Murray M. Humphries Research People Research Equipment Pictures Collaborators & Funding

Paul Jensen

PhD McGill University (2013)

PhD Research

My research is focused on the ecology and management of American martens (Martes americana) in Adirondack Park of northern New York State. Martens are an important species both ecologically and as a furbearer that is harvested by trappers. In New York, martens have a limited distribution, are geographically isolated from other marten populations in the U.S. and Canada, and occur at the southernmost extent of their range in the northeast. Furthermore, martens are easily trapped and can be overharvested, therefore, this species must be carefully managed and closely monitored.

In addition to addressing some basic questions on marten ecology, such as distribution and habitat selection, I am investigating marten and fisher (Martes pennanti) population dynamics relative to mast cycles and prey availability as well as harvest management of martens in the northeast.

Research Approaches


Photographic bait station and snow-tracking surveys are being conducted to determine marten distribution across the Adirondacks and co-occurrence patterns with fishers. I am planning to analyze these data within the framework of occupancy models.

Habitat Selection

I am using radio telemetry to study stand-scale and fine-scale habitat selection by martens and how selection at these scales is influenced by prey availability. Study areas include a northern site in the High Peaks region and a second site in the southwestern Adirondacks. Due to the remoteness of these areas I am using aerial telemetry techniques to monitor study animals and collect relocation data. I am also backtracking collared martens in the winter to better understand important fine-scale habitat features within home ranges.

Trophic Interactions

I am collaborating with the SUNY-ESF Adirondack Ecological Center and Maine Department of Inland Fisheries and Wildlife to investigate American beech (Fagus grandifolia) mast cycles, the influence of these cycles on small mammal populations, and potential numerical and functional responses by martens and fishers.

Harvest Management

I am also collaborating with the New Brunswick Department of Natural Resources, Fish & Wildlife Branch to better understand population and harvest dynamics of martens. Specifically, I am interested in the possibility of using harvest data to estimate abundance over time (using age-structured population reconstruction methods), testing the utility of harvest-based indices (e.g., harvest density, M:F, J:A, J:AF ratios) to infer harvest intensity, and examining mechanisms related to observed cycles in the marten harvest. In addition to analyzing a long-term dataset from New Brunswick, I will be conducting similar analyses from data collected from New York State, where harvest intensity is low.

Selected Publications

  • Jensen, P.G., C. Demers, S. McNulty, W. Jakubas, M.M. Humphries. 2012. Responses of marten and fisher to fluctuations in prey populations and mast crops in northern hardwood forest. Journal of Wildlife Management 76:489502.

  • Jakubas, W. J., C. R. McLaughlin, P. G. Jensen, and S. A. McNulty. 2005. Alternate year beechnut production and its influence on bear and marten populations. Pages 79-87 in: Evans, C. A., J. A. Lucas, and M. J. Twery (Eds.), Beech Bark Disease: Proceedings of the Beech Bark Disease Symposium. Gen. Tech. Rep. NE-331. Newtown Square PA, U.S. Department of Agriculture, Forest Service, Northern Research Station. 149 p.

  • Curtis, P. D., and P. G. Jensen. 2004. Habitat features affecting beaver occupancy along roadsides in New York State. Journal of Wildlife Management 68:278-287.

  • Jensen, P. G., P. D. Curtis, M. E. Lehnert, and D. L. Hamelin. 2001. Habitat and structural factors influencing beaver interference with highway culverts. Wildlife Society Bulletin 29:654-664.

  • Jensen, P. G., P. J. Pekins, and J. B. Holter. 1999. Compensatory effect of the heat increment of feeding on thermoregulation costs of white-tailed deer fawns in winter. Canadian Journal of Zoology 77:1474-1485.

  • Smith, D. F., P. J. Pekins, R. N. Coup, M. D. Tarr, P. G. Jensen, and K. S. Smith. 1996. Metabolic rates of New England and eastern cottontails during winter. Northeast Wildlife 53:25-33.


This research is being funded by the New York State Department of Environmental Conservation, Division of Fish, Wildlife and Marine Resources through a grant from the Federal Aid in Wildlife Restoration Program.

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Created: January 2005
Last Updated: January 2014