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New Jersey Endangered and Threatened Species Field Guide
Mid-Atlantic Coast leopard frog
Species Group: Amphibian
State: Other Classification
This is a medium sized frog, with colors ranging from dark olive-green or brown to gray or light green with large, rounded dark spots on the back and spotting on the sides and legs. Like related frog species, the mid-Atlantic coast (MAC) leopard frog has extensive webbing in the hind feet and light-colored dorsolateral ridges, or skin folds extending along the sides of the back. This frog is distinguished from other species in the leopard frog complex by its unique mating call, as well as its large external vocal sacs, a faint tympanic (ear) spot, and dark patterning on the back of the thigh.
Distribution and Habitat
Regionally, the species’ range extends along the Atlantic coast from Connecticut to North Carolina. Although it is considered stable in the core of its range, the MAC leopard frog is at risk of local extinction in peripheral areas of its range. In New Jersey, this species occurs throughout much of the northern part of the state, except for the most northwest portion, and along the western coast to the southern tip of the state.
The MAC leopard frog is not found directly in salt marshes, but can be found in coastal freshwater impoundments, wet meadows, tidally influenced backwaters, and slow-flowing river floodplains. They generally prefer the same large, early-successional, mesic lowlands in which southern and northern leopard frogs are found, but MAC leopard frogs are more tolerant of invasive and problematic plants such as common reed and cattail.
Although tadpoles eat mostly plant matter, adult MAC leopard frogs eat many insects that we do not like, such as mosquitoes and ticks.
The main breeding season begins in early spring, generally during March and April. MAC leopard frogs congregate at breeding pools to reproduce. Females lay globular egg masses that can contain thousands of eggs. Eggs hatch into tadpoles within a week or two and tadpoles complete metamorphosis by August. Like some other large frogs, MAC leopard frogs have a minor, second breeding season in the fall. The late season tadpoles survive under the ice in permanent breeding pools until the next spring, when they finish metamorphosis.
Current Threats, Status & Conservation
The MAC leopard frog was first thought to exist by its namesake, Carl Kauffeld, in 1937, but improved bioacoustic and genetic technology allowed scientists to distinguish the MAC leopard frog as a separate species within the leopard frog complex in 2012. The MAC leopard frog is one of only two new frog species to be discovered in North America since 1986. This frog is an especially important find in light of the current global declines in amphibian populations as a result of disease, climate change, and habitat fragmentation and degradation.
Despite only recently being recognized as a species, the MAC leopard frog faces habitat loss and degradation as a result of human development. This is especially true in New Jersey, which has more urban development than any other type of land cover. Human development degrades and fragments critical wetland breeding habitats, creating isolated wildlife populations which results in low genetic variability and increased stress on wildlife populations for reproduction and survival. Moreover, most MAC leopard frogs live relatively close to the coast, with just under half of all known populations found no more than 1km inland. Proximity to the ocean makes MAC leopard frog populations susceptible to habitat loss as a result of major storms and sea level rise.
How You Can Help
Because this species is so new to science, biologists are still investigating the MAC leopard frog’s biology and ecology to identify major conservation threats. Towards this goal, CWF began the Kauffeld’s Calling Frogs program in 2018, where citizen scientists conduct state-wide breeding call monitoring surveys in order to better understand this species’ distribution. For more information on Kauffeld’s Calling Frogs and other CWF amphibian conservation programs, please visit our projects page.
- Feinberg JA, Newman CE, Watkins-Colwell GJ, Schlesinger MD, Zarate B, Curry BR, et al. (2014) Cryptic Diversity in Metropolis: Confirmation of a New Leopard Frog Species (Anura: Ranidae) from New York City and Surrounding Atlantic Coast Regions. PLoS ONE 9(10): e108213. https://doi.org/10.1371/journal.pone.0108213
- Hasse, J.E. and R.G. Lathrop. 2010. Changing Landscapes In the Garden State: Urban Growth and Open Space Loss In NJ 1986 thru 2007. Center for Remote Sensing and Spatial Analysis, Rutgers University, New Brunswick, NJ U.S.A.
- NatureServe. 2017. NatureServe Explorer: An online encyclopedia of life.
- . Version 7.1. NatureServe, Arlington, Virginia. Available http://explorer.natureserve.org. (Accessed: February 2, 2018).
- Schlesinger, M.D., J.A. Feinberg, N.H. Nazdrowicz, J.D. Kleopfer, J. Beane, J.F. Bunnell, J. Burger, E. Corey, K. Gipe, J.W. Jaycox, E. Kiviat, J. Kubel, D. Quinn, C. Raithel, S. Wenner, E.L. White, B. Zarate, and H.B. Shaffer. 2017. Distribution, identification, landscape setting, and conservation of Rana kauffeldi in the northeastern U.S. Report to the Wildlife Management Institute for Regional Conservation Needs grant RCN 2013-03. Available from New York Natural Heritage Program, Albany, NY.
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