Calling Phenology in Rana sylvatica (Wood Frog) at High-elevation Ponds in the White Mountains, New Hampshire

Scott D. Smyers^1,*, Michael T. Jones^2,3, Lisabeth L. Willey^2,4, Tigran Tadevosyan¹, Joe Martinez⁵, Kyle Cormier¹, and Dominic B. Kemmett¹

¹Oxbow Associates, Inc., PO Box 971, Acton, MA 01720.²Beyond Ktaadn, 90 Whitaker Road, New Salem, MA 01355. ³Current address - Massachusetts Natural Heritage and Endangered Species Program, Division of Fisheries and Wildlife, 1 Rabbit Hill Road, Westborough, MA 01581. ⁴Current address - Department of Environmental Studies, 40 Avon Street, Antioch University New England, Keene, NH 03431. ⁵Museum of Comparative Zoology, Harvard University, 26 Oxford Street, Cambridge, MA 02138. *Corresponding author.

Northeastern Naturalist, Volume 28, Special Issue 11 (2021): 156–179

Abstract
Permanent, fishless, alpine and subalpine ponds are extremely rare in New England, and amphibians occupying these ponds are unique bioindicators of environmental change because they are subject to different ecological pressures compared with lowland populations. Further, alpine and montane ecosystems are expected to undergo rapid change in the coming decades. Therefore, uncoupling the interacting effects of temperature, precipitation, and ice-out on breeding efforts may identify specific ecological mechanisms driving reproduction of amphibians. The reproductive phenology of amphibians in climatically extreme alpine environments in the eastern United States is historically under-reported and remains poorly understood. To evaluate the reproductive phenology of amphibians near the upper extreme of their vertical distribution in the White Mountains, NH, we digitally recorded amphibian calls between 2010 and 2020 at 3 permanent, fishless ponds: Hermit Lake (1180 m), Eagle Lake (1278 m), and Lakes of the Clouds (1546 m). Our study revealed dynamic changes in species assemblages and provides the first report of Hyla versicolor (Gray Tree Frog) in a subalpine context (at Hermit Lake). We analyzed the calling phenology of the earliest breeding North American anuran, Rana sylvatica (Wood Frog), and found differences in calling phenology among the 3 ponds and temporary changes in calling phenology correlated with interpolated daily weather parameters. We stress the need for further research to understand both short- and long-term, weather-driven reproductive dynamics in amphibian phenology in high mountains and their corresponding demographic effects.

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