MV Blog

DISPLAYING POSTS TAGGED: frogs (6)

Alpine frogs and chytrid fungus

Author
by Kate C
Publish date
17 January 2014
Comments
Comments (0)

Frogs were an important focus for the Alps Bioscan survey in Victoria's Alpine National Park in November last year. The deadly amphibian chytrid fungus, Batrachochytrium dendrobatidis, thrives in cool environments, meaning high-altitude frog populations are particularly susceptible.

Dr Katie Smith, Collection Manager of Vertebrates, led the frog-hunting team at the Alps and explained why this fungus is so insidious. "It's a major contributor to global amphibian decline. Lots of frogs worldwide are affected," she said. "It penetrates their skin and leads to death in some species and individuals, while some are able to survive it and act as carriers."

View this video with a transcript

The museum's frog team searched for frogs in several sites in the Alps and collected skin swabs from every frog found. The swabs will be tested for the presence of chytrid (pronounced 'kit-trid') as part of ongoing monitoring by researchers from the Arthur Rylah Institute for Environmental Research. "We need to know what populations have it and whether this leads to changes in those populations, such as whether there's lower species diversity in areas where chytrid fungus is present."

The chytrid fungus has a free-living stage called a zoospore and a reproductive stage called a zoosporangium. Zoospores can live several weeks in the water until they find a host frog to infect. Once settled, the zoosporangia cause the frog's skin to thicken and slough away. There are a few hypotheses as to how the chytrid fungus kills frogs. One hypothesis proposes that a frog with a heavy chytrid infestation can't maintain its salt balance. Sodium and potassium levels, essential for normal muscle and nerve function, drop significantly and the frog dies from cardiac arrest.

froglet A froglet found during the Alps Bioscan. Froglet species seem to have some resistance to chytrid fungus, and may act as carriers between water bodies.
Image: David Paul
Source: Museum Victoria
 

Researchers believe that the fungus arrived in Australia in the 1970s, and is linked to the sudden decline (and in some cases, extinction,) of several local species, including the Southern Gastric Brooding Frog and the Southern Corroborree Frog. There are a few theories about how it got here, but the most likely culprit is the international trade in African Clawed Frogs for use in pregnancy tests. In the 1930s it was discovered that injecting one of these frogs with the urine of a pregnant woman caused the animal to produce eggs. Hundreds of thousands of frogs were brought into Australia from Africa for this purpose and probably, with them, the chytrid fungus. While the fungus was first identified in 1998, retrospective examination of historical specimens found the earliest known chytrid infestation on an animal collected in 1938. This African Clawed Frog specimen, held by the South African Museum, supports the theory of African origin.

Once loose in a new environment, chytrid fungus can spread rapidly. "It can be spread by frogs – anything that moves through those water bodies, even other animals that visit those areas and researchers themselves," explained Katie. "You might walk into one site, jump in the car and accidentally transfer it to a healthy population."

You can help prevent the spread of chytrid fungus in a couple of ways. Firstly, says Katie, "never move a frog, tadpoles or eggs that you find in one area to another area, because you don't know which populations may have the chytrid fungus." Frogs are protected in Australia which means that you cannot legally catch, remove or relocate them; the threat of chytrid fungus is another good reason to leave them where they are. Frogs often hitchhike from Queensland in bunches of bananas, so if you find a stowaway in your supermarket, follow the instructions of the Victorian Frog Group and never release the frog into the wild.

Katie continued, "secondly, if you're moving between water bodies, wash your shoes really well and anything else you put in water." The Alps Bioscan teams bleached and scrubbed shoes and equipment between each aquatic field site, and Katie's frog team wore fresh surgical gloves when handling each frog.

The results from the survey and chytrid tests will be available later this year once the researchers have completed their analysis.

Links:

Ché Weldon, Louis H. du Preez, Alex D. Hyatt, Reinhold Muller,and Rick Speare. Origin of the Amphibian Chytrid FungusEmerg Infect Dis. 2004 December; 10(12): 2100–2105.

David Hunter, Rod Pietsch, Nick Clemann, Michael Scroggie, Gregory Hollis and Gerry Marantelli. Prevalence of the Amphibian Chytrid Fungus (Batrachochytrium dendrobatidis) in Populations of Two Frog Species in the Australian Alps. 

