zoo


This 8 September 2020 video from Blijdorp zoo in Rotterdam in the Netherlands says about itself, translated:

A highly endangered lesser Antillean iguana has hatched in Blijdorp Zoo, a memorable moment for the international breeding program in which Blijdorp plays an important role. On May 15, 2018, four young lesser Antillean iguanas came to Rotterdam from St. Eustatius island: two females and two males. … And now, more than two years later, the first young lizard has been born.

The youngster is about 25 centimeter long.

Panama Canal island lizards, new research


This 2011 video says about itself:

Bunch off large lizards on a small Island near Pedasi, Panama

From the Smithsonian Tropical Research Institute in Panama:

Biodiversity may limit invasions: Lessons from lizards on Panama Canal islands

August 10, 2020

Summary: Introduced species can become invasive, damaging ecosystems and disrupting economies through explosive population growth. One mechanism underlying population expansion in invasive populations is ‘enemy release’, whereby the invader experiences relaxation of agonistic interactions with other species, including parasites.

When the U.S. flooded Panama’s Chagres River valley in 1910, Gatun Lake held the record as the world’s biggest reservoir. This record was surpassed, but researchers at the Smithsonian Tropical Research Institute (STRI), who are now studying invading lizards on the tiny islands that dot the lake, discovered that islands with native lizards act as another kind of reservoir, harboring the parasites that control invaders. The study, published in the journal Biology Letters, is valuable experimental evidence that biodiversity is better, making ecosystems more resistant to invasion.

As part of another study to find out how many generations it takes for slender anole lizards (Anolis apletophallus) to adapt to climate change, a research team led by Christian Cox, a visiting scientist at STRI from Florida International University, and Mike Logan from the University of Nevada, Reno, transplanted lizards from the tropical forest on the mainland to the islands, which tend to be hotter and drier. Before the transplant, they did a general health check of the lizards that included counting the number of parasites (mites) on their bodies.

When they came back several times during the next two years to see how the lizards were doing in their new habitats, they recounted the number of mites.

“We found that on the islands with no resident species of anole lizard, the slender anole lizards that were transplanted to the islands lost their mites within a single generation, and the mites are still gone several generations later (up until the present),” Cox said. “Indeed, individual founding lizards that had mites during the initial transplant had no mites when they were later recaptured. In contrast, anole lizards that were transplanted to an island with another resident (native) species of anole lizard kept their mites for three generations, and some of the founders on the two-species island never lost their mites.”

“Our study turned out to be a large-scale experimental test of the enemy release hypothesis,” said Logan, who did this work as a three-year STRI/Tupper postdoctoral fellow. “Often, when an invasive animal shows up in a new place, all of its pathogens and parasites are left behind or do not survive, giving it an extra survival advantage in the new place: thus the term enemy release.”

The team also found that the two-species island had lower density and lower biomass per unit area of the invasive lizard species, indicating that the continued presence of the mites may be keeping their populations under control.

“Our study is a clear example of something that conservationists have been trying to communicate to the public for some time,” Logan said. “Diverse native communities sometimes function as ‘enemy reservoirs’ for parasites and diseases the keep down the numbers of invaders.”

Funding for this study was provided by the Smithsonian Institution, Georgia Southern University, the Theodore Roosevelt Memorial Foundation and the American Museum of Natural History.

Lizards with many tails, new research


This 2018 video is called Two tail lizard.

From Curtin University in Australia:

Double take: New study analyzes global, multiple-tailed lizards

July 7, 2020

Curtin research into abnormal regeneration events in lizards has led to the first published scientific review on the prevalence of lizards that have re-generated not just one, but two, or even up to six, tails.

PhD Candidate Mr James Barr, from Curtin University’s School of Molecular and Life Sciences, said while the phenomena of multiple-tailed lizards are widely known to occur, documented events were generally limited to opportunistic, single observations of one in its natural environment.

“This limited available research about multiple-tailed lizards has made it difficult for biologists to fully understand their ecological importance, and our study helps to highlight this knowledge gap,” Mr Barr said.

Many species of lizards have the ability to self-amputate a portion of their tail, an event known as caudal autotomy, as a defence mechanism when they are being attacked by a predator.

Most commonly the tail grows back as a single rod of cartilage, but Mr Barr explained that sometimes an anomaly occurs, resulting in the regeneration of more than just one tail.

