Conservation: Northern leopard frogs are common throughout southern Ontario inhabiting northern regions such as the Hudson Bay Lowlands and down south in urban areas like Toronto. In British Columbia however, these frogs are at risk of disappearing completely with only three known populations. The Kootenay Lake population is believed to be the only remaining natural population in the province while the Kootenay Floodplane populations are part of an initiative to reintroduce leopard frogs and restore their habitat. Another population, on Vancouver Island was believed to be introduced by accident in the 1930s. British Columbia represents the westernmost extent of the leopard frog's range. Range edges often have smaller populations as only some are able to survive a certain climate or habitat threshold. Other factors however, have caused challenges to leopard frogs. Of these are the introduction of predatory fish such as bass, bullhead and sunfish which prey on their eggs and tadpoles, and American bullfrogs which carry the harmful fungal pathogen chytridiomycota sp, or chytrid. The introduction of purple loosestrife also creates problems as it alters the habitat through eutrophication, making many habitats unusable to the leopard frog.
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Predator Defense: The unkenreflex is a common defense against predators utilized by a variety of amphibian species including fire-bellied toads and several newt species. While the animal may appear cryptic from above, when threatened they will raise all their legs revealing their brightly coloured ventrals. This warns predators of dangerous of distasteful toxins the animal may possess. Leopard frogs however, do not have a contrastingly colourful underbelly leading it to be referred to as a "partial unkenreflex" and is only displayed when escape is not a viable option.
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Colour and Morphs: Axanthic Northern leopard frogs have been known to display Axanthicism, a pigment mutation that occurs in some animals, more commonly in green frogs, and inhibits the animal’s ability to produce yellow pigment. Many frogs produce both yellow pigment and reflect blue to create their green colouration for camouflage. Without the yellow pigment, axanthic individuals appear blue instead. Sometimes axanthic colouration can also be caused by diet, as food, not containing enough carotenoids consumed over a large period of time
Sources:
"COSEWIC Assessment and Update Status Report on the Northern Leopard Frog Lithobates pipiens." Government of Canada, Committee on the Status of Endangered Wildlife in Canada, 2009, www.sararegistry.gc.ca/virtual_sara/files/cosewic/sr_northern_leopard_frog_0809i_e.pdf. Accessed 17 Dec. 2021. Haberl, Werner, and John W. Wilkinson. "A Note on the Unkenreflex and Similar Defensive Postures in Rana temporaria (Anura, Amphibia)." The British Herpetological Society, 1997, www.thebhs.org/publications/the-herpetological-bulletin/issue-number-61-autumn-1997/2665-hb061-05/file. Accessed 17 Dec. 2021. Hall, Emily M., et al. "Axanthism in the Southern Leopard Frog, Lithobates sphenocephalus (Cope, 1886), (Anura: Ranidae) from the State of Tennessee, USA." , Herpetology Notes, 4 Aug. 2018, www.biotaxa.org/hn/article/download/36421/34334/0. Accessed 4 Nov. 2021. "Northern Leopard Frog." Ontario Nature, 2021, ontarionature.org/programs/community-science/reptile-amphibian-atlas/northern-leopard-frog/. Accessed 4 Nov. 2021. Ohanjanian, Penny, and Kathy Paige. "Northern Leopard Frog." Province of British Columbia, 2004, www.env.gov.bc.ca/wld/frpa/iwms/documents/Amphibians/a_northernleopardfrog.pdf. Accessed 17 Dec. 2021. "Recovery Strategy for the Northern Leopard Frog (Lithobates pipiens), Rocky Mountain Population in Canada." Species at Risk Act, Government of Canada, 2017, www.registrelep-sararegistry.gc.ca/virtual_sara/files/plans/rs_northern_leopard_frog_rocky_e_final.pdf. Accessed 4 Nov. 2021. |