Oral presentation- Open Session 12th International Mammalogical Congress

Shifting habitat paradigms? Disagreement between the observed and predicted distribution of an expanding fisher (Martes pennanti) population based on previously documented habitat requirements (#38)

Maggie D Triska 1 , Thomas L Serfass 2
  1. The University of Western Australia, Crawley, Western Australia, Australia
  2. Frostburg State University, Frostburg, Maryland, United States of America

Fishers (Martes pennanti) were extirpated from North Dakota, USA, during the late 19th century. However, there has been an increase in verified fisher sightings in the eastern third of the state over the past 15 years. Prior research supports old-growth forest as a habitat requirement of the fisher, but forested areas in North Dakota exist mainly as narrow, riparian strips and shelterbelts within a prairie/agriculture matrix. Thus, to verify the presence of fishers and to delineate their current and potential future distribution, we assessed verified reports and completed remote-camera field surveys and simulation modeling. Verified reports were concentrated in the northeast portion of the state and were less frequent farther south and west, which was consistent with remote camera detections collected in riparian forest over a 2 year period in the eastern 1/3 of the state. Simulation models, including Least-Cost Path (LCP) analysis and a spatially explicit population model, completed in program HexSim, did not accurately predict the observed pathways or distribution of fishers when they were parameterised with habitat requirements from published literature. However, when the strength of the requirement for forest habitat was reduced, LCP identified potentially important riparian corridors and HexSim scenarios predicted occupancy of large patches where populations were most likely to persist in the future. Overall, the results and predictability of the model would be greatly improved from additional behavioral and habitat studies in the region as habitat paradigms from prior research did not support the observed recolonization and distribution of fishers within the state.