Document Type

Article

Publication Version

Version of Record

Publication Date

7-2015

Keywords

Castor canadensis, dam, marsh, meadow, pond, population, Voyageurs National Park.

Abstract

Beaver ponds and beaver-impounded vegetation are indicators of past or present beaver activity that can be detected from aerial photography. A method to quantitatively relate these beaver works with the density of active beaver colonies could benefit beaver management, particularly in areas lacking beaver population data. We compared historical maps (1961–2006) of beaver works at Voyageurs National Park, Minnesota, USA with concurrent aerial surveys of beaver colonies. We tested 2 landscape-scale models of beaver colony density previously developed for a period of beaver population expansion (1940–1986), but they failed to predict colony density after 1986, a period of declining beaver population. We developed a new landscape-scale regression, calculating that 2.15% of the landscape would be flooded by every 100 additional beaver colonies (R2 = 0.53, P = 0.027). Classification tree analysis of individual pond sites showed that open water pond and impounded marsh area were the primary predictors of beaver colony presence or absence, but that the classification trees were far better at identifying inactive sites (> 93% correct) than active sites (35–38% correct). The area of open water in beaver ponds is a good but not perfect indicator of beaver activity that can be used by wildlife managers as a landscape-scale indicator of beaver colony density.

Publication Title

The Journal of Wildlife Management

Volume

79

Issue

7

First Page

1072

Last Page

1080

Pages

9

Type

text

Format

application/pdf

Language

en

DOI of Published Version

10.1002/jwmg.927

Publisher

Wiley

Rights

This article is a U.S. Government work and is in the public domain in the USA.

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