Elephants help frogs survive


This 2010 music video is called Crazy frog – Nellie the elephant.

From the Wildlife Conservation Society:

Frogs find refuge in elephant tracks

Study says pachyderm puddles are amphibian condos

June 4, 2019

Summary: Researchers in Myanmar describe flooded elephant tracks as key breeding grounds and ‘stepping stones’ connecting populations.

Frogs need elephants. That’s what a new WCS-led study says that looked at the role of water-filled elephant tracks in providing predator-free breeding grounds and pathways connecting frog populations.

Publishing in the journal Mammalia, the researchers found that rain-filled tracks of Asian elephants (Elephas maximus) were filled with frog egg masses and tadpoles. The tracks can persist for a year or more and provide temporary habitat during the dry season where alternate sites are unavailable. Trackways could also function as “stepping stones” that connect frog populations.

This study was made available online in September 2018 ahead of final publication in print in May 2019.

The researchers made their observations in Myanmar’s Htamanthi Wildlife Sanctuary.

Elephants are widely recognized as “ecosystem engineers”, where they extensively modify vegetation through browsing, trampling, and seed dispersal, and convert large amounts of plant biomass into dung that is an important nutrient input for terrestrial and aquatic systems. At smaller scales, local plant species richness is enhanced when elephants open gaps in the forest canopy, browsing damage to trees creates refuges for small vertebrates (lizards and small mammals), and dung piles provide food for a diversity of beetles.

However, most research on ecosystem engineering by elephants has focused on savanna elephants (Loxodonta Africana) and to a lesser extent, forest elephants (Loxodonta cyclotis) in Africa; the role of Asian elephants as ecosystem engineers is much less well-known. Asian elephants are considered Endangered by IUCN due to habitat loss, poaching and retribution for crop raiding and human/elephant conflict.

Said Steven Platt, Associate Conservation Herpetologist with WCS’s Myanmar Program and lead author of the study: “Elephant tracks are virtual condominiums for frogs. This study underscores the critical role wildlife play in ecosystems in sometimes unexpected ways. When you lose one species, you may be unknowingly affecting others, which is why protecting intact ecosystems with full assemblages of wildlife is so important.”

Advertisements

Climate change kills British frogs


This BBC video from England says about itself:

Common frogs on Springwatch (2016)

Common frogs (Rana temporaria) breed in the spring and this clip looks at this activity from all angles including the perils.

From the Zoological Society of London in England:

Climate change responsible for severe infectious disease in UK frogs

Compelling research reveals fatal spread of Ranavirus will increase if carbon emissions are not reduced

May 10, 2019

Climate change has already increased the spread and severity of a fatal disease caused by Ranavirus that infects common frogs (Rana temporaria) in the UK, according to research led by ZSL’s Institute of Zoology, UCL and Queen Mary University of London published today in Global Change Biology (10 May 2019).

Historic trends in mass-mortality events attributed to the disease were found to match the pattern of increased temperatures recorded over recent decades, with disease outbreaks predicted to become more severe, more widespread and occurring over a greater proportion of the year within the next few decades, if carbon emissions continue at their current rate.

The research conducted by international conservation charity ZSL (Zoological Society of London), UCL, Queen Mary University of London and University of Plymouth used a three-pronged approach involving cell cultures, live models and historic data from the Met Office and Froglife’s Frog Mortality Project, with the research demonstrating that warm weather where temperatures reach 16°C, dramatically increases the risk of Ranavirus causing a disease outbreak in common frogs.

The findings help explain the seasonality of the disease, with incidence peaking during the hottest months of the summer, showing that climate change could see outbreaks becoming more frequent from April to October. Disease outbreaks in the spring could result in the deaths of large numbers of tadpoles, which could have repercussions for population survival. Up to now, Ranavirus disease has been largely restricted to England, but as average monthly temperatures increase to exceed 16°C in more areas over longer periods, as predicted by the IPCC’s high carbon-emission model, the disease is likely to spread across most of the UK in the next 50 years.

Dr Stephen Price, lead author from ZSL’s Institute of Zoology and UCL said: “Climate change isn’t something that’s just happening in faraway places — it’s something real and present that’s already had hard-to-predict impacts on wildlife in our own back gardens here in the UK.

“A number of scientists have already alluded to the fact that climate change could increase the spread of disease, but this is one of the first studies that provides strong evidence of the impact of climate change on wildlife disease, and helps to explain how it may facilitate the spread of Ranavirus across the UK.”

ZSL scientists suggest that frogs may be better able to cope with infection if they have areas in which they can cool down — adding log piles, vegetation or nearby shady patches as well as keeping ponds deep will help reduce the level of sun exposure frogs receive, and thus reduce the growth rate of the virus.

Professor Trenton Garner at ZSL’s Institute of Zoology said: “Many studies in amphibian disease cannot do much beyond saying ‘we have a problem’. This research offers a number of options for mitigation; however, this is only a short-term solution of course — if we don’t eventually slow and reverse human-driven climate change, we unfortunately can only expect things to get worse for our amphibians.”

To find out more about ZSL’s amphibian health work, visit here.

