Chapter 7 Ecology of Snowshoe Hares in Southern Boreal and Montane

• Main Author: Karen E. Hodges
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Canada; Yukon; Alaska
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.192.4100; http://www.fs.fed.us/rm/pubs/rmrs_gtr030/rmrs_gtr030_163_206.pdf

Abstract—Snowshoe hares occur in many of the montane and sub-boreal forests of the continental United States, as well as throughout the boreal forests of Canada and Alaska. Population dynamics in their southern range were previously thought to be noncyclic, in contrast to the strong 10-year fluctuation that typifies boreal populations of snowshoe hares. Time series data and studies of hare demography indicate that northern and southern populations of hares may instead have similar population dynamics. Hares in southern areas appear to experience two- to 25-fold fluctuations in numbers with peaks eight to 11 years apart. Peak and low densities may be lower in southern areas than in northern ones; in the south, peak densities are commonly one to two hares/ha, whereas northern hare populations commonly have peak densities up to four to six hares/ha. Demographically, survival estimates (30-day) range from approximately 0.65-0.95 in Wisconsin, with lowest survival occurring as populations decline; these values parallel those of cyclic hares in Yukon. Annual reproductive output may vary regionally, but interpretation of this pattern is hindered by noncomparable methodologies. 163 Chapter 7—Hodges The southern range of snowshoe hares is roughly delineated by the range of suitable forested habitats. Along the eastern seaboard, hares use spruce/fir and deciduous forests as far south as Tennessee and the Virginias. Around the Great Lakes, hares occur throughout the sub-boreal coniferous forests. In the Rockies and westward, hares mainly use the coniferous forests that extend along the mountains down into New Mexico and California. Throughout their range, hares are predominantly associated with forests that have a well-developed understory that provides protection from predation and supplies them with food. Such habitat structure is common in early seral stages but may also occur in coniferous forests with mature but relatively open overstories or in eastern deciduous forests.