Ecosystems

, Volume 17, Issue 3, pp 442–457

Cascading Effects of Climate Change on Forest Ecosystems: Biogeochemical Links Between Trees and Moose in the Northeast USA

  • L. M. Christenson
  • M. J. Mitchell
  • P. M. Groffman
  • G. M. Lovett
Article

DOI: 10.1007/s10021-013-9733-5

Cite this article as:
Christenson, L.M., Mitchell, M.J., Groffman, P.M. et al. Ecosystems (2014) 17: 442. doi:10.1007/s10021-013-9733-5

Abstract

The relationship between herbivores, plants and nutrient dynamics, has been investigated in many systems; however, how these relationships are influenced by changing climate has had much less attention. In the northeastern USA, both moose populations and winter climate have been changing. Moose, once extirpated from the region, have made a comeback; while locally, snow depth and duration of snow cover have declined. There is considerable uncertainty in how these changes will interact to influence forested systems. We used small experimental plots and transects along with snow removal (to elicit soil freezing and expose potential forage plants), mechanical browsing, and fecal additions (labeled with 15N) to examine ecosystem responses. We found that snow removal changed moose browsing behavior, with balsam fir more heavily browsed than sugar maple or Viburnum under low snow conditions. Soil freezing alone did not significantly alter N dynamics or selected plant responses, but there were significant interactions with moose activity. The combined effects of moose fecal additions, mechanical browsing, and soil freezing resulted in higher levels of NO3 leaching under fir and maple, whereas Viburnum had essentially no response to these multiple factors. Our results suggest that declines in snow depth can initiate a cascade of ecosystem responses, beginning with exposure of plants to increased browsing that then triggers a series of responses that can lead to higher N losses, precipitated by decreased N demand in plants compromised by soil freezing damage. Balsam fir may be particularly susceptible to this cascade of multiple stresses.

Key words

climate changesnow pack depthsoil freezingN cyclingherbivoresmoose15N stable isotopes

Supplementary material

10021_2013_9733_MOESM1_ESM.docx (390 kb)
Supplementary material 1 (DOCX 390 kb)

Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • L. M. Christenson
    • 1
  • M. J. Mitchell
    • 2
  • P. M. Groffman
    • 3
  • G. M. Lovett
    • 3
  1. 1.Vassar CollegePoughkeepsieUSA
  2. 2.SUNY College of Environmental Science and ForestrySyracuseUSA
  3. 3.Cary Institute of Ecosystem StudiesMillbrookUSA