BROWSE REMOVAL, PLANT CONDITION, AND TWINNING RATES BEFORE AND AFTER SHORT-TERM CHANGES IN MOOSE DENSITY

Authors

  • Thomas F. Paragi Alaska Department of Fish and Game
  • C. Tom Seaton Alaska Department of Fish and Game
  • Kalin A. Kellie Alaska Department of Fish and Game
  • Rodney D. Boertje Alaska Department of Fish and Game
  • Knut Kielland Institute of Arctic Biology, University of Alaska-Fairbanks
  • Donald D. Young, Jr. Alaska Department of Fish and Game
  • Mark A. Keech Alaska Department of Fish and Game
  • Stephen D. DuBois Alaska Department of Fish and Game

Keywords:

Alaska, Density Dependent, , Forage, Intraspecific Competition, Nutritional Condition

Abstract

We monitored forage-based indices of intraspecific  competition at changing moose (Alces alces) densities to  gauge short-term, density-dependent environmental feedback and to ultimately improve management of moose for elevated sustained yield. In 4 areas of interior Alaska where moose density recently changed, we evaluated the magnitude of change among 4 browse indices: proportional offtake of current annual growth biomass (OFTK), proportion of current twigs that were browsed (PTB), mean twig diameter at point of browsing (DPB), and proportion of plants with broomed architecture. In 1 area where moose density increased 100% in 6 years following effective predation control, browse removal increased 138% for OFTK, 20% for PTB, and 16–

42% for DPB of primary browse species, with a 44% increase in brooming. We also studied 3 areas where moose density declined 31–41% following elevated antlerless harvests of 2–

4 years duration. In these areas (with intervals of 3–

12 years between browse surveys) we found declines of 30–40% in OFTK, 26–68% in PTB, and 11–

37% in DPB, but changes in plant architecture were inconsistent. The proportion of parturient cows with neonate twins did not change between browse surveys, presumably because of a substantial lag time influenced by life history of the dominant reproductive cohorts and little change in browse nutrient content and digestibility. Of the 4 browse indices studied, proportional OFTK most consistently reflected the direction and magnitude of short-term changes in moose density. Area-specific measures of habitat and animal conditions at high moose density provided an objective means for gauging the capacity of the respective ecosystems to support moose and maintain forage plants. We used these measures of winter forage and moose condition to justify implementing harvest strategies and to ultimately reduce high moose densities below levels of strong negative feedback.

Author Biographies

Thomas F. Paragi, Alaska Department of Fish and Game

Wildlife Biologist III

C. Tom Seaton, Alaska Department of Fish and Game

Wildlife Biologist III

Kalin A. Kellie, Alaska Department of Fish and Game

Wildlife Biologist III

Rodney D. Boertje, Alaska Department of Fish and Game

Wildlife Biologist III (retired)

Knut Kielland, Institute of Arctic Biology, University of Alaska-Fairbanks

Associate Professor

Donald D. Young, Jr., Alaska Department of Fish and Game

Wildlife Biologist III

Mark A. Keech, Alaska Department of Fish and Game

Wildlife Biologist III (formerly)

Stephen D. DuBois, Alaska Department of Fish and Game

Wildlife Biologist III (retired)

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Published

2015-04-07

How to Cite

Paragi, T. F., Seaton, C. T., Kellie, K. A., Boertje, R. D., Kielland, K., Young, Jr., D. D., Keech, M. A., & DuBois, S. D. (2015). BROWSE REMOVAL, PLANT CONDITION, AND TWINNING RATES BEFORE AND AFTER SHORT-TERM CHANGES IN MOOSE DENSITY. Alces: A Journal Devoted to the Biology and Management of Moose, 51, 1–21. Retrieved from http://alcesjournal.org/index.php/alces/article/view/142

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Articles