Growling grass frog


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Year 6/7 students from Hawkesdale P12 College create slideshows about threatened species from Victoria.

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Growling grass frog

  1. 1. Growling Grass Frog By Chloe Huismann,
  2. 2. Growling Grass Frog Litoria raniformis Hylidae:Anura:Amphibia:Chordata:Animalia (Frogs) <ul><li>The Growling grass frog is a threatened species that lives through out southern SA along the Murray River through Victoria to NSW and populations through Tasmania. </li></ul>
  3. 3. Movement Patterns <ul><li>The Growling Grass Frog is a highly mobile species, capable of moving up to 1km in 24 hours. Recent research suggests that in areas other than the semi arid part of the species range there are interactions between neighbouring </li></ul><ul><li>populations </li></ul><ul><li>When the growling grass frog is restricted to small, permanent water bodies. When dispersal is low low indicating high levels of site fidelity with individuals tending to move shorter distances. When occupying ephemeral waterbodies, the Growling Grass Frog has significantly higher levels of dispersal, indicating lower site fidelity, with individuals moving large distances </li></ul><ul><li>When the Growling Grass Frog is restricted to small, permanent water bodies, When dispersal is </li></ul>
  4. 4. Description <ul><li>The Growling Grass Frog (Litoria raniformis) is </li></ul><ul><li>one of Victoria’s most endangered frogs. It is up </li></ul><ul><li>to 10cm long with a ‘warty’ back. The upper </li></ul><ul><li>surface is dark olive to bright emerald green or </li></ul><ul><li>brown, usually with large blotches of brown, </li></ul><ul><li>bronze or gold. It has a large tympanum (ear) and </li></ul><ul><li>the top of the front leg. Adult males are renowned </li></ul><ul><li>for their distinctive calls, which consist of a long </li></ul><ul><li>modulated growl or drone, folloed by a few </li></ul><ul><li>short grunts: “crawark-crawark-crawark-crokcrok </li></ul>
  5. 5. Habitat <ul><li>The Growling Grass Frog is found mostly in emergent vegetation. It can be found floating in warmer waters then 18 to 25 degrees. The habitat also must have certain qualities for breeding </li></ul>
  6. 6. Why is the Growling Grass Frog Threatened? <ul><li>The Growling Grass Frog is threatened by traffic. Vic roads have spent over $250,000 on tunnels for frogs such as growling grass frog on the highway bypass, but on the other sides of the tunnels are going to be built . The plan may also require of one of the tunnels to be put down. </li></ul>
  7. 7. Habitat Degradation <ul><li>Overgrazing by livestock around the edges of wetlands disturbs essential habitat by destroying the surrounding vegetation and affecting the quality of the water. The removal of aquatic vegetation destroys refuge habitat and shelter for tadpoles. The clearing of terrestrial vegetation, fallen logs and ground debris surrounding wetlands removes essential habitat. </li></ul>
  8. 8. Habitat Loss <ul><li>Habitat loss and fragmentation are considered to be the primary threat to Growling Grass Frog populations. The draining and infilling or flooding of permanent and non-permanent wetlands plus their adjoining watercourses and vegetation removes critical movement corridors, refuge and breeding habitat and displaces the species from their natural habitat. Artificially irrigated areas and farm dams have replaced some habitat, but these do not provide shelter and foraging habitat. </li></ul>
  9. 9. Disease <ul><li>Chytrid fungus, a water-borne pathogen responsible for the Chytridiomycosis (an infectious disease which affects amphibians worldwide), is widespread in frog populations in eastern Australia and has recently been detected in the Growling Grass Frog and the closely related Green and Golden Bell Frog .Chytridiomycosis disease is believed to be a significant cause of death in some frog species in recent years and is also found in a small proportion of apparently healthy frogs and tadpoles </li></ul>
  10. 10. Predation by introduced fish <ul><li>Mosquito fish and Plague Minnows have been proven to prey on Growling Grass Frog eggs and tadpoles although there is no evidence completely that they are responsible for most of the death it is proven they do prey on them </li></ul>
  11. 11. Biocides <ul><li>Because this species has a semi-aquatic lifestyle and semi-permeable epidermis that is used for gas exchange with the environment, amphibians are particularly susceptible to toxins. Toxic compounds in various biocides have been demonstrated to cause death, morbidity and or abnormalities in many frog species </li></ul>
  12. 12. Road Kills <ul><li>Growling Grass Frogs are regularly killed when they cross roads especially where rice bays and supply channels are adjacent to the road </li></ul>
  13. 13. Ultra Violet B Radiation <ul><li>ultraviolet-B radiation, levels of which have increased due to anthropogenic depletion of the ozone layer ,are known to have an adverse impact on amphibians . As Growling Grass Frogs are frequently active during the day, exposure to harmful levels of UV-B radiation has been postulated as a potential cause of decline </li></ul>
  14. 14. Previous Recovery Actions Include <ul><li>surveys carried out in the species known range; </li></ul><ul><li>research and monitoring in NSW, South Australia and Victoria; </li></ul><ul><li>forestry prescriptions to mitigate the impacts of forestry operations; </li></ul><ul><li>State Forest surveys; </li></ul><ul><li>the preparation of a Hygiene Protocol for the control of Disease in Frogs to reduce the transfer of disease-causing pathogens between frog populations; and </li></ul><ul><li>providing information on the Growling Grass Frog to the community). </li></ul>
  15. 15. <ul><li>The Growling Grass Frog was once widespread </li></ul><ul><li>and common through much of south-eastern </li></ul><ul><li>Australia and Tasmania, but the range and </li></ul><ul><li>numbers of the frog have declined since the </li></ul><ul><li>1980s with many populations disappearing. It has </li></ul><ul><li>disappeared completely from the ACT and is now </li></ul><ul><li>recognised as threatened over the rest of its </li></ul><ul><li>range. </li></ul>Records since European Settlement
  16. 16. Breeding <ul><li>Growling Grass Frogs generally breed between November and March, following local flooding and a marked rise in water levels (from rain or other sources) which triggers calling in breeding males. Breeding usually occurs in still or slow moving water. It is proven that vegetation composition is a significant determinant of breeding habitat quality for the Growling Grass Frog; all sites where reproduction was recorded displayed extensive growth of either emergent or submerging vegetation. Most breeding sites located in recent surveys in NSW were overflow areas such as oxbows, billabongs or levee swamps, which were subject to excessive disturbance by grazing (sheep and cattle) </li></ul>
  17. 17. Breeding <ul><li>Most breeding sites located in recent surveys in NSW were overflow areas such as oxbows, billabongs or levee swamps, which were subject to excessive disturbance by grazing (sheep and cattle) </li></ul><ul><li>Females have been recorded laying up to almost 4000 eggs .Eggs are pigmented and contained within a floating jelly raft that eventually breaks up and sinks. Egg-laying occurs within days of flooding and tadpoles hatch 2-4 days later. Metamorphosis of tadpoles generally takes around 3 months but may take up to 12 months in some circumstances </li></ul>
  18. 18. Feeding <ul><li>Growling Grass Frogs normally feed on terrestrial invertebrates such as beetles, termites, cockroaches, moths and butterflies. </li></ul><ul><li>They sometimes prey on other frog smaller then them and lizards snakes and small fish. </li></ul>
  19. 19. Facts Growling Grass Frog can walk a distance of 1km in 24hrs The Growling Grass Frog is one of the largest frog species in Australia The female Growling Grass Frog is Larger than the male
  20. 20. References <ul><li> </li></ul><ul><li> </li></ul><ul><li> </li></ul><ul><li> </li></ul><ul><li> </li></ul>