Frogs, bogs and fungi

Author
by Mark Norman
Publish date
2 December 2011
Comments
Comments (0)

Mark is Head of Sciences at Museum Victoria. He's reporting back from Neds Corner in this series of blog posts.

By 25 November, rain drenched Neds Corner and the clay turned to slippery mud. Great weather for frogs. With the rain's arrival, frogs emerged from the mud as our vehicles sank into it.

Rain at Ned's Corner Rain at Ned's Corner. Left: The view from the homestead porch | Right: Boggy road
Image: M. Hewish / M. Cheng
Source: M. Hewish / M. Cheng
 

Pobblebonk frogs turned up everywhere. In our pitfall trap lines, 30 pits contained 37 frogs. These frogs bury into the soil in the dry weather and wait for the rains. Then they emerge to feed and mate.

Pobblebonk Frog Pobblebonk Frog (Limnodynastes dumerili) at Neds Corner.
Image: David Paul
Source: Museum Victoria
 

The other frogs we encountered were the Spadefoot, Spotted and Barking Marsh Frogs, Peron's Tree Frog and a froglet (genus Crinia). The tree frogs can be recognised by their padded toes, good for climbing.

Peron's Tree Frog Peron's Tree Frog (Litoria peroni) with beautiful green spots.
Image: Patrick Honan
Source: Museum Victoria
 

The wetter weather was also good for the fungi and Dr Teresa Lebel from the National Herbarium of Victoria found many new records for this region. In arid country many types of fungus rest under the soil in a shrivelled state. As soon as the water reaches them, their stalks hydrate and the heads of species like puffball fungi emerge above the mud to release their spores.

Fungi after rain at Ned's Corner. Fungi after rain at Ned's Corner. Left: Fruiting bodies of the Earth Star fungus | Right: Tinder Conch fungus
Image: Mark Norman
Source: Museum Victoria
 

One of the fungus highlights was finding fallen white shelf fungi at the bases of big River Red Gums. The spongy dead fungus is called Tinder Conch fungus as Aboriginal peoples used it for carrying the slow-burning coals needed for fire starting.

Our survey team was not as well-adapted as the frogs and managed to bog three cars in one day, but a combination of winches and effort got us all home safe and sound.

Bush Blitz is a biodiversity partnership discovery program between the Australian Government, BHP Billiton and Earthwatch Australia, that aims to document the plants and animals across Australia's National Reserve System. Museum Victoria also participated in Bush Blitz at Lake Condah in March 2011.

Links:

Parks Australia blog

Bush Blitz

Frogs of Victoria infosheet series

Royal Botanical Gardens Fungimap

Postgraduate trifecta

Author
by Kate C
Publish date
14 November 2011
Comments
Comments (1)

Congratulations to Katie Smith, Natalie Calder and Skipton Woolley for handing in their postgraduate theses in the last fortnight. All three have done major pieces of research that combined new field studies with Museum Victoria Natural Sciences collections.

For her PhD, Katie Smith assessed the hybrid zone between two closely-related south-eastern Australian tree frogs, Litoria ewingi and Litoria paraewingi. A hybrid zone is an area where the geographic distribution of two species overlap in a narrow contact zone. They subsequently share habitat and sometimes cross-breed.

Two frogs Top: Litoria ewingi calling. Bottom: Litoria paraewingi. Can you spot the difference between these two species?
Image: Katie Smith | Fran Lyndon-Gee
Source: Museum Victoria
 

In the 1960s, Murray Littlejohn first reported hybridisation in these species in the Kinglake area, collecting specimens and recordings of the male advertisement calls in the 1960s. Katie built upon Murray's work, performing genetic and acoustic analysis on the original specimens and recordings and recent samples to compare the hybrid zone then and now. Says Katie, "it makes you realise what a good job Murray did! It's amazing that he even worked out they are different species because their appearance and calls are so similar."

recording frog calls in the field Main: Murray Littlejohn recording frog calls in the 1960s. Inset: Katie Smith recording frog calls for her PhD.
Source: Murray Littlejohn | Museum Victoria
 

