Ecology of American Martens in Northern Hardwood Forests PDF Download

Author: Paul Jensen
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Languages : en
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Book Description
"Effective wildlife management and conservation is based on a sound understanding of ecological processes that operate on multiple temporal and spatial scales and how these processes affect populations. For forest carnivores such as American martens (Martes americana) that have large space requirements, are sensitive to landscape changes, and are closely linked to prey populations, multi-scale studies have the potential to provide useful information for conservation. However, the challenges of collecting data over long time series and broad landscapes are significant. Here, I apply harvest and field-based data to investigate aspects of marten ecology at multiple scales in a northern hardwood forest system. I investigated temporal trends in the relationship among mast-producing trees, small mammal relative abundance, and marten and fisher (Martes pennanti) harvests. A large proportion of the annual variation in harvest success rates for both species could be explained by models including American beech seed production (Fagus grandifolia) as a key predictor variable. Based on these results I hypothesized that marten space use was inversely related to mast crop production (resulting in differential vulnerability to trapping) and tested this hypothesis using location data from radio collared martens. Autumn/winter home range area and daily movement rates differed among years and were greater in mast failure years than those when mast was produced followed by typical winter conditions. However, differences in these metrics were not significant between mast failures and a year when large mast crops were produced followed by a mild winter with reduced snowfall. Thus, the influence of food abundance on marten space use appears to be mediated by winter conditions such as snow depth. Additionally, I investigated marten resource selection at multiple spatial scales within the southern portion of the Northern Appalachians ecoregion (NAP) to better understand 1.) environmental variables constraining the distribution of martens at the southern extent of their range in eastern North America (i.e., first-order species distribution model; SDM), 2.) variables influencing distribution on a more localized landscape (second-order), and 3.) selection of specific forest stand types within home ranges. Of the 3 spatial scales that I examined, martens exhibited the strongest selection at the ecoregional-scale and results supported the hypothesis that a combination of factors including competition with fishers, forest structure/complexity, and land cover were the primary drivers influencing marten distribution in this landscape. In particular, annual snowfall had the greatest relative contribution to the models (42.2-46.3%) and marten presence was associated with mean annual snowfall ≥ 230 cm. These results supported previously hypothesized mechanisms involving relationships among fishers, martens, and snow. Lastly, I discussed how harvest monitoring data can be used to further our understanding of marten-fisher interactions and provided examples of the use of the SDM as a conservation tool. Research presented here identifies novel and unexpected ecological connections among mesocarnivores, small mammals, forest seed production, and snow cover that will assist with the continuation of sustainable harvests and conservation of martens within the northeastern U.S. and southeastern Canada." --