Costa Rican frogs, new species discovery


A male Warszewitsch's frog in its natural habitat (El Valle de Antón, Panama). Credit: Dr Robert Puschendorf

From ScienceDaily:

The truth about a true frog: Unknown Costa Rican frog hidden amongst a widespread species

The discovery highlights the urgent need of modern DNA tools when studying rapidly declining animal groups like amphibians

April 11, 2019

Known to science since 1857, a common species of true frog (a “true frog” is one assigned to the family Ranidae), found from north-eastern Honduras, through Nicaragua and Costa Rica to central Panama, turns out to have been keeping its “multiple identities” a secret all along.

According to British and Costa Rican herpetologists, who recently used DNA barcoding to study the species in question, what we currently call Warszewitsch’s frog is in fact a group of “cryptic” species. The study, conducted in the Área de Conservación Guanacaste (ACG), Costa Rica, by James Cryer, Dr Robert Puschendorf, Dr Felicity Wynne from the University of Plymouth, and Dr Stephen Price, UCL, is published in the open-access journal ZooKeys.

In their paper, the authors suggest that the well-known Central American frog species, commonly known as the Warszewitsch’s frog, may in fact consist of multiple different “cryptic” species. This phenomenon is well documented among tropical amphibian fauna, where high levels of genetic variation within populations of a single species surpass levels found between different, classified species.

By utilizing a technique known as DNA barcoding, which compares short snippets of DNA sequences between individuals sampled, the scientists analysed specimens from three different geographic areas within Costa Rica and Panama. In this case, the researchers used sequences derived from mitochondria, the energy-producing “power houses” found in animal cells. Their results indicated there was enough genetic variation to suggest cryptic species are indeed present.

The team chose this particular species because cryptic species were previously identified at two Panamanian sites. Now, the samples from Costa Rica broaden the study area, suggesting that there could be multiple species going by the name Warszewitsch’s frog all across its known distribution.

Conservation biologist and lead author James Cryer says:

“The next step will be to gather more samples throughout the full range of the species. Additionally, if we are to fully discern one species variant from another, further studies that compare the physical, behavioural and ecological characteristics of the frogs, alongside more genetic testing is needed.”

Overall, findings like these are important to help improve our understanding of amphibian biodiversity and, thus, work towards its conservation.

“If indeed there are multiple species, it may be that they have different ecological requirements, and therefore different approaches to their conservation are needed.” Cryer says. “This study further reinforces the power of DNA barcoding for rapid, preliminary species identification. Especially in the tropics, where habitat loss, climate change and infectious disease continually threaten many undescribed amphibian species.”

Japanese scientists have identified the molecular mechanism that gives the skin secretions of a species of frog effective antimicrobial properties. Unraveling the molecular mechanism that facilitates antimicrobial activity of these peptides can help us better understand how the defense system of the frog has evolved, and how this can be used to fight microbial infections of medical importance: here.

Seychelles frogs, new research


Metamorph Sooglossus sechellensis balanced on a 10 pence coin. Credit: Dr. Jim Labisko

From the University of Kent in England:

Conservationists discover hidden diversity in ancient frog family

April 11, 2019

Research scientists led by the University of Kent have uncovered hidden diversity within a type of frog found only in the Seychelles, showing that those on each island have their own distinct lineage.

The family tree of sooglossid frogs dates back at least 63 million years. They are living ancestors of those frogs that survived the meteor strike on earth approximately 66 million years ago, and their most recent common ancestor dates back some 63 million years, making them a highly evolutionarily distinct group.

However, recent work on their genetics led by Dr Jim Labisko from Kent’s School of Anthropology and Conversation revealed that until they can complete further investigations into their evolutionary relationships and verify the degree of differentiation between each island population, each island lineage needs to be considered as a potential new species, known as an Evolutionarily Significant Unit (ESU). As a result, Dr Labisko advises conservation managers they should do likewise and consider each as an ESU.

There are just four species of sooglossid frog; the Seychelles frog (Sooglossus sechellensis), Thomasset’s rock frog (So. thomasseti), Gardiner’s Seychelles frog (Sechellophryne gardineri) and the Seychelles palm frog (Se. pipilodryas).

Of the currently recognised sooglossid species, two (So. thomasseti and Se. pipilodryas) have been assessed as Critically Endangered, and two (So. sechellensis and Se. gardineri) as Endangered for the International Union for Conservation of Nature IUCN Red List. All four species are in the top 50 of ZSL’s (Zoological Society of London) Evolutionarily Distinct Globally Endangered (EDGE) amphibians.

Given the Red List and EDGE status of these unique frogs Dr Labisko and his colleagues are carrying out intensive monitoring to assess the level of risk from both climate change and disease to the endemic amphibians of the Seychelles.

Dr Labisko, who completed his PhD on sooglossid frogs at Kent’s Durrell Institute of Conservation and Ecology in 2016 said many of these frogs are so small and good at hiding the only way to observe them is by listening for their calls. Although tiny, the sound they emit can be around 100 decibels, equivalent to the sound volume of a power lawnmower.

