Eastern Hemlock (Tsuga canadensis) is a foundation species native to eastern North America that is being eliminated from much of its range due to predation from the introduced Hemlock Woolly Adelgid (Adelges tsugae). In theory, isolated and disjunct populations of hemlock on the periphery of the species' range have a greater likelihood of surviving the adelgid infestation. Thus, peripheral hemlock populations may become increasingly important for the survival of the species in the future and methods to accurately locate such populations are necessary.
Because previous research has suggested that hemlock location may be related to topographic variation, hemlock-topography relationships in a disjunct hemlock population located at the hemlock range periphery in southwest Wisconsin were investigated. All areas supporting hemlocks within the watershed of the Kickapoo River were mapped and topographic differences between these hemlock areas and surrounding non-hemlock areas were analyzed based on terrain data derived from a 1/3 arcsecond resolution Digital Elevation Model.
This analysis revealed that hemlock presence in southwest Wisconsin is significantly related to topographic variation, as hemlocks are more commonly found on terrains with steep slopes, northerly aspects, and low relative elevations. Also, hemlock presence is less aspect dependent at the lowest relative elevations. Overall, these results suggest that topographic analysis can play a role in efforts to locate peripheral hemlock populations, although other environmental factors must also be considered.
|Commitee:||Greene, Raymond, Romano, Susan|
|School:||Western Illinois University|
|School Location:||United States -- Illinois|
|Source:||MAI 50/06M, Masters Abstracts International|
|Subjects:||Morphology, Ecology, Geography|
|Keywords:||Eastern hemlock, Kickapoo valley, Tsuga canadensis, Wisconsin|
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