Katie found that the hybrid zone is quite stable which is particularly interesting because the Kinglake area has changed dramatically over the decades through agricultural and residential development. Her fieldwork, completed before the 2009 bushfires, can't comment on the effect of fire on the hybrid zone but she hopes that ongoing surveys will keep an eye on the situation. When she handed in her thesis, her colleague Susi made a special batch of hybrid frog cupcakes to celebrate!

frog cupcakes Hybrid frog cupcakes for afternoon tea!`
Image: Susi Maldonado
Source: Susi Madonado
 

Natalie Calder's Masters thesis investigated how larval fishes use tide cycles to disperse in Port Phillip Bay. She worked at Governor Reef, near Indented Head on the Bellarine Peninsula, measuring where these tiny hatchlings place themselves in the water column.

As Nat explains, "Upon hatching larvae are translucent, lack scales and are usually less than 1mm long. Studies throughout the first half of the 20th century assumed that larvae were passive particles, at the mercy of tides and currents, with little or no control over where they dispersed."

Three larval fishes Three larval fishes. Top: Zeidae (dory family) without fins, jaws or pigmented eyes. Middle: Hemiramphidae (garfish or halfbeak family) in relatively late stage of development, with visible muscle bands. Bottom: Triglidae (gunard or sea robin family) with partially-developed fins, well-developed eyes but still-visible egg yolk sac.
Image: Natalie Calder
Source: Museum Victoria
 

Since then, scientists have observed that fish larvae display more complex behaviour, and Nat's research contributes to this body of knowledge. She found that fish larvae are quite selective and effectively 'surf' the tides in and out of Port Phillip Bay by exploiting properties of the currents. They rise in the water column to catch fast-moving surface waters during incoming tides, ensuring they stay in the bay rather than be swept out to sea. This better understanding of how larval fish disperse could help ensure the network of marine protected areas are sufficiently connected to keep fish populations healthy.

Another major piece of Masters research with implications for marine reserves was completed by Skipton Woolley, who used marine worms called polychaetes to model the biodiversity of large-scale ecological systems. Using data from museum collections and from new fieldwork in the Kimberley region of Western Australia, he tested whether polychaetes are a good group to use when assessing biodiversity. The idea is that it's not often practical to count every species in an ecosystem, but if the diversity of one group correlates with biodiversity overall, they become a handy indicator that can be used to compare between regions.

By examining 342 species from seven families, he found that that polychaetes are indeed a useful group, because where you find numerous species of polychaetes, you find numerous species of other animals, such as echinoderms and crustaceans. Thus, concludes Skip, "worms are amazing!"

scaleworm A scaleworm from Skip's Masters project, Iphione muricata (family Polynoidae). The numerous white hairy structures, or chaetae, are what give this group their name - the polychaetes.
Source: Museum Victoria
 

Amazing too are our students who contribute so much to the museum's research work. Well done Katie, Nat and Skip!

Links:

Information for prospective students

MV News: Victoria frogs and bushfires

WA Museum: Marine Life of the Kimberley Region

Hunting for herpetiles

Author
by Kate C
Publish date
11 November 2011
Comments
Comments (0)

During the recent Prom Bioscan biodiversity survey of Wilsons Promontory, Dr Joanna Sumner led the herpetology (reptiles and amphibians) group. She and her troops - Katie Smith, Claire Keely, Susi Maldonado, Maggie Haines and Parks Victoria's Steve Wright – used a combination of trapping and active searching to find nine skink species, three elapid snake species and five frog species over several survey sites.

  Claire and Susi doing fieldwork Claire and Susi checking funnel traps opposite Lilly Pilly Gully carpark.
Image: Jo Sumner
Source: Museum Victoria

Reported Jo,

We captured, tissue sampled and released 59 individual reptiles and amphibians. Tissue samples will be put in our frozen tissue collection and used in research on species identification of some these groups. The overall diversity of reptile species in the Prom is very low compared to other areas in Australia. We sighted all three snakes previously recorded, 50% of known frog species and 75% of skinks known to the area. We did not record any of threatened species previously recorded on the Prom however, such as Litoria raniformis and Egernia coventryi.

