Hoving, C.L., Harrison, D.J., Krohn, W.B., Jakubas, W.J. & McCollough, M.A. 2004: Canada lynx Lynx canadensis habitat and forest succession in northern Maine, USA. - Wildl. Biol. 10: 285-294.
The contiguous United States population of Canada lynx Lynx canadensis was listed as threatened in 2000. The long-term viability of lynx populations at the southern edge of their geographic range has been hypothesized to be dependent on old growth forests; however, lynx are a specialist predator on snowshoe hare Lepus americanus, a species associated with early-successional forests. To quantify the effects of succession and forest management on landscape-scale (100 km²) patterns of habitat occupancy by lynx, we compared landscape attributes in northern Maine, USA, where lynx had been detected on snow track surveys to landscape attributes where surveys had been conducted, but lynx tracks had not been detected. Models were constructed a prioriand compared using logistic regression and Akaike’s Information Criterion (AIC), which quantitatively balances data fit and parsimony. In the models with the lowest (i.e. best) AIC, lynx were more likely to occur in landscapes with much regenerating forest, and less likely to occur in landscapes with much recent clearcut, partial harvest and forested wetland. Lynx were not associated positively or negatively with mature coniferous forest. A probabilistic map of the model indicated a patchy distribution of lynx habitat in northern Maine. According to an additional survey of the study area for lynx tracks during the winter of 2003, the model correctly classified 63.5% of the lynx occurrences and absences. Lynx were more closely associated with young forests than mature forests; however, old-growth forests were functionally absent from the landscape. Lynx habitat could be reduced in northern Maine, given recent trends in forest management practices. Harvest strategies have shifted from clearcutting to partial harvesting. If this trend continues, future landscapes will shift away from extensive regenerating forests and toward landscapes dominated by polesized and larger stands. Because Maine presently supports the only verified populations of this federally threatened species in the eastern United States, changes in forest management practices could affect recovery efforts throughout that region.
Key words: AIC, habitat, Lepus americanus, Lynx canadensis, Maine, model, regeneration, succession
Christopher L. Hoving*, Department of Wildlife Ecology and Maine Cooperative Fish and Wildlife Research Unit, 5755 Nutting Hall, Rm. 210, Orono, Maine 04469, USA - e-mail: hovingc@michigan.gov
Daniel J. Harrison, Department of Wildlife Ecology, 5755 Nutting Hall, Room 210, Orono, Maine 04469, USA - e-mail: harrison@umenfa.maine.edu
William B. Krohn, United States Geological Survey, Maine Cooperative Fish and Wildlife Research Unit, 5755 Nutting Hall, Room 210, Orono, Maine 04469, USA - e-mail: wkrohn@umenfa.maine.edu
Walter J. Jakubas, Maine Department of Inland Fisheries and Wildlife, 650 State St., Bangor Maine 04401-5654, USA -e -mail: walter.jakubas@maine.gov
Mark A. McCollough, United States Fish and Wildlife Service, 1168 Main Street, Old Town, Maine 04468, USA - e-mail: mark_mccollough@fws.gov
* Present address: Michigan Department of Natural Resources, 621 North 10th St., Plainwell, Michigan 49080, USA
Corresponding author: Christopher L. Hoving
Received 13 August 2002, accepted 2 December 2003
Associate Editor: Henrik Andrén