Dr Labisko’s team are using sound monitors to record the vocal activity of sooglossid frogs for five minutes every hour, every day of the year, in combination with dataloggers that are sampling temperature and moisture conditions on an hourly basis

Dr Labisko said: ‘Amphibians play a vital role in the ecosystem as predators, munching on invertebrates like mites and mosquitos, so they contribute to keeping diseases like malaria and dengue in check. Losing them will have serious implications for human health.’

As a result of this study into the frogs, the research team will also contribute to regional investigations into climate change, making a local impact in the Seychelles.

Amphibians around the world are threatened by a lethal fungus known as chytrid. The monitoring of these sooglossid frogs will provide crucial data on amphibian behaviour in relation to climate and disease. If frogs are suddenly not heard in an area where they were previously, this could indicate a range-shift in response to warming temperatures, or the arrival of disease such as chytrid — the Seychelles is one of only two global regions of amphibian diversity where the disease is yet to be detected.

It may also impact on a variety of other endemic Seychelles flora and fauna, including the caecilians, a legless burrowing amphibian that is even more difficult to study than the elusive sooglossids.

Researchers know that caecilians can be found in similar habitats to the frogs, so they can use the frog activity and environmental data they are collecting to infer caecilian presence or absence and generate appropriate conservation strategies as a result.

Endemic, endangered and evolutionarily significant: cryptic lineages in Seychelles’ frogs (Anura: Sooglossidae) by Jim Labisko Richard A Griffiths Lindsay Chong-Seng Nancy Bunbury Simon T Maddock Kay S Bradfield Michelle L Taylor Jim J Groombridge is published in the Biological Journal of the Linnean Society.

Splendid leaf frog in Costa Rica, video


This 31 March 2019 video says about itself:

On this episode of Breaking Trail, the Brave Crew is in location in Costa Rica, and they FINALLY find a very special frog… the Splendid Leaf Frog! This is one RARE frog!

Get ready, you’re about to meet a rare frog that leaps back!

Breaking Trail leaves the map behind and follows adventurer and animal expert Coyote Peterson and his crew as they encounter a variety of wildlife in the most amazing environments on the planet!

Small Brazilian frogs are fluorescent


This 29 March 2019 video says about itself:

Fluorescence in pumpkin toadlets

Brachycephalus ephippium, commonly known as pumpkin toadlet, is a tiny, brightly-colored and poisonous frog from the Brazilian Atlantic forest. Under natural lighting, their skin appears orange. Under UV lighting, fluorescent patterns are visible. The fluorescence could be used for intraspecific communication or as a warning signal directed at potential predators.

From New York University in the USA:

Fluorescence discovered in tiny Brazilian frogs

March 29, 2019

An international team of researchers was studying the acoustic communications of certain miniature frogs. When they discovered that Brachycephalus ephippium could not hear its own mating calls, they searched for alternative visual signals the frogs could use to communicate instead. Unexpectedly, when they shone an ultra-violet (UV) lamp on the frogs, their backs and heads glowed intensely.

“The fluorescent patterns are only visible to the human eye under a UV lamp. In nature, if they were visible to other animals, they could be used as intra-specific communication signals or as reinforcement of their aposematic coloration, warning potential predators of their toxicity“, says Sandra Goutte.

Pumpkin toadlets (also called Brachycephalus ephippium) are tiny, brightly-colored, and poisonous frogs that can be found in the Brazilian Atlantic forest. During the mating season, they can be seen by day walking around the forest and producing soft buzzing calls in search of a mate.

An international team of researchers led by NYU Abu Dhabi Postdoctoral Associate Sandra Goutte was studying the acoustic communications of these miniature frogs. When they discovered that Brachycephalus ephippium could not hear its own mating calls, they searched for alternative visual signals the frogs could use to communicate instead. Unexpectedly, when they shone an ultra-violet (UV) lamp on the frogs, their backs and heads glowed intensely.

In a new paper published in the journal Scientific Reports, the researchers report that fluorescent patterns are created by bony plates lying directly beneath a very thin skin. In fact, the toadlet’s entire skeleton is highly fluorescent, but the fluorescence is only externally visible where the layer of skin tissue over the bones is very thin (about seven micrometers thick). The lack of dark skin pigment cells (which block the passage of light) and the thinness of the skin allow the ultraviolet light to pass through and excite the fluorescence of the bony plates of the skull. The fluorescent light is then reflected back from the frog’s bone, and can be seen as bluish-white markings by the observer if they have a UV lamp.

“The fluorescent patterns are only visible to the human eye under a UV lamp. In nature, if they were visible to other animals, they could be used as intra-specific communication signals or as reinforcement of their aposematic coloration, warning potential predators of their toxicity,” said Goutte. “However, more research on the behavior of these frogs and their predators is needed to pinpoint the potential function of this unique luminescence.”

The researchers compared the skeletons of the two species of pumpkin toadlets to closely related, non-fluorescent species. The pumpkin toadlets’ bones proved to be much more fluorescent. Pumpkin toadlets are diurnal, and in their natural habitat, the UV or near-UV components of daylight might be able to create fluorescence at a level detectable by certain species.