 

If you're ever wondered what herpetology fieldwork looks like, here's a video from Wilsons Prom where Jo explains how she traps skinks and takes tissue samples.

 

Watch this video with a transcript

Bush Blitz frogs

Author
by Kate C
Publish date
28 March 2011
Comments
Comments (4)

There are records of seven species of frogs here in the Lake Condah region; all seven are relatively common across south-eastern Australia. Last week, MV frog experts Josh Hale and Katie Smith tracked down six of the seven species within a day or two. The last one, the Southern Toadlet (Pseudophryne semimarmorata) is proving elusive but Josh is back this week to keep looking.

On rainy nights, we’ve seen frogs hopping around the base camp. Bush Blitzers have found them by turning over rocks where they shelter during the day. They've also been identified by the distinctive calls of the males.

Pobblebonk frog Pobblebonk or Banjo Frog (Limnodynastes dumerilli) at Lake Condah Mission. This frog was found moving over mown grass.
Image: Julian Finn
Source: Museum Victoria
 

Froglet The Southern Smooth Froglet, Geocrinia laevis.
Image: Julian Finn
Source: Museum Victoria
 

Many of the frogs we’ve seen are young juveniles, which means they were tadpoles over the past season. Josh remarked on the unusually large numbers of young frogs and attributes this to the very wet summer; the same conditions that have kept the vegetation unseasonably green. It’s an indication that frogs can build up populations quickly here and recover after years of drought.

Green morph of Brown Tree Frog Green morph of Brown Tree Frog, Litoria ewingii. This species is more often brown.
Image: Julian Finn
Source: Museum Victoria
 

Brown Tree Frog Brown Tree Frog, Litoria ewingii, in its more common brown morph.
Image: Julian Finn
Source: Museum Victoria
 

“Many frogs all round the world are declining so to see healthy breeding populations like this is really encouraging,” says Josh. Frogs make up an important part of the food chain and become prey for birds, mammals and reptiles.

striped marsh frog Striped Marsh Frog, Limnodynastes peronii. These frogs are remarkably well camouflaged.
Image: Julian Finn
Source: Museum Victoria
 

Spotted Marsh Frog Spotted Marsh Frog, Limnodynastes tasmaniensis.
Image: Julian Finn
Source: Museum Victoria
 

Bush Blitz is a three-year biodiversity discovery program supported by the Australian Government, BHP Billiton, Earthwatch Australia and Terrestrial Ecosystems Research Network (TERN) AusPlots.

Links:

Frogs of Victoria

Bushfire survivors

Author
by Kate C
Publish date
23 September 2010
Comments
Comments (0)

An article in the Age today shared the good news that the rare leafy liverwort Pedinophyllum monoicum survived the Black Saturday bushfire disaster in tiny remnants of Yarra Ranges rainforest. It was discovered through the Rainforest Recovery Project which is revisiting sites that were sampled prior to the fires.

This sort of work is critical to our understanding about how ecosystems recover - or don't - from bushfire. MV Curator of Hepetology, Jane Melville, received an Australian Research Council Linkage Grant in June this year to continue her work on the ecology, demography and genetics of frogs in the Kinglake region. A surprising number and diversity of frogs survived the February 2009 fires.

Toolangi frog field site This field site in Toolangi was badly affected by bushfire, yet yielded an adult frog previously caught in 2008. It is thought that frogs survived the fire by hiding in and around bodies of water like this dam.
Image: Bec Bray
Source: Museum Victoria
 

Frogs and liverworts share one characteristic that make them particularly important indicators: they are very sensitive to drying out. Neither would survive a direct fire front but  persist in unburnt pockets (or refugia) that offer protection. Long-term studies will monitor how the forests recover in coming years; since frogs are mobile, it is hoped that they will spread relatively quickly back into their former range. Rainforest plants generally aren't quite so responsive so we're very fortunate that this small, tender plant made it through the fires.

Links:

Type specimen of Pedinophyllum monoicum held at Te Papa Tongarewa

What is a liverwort? - Australian National Botanic Gardens

About this blog

Updates on what's happening at Melbourne Museum, the Immigration Museum, Scienceworks, the Royal Exhibition Building, and beyond.

Categories