“Sometimes following an incomplete autotomy event, when the lizard’s original tail does not fully separate from its body, a secondary tail regenerates, resulting in the lizard having two separate tails,” Mr Barr said.

“There have even been records of lizards re-generating up to six tails.

“Our study indicates that this phenomenon may actually be occurring more frequently in lizards than previously thought.

“We analysed the available two-tailed lizard data from more than 175 species across 22 families, from 63 different countries. Contrasting this data with all comparable lizard population numbers, our findings suggest an average of 2.75 per cent of all lizards within populations could have two tails or more at any one time.

“This is quite a surprisingly high number, and it really begins to make us wonder what ecological impacts this could have, especially noting that to the lizard, an extra tail represents a considerable increase in body mass to drag around.”

Co-researcher Curtin University Associate Professor Bill Bateman explained that while there is a significant lack of studies to understand these potential ecological impacts, his team believes that having two tails might affect the overall fitness and life history for individual lizards, and their overall populations.

“Shedding a tail to escape a predator and then regenerating it seems like a good tactic; however, when this regeneration goes awry and results in multiple abnormal tails, this is likely to have an effect on the lizard.

“It could affect a range of things, such as their kinetic movements, restrictions they might have when trying to escape a predator, their anti-predation tactics, and socially speaking, how other lizards might react to them,” Professor Bateman said.

“For example, could having two tails potentially affect their ability to find a mate, and therefore reduce opportunities for reproduction? Or on the contrary, could it potentially be of benefit?

“Behaviourally testing out these hypotheses would be an interesting and important future research direction, so biologists can learn more about the lifestyles of these multiple-tailed lizards.”

‘Extinct’ lizard rediscovered in Sumatra, Indonesia


This 4 June 2020 video, in Indonesian, is about the rediscovery after over a century of Modigliani’s lizard.

By Dyna Rochmyaningsih today:

A nose-horned dragon lizard lost to science for over 100 years has been found

Indonesia’s Modigliani’s lizards are bright green but can shift shades like a chameleon

Nearly 130 years ago, Italian explorer Elio Modigliani arrived at a natural history museum in Genoa with a lizard he’d reportedly collected from the forests of Indonesia.

Based on Modigliani’s specimen, the striking lizard — notable for a horn that protrudes from its nose — got its official taxonomic description and name, Harpesaurus modiglianii, in 1933. But no accounts of anyone finding another such lizard were ever recorded, until now.

In June 2018, Chairunas Adha Putra, an independent wildlife biologist conducting a bird survey in a mountainous region surrounding Lake Toba in Indonesia’s North Sumatra, called herpetologist Thasun Amarasinghe. Near the lake, which fills the caldera of a supervolcano, Putra had found “a dead lizard with interesting morphological features, but he wasn’t sure what it was,” says Amarasinghe, who later asked the biologist to send the specimen to Jakarta.

It took only a look at the lizard’s nose-horn for Amarasinghe to suspect that he was holding Modigliani’s lizard. “It is the only nose-horned lizard species found in North Sumatra,” he says.

Wooden arts and folktales of the Bataks — indigenous people native to the region — show that lizards have a special place in the people’s mythology. “But simply there was no report at all about this species” following Modigliani’s, says Amarasinghe, of the University of Indonesia in Depok.

He asked Putra to get back to the caldera to see if there was a living population. After five days, Putra found what he was looking for one evening, “lying on a low branch, probably sleeping,” according to the biologist. He took pictures of the lizard and measured the size and shape of its body parts, such as the length of its nose-horn and head. He also observed its behavior before finally releasing it the same night.

Using this data, Amarasinghe compared the lizard with the one described in 1933, and concluded that the living lizard and the dead one that Putra had stumbled across were in fact Modigliani’s nose-horned lizards. The Genoa museum’s dead specimen is pale blue due to preservation, but it’s now known that the lizard’s natural color is mostly luminous green. Its camouflage and tree-dwelling behavior are similar to African mountain chameleons, Amarasinghe, Putra and colleagues report in the May Taprobanica: The Journal of Asian Biodiversity.

