Rana Essays - Rana, Lithobates, Amphibians, Northern Leopard Frog

Rana Pipiens Leopard Frog - Rana Pipiens Distribution: Found throughout Ontario but more abundant in southern and central Americas. Range: Adults maintain small home ranges (up to 500 m2) in fields or open forest during the summer. Where terrestrial habitats are quite dry, home ranges include some shoreline. A minimum of 4 ha of terrestrial habitat is recommended for the vicinity of breeding sites, however, individual adults may move several kilometres away. Most recently metamorphosed froglets stay within 20 m of shoreline although some froglets begin dispersal before metamorphosis is entirely complete. Diet: Larvae eat algae, phytoplankton, periphyton and detritus. Adults eat mainly invertebrates but will also take tadpoles or very small froglets. Reproduction: Successful breeding sites are permanent ponds, marshes, or pools or backwaters of streams. Eggs and tadpoles require warm (prefer 18o - 28o C), shallow, sunny areas. Breeding occurs from mid-March to mid-May in southern Ontario, and a few weeks later further north. Metamorphosis occurs in 2-3 months. Tadpoles require minimum oxygen concentrations of 3 ppm. Habitat: Relative to bullfrogs and green frogs, leopard frogs use open fields more and prefer denser terrestrial vegetation. In aquatic habitats, submerged vegetation, detritus and soft mud are used for cover. Lookout/Sunning Froglets require muddy shorelines, lily pads, rocks, logs or beaver dams with clear access to deeper water. Adults prefer unmowed fields (15 - 30 cm high, no more than 1 m high vegetation) or open forest in the vicinity of shallow open marshes. Connectivity/Corridors Corridors may be required among breeding, hibernation and summeringhabitats, within 2 km. These may be either aquatic (streams or rivers) or terrestrial (field or forest, usually not cropland except during periods of irrigation). Hibernation Hibernate in deep or running water that will not freeze solid or become anoxic. Are found hibernating on muddy substrate or under rocks, sunken logs, leaf litter or vegetation. Oxygen levels at one known successful hibernation site were 7 ppm. Tadpoles metamorphose in the year of hatching. Hydrology Permanent wetlands with fishless areas or near fishless (temporary) wetlands. Breeding requires sufficient water for metamorphosis to be completed (mid-late August). Soils/Substrate In water prefer muddy bottom. On land prefer moist soil, leaf litter or moss. Design Criteria Vegetation Prefer egg-laying sites with emergent vegetation on about 2/3 of edge and submergent vegetation in 1/2 of surface area in May. Structures Rocks, logs, floating vegetation or dams to sun on, with access to deep water. Submerged vegetation, logs or rocks to hide in. Soils, Slope, & Substrate Prefer wetlands with gradual slope at edge. Hydrology Hibernate in streams with minimum depth 90 cm, moderate mid-depth water velocity, minimal sedimentation, and rocks with average diameter of 20 cm. Critical Periods Breed April-June, metamorphose July-September Other Considerations Froglets are used as bait for fishing. Has declined in much of its western range and apparently in northern Ontario. Tadpoles and froglets are vulnerable to predation by large Bullfrogs and fish. Bibliography References Cook, F. R. 1966. Amphibians and reptiles of Saskatchewan. Regina: Saskatchewan Museum of Natural History, Department of Natural Resources. . 1984. Introduction to Canadian Amphibians and Reptiles. Ottawa: National Museum of Natural Sciences. Corn, P. S., and J. C. Fogleman. 1984. Extinction of Montane Populations of the Northern Leopard Frog (Rana pipiens) in Colorado. Journal of Herpetology 18: 147152. Cunjak, R. A. 1986. Winter Habitat of Northern Leopard Frogs, Rana pipiens, in a Southern Ontario Stream. Canadian Journal of Zoology 64: 255257. Emery, A. R., A. H. Berst, and K. Lodaira. 1972. Underice Observations of Wintering Sites of Leopard Frogs. Copeia 1972 (1): 123126. Hammerson Geoffrey A. 1982. Bullfrog Eliminating Leopard Frogs in Colorado? Herp Review 13 (4): 115116. Hine, R. L., B. L. Les, and B. F. Hellmich. 1981. Leopard Frog Populations and Mortality in Wisconsin, 197476. Department of Natural Resources, Madison, Wisconsin. McAlpine, D. F., and T. G. Dilworth. 1989. Microhabitat and Prey Size among Three Species of Rana (Anura: Ranidae) sympatric in eastern Canada. Canadian Journal of Zoology 67: 22442252. Merrell, D. J. 1977. Life History of the Leopard Frog, Rana pipiens, in Minnesota. Minneapolis, Minnesota: Bell Museum of Natural History, University of Minnesota. Niven, B. S., J. C. Moore, and M. G. Stewart. 1982. The Precise Environment of Some WellKnown Animals X. The Leopard Frog (Rana pipiens). Brisbane, Australia: School of Environmental Studies. AES Paper 6/82. 32 p. Roberts, W. E. 1981. What Happened to the Leopard Frogs? Alberta Naturalist 11: 14. Seburn, C. N. L., Seburn David C., and C. A. Paszkowski. in press. Northern Leopard Frog (Rana pipiens) Dispersal in Relation to Habitat. Amphibians in Decline: The Report of the Canadian Declining Amphibian Populations Task Force. Wassersug, R.