Beaver Dam Abundance and Concentration in Central New York over Three Decades Inferred from Aerial Imagery

Aidan E. Woods^1,*, Michael M. Loranty², Timothy S. McCay³, and Heidi R. Riley⁴

¹Department of Geography, Colgate University, 13 Oak Drive, Hamilton, NY 13346. ²Department of Geography and Environmental Studies Program, Colgate , Hamilton, NY 13346. ³Department of Biology and Environmental Studies Program, Colgate University, Hamilton, NY 13346. ⁴Outdoor Education Program, Colgate University, Hamilton, NY 13346. *Corresponding author.

Northeastern Naturalist, Volume 32, Issue 2 (2025): 329–347

First published early online: 13 June 2025

Abstract
Using aerial imagery collected in 1994, 2003, 2013, and 2022, we identified and marked the locations of dams built by Castor canadensis (North American Beaver, hereafter Beaver) on streams and ponds in Madison and Oneida counties in New York to examine dynamics in their abundance and spatial distribution over that time. We overlaid the dam data with watersheds, census data from 2020, and land-cover maps to explore the dams’ spatiotemporal relationships with landscape characteristics and human population density. Our findings indicate that the largest changes in dam density happen in a select few watersheds and census blocks, affirming that despite their ability to survive near and among humans, Beavers in central New York thrive farther from dense human settlements, and that there are many possible environmental factors. Our results demonstrate that the abundance of dams in these 2 counties has grown, especially near existing dams and in woody and emergent wetlands. By inventorying these dams, we also provide a database for a region for which there is no current catalog of beaver dams, laying groundwork for more regional investigations but also aggregated larger-scale studies.

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