The reptile belongs to the Agamidae family of lizards, which are commonly called dragon lizards and include species such as bearded dragons (SN: 6/14/17). Shai Meiri, a herpetologist at Tel Aviv University, has previously shown that many dragon lizards live in small, hard-to-access areas, making the reptiles difficult to study. There are 30 agamid species that have never been seen since they were first described, and 19 species which are known from just a single specimen, Meiri says.

While thrilled with their find, Amarasinghe and Putra are worried about the lizard’s future. “The living dragon was found outside a conservation area, and massive deforestation is happening nearby,” Amarasinghe says.

But the rediscovery offers a glimmer of hope for the lizard’s conservation, Meiri says. Before the reptile resurfaced, no one knew where exactly Modigliani’s lizard lived, or whether it had already gone extinct, he says. But now, “we can study it, understand its conservation needs and hopefully implement conservation measures.”

Amazing chameleons, video


This 1 June 2020 video says about itself:

Amazing chameleons! Colorful reptiles hunt, chameleon species from Africa, Madagascar, India!

Chameleons are amazing reptiles and among the most specialized lizards. They are great hunters with their rocket fast tongues, eyes moving independently, and great camouflage. Watch this video to learn the basic information about chameleons and see them in the wild. Enjoy the natural footage of hunting chameleons from Madagascar, beautiful three-horned chameleons, or tiny Namaqua Dwarf chameleon in the coastal desert of South Africa. Tiny chameleon – Brookesia, is also in this video! One of the biggest, Parson’s chameleon and one of the most famous, Panther chameleon, is there too!

Bermuda skink at empty Bermuda petrel nest


This video says about itself:

Bermuda Skink Visits Cahow Cam 1 Burrow – May 29, 2020

A Bermuda skink slinks into the recently fledged cahow chick‘s nesting burrow on the afternoon of May 29. Historically, these critically endangered skinks have a long-standing, important relationship with the cahows as they help keep the nests clean.

Greek islands lizards new love life


This 2018 video says about itself:

Erhard’s wall lizard (Podarcis erhardii), also called the Aegean wall lizard, is a species of lizard in the family Lacertidae. The species is endemic to Southeast Europe. Sithonia, Greece.

From Washington University in St. Louis in the USA:

Lizards develop new ‘love language’

Animal chemical signals shift after only four generations

April 21, 2020

Relocated in small groups to experimental islands, lizards rapidly and repeatedly developed new chemical signals for communicating with each other. Free from the risk of predators and intent to attract potential mates, male lizards produce a novel chemical calling card, according to new research from Washington University in St. Louis.

Studies of animal signal evolution usually focus on acoustic and visual signals — like the complex warbling in a bird’s song or the bright flashes of color on fish scales. Chemical signals between animals are less obvious to humans and more technically complex to parse. Much of the existing research on these signals has focused on insect pheromones relevant to certain agricultural applications.

But chemical signals are the oldest and most widespread communication mode, spanning bacteria to beavers. As such, they represent a valuable opportunity for decoding how animals communicate and perceive the world around them, researchers said.

“What we’ve discovered is that within species there is important variation in chemical signals depending on your context: Who’s trying to eat you, who wants to mate with you and who you’re trying to compete with,” said Colin Donihue, a postdoctoral fellow in biology in Arts & Sciences at Washington University in St. Louis and lead author of a new study published April 21 in the Journal of Animal Ecology.

Both lizards and snakes collect chemical cues from their surroundings by flicking out their slender forked tongues, then process those cues using a well-developed sensory organ in the roof of their mouths.

Lizards deposit their chemical messages encoded in secretions from specialized glands located on their inner thighs. The secretions are a waxy cocktail of lipid compounds that contains detailed information about the individual lizard that produced them.

In this study, researchers relocated groups of eight male and 12 female Aegean wall lizards (Podarcis erhardii) from a single source population in Naxos, Greece, to five small islets that lacked predators. Under normal conditions, these lizards would have to contend with a number of native and non-native predators — including snakes, birds and cats.

Free from predators on the small islets, the lizard populations grew rapidly and competition for resources was fierce.

Each of the relocated lizards was individually tagged so they could be identified when the researchers returned to check up on them. Over the next four years, the scientists revisited the populations, tracking the fates of the relocated lizards and their offspring.

What they found was striking: On each of the predator-free islands, lizards rapidly and repeatedly developed a new chemical “mix” that was distinct from that of lizards in the source population. The changes were apparent after only four generations.

For the first time, researchers believe that they have demonstrated solid evidence that lizards can “put on a new cologne” to suit their setting.

“Signals to attract mates are often conspicuous to predators,” said Simon Baeckens, a postdoctoral fellow at the University of Antwerp in Belgium and co-author of the new paper. “As such, sexual signals present a compromise between attractiveness and avoidance of detection. However, on these islets, there is no constraint on the evolution of highly conspicuous and attractive signals.

“In the experimental islands, we found that the ‘signal richness’ of the lizard secretions is the highest — meaning that the number of different compounds that we could detect in the secretion is the highest,” Baeckens added. “Our previous research suggests that this more elaborate signal might advertise the high quality of a male.”

Donihue continued: “Animals have spent over a billion years developing a complex chemical communication library. But we only invented the technology to identify many of those chemicals a century ago, and the experiments for understanding what those chemicals mean for the animals in nature have only just begun.

“We found that animal chemical cues can rapidly and flexibly change to suit new settings, but this is only the beginning for understanding what the lizards are saying to each other.”

New Caribbean black iguana species discovery


This 15 April 2020 video in Spanish is about the new discovery of a new Caribbean black iguana species.

From ScienceDaily:

A new species of black endemic iguanas in Caribbeans is proposed for urgent conservation

April 14, 2020

A newly discovered endemic species of melanistic black iguana (Iguana melanoderma), discovered in Saba and Montserrat islands, the Lesser Antilles (Eastern Caribbean), appears to be threatened by unsustainable harvesting (including pet trade) and both competition and hybridization from escaped or released invasive alien iguanas from South and Central America. International research group calls for urgent conservation measures in the article, recently published in the open-access journal ZooKeys.

So far, there have been three species of iguana known from The Lesser Antilles: the Lesser Antillean iguana (Iguana delicatissima), a species endemic to the northernmost islands of the Lesser Antilles; and two introduced ones: the common iguana (Iguana iguana iguana) from South America and the green iguana (Iguana rhinolopha) from Central America.

The newly described species is characterised with private microsatellite alleles, unique mitochondrial ND4 haplotypes and a distinctive black spot between the eye and the ear cavity (tympanum). Juveniles and young adults have a dorsal carpet pattern, the colouration is darkening with aging (except for the anterior part of the snout).

It has already occurred before in Guadeloupe that Common Green Iguana displaced the Lesser Antilles iguanas through competition and hybridization which is on the way also in the Lesser Antilles. Potentially invasive common iguanas from the Central and South American lineages are likely to invade other islands and need to be differentiated from the endemic melanistic iguanas of the area.

The IUCN Red List lists the green iguana to be of “Least Concern”, but failed to differentiate between populations, some of which are threatened by extinction. With the new taxonomic proposal, these endemic insular populations can be considered as a conservation unit with their own assessments.

“With the increase in trade and shipping in the Caribbean region and post-hurricane restoration activities, it is very likely that there will be new opportunities for invasive iguanas to colonize new islands inhabited by endemic lineages,” shares the lead researcher prof. Frédéric Grandjean from the University of Poitiers (France).

Scientists describe the common melanistic iguanas from the islands of Saba and Montserrat as a new taxon and aim to establish its relationships with other green iguanas. That can help conservationists to accurately differentiate this endemic lineage from invasive iguanas and investigate its ecology and biology population on these two very small islands that are subject to a range of environmental disturbances including hurricanes, earthquakes and volcanic eruptions.

“Priority actions for the conservation of the species Iguana melanoderma are biosecurity, minimization of hunting, and habitat conservation. The maritime and airport authorities of both islands must be vigilant about the movements of iguanas, or their sub-products, in either direction, even if the animals remain within the same nation’s territory. Capacity-building and awareness-raising should strengthen the islands’ biosecurity system and could enhance pride in this flagship species,” concludes Prof. Grandjean.

The key stakeholders in conservation efforts for the area are the Dutch Caribbean Nature Alliance (DCNA), the Saba Conservation Foundation (SCF), the Montserrat National Trust (MNT) and the UK Overseas Territories Conservation Forum (UKOTCF), which, the research team hope, could take measures in order to protect the flagship insular iguana species, mainly against